diff options
| author |   Marcus Fritzsch <marcus_fritzsch@mentor.com> | 2017-07-05 13:56:50 +0200 |
|---|---|---|
| committer | Marcus Fritzsch <marcus_fritzsch@mentor.com> | 2017-08-08 17:24:00 +0200 |
| commit | e7c854bbf61d50410589a5ad56c961bf7a6ce29e (patch) | |
| tree | 0fdb724d1d80857d06c77ad17a9f26a04d738e42 | |
| parent | fc5950be006125db759b253d0a141953a7908bd3 (diff) | |
Add nlohnmann/json header only c++11+ json library v. 2.1.1
Signed-off-by: Marcus Fritzsch <marcus_fritzsch@mentor.com>
| -rw-r--r-- | include/json.hpp | 13003 |
1 files changed, 13003 insertions, 0 deletions
diff --git a/include/json.hpp b/include/json.hpp new file mode 100644 index 0000000..6dfc183 --- /dev/null +++ b/include/json.hpp @@ -0,0 +1,13003 @@ +/* + __ _____ _____ _____ + __| | __| | | | JSON for Modern C++ +| | |__ | | | | | | version 2.1.1 +|_____|_____|_____|_|___| https://github.com/nlohmann/json + +Licensed under the MIT License <http://opensource.org/licenses/MIT>. +Copyright (c) 2013-2017 Niels Lohmann <http://nlohmann.me>. + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. +*/ + +#ifndef NLOHMANN_JSON_HPP +#define NLOHMANN_JSON_HPP + +#include <algorithm> // all_of, copy, fill, find, for_each, none_of, remove, reverse, transform +#include <array> // array +#include <cassert> // assert +#include <cctype> // isdigit +#include <ciso646> // and, not, or +#include <cmath> // isfinite, labs, ldexp, signbit +#include <cstddef> // nullptr_t, ptrdiff_t, size_t +#include <cstdint> // int64_t, uint64_t +#include <cstdlib> // abort, strtod, strtof, strtold, strtoul, strtoll, strtoull +#include <cstring> // strlen +#include <forward_list> // forward_list +#include <functional> // function, hash, less +#include <initializer_list> // initializer_list +#include <iomanip> // setw +#include <iostream> // istream, ostream +#include <iterator> // advance, begin, back_inserter, bidirectional_iterator_tag, distance, end, inserter, iterator, iterator_traits, next, random_access_iterator_tag, reverse_iterator +#include <limits> // numeric_limits +#include <locale> // locale +#include <map> // map +#include <memory> // addressof, allocator, allocator_traits, unique_ptr +#include <numeric> // accumulate +#include <sstream> // stringstream +#include <stdexcept> // domain_error, invalid_argument, out_of_range +#include <string> // getline, stoi, string, to_string +#include <type_traits> // add_pointer, conditional, decay, enable_if, false_type, integral_constant, is_arithmetic, is_base_of, is_const, is_constructible, is_convertible, is_default_constructible, is_enum, is_floating_point, is_integral, is_nothrow_move_assignable, is_nothrow_move_constructible, is_pointer, is_reference, is_same, is_scalar, is_signed, remove_const, remove_cv, remove_pointer, remove_reference, true_type, underlying_type +#include <utility> // declval, forward, make_pair, move, pair, swap +#include <vector> // vector + +// exclude unsupported compilers +#if defined(__clang__) + #if (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__) < 30400 + #error "unsupported Clang version - see https://github.com/nlohmann/json#supported-compilers" + #endif +#elif defined(__GNUC__) + #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) < 40900 + #error "unsupported GCC version - see https://github.com/nlohmann/json#supported-compilers" + #endif +#endif + +// disable float-equal warnings on GCC/clang +#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__) + #pragma GCC diagnostic push + #pragma GCC diagnostic ignored "-Wfloat-equal" +#endif + +// disable documentation warnings on clang +#if defined(__clang__) + #pragma GCC diagnostic push + #pragma GCC diagnostic ignored "-Wdocumentation" +#endif + +// allow for portable deprecation warnings +#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__) + #define JSON_DEPRECATED __attribute__((deprecated)) +#elif defined(_MSC_VER) + #define JSON_DEPRECATED __declspec(deprecated) +#else + #define JSON_DEPRECATED +#endif + +// allow to disable exceptions +#if not defined(JSON_NOEXCEPTION) || defined(__EXCEPTIONS) + #define JSON_THROW(exception) throw exception + #define JSON_TRY try + #define JSON_CATCH(exception) catch(exception) +#else + #define JSON_THROW(exception) std::abort() + #define JSON_TRY if(true) + #define JSON_CATCH(exception) if(false) +#endif + +/*! +@brief namespace for Niels Lohmann +@see https://github.com/nlohmann +@since version 1.0.0 +*/ +namespace nlohmann +{ + +/*! +@brief unnamed namespace with internal helper functions + +This namespace collects some functions that could not be defined inside the +@ref basic_json class. + +@since version 2.1.0 +*/ +namespace detail +{ +/////////////////////////// +// JSON type enumeration // +/////////////////////////// + +/*! +@brief the JSON type enumeration + +This enumeration collects the different JSON types. It is internally used to +distinguish the stored values, and the functions @ref basic_json::is_null(), +@ref basic_json::is_object(), @ref basic_json::is_array(), +@ref basic_json::is_string(), @ref basic_json::is_boolean(), +@ref basic_json::is_number() (with @ref basic_json::is_number_integer(), +@ref basic_json::is_number_unsigned(), and @ref basic_json::is_number_float()), +@ref basic_json::is_discarded(), @ref basic_json::is_primitive(), and +@ref basic_json::is_structured() rely on it. + +@note There are three enumeration entries (number_integer, number_unsigned, and +number_float), because the library distinguishes these three types for numbers: +@ref basic_json::number_unsigned_t is used for unsigned integers, +@ref basic_json::number_integer_t is used for signed integers, and +@ref basic_json::number_float_t is used for floating-point numbers or to +approximate integers which do not fit in the limits of their respective type. + +@sa @ref basic_json::basic_json(const value_t value_type) -- create a JSON +value with the default value for a given type + +@since version 1.0.0 +*/ +enum class value_t : uint8_t +{ + null, ///< null value + object, ///< object (unordered set of name/value pairs) + array, ///< array (ordered collection of values) + string, ///< string value + boolean, ///< boolean value + number_integer, ///< number value (signed integer) + number_unsigned, ///< number value (unsigned integer) + number_float, ///< number value (floating-point) + discarded ///< discarded by the the parser callback function +}; + +/*! +@brief comparison operator for JSON types + +Returns an ordering that is similar to Python: +- order: null < boolean < number < object < array < string +- furthermore, each type is not smaller than itself + +@since version 1.0.0 +*/ +inline bool operator<(const value_t lhs, const value_t rhs) noexcept +{ + static constexpr std::array<uint8_t, 8> order = {{ + 0, // null + 3, // object + 4, // array + 5, // string + 1, // boolean + 2, // integer + 2, // unsigned + 2, // float + } + }; + + // discarded values are not comparable + if (lhs == value_t::discarded or rhs == value_t::discarded) + { + return false; + } + + return order[static_cast<std::size_t>(lhs)] < + order[static_cast<std::size_t>(rhs)]; +} + + +///////////// +// helpers // +///////////// + +// alias templates to reduce boilerplate +template<bool B, typename T = void> +using enable_if_t = typename std::enable_if<B, T>::type; + +template<typename T> +using uncvref_t = typename std::remove_cv<typename std::remove_reference<T>::type>::type; + +// taken from http://stackoverflow.com/a/26936864/266378 +template<typename T> +using is_unscoped_enum = + std::integral_constant<bool, std::is_convertible<T, int>::value and + std::is_enum<T>::value>; + +/* +Implementation of two C++17 constructs: conjunction, negation. This is needed +to avoid evaluating all the traits in a condition + +For example: not std::is_same<void, T>::value and has_value_type<T>::value +will not compile when T = void (on MSVC at least). Whereas +conjunction<negation<std::is_same<void, T>>, has_value_type<T>>::value will +stop evaluating if negation<...>::value == false + +Please note that those constructs must be used with caution, since symbols can +become very long quickly (which can slow down compilation and cause MSVC +internal compiler errors). Only use it when you have to (see example ahead). +*/ +template<class...> struct conjunction : std::true_type {}; +template<class B1> struct conjunction<B1> : B1 {}; +template<class B1, class... Bn> +struct conjunction<B1, Bn...> : std::conditional<bool(B1::value), conjunction<Bn...>, B1>::type {}; + +template<class B> struct negation : std::integral_constant < bool, !B::value > {}; + +// dispatch utility (taken from ranges-v3) +template<unsigned N> struct priority_tag : priority_tag < N - 1 > {}; +template<> struct priority_tag<0> {}; + + +////////////////// +// constructors // +////////////////// + +template<value_t> struct external_constructor; + +template<> +struct external_constructor<value_t::boolean> +{ + template<typename BasicJsonType> + static void construct(BasicJsonType& j, typename BasicJsonType::boolean_t b) noexcept + { + j.m_type = value_t::boolean; + j.m_value = b; + j.assert_invariant(); + } +}; + +template<> +struct external_constructor<value_t::string> +{ + template<typename BasicJsonType> + static void construct(BasicJsonType& j, const typename BasicJsonType::string_t& s) + { + j.m_type = value_t::string; + j.m_value = s; + j.assert_invariant(); + } +}; + +template<> +struct external_constructor<value_t::number_float> +{ + template<typename BasicJsonType> + static void construct(BasicJsonType& j, typename BasicJsonType::number_float_t val) noexcept + { + // replace infinity and NAN by null + if (not std::isfinite(val)) + { + j = BasicJsonType{}; + } + else + { + j.m_type = value_t::number_float; + j.m_value = val; + } + j.assert_invariant(); + } +}; + +template<> +struct external_constructor<value_t::number_unsigned> +{ + template<typename BasicJsonType> + static void construct(BasicJsonType& j, typename BasicJsonType::number_unsigned_t val) noexcept + { + j.m_type = value_t::number_unsigned; + j.m_value = val; + j.assert_invariant(); + } +}; + +template<> +struct external_constructor<value_t::number_integer> +{ + template<typename BasicJsonType> + static void construct(BasicJsonType& j, typename BasicJsonType::number_integer_t val) noexcept + { + j.m_type = value_t::number_integer; + j.m_value = val; + j.assert_invariant(); + } +}; + +template<> +struct external_constructor<value_t::array> +{ + template<typename BasicJsonType> + static void construct(BasicJsonType& j, const typename BasicJsonType::array_t& arr) + { + j.m_type = value_t::array; + j.m_value = arr; + j.assert_invariant(); + } + + template<typename BasicJsonType, typename CompatibleArrayType, + enable_if_t<not std::is_same<CompatibleArrayType, + typename BasicJsonType::array_t>::value, + int> = 0> + static void construct(BasicJsonType& j, const CompatibleArrayType& arr) + { + using std::begin; + using std::end; + j.m_type = value_t::array; + j.m_value.array = j.template create<typename BasicJsonType::array_t>(begin(arr), end(arr)); + j.assert_invariant(); + } +}; + +template<> +struct external_constructor<value_t::object> +{ + template<typename BasicJsonType> + static void construct(BasicJsonType& j, const typename BasicJsonType::object_t& obj) + { + j.m_type = value_t::object; + j.m_value = obj; + j.assert_invariant(); + } + + template<typename BasicJsonType, typename CompatibleObjectType, + enable_if_t<not std::is_same<CompatibleObjectType, + typename BasicJsonType::object_t>::value, + int> = 0> + static void construct(BasicJsonType& j, const CompatibleObjectType& obj) + { + using std::begin; + using std::end; + + j.m_type = value_t::object; + j.m_value.object = j.template create<typename BasicJsonType::object_t>(begin(obj), end(obj)); + j.assert_invariant(); + } +}; + + +//////////////////////// +// has_/is_ functions // +//////////////////////// + +/*! +@brief Helper to determine whether there's a key_type for T. + +This helper is used to tell associative containers apart from other containers +such as sequence containers. For instance, `std::map` passes the test as it +contains a `mapped_type`, whereas `std::vector` fails the test. + +@sa http://stackoverflow.com/a/7728728/266378 +@since version 1.0.0, overworked in version 2.0.6 +*/ +#define NLOHMANN_JSON_HAS_HELPER(type) \ + template<typename T> struct has_##type { \ + private: \ + template<typename U, typename = typename U::type> \ + static int detect(U &&); \ + static void detect(...); \ + public: \ + static constexpr bool value = \ + std::is_integral<decltype(detect(std::declval<T>()))>::value; \ + } + +NLOHMANN_JSON_HAS_HELPER(mapped_type); +NLOHMANN_JSON_HAS_HELPER(key_type); +NLOHMANN_JSON_HAS_HELPER(value_type); +NLOHMANN_JSON_HAS_HELPER(iterator); + +#undef NLOHMANN_JSON_HAS_HELPER + + +template<bool B, class RealType, class CompatibleObjectType> +struct is_compatible_object_type_impl : std::false_type {}; + +template<class RealType, class CompatibleObjectType> +struct is_compatible_object_type_impl<true, RealType, CompatibleObjectType> +{ + static constexpr auto value = + std::is_constructible<typename RealType::key_type, + typename CompatibleObjectType::key_type>::value and + std::is_constructible<typename RealType::mapped_type, + typename CompatibleObjectType::mapped_type>::value; +}; + +template<class BasicJsonType, class CompatibleObjectType> +struct is_compatible_object_type +{ + static auto constexpr value = is_compatible_object_type_impl < + conjunction<negation<std::is_same<void, CompatibleObjectType>>, + has_mapped_type<CompatibleObjectType>, + has_key_type<CompatibleObjectType>>::value, + typename BasicJsonType::object_t, CompatibleObjectType >::value; +}; + +template<typename BasicJsonType, typename T> +struct is_basic_json_nested_type +{ + static auto constexpr value = std::is_same<T, typename BasicJsonType::iterator>::value or + std::is_same<T, typename BasicJsonType::const_iterator>::value or + std::is_same<T, typename BasicJsonType::reverse_iterator>::value or + std::is_same<T, typename BasicJsonType::const_reverse_iterator>::value or + std::is_same<T, typename BasicJsonType::json_pointer>::value; +}; + +template<class BasicJsonType, class CompatibleArrayType> +struct is_compatible_array_type +{ + static auto constexpr value = + conjunction<negation<std::is_same<void, CompatibleArrayType>>, + negation<is_compatible_object_type< + BasicJsonType, CompatibleArrayType>>, + negation<std::is_constructible<typename BasicJsonType::string_t, + CompatibleArrayType>>, + negation<is_basic_json_nested_type<BasicJsonType, CompatibleArrayType>>, + has_value_type<CompatibleArrayType>, + has_iterator<CompatibleArrayType>>::value; +}; + +template<bool, typename, typename> +struct is_compatible_integer_type_impl : std::false_type {}; + +template<typename RealIntegerType, typename CompatibleNumberIntegerType> +struct is_compatible_integer_type_impl<true, RealIntegerType, CompatibleNumberIntegerType> +{ + // is there an assert somewhere on overflows? + using RealLimits = std::numeric_limits<RealIntegerType>; + using CompatibleLimits = std::numeric_limits<CompatibleNumberIntegerType>; + + static constexpr auto value = + std::is_constructible<RealIntegerType, + CompatibleNumberIntegerType>::value and + CompatibleLimits::is_integer and + RealLimits::is_signed == CompatibleLimits::is_signed; +}; + +template<typename RealIntegerType, typename CompatibleNumberIntegerType> +struct is_compatible_integer_type +{ + static constexpr auto value = + is_compatible_integer_type_impl < + std::is_integral<CompatibleNumberIntegerType>::value and + not std::is_same<bool, CompatibleNumberIntegerType>::value, + RealIntegerType, CompatibleNumberIntegerType > ::value; +}; + + +// trait checking if JSONSerializer<T>::from_json(json const&, udt&) exists +template<typename BasicJsonType, typename T> +struct has_from_json +{ + private: + // also check the return type of from_json + template<typename U, typename = enable_if_t<std::is_same<void, decltype(uncvref_t<U>::from_json( + std::declval<BasicJsonType>(), std::declval<T&>()))>::value>> + static int detect(U&&); + static void detect(...); + + public: + static constexpr bool value = std::is_integral<decltype( + detect(std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value; +}; + +// This trait checks if JSONSerializer<T>::from_json(json const&) exists +// this overload is used for non-default-constructible user-defined-types +template<typename BasicJsonType, typename T> +struct has_non_default_from_json +{ + private: + template < + typename U, + typename = enable_if_t<std::is_same< + T, decltype(uncvref_t<U>::from_json(std::declval<BasicJsonType>()))>::value >> + static int detect(U&&); + static void detect(...); + + public: + static constexpr bool value = std::is_integral<decltype(detect( + std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value; +}; + +// This trait checks if BasicJsonType::json_serializer<T>::to_json exists +template<typename BasicJsonType, typename T> +struct has_to_json +{ + private: + template<typename U, typename = decltype(uncvref_t<U>::to_json( + std::declval<BasicJsonType&>(), std::declval<T>()))> + static int detect(U&&); + static void detect(...); + + public: + static constexpr bool value = std::is_integral<decltype(detect( + std::declval<typename BasicJsonType::template json_serializer<T, void>>()))>::value; +}; + + +///////////// +// to_json // +///////////// + +template<typename BasicJsonType, typename T, enable_if_t< + std::is_same<T, typename BasicJsonType::boolean_t>::value, int> = 0> +void to_json(BasicJsonType& j, T b) noexcept +{ + external_constructor<value_t::boolean>::construct(j, b); +} + +template<typename BasicJsonType, typename CompatibleString, + enable_if_t<std::is_constructible<typename BasicJsonType::string_t, + CompatibleString>::value, int> = 0> +void to_json(BasicJsonType& j, const CompatibleString& s) +{ + external_constructor<value_t::string>::construct(j, s); +} + +template<typename BasicJsonType, typename FloatType, + enable_if_t<std::is_floating_point<FloatType>::value, int> = 0> +void to_json(BasicJsonType& j, FloatType val) noexcept +{ + external_constructor<value_t::number_float>::construct(j, static_cast<typename BasicJsonType::number_float_t>(val)); +} + +template < + typename BasicJsonType, typename CompatibleNumberUnsignedType, + enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t, + CompatibleNumberUnsignedType>::value, int> = 0 > +void to_json(BasicJsonType& j, CompatibleNumberUnsignedType val) noexcept +{ + external_constructor<value_t::number_unsigned>::construct(j, static_cast<typename BasicJsonType::number_unsigned_t>(val)); +} + +template < + typename BasicJsonType, typename CompatibleNumberIntegerType, + enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t, + CompatibleNumberIntegerType>::value, int> = 0 > +void to_json(BasicJsonType& j, CompatibleNumberIntegerType val) noexcept +{ + external_constructor<value_t::number_integer>::construct(j, static_cast<typename BasicJsonType::number_integer_t>(val)); +} + +template<typename BasicJsonType, typename UnscopedEnumType, + enable_if_t<is_unscoped_enum<UnscopedEnumType>::value, int> = 0> +void to_json(BasicJsonType& j, UnscopedEnumType e) noexcept +{ + external_constructor<value_t::number_integer>::construct(j, e); +} + +template < + typename BasicJsonType, typename CompatibleArrayType, + enable_if_t < + is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value or + std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value, + int > = 0 > +void to_json(BasicJsonType& j, const CompatibleArrayType& arr) +{ + external_constructor<value_t::array>::construct(j, arr); +} + +template < + typename BasicJsonType, typename CompatibleObjectType, + enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value, + int> = 0 > +void to_json(BasicJsonType& j, const CompatibleObjectType& arr) +{ + external_constructor<value_t::object>::construct(j, arr); +} + + +/////////////// +// from_json // +/////////////// + +// overloads for basic_json template parameters +template<typename BasicJsonType, typename ArithmeticType, + enable_if_t<std::is_arithmetic<ArithmeticType>::value and + not std::is_same<ArithmeticType, + typename BasicJsonType::boolean_t>::value, + int> = 0> +void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val) +{ + switch (static_cast<value_t>(j)) + { + case value_t::number_unsigned: + { + val = static_cast<ArithmeticType>( + *j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>()); + break; + } + case value_t::number_integer: + { + val = static_cast<ArithmeticType>( + *j.template get_ptr<const typename BasicJsonType::number_integer_t*>()); + break; + } + case value_t::number_float: + { + val = static_cast<ArithmeticType>( + *j.template get_ptr<const typename BasicJsonType::number_float_t*>()); + break; + } + default: + { + JSON_THROW( + std::domain_error("type must be number, but is " + j.type_name())); + } + } +} + +template<typename BasicJsonType> +void from_json(const BasicJsonType& j, typename BasicJsonType::boolean_t& b) +{ + if (not j.is_boolean()) + { + JSON_THROW(std::domain_error("type must be boolean, but is " + j.type_name())); + } + b = *j.template get_ptr<const typename BasicJsonType::boolean_t*>(); +} + +template<typename BasicJsonType> +void from_json(const BasicJsonType& j, typename BasicJsonType::string_t& s) +{ + if (not j.is_string()) + { + JSON_THROW(std::domain_error("type must be string, but is " + j.type_name())); + } + s = *j.template get_ptr<const typename BasicJsonType::string_t*>(); +} + +template<typename BasicJsonType> +void from_json(const BasicJsonType& j, typename BasicJsonType::number_float_t& val) +{ + get_arithmetic_value(j, val); +} + +template<typename BasicJsonType> +void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val) +{ + get_arithmetic_value(j, val); +} + +template<typename BasicJsonType> +void from_json(const BasicJsonType& j, typename BasicJsonType::number_integer_t& val) +{ + get_arithmetic_value(j, val); +} + +template<typename BasicJsonType, typename UnscopedEnumType, + enable_if_t<is_unscoped_enum<UnscopedEnumType>::value, int> = 0> +void from_json(const BasicJsonType& j, UnscopedEnumType& e) +{ + typename std::underlying_type<UnscopedEnumType>::type val; + get_arithmetic_value(j, val); + e = static_cast<UnscopedEnumType>(val); +} + +template<typename BasicJsonType> +void from_json(const BasicJsonType& j, typename BasicJsonType::array_t& arr) +{ + if (not j.is_array()) + { + JSON_THROW(std::domain_error("type must be array, but is " + j.type_name())); + } + arr = *j.template get_ptr<const typename BasicJsonType::array_t*>(); +} + +// forward_list doesn't have an insert method +template<typename BasicJsonType, typename T, typename Allocator> +void from_json(const BasicJsonType& j, std::forward_list<T, Allocator>& l) +{ + // do not perform the check when user wants to retrieve jsons + // (except when it's null.. ?) + if (j.is_null()) + { + JSON_THROW(std::domain_error("type must be array, but is " + j.type_name())); + } + if (not std::is_same<T, BasicJsonType>::value) + { + if (not j.is_array()) + { + JSON_THROW(std::domain_error("type must be array, but is " + j.type_name())); + } + } + for (auto it = j.rbegin(), end = j.rend(); it != end; ++it) + { + l.push_front(it->template get<T>()); + } +} + +template<typename BasicJsonType, typename CompatibleArrayType> +void from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<0>) +{ + using std::begin; + using std::end; + + std::transform(j.begin(), j.end(), + std::inserter(arr, end(arr)), [](const BasicJsonType & i) + { + // get<BasicJsonType>() returns *this, this won't call a from_json + // method when value_type is BasicJsonType + return i.template get<typename CompatibleArrayType::value_type>(); + }); +} + +template<typename BasicJsonType, typename CompatibleArrayType> +auto from_json_array_impl(const BasicJsonType& j, CompatibleArrayType& arr, priority_tag<1>) +-> decltype( + arr.reserve(std::declval<typename CompatibleArrayType::size_type>()), + void()) +{ + using std::begin; + using std::end; + + arr.reserve(j.size()); + std::transform( + j.begin(), j.end(), std::inserter(arr, end(arr)), [](const BasicJsonType & i) + { + // get<BasicJsonType>() returns *this, this won't call a from_json + // method when value_type is BasicJsonType + return i.template get<typename CompatibleArrayType::value_type>(); + }); +} + +template<typename BasicJsonType, typename CompatibleArrayType, + enable_if_t<is_compatible_array_type<BasicJsonType, CompatibleArrayType>::value and + not std::is_same<typename BasicJsonType::array_t, CompatibleArrayType>::value, int> = 0> +void from_json(const BasicJsonType& j, CompatibleArrayType& arr) +{ + if (j.is_null()) + { + JSON_THROW(std::domain_error("type must be array, but is " + j.type_name())); + } + + // when T == BasicJsonType, do not check if value_t is correct + if (not std::is_same<typename CompatibleArrayType::value_type, BasicJsonType>::value) + { + if (not j.is_array()) + { + JSON_THROW(std::domain_error("type must be array, but is " + j.type_name())); + } + } + from_json_array_impl(j, arr, priority_tag<1> {}); +} + +template<typename BasicJsonType, typename CompatibleObjectType, + enable_if_t<is_compatible_object_type<BasicJsonType, CompatibleObjectType>::value, int> = 0> +void from_json(const BasicJsonType& j, CompatibleObjectType& obj) +{ + if (not j.is_object()) + { + JSON_THROW(std::domain_error("type must be object, but is " + j.type_name())); + } + + auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>(); + using std::begin; + using std::end; + // we could avoid the assignment, but this might require a for loop, which + // might be less efficient than the container constructor for some + // containers (would it?) + obj = CompatibleObjectType(begin(*inner_object), end(*inner_object)); +} + +// overload for arithmetic types, not chosen for basic_json template arguments +// (BooleanType, etc..); note: Is it really necessary to provide explicit +// overloads for boolean_t etc. in case of a custom BooleanType which is not +// an arithmetic type? +template<typename BasicJsonType, typename ArithmeticType, + enable_if_t < + std::is_arithmetic<ArithmeticType>::value and + not std::is_same<ArithmeticType, typename BasicJsonType::number_unsigned_t>::value and + not std::is_same<ArithmeticType, typename BasicJsonType::number_integer_t>::value and + not std::is_same<ArithmeticType, typename BasicJsonType::number_float_t>::value and + not std::is_same<ArithmeticType, typename BasicJsonType::boolean_t>::value, + int> = 0> +void from_json(const BasicJsonType& j, ArithmeticType& val) +{ + switch (static_cast<value_t>(j)) + { + case value_t::number_unsigned: + { + val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>()); + break; + } + case value_t::number_integer: + { + val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_integer_t*>()); + break; + } + case value_t::number_float: + { + val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_float_t*>()); + break; + } + case value_t::boolean: + { + val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::boolean_t*>()); + break; + } + default: + { + JSON_THROW(std::domain_error("type must be number, but is " + j.type_name())); + } + } +} + +struct to_json_fn +{ + private: + template<typename BasicJsonType, typename T> + auto call(BasicJsonType& j, T&& val, priority_tag<1>) const noexcept(noexcept(to_json(j, std::forward<T>(val)))) + -> decltype(to_json(j, std::forward<T>(val)), void()) + { + return to_json(j, std::forward<T>(val)); + } + + template<typename BasicJsonType, typename T> + void call(BasicJsonType&, T&&, priority_tag<0>) const noexcept + { + static_assert(sizeof(BasicJsonType) == 0, + "could not find to_json() method in T's namespace"); + } + + public: + template<typename BasicJsonType, typename T> + void operator()(BasicJsonType& j, T&& val) const + noexcept(noexcept(std::declval<to_json_fn>().call(j, std::forward<T>(val), priority_tag<1> {}))) + { + return call(j, std::forward<T>(val), priority_tag<1> {}); + } +}; + +struct from_json_fn +{ + private: + template<typename BasicJsonType, typename T> + auto call(const BasicJsonType& j, T& val, priority_tag<1>) const + noexcept(noexcept(from_json(j, val))) + -> decltype(from_json(j, val), void()) + { + return from_json(j, val); + } + + template<typename BasicJsonType, typename T> + void call(const BasicJsonType&, T&, priority_tag<0>) const noexcept + { + static_assert(sizeof(BasicJsonType) == 0, + "could not find from_json() method in T's namespace"); + } + + public: + template<typename BasicJsonType, typename T> + void operator()(const BasicJsonType& j, T& val) const + noexcept(noexcept(std::declval<from_json_fn>().call(j, val, priority_tag<1> {}))) + { + return call(j, val, priority_tag<1> {}); + } +}; + +// taken from ranges-v3 +template<typename T> +struct static_const +{ + static constexpr T value{}; +}; + +template<typename T> +constexpr T static_const<T>::value; +} // namespace detail + + +/// namespace to hold default `to_json` / `from_json` functions +namespace +{ +constexpr const auto& to_json = detail::static_const<detail::to_json_fn>::value; +constexpr const auto& from_json = detail::static_const<detail::from_json_fn>::value; +} + + +/*! +@brief default JSONSerializer template argument + +This serializer ignores the template arguments and uses ADL +([argument-dependent lookup](http://en.cppreference.com/w/cpp/language/adl)) +for serialization. +*/ +template<typename = void, typename = void> +struct adl_serializer +{ + /*! + @brief convert a JSON value to any value type + + This function is usually called by the `get()` function of the + @ref basic_json class (either explicit or via conversion operators). + + @param[in] j JSON value to read from + @param[in,out] val value to write to + */ + template<typename BasicJsonType, typename ValueType> + static void from_json(BasicJsonType&& j, ValueType& val) noexcept( + noexcept(::nlohmann::from_json(std::forward<BasicJsonType>(j), val))) + { + ::nlohmann::from_json(std::forward<BasicJsonType>(j), val); + } + + /*! + @brief convert any value type to a JSON value + + This function is usually called by the constructors of the @ref basic_json + class. + + @param[in,out] j JSON value to write to + @param[in] val value to read from + */ + template<typename BasicJsonType, typename ValueType> + static void to_json(BasicJsonType& j, ValueType&& val) noexcept( + noexcept(::nlohmann::to_json(j, std::forward<ValueType>(val)))) + { + ::nlohmann::to_json(j, std::forward<ValueType>(val)); + } +}; + + +/*! +@brief a class to store JSON values + +@tparam ObjectType type for JSON objects (`std::map` by default; will be used +in @ref object_t) +@tparam ArrayType type for JSON arrays (`std::vector` by default; will be used +in @ref array_t) +@tparam StringType type for JSON strings and object keys (`std::string` by +default; will be used in @ref string_t) +@tparam BooleanType type for JSON booleans (`bool` by default; will be used +in @ref boolean_t) +@tparam NumberIntegerType type for JSON integer numbers (`int64_t` by +default; will be used in @ref number_integer_t) +@tparam NumberUnsignedType type for JSON unsigned integer numbers (@c +`uint64_t` by default; will be used in @ref number_unsigned_t) +@tparam NumberFloatType type for JSON floating-point numbers (`double` by +default; will be used in @ref number_float_t) +@tparam AllocatorType type of the allocator to use (`std::allocator` by +default) +@tparam JSONSerializer the serializer to resolve internal calls to `to_json()` +and `from_json()` (@ref adl_serializer by default) + +@requirement The class satisfies the following concept requirements: +- Basic + - [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible): + JSON values can be default constructed. The result will be a JSON null + value. + - [MoveConstructible](http://en.cppreference.com/w/cpp/concept/MoveConstructible): + A JSON value can be constructed from an rvalue argument. + - [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible): + A JSON value can be copy-constructed from an lvalue expression. + - [MoveAssignable](http://en.cppreference.com/w/cpp/concept/MoveAssignable): + A JSON value van be assigned from an rvalue argument. + - [CopyAssignable](http://en.cppreference.com/w/cpp/concept/CopyAssignable): + A JSON value can be copy-assigned from an lvalue expression. + - [Destructible](http://en.cppreference.com/w/cpp/concept/Destructible): + JSON values can be destructed. +- Layout + - [StandardLayoutType](http://en.cppreference.com/w/cpp/concept/StandardLayoutType): + JSON values have + [standard layout](http://en.cppreference.com/w/cpp/language/data_members#Standard_layout): + All non-static data members are private and standard layout types, the + class has no virtual functions or (virtual) base classes. +- Library-wide + - [EqualityComparable](http://en.cppreference.com/w/cpp/concept/EqualityComparable): + JSON values can be compared with `==`, see @ref + operator==(const_reference,const_reference). + - [LessThanComparable](http://en.cppreference.com/w/cpp/concept/LessThanComparable): + JSON values can be compared with `<`, see @ref + operator<(const_reference,const_reference). + - [Swappable](http://en.cppreference.com/w/cpp/concept/Swappable): + Any JSON lvalue or rvalue of can be swapped with any lvalue or rvalue of + other compatible types, using unqualified function call @ref swap(). + - [NullablePointer](http://en.cppreference.com/w/cpp/concept/NullablePointer): + JSON values can be compared against `std::nullptr_t` objects which are used + to model the `null` value. +- Container + - [Container](http://en.cppreference.com/w/cpp/concept/Container): + JSON values can be used like STL containers and provide iterator access. + - [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer); + JSON values can be used like STL containers and provide reverse iterator + access. + +@invariant The member variables @a m_value and @a m_type have the following +relationship: +- If `m_type == value_t::object`, then `m_value.object != nullptr`. +- If `m_type == value_t::array`, then `m_value.array != nullptr`. +- If `m_type == value_t::string`, then `m_value.string != nullptr`. +The invariants are checked by member function assert_invariant(). + +@internal +@note ObjectType trick from http://stackoverflow.com/a/9860911 +@endinternal + +@see [RFC 7159: The JavaScript Object Notation (JSON) Data Interchange +Format](http://rfc7159.net/rfc7159) + +@since version 1.0.0 + +@nosubgrouping +*/ +template < + template<typename U, typename V, typename... Args> class ObjectType = std::map, + template<typename U, typename... Args> class ArrayType = std::vector, + class StringType = std::string, + class BooleanType = bool, + class NumberIntegerType = std::int64_t, + class NumberUnsignedType = std::uint64_t, + class NumberFloatType = double, + template<typename U> class AllocatorType = std::allocator, + template<typename T, typename SFINAE = void> class JSONSerializer = adl_serializer + > +class basic_json +{ + private: + template<detail::value_t> friend struct detail::external_constructor; + /// workaround type for MSVC + using basic_json_t = basic_json<ObjectType, ArrayType, StringType, + BooleanType, NumberIntegerType, NumberUnsignedType, NumberFloatType, + AllocatorType, JSONSerializer>; + + public: + using value_t = detail::value_t; + // forward declarations + template<typename U> class iter_impl; + template<typename Base> class json_reverse_iterator; + class json_pointer; + template<typename T, typename SFINAE> + using json_serializer = JSONSerializer<T, SFINAE>; + + ///////////////////// + // container types // + ///////////////////// + + /// @name container types + /// The canonic container types to use @ref basic_json like any other STL + /// container. + /// @{ + + /// the type of elements in a basic_json container + using value_type = basic_json; + + /// the type of an element reference + using reference = value_type&; + /// the type of an element const reference + using const_reference = const value_type&; + + /// a type to represent differences between iterators + using difference_type = std::ptrdiff_t; + /// a type to represent container sizes + using size_type = std::size_t; + + /// the allocator type + using allocator_type = AllocatorType<basic_json>; + + /// the type of an element pointer + using pointer = typename std::allocator_traits<allocator_type>::pointer; + /// the type of an element const pointer + using const_pointer = typename std::allocator_traits<allocator_type>::const_pointer; + + /// an iterator for a basic_json container + using iterator = iter_impl<basic_json>; + /// a const iterator for a basic_json container + using const_iterator = iter_impl<const basic_json>; + /// a reverse iterator for a basic_json container + using reverse_iterator = json_reverse_iterator<typename basic_json::iterator>; + /// a const reverse iterator for a basic_json container + using const_reverse_iterator = json_reverse_iterator<typename basic_json::const_iterator>; + + /// @} + + + /*! + @brief returns the allocator associated with the container + */ + static allocator_type get_allocator() + { + return allocator_type(); + } + + /*! + @brief returns version information on the library + + This function returns a JSON object with information about the library, + including the version number and information on the platform and compiler. + + @return JSON object holding version information + key | description + ----------- | --------------- + `compiler` | Information on the used compiler. It is an object with the following keys: `c++` (the used C++ standard), `family` (the compiler family; possible values are `clang`, `icc`, `gcc`, `ilecpp`, `msvc`, `pgcpp`, `sunpro`, and `unknown`), and `version` (the compiler version). + `copyright` | The copyright line for the library as string. + `name` | The name of the library as string. + `platform` | The used platform as string. Possible values are `win32`, `linux`, `apple`, `unix`, and `unknown`. + `url` | The URL of the project as string. + `version` | The version of the library. It is an object with the following keys: `major`, `minor`, and `patch` as defined by [Semantic Versioning](http://semver.org), and `string` (the version string). + + @liveexample{The following code shows an example output of the `meta()` + function.,meta} + + @complexity Constant. + + @since 2.1.0 + */ + static basic_json meta() + { + basic_json result; + + result["copyright"] = "(C) 2013-2017 Niels Lohmann"; + result["name"] = "JSON for Modern C++"; + result["url"] = "https://github.com/nlohmann/json"; + result["version"] = + { + {"string", "2.1.1"}, + {"major", 2}, + {"minor", 1}, + {"patch", 1} + }; + +#ifdef _WIN32 + result["platform"] = "win32"; +#elif defined __linux__ + result["platform"] = "linux"; +#elif defined __APPLE__ + result["platform"] = "apple"; +#elif defined __unix__ + result["platform"] = "unix"; +#else + result["platform"] = "unknown"; +#endif + +#if defined(__clang__) + result["compiler"] = {{"family", "clang"}, {"version", __clang_version__}}; +#elif defined(__ICC) || defined(__INTEL_COMPILER) + result["compiler"] = {{"family", "icc"}, {"version", __INTEL_COMPILER}}; +#elif defined(__GNUC__) || defined(__GNUG__) + result["compiler"] = {{"family", "gcc"}, {"version", std::to_string(__GNUC__) + "." + std::to_string(__GNUC_MINOR__) + "." + std::to_string(__GNUC_PATCHLEVEL__)}}; +#elif defined(__HP_cc) || defined(__HP_aCC) + result["compiler"] = "hp" +#elif defined(__IBMCPP__) + result["compiler"] = {{"family", "ilecpp"}, {"version", __IBMCPP__}}; +#elif defined(_MSC_VER) + result["compiler"] = {{"family", "msvc"}, {"version", _MSC_VER}}; +#elif defined(__PGI) + result["compiler"] = {{"family", "pgcpp"}, {"version", __PGI}}; +#elif defined(__SUNPRO_CC) + result["compiler"] = {{"family", "sunpro"}, {"version", __SUNPRO_CC}}; +#else + result["compiler"] = {{"family", "unknown"}, {"version", "unknown"}}; +#endif + +#ifdef __cplusplus + result["compiler"]["c++"] = std::to_string(__cplusplus); +#else + result["compiler"]["c++"] = "unknown"; +#endif + return result; + } + + + /////////////////////////// + // JSON value data types // + /////////////////////////// + + /// @name JSON value data types + /// The data types to store a JSON value. These types are derived from + /// the template arguments passed to class @ref basic_json. + /// @{ + + /*! + @brief a type for an object + + [RFC 7159](http://rfc7159.net/rfc7159) describes JSON objects as follows: + > An object is an unordered collection of zero or more name/value pairs, + > where a name is a string and a value is a string, number, boolean, null, + > object, or array. + + To store objects in C++, a type is defined by the template parameters + described below. + + @tparam ObjectType the container to store objects (e.g., `std::map` or + `std::unordered_map`) + @tparam StringType the type of the keys or names (e.g., `std::string`). + The comparison function `std::less<StringType>` is used to order elements + inside the container. + @tparam AllocatorType the allocator to use for objects (e.g., + `std::allocator`) + + #### Default type + + With the default values for @a ObjectType (`std::map`), @a StringType + (`std::string`), and @a AllocatorType (`std::allocator`), the default + value for @a object_t is: + + @code {.cpp} + std::map< + std::string, // key_type + basic_json, // value_type + std::less<std::string>, // key_compare + std::allocator<std::pair<const std::string, basic_json>> // allocator_type + > + @endcode + + #### Behavior + + The choice of @a object_t influences the behavior of the JSON class. With + the default type, objects have the following behavior: + + - When all names are unique, objects will be interoperable in the sense + that all software implementations receiving that object will agree on + the name-value mappings. + - When the names within an object are not unique, later stored name/value + pairs overwrite previously stored name/value pairs, leaving the used + names unique. For instance, `{"key": 1}` and `{"key": 2, "key": 1}` will + be treated as equal and both stored as `{"key": 1}`. + - Internally, name/value pairs are stored in lexicographical order of the + names. Objects will also be serialized (see @ref dump) in this order. + For instance, `{"b": 1, "a": 2}` and `{"a": 2, "b": 1}` will be stored + and serialized as `{"a": 2, "b": 1}`. + - When comparing objects, the order of the name/value pairs is irrelevant. + This makes objects interoperable in the sense that they will not be + affected by these differences. For instance, `{"b": 1, "a": 2}` and + `{"a": 2, "b": 1}` will be treated as equal. + + #### Limits + + [RFC 7159](http://rfc7159.net/rfc7159) specifies: + > An implementation may set limits on the maximum depth of nesting. + + In this class, the object's limit of nesting is not constraint explicitly. + However, a maximum depth of nesting may be introduced by the compiler or + runtime environment. A theoretical limit can be queried by calling the + @ref max_size function of a JSON object. + + #### Storage + + Objects are stored as pointers in a @ref basic_json type. That is, for any + access to object values, a pointer of type `object_t*` must be + dereferenced. + + @sa @ref array_t -- type for an array value + + @since version 1.0.0 + + @note The order name/value pairs are added to the object is *not* + preserved by the library. Therefore, iterating an object may return + name/value pairs in a different order than they were originally stored. In + fact, keys will be traversed in alphabetical order as `std::map` with + `std::less` is used by default. Please note this behavior conforms to [RFC + 7159](http://rfc7159.net/rfc7159), because any order implements the + specified "unordered" nature of JSON objects. + */ + using object_t = ObjectType<StringType, + basic_json, + std::less<StringType>, + AllocatorType<std::pair<const StringType, + basic_json>>>; + + /*! + @brief a type for an array + + [RFC 7159](http://rfc7159.net/rfc7159) describes JSON arrays as follows: + > An array is an ordered sequence of zero or more values. + + To store objects in C++, a type is defined by the template parameters + explained below. + + @tparam ArrayType container type to store arrays (e.g., `std::vector` or + `std::list`) + @tparam AllocatorType allocator to use for arrays (e.g., `std::allocator`) + + #### Default type + + With the default values for @a ArrayType (`std::vector`) and @a + AllocatorType (`std::allocator`), the default value for @a array_t is: + + @code {.cpp} + std::vector< + basic_json, // value_type + std::allocator<basic_json> // allocator_type + > + @endcode + + #### Limits + + [RFC 7159](http://rfc7159.net/rfc7159) specifies: + > An implementation may set limits on the maximum depth of nesting. + + In this class, the array's limit of nesting is not constraint explicitly. + However, a maximum depth of nesting may be introduced by the compiler or + runtime environment. A theoretical limit can be queried by calling the + @ref max_size function of a JSON array. + + #### Storage + + Arrays are stored as pointers in a @ref basic_json type. That is, for any + access to array values, a pointer of type `array_t*` must be dereferenced. + + @sa @ref object_t -- type for an object value + + @since version 1.0.0 + */ + using array_t = ArrayType<basic_json, AllocatorType<basic_json>>; + + /*! + @brief a type for a string + + [RFC 7159](http://rfc7159.net/rfc7159) describes JSON strings as follows: + > A string is a sequence of zero or more Unicode characters. + + To store objects in C++, a type is defined by the template parameter + described below. Unicode values are split by the JSON class into + byte-sized characters during deserialization. + + @tparam StringType the container to store strings (e.g., `std::string`). + Note this container is used for keys/names in objects, see @ref object_t. + + #### Default type + + With the default values for @a StringType (`std::string`), the default + value for @a string_t is: + + @code {.cpp} + std::string + @endcode + + #### Encoding + + Strings are stored in UTF-8 encoding. Therefore, functions like + `std::string::size()` or `std::string::length()` return the number of + bytes in the string rather than the number of characters or glyphs. + + #### String comparison + + [RFC 7159](http://rfc7159.net/rfc7159) states: + > Software implementations are typically required to test names of object + > members for equality. Implementations that transform the textual + > representation into sequences of Unicode code units and then perform the + > comparison numerically, code unit by code unit, are interoperable in the + > sense that implementations will agree in all cases on equality or + > inequality of two strings. For example, implementations that compare + > strings with escaped characters unconverted may incorrectly find that + > `"a\\b"` and `"a\u005Cb"` are not equal. + + This implementation is interoperable as it does compare strings code unit + by code unit. + + #### Storage + + String values are stored as pointers in a @ref basic_json type. That is, + for any access to string values, a pointer of type `string_t*` must be + dereferenced. + + @since version 1.0.0 + */ + using string_t = StringType; + + /*! + @brief a type for a boolean + + [RFC 7159](http://rfc7159.net/rfc7159) implicitly describes a boolean as a + type which differentiates the two literals `true` and `false`. + + To store objects in C++, a type is defined by the template parameter @a + BooleanType which chooses the type to use. + + #### Default type + + With the default values for @a BooleanType (`bool`), the default value for + @a boolean_t is: + + @code {.cpp} + bool + @endcode + + #### Storage + + Boolean values are stored directly inside a @ref basic_json type. + + @since version 1.0.0 + */ + using boolean_t = BooleanType; + + /*! + @brief a type for a number (integer) + + [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows: + > The representation of numbers is similar to that used in most + > programming languages. A number is represented in base 10 using decimal + > digits. It contains an integer component that may be prefixed with an + > optional minus sign, which may be followed by a fraction part and/or an + > exponent part. Leading zeros are not allowed. (...) Numeric values that + > cannot be represented in the grammar below (such as Infinity and NaN) + > are not permitted. + + This description includes both integer and floating-point numbers. + However, C++ allows more precise storage if it is known whether the number + is a signed integer, an unsigned integer or a floating-point number. + Therefore, three different types, @ref number_integer_t, @ref + number_unsigned_t and @ref number_float_t are used. + + To store integer numbers in C++, a type is defined by the template + parameter @a NumberIntegerType which chooses the type to use. + + #### Default type + + With the default values for @a NumberIntegerType (`int64_t`), the default + value for @a number_integer_t is: + + @code {.cpp} + int64_t + @endcode + + #### Default behavior + + - The restrictions about leading zeros is not enforced in C++. Instead, + leading zeros in integer literals lead to an interpretation as octal + number. Internally, the value will be stored as decimal number. For + instance, the C++ integer literal `010` will be serialized to `8`. + During deserialization, leading zeros yield an error. + - Not-a-number (NaN) values will be serialized to `null`. + + #### Limits + + [RFC 7159](http://rfc7159.net/rfc7159) specifies: + > An implementation may set limits on the range and precision of numbers. + + When the default type is used, the maximal integer number that can be + stored is `9223372036854775807` (INT64_MAX) and the minimal integer number + that can be stored is `-9223372036854775808` (INT64_MIN). Integer numbers + that are out of range will yield over/underflow when used in a + constructor. During deserialization, too large or small integer numbers + will be automatically be stored as @ref number_unsigned_t or @ref + number_float_t. + + [RFC 7159](http://rfc7159.net/rfc7159) further states: + > Note that when such software is used, numbers that are integers and are + > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense + > that implementations will agree exactly on their numeric values. + + As this range is a subrange of the exactly supported range [INT64_MIN, + INT64_MAX], this class's integer type is interoperable. + + #### Storage + + Integer number values are stored directly inside a @ref basic_json type. + + @sa @ref number_float_t -- type for number values (floating-point) + + @sa @ref number_unsigned_t -- type for number values (unsigned integer) + + @since version 1.0.0 + */ + using number_integer_t = NumberIntegerType; + + /*! + @brief a type for a number (unsigned) + + [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows: + > The representation of numbers is similar to that used in most + > programming languages. A number is represented in base 10 using decimal + > digits. It contains an integer component that may be prefixed with an + > optional minus sign, which may be followed by a fraction part and/or an + > exponent part. Leading zeros are not allowed. (...) Numeric values that + > cannot be represented in the grammar below (such as Infinity and NaN) + > are not permitted. + + This description includes both integer and floating-point numbers. + However, C++ allows more precise storage if it is known whether the number + is a signed integer, an unsigned integer or a floating-point number. + Therefore, three different types, @ref number_integer_t, @ref + number_unsigned_t and @ref number_float_t are used. + + To store unsigned integer numbers in C++, a type is defined by the + template parameter @a NumberUnsignedType which chooses the type to use. + + #### Default type + + With the default values for @a NumberUnsignedType (`uint64_t`), the + default value for @a number_unsigned_t is: + + @code {.cpp} + uint64_t + @endcode + + #### Default behavior + + - The restrictions about leading zeros is not enforced in C++. Instead, + leading zeros in integer literals lead to an interpretation as octal + number. Internally, the value will be stored as decimal number. For + instance, the C++ integer literal `010` will be serialized to `8`. + During deserialization, leading zeros yield an error. + - Not-a-number (NaN) values will be serialized to `null`. + + #### Limits + + [RFC 7159](http://rfc7159.net/rfc7159) specifies: + > An implementation may set limits on the range and precision of numbers. + + When the default type is used, the maximal integer number that can be + stored is `18446744073709551615` (UINT64_MAX) and the minimal integer + number that can be stored is `0`. Integer numbers that are out of range + will yield over/underflow when used in a constructor. During + deserialization, too large or small integer numbers will be automatically + be stored as @ref number_integer_t or @ref number_float_t. + + [RFC 7159](http://rfc7159.net/rfc7159) further states: + > Note that when such software is used, numbers that are integers and are + > in the range \f$[-2^{53}+1, 2^{53}-1]\f$ are interoperable in the sense + > that implementations will agree exactly on their numeric values. + + As this range is a subrange (when considered in conjunction with the + number_integer_t type) of the exactly supported range [0, UINT64_MAX], + this class's integer type is interoperable. + + #### Storage + + Integer number values are stored directly inside a @ref basic_json type. + + @sa @ref number_float_t -- type for number values (floating-point) + @sa @ref number_integer_t -- type for number values (integer) + + @since version 2.0.0 + */ + using number_unsigned_t = NumberUnsignedType; + + /*! + @brief a type for a number (floating-point) + + [RFC 7159](http://rfc7159.net/rfc7159) describes numbers as follows: + > The representation of numbers is similar to that used in most + > programming languages. A number is represented in base 10 using decimal + > digits. It contains an integer component that may be prefixed with an + > optional minus sign, which may be followed by a fraction part and/or an + > exponent part. Leading zeros are not allowed. (...) Numeric values that + > cannot be represented in the grammar below (such as Infinity and NaN) + > are not permitted. + + This description includes both integer and floating-point numbers. + However, C++ allows more precise storage if it is known whether the number + is a signed integer, an unsigned integer or a floating-point number. + Therefore, three different types, @ref number_integer_t, @ref + number_unsigned_t and @ref number_float_t are used. + + To store floating-point numbers in C++, a type is defined by the template + parameter @a NumberFloatType which chooses the type to use. + + #### Default type + + With the default values for @a NumberFloatType (`double`), the default + value for @a number_float_t is: + + @code {.cpp} + double + @endcode + + #### Default behavior + + - The restrictions about leading zeros is not enforced in C++. Instead, + leading zeros in floating-point literals will be ignored. Internally, + the value will be stored as decimal number. For instance, the C++ + floating-point literal `01.2` will be serialized to `1.2`. During + deserialization, leading zeros yield an error. + - Not-a-number (NaN) values will be serialized to `null`. + + #### Limits + + [RFC 7159](http://rfc7159.net/rfc7159) states: + > This specification allows implementations to set limits on the range and + > precision of numbers accepted. Since software that implements IEEE + > 754-2008 binary64 (double precision) numbers is generally available and + > widely used, good interoperability can be achieved by implementations + > that expect no more precision or range than these provide, in the sense + > that implementations will approximate JSON numbers within the expected + > precision. + + This implementation does exactly follow this approach, as it uses double + precision floating-point numbers. Note values smaller than + `-1.79769313486232e+308` and values greater than `1.79769313486232e+308` + will be stored as NaN internally and be serialized to `null`. + + #### Storage + + Floating-point number values are stored directly inside a @ref basic_json + type. + + @sa @ref number_integer_t -- type for number values (integer) + + @sa @ref number_unsigned_t -- type for number values (unsigned integer) + + @since version 1.0.0 + */ + using number_float_t = NumberFloatType; + + /// @} + + private: + + /// helper for exception-safe object creation + template<typename T, typename... Args> + static T* create(Args&& ... args) + { + AllocatorType<T> alloc; + auto deleter = [&](T * object) + { + alloc.deallocate(object, 1); + }; + std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter); + alloc.construct(object.get(), std::forward<Args>(args)...); + assert(object != nullptr); + return object.release(); + } + + //////////////////////// + // JSON value storage // + //////////////////////// + + /*! + @brief a JSON value + + The actual storage for a JSON value of the @ref basic_json class. This + union combines the different storage types for the JSON value types + defined in @ref value_t. + + JSON type | value_t type | used type + --------- | --------------- | ------------------------ + object | object | pointer to @ref object_t + array | array | pointer to @ref array_t + string | string | pointer to @ref string_t + boolean | boolean | @ref boolean_t + number | number_integer | @ref number_integer_t + number | number_unsigned | @ref number_unsigned_t + number | number_float | @ref number_float_t + null | null | *no value is stored* + + @note Variable-length types (objects, arrays, and strings) are stored as + pointers. The size of the union should not exceed 64 bits if the default + value types are used. + + @since version 1.0.0 + */ + union json_value + { + /// object (stored with pointer to save storage) + object_t* object; + /// array (stored with pointer to save storage) + array_t* array; + /// string (stored with pointer to save storage) + string_t* string; + /// boolean + boolean_t boolean; + /// number (integer) + number_integer_t number_integer; + /// number (unsigned integer) + number_unsigned_t number_unsigned; + /// number (floating-point) + number_float_t number_float; + + /// default constructor (for null values) + json_value() = default; + /// constructor for booleans + json_value(boolean_t v) noexcept : boolean(v) {} + /// constructor for numbers (integer) + json_value(number_integer_t v) noexcept : number_integer(v) {} + /// constructor for numbers (unsigned) + json_value(number_unsigned_t v) noexcept : number_unsigned(v) {} + /// constructor for numbers (floating-point) + json_value(number_float_t v) noexcept : number_float(v) {} + /// constructor for empty values of a given type + json_value(value_t t) + { + switch (t) + { + case value_t::object: + { + object = create<object_t>(); + break; + } + + case value_t::array: + { + array = create<array_t>(); + break; + } + + case value_t::string: + { + string = create<string_t>(""); + break; + } + + case value_t::boolean: + { + boolean = boolean_t(false); + break; + } + + case value_t::number_integer: + { + number_integer = number_integer_t(0); + break; + } + + case value_t::number_unsigned: + { + number_unsigned = number_unsigned_t(0); + break; + } + + case value_t::number_float: + { + number_float = number_float_t(0.0); + break; + } + + case value_t::null: + { + break; + } + + default: + { + if (t == value_t::null) + { + JSON_THROW(std::domain_error("961c151d2e87f2686a955a9be24d316f1362bf21 2.1.1")); // LCOV_EXCL_LINE + } + break; + } + } + } + + /// constructor for strings + json_value(const string_t& value) + { + string = create<string_t>(value); + } + + /// constructor for objects + json_value(const object_t& value) + { + object = create<object_t>(value); + } + + /// constructor for arrays + json_value(const array_t& value) + { + array = create<array_t>(value); + } + }; + + /*! + @brief checks the class invariants + + This function asserts the class invariants. It needs to be called at the + end of every constructor to make sure that created objects respect the + invariant. Furthermore, it has to be called each time the type of a JSON + value is changed, because the invariant expresses a relationship between + @a m_type and @a m_value. + */ + void assert_invariant() const + { + assert(m_type != value_t::object or m_value.object != nullptr); + assert(m_type != value_t::array or m_value.array != nullptr); + assert(m_type != value_t::string or m_value.string != nullptr); + } + + public: + ////////////////////////// + // JSON parser callback // + ////////////////////////// + + /*! + @brief JSON callback events + + This enumeration lists the parser events that can trigger calling a + callback function of type @ref parser_callback_t during parsing. + + @image html callback_events.png "Example when certain parse events are triggered" + + @since version 1.0.0 + */ + enum class parse_event_t : uint8_t + { + /// the parser read `{` and started to process a JSON object + object_start, + /// the parser read `}` and finished processing a JSON object + object_end, + /// the parser read `[` and started to process a JSON array + array_start, + /// the parser read `]` and finished processing a JSON array + array_end, + /// the parser read a key of a value in an object + key, + /// the parser finished reading a JSON value + value + }; + + /*! + @brief per-element parser callback type + + With a parser callback function, the result of parsing a JSON text can be + influenced. When passed to @ref parse(std::istream&, const + parser_callback_t) or @ref parse(const CharT, const parser_callback_t), + it is called on certain events (passed as @ref parse_event_t via parameter + @a event) with a set recursion depth @a depth and context JSON value + @a parsed. The return value of the callback function is a boolean + indicating whether the element that emitted the callback shall be kept or + not. + + We distinguish six scenarios (determined by the event type) in which the + callback function can be called. The following table describes the values + of the parameters @a depth, @a event, and @a parsed. + + parameter @a event | description | parameter @a depth | parameter @a parsed + ------------------ | ----------- | ------------------ | ------------------- + parse_event_t::object_start | the parser read `{` and started to process a JSON object | depth of the parent of the JSON object | a JSON value with type discarded + parse_event_t::key | the parser read a key of a value in an object | depth of the currently parsed JSON object | a JSON string containing the key + parse_event_t::object_end | the parser read `}` and finished processing a JSON object | depth of the parent of the JSON object | the parsed JSON object + parse_event_t::array_start | the parser read `[` and started to process a JSON array | depth of the parent of the JSON array | a JSON value with type discarded + parse_event_t::array_end | the parser read `]` and finished processing a JSON array | depth of the parent of the JSON array | the parsed JSON array + parse_event_t::value | the parser finished reading a JSON value | depth of the value | the parsed JSON value + + @image html callback_events.png "Example when certain parse events are triggered" + + Discarding a value (i.e., returning `false`) has different effects + depending on the context in which function was called: + + - Discarded values in structured types are skipped. That is, the parser + will behave as if the discarded value was never read. + - In case a value outside a structured type is skipped, it is replaced + with `null`. This case happens if the top-level element is skipped. + + @param[in] depth the depth of the recursion during parsing + + @param[in] event an event of type parse_event_t indicating the context in + the callback function has been called + + @param[in,out] parsed the current intermediate parse result; note that + writing to this value has no effect for parse_event_t::key events + + @return Whether the JSON value which called the function during parsing + should be kept (`true`) or not (`false`). In the latter case, it is either + skipped completely or replaced by an empty discarded object. + + @sa @ref parse(std::istream&, parser_callback_t) or + @ref parse(const CharT, const parser_callback_t) for examples + + @since version 1.0.0 + */ + using parser_callback_t = std::function<bool(int depth, + parse_event_t event, + basic_json& parsed)>; + + + ////////////////// + // constructors // + ////////////////// + + /// @name constructors and destructors + /// Constructors of class @ref basic_json, copy/move constructor, copy + /// assignment, static functions creating objects, and the destructor. + /// @{ + + /*! + @brief create an empty value with a given type + + Create an empty JSON value with a given type. The value will be default + initialized with an empty value which depends on the type: + + Value type | initial value + ----------- | ------------- + null | `null` + boolean | `false` + string | `""` + number | `0` + object | `{}` + array | `[]` + + @param[in] value_type the type of the value to create + + @complexity Constant. + + @throw std::bad_alloc if allocation for object, array, or string value + fails + + @liveexample{The following code shows the constructor for different @ref + value_t values,basic_json__value_t} + + @since version 1.0.0 + */ + basic_json(const value_t value_type) + : m_type(value_type), m_value(value_type) + { + assert_invariant(); + } + + /*! + @brief create a null object + + Create a `null` JSON value. It either takes a null pointer as parameter + (explicitly creating `null`) or no parameter (implicitly creating `null`). + The passed null pointer itself is not read -- it is only used to choose + the right constructor. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this constructor never throws + exceptions. + + @liveexample{The following code shows the constructor with and without a + null pointer parameter.,basic_json__nullptr_t} + + @since version 1.0.0 + */ + basic_json(std::nullptr_t = nullptr) noexcept + : basic_json(value_t::null) + { + assert_invariant(); + } + + /*! + @brief create a JSON value + + This is a "catch all" constructor for all compatible JSON types; that is, + types for which a `to_json()` method exsits. The constructor forwards the + parameter @a val to that method (to `json_serializer<U>::to_json` method + with `U = uncvref_t<CompatibleType>`, to be exact). + + Template type @a CompatibleType includes, but is not limited to, the + following types: + - **arrays**: @ref array_t and all kinds of compatible containers such as + `std::vector`, `std::deque`, `std::list`, `std::forward_list`, + `std::array`, `std::set`, `std::unordered_set`, `std::multiset`, and + `unordered_multiset` with a `value_type` from which a @ref basic_json + value can be constructed. + - **objects**: @ref object_t and all kinds of compatible associative + containers such as `std::map`, `std::unordered_map`, `std::multimap`, + and `std::unordered_multimap` with a `key_type` compatible to + @ref string_t and a `value_type` from which a @ref basic_json value can + be constructed. + - **strings**: @ref string_t, string literals, and all compatible string + containers can be used. + - **numbers**: @ref number_integer_t, @ref number_unsigned_t, + @ref number_float_t, and all convertible number types such as `int`, + `size_t`, `int64_t`, `float` or `double` can be used. + - **boolean**: @ref boolean_t / `bool` can be used. + + See the examples below. + + @tparam CompatibleType a type such that: + - @a CompatibleType is not derived from `std::istream`, + - @a CompatibleType is not @ref basic_json (to avoid hijacking copy/move + constructors), + - @a CompatibleType is not a @ref basic_json nested type (e.g., + @ref json_pointer, @ref iterator, etc ...) + - @ref @ref json_serializer<U> has a + `to_json(basic_json_t&, CompatibleType&&)` method + + @tparam U = `uncvref_t<CompatibleType>` + + @param[in] val the value to be forwarded + + @complexity Usually linear in the size of the passed @a val, also + depending on the implementation of the called `to_json()` + method. + + @throw what `json_serializer<U>::to_json()` throws + + @liveexample{The following code shows the constructor with several + compatible types.,basic_json__CompatibleType} + + @since version 2.1.0 + */ + template<typename CompatibleType, typename U = detail::uncvref_t<CompatibleType>, + detail::enable_if_t<not std::is_base_of<std::istream, U>::value and + not std::is_same<U, basic_json_t>::value and + not detail::is_basic_json_nested_type< + basic_json_t, U>::value and + detail::has_to_json<basic_json, U>::value, + int> = 0> + basic_json(CompatibleType && val) noexcept(noexcept(JSONSerializer<U>::to_json( + std::declval<basic_json_t&>(), std::forward<CompatibleType>(val)))) + { + JSONSerializer<U>::to_json(*this, std::forward<CompatibleType>(val)); + assert_invariant(); + } + + /*! + @brief create a container (array or object) from an initializer list + + Creates a JSON value of type array or object from the passed initializer + list @a init. In case @a type_deduction is `true` (default), the type of + the JSON value to be created is deducted from the initializer list @a init + according to the following rules: + + 1. If the list is empty, an empty JSON object value `{}` is created. + 2. If the list consists of pairs whose first element is a string, a JSON + object value is created where the first elements of the pairs are + treated as keys and the second elements are as values. + 3. In all other cases, an array is created. + + The rules aim to create the best fit between a C++ initializer list and + JSON values. The rationale is as follows: + + 1. The empty initializer list is written as `{}` which is exactly an empty + JSON object. + 2. C++ has now way of describing mapped types other than to list a list of + pairs. As JSON requires that keys must be of type string, rule 2 is the + weakest constraint one can pose on initializer lists to interpret them + as an object. + 3. In all other cases, the initializer list could not be interpreted as + JSON object type, so interpreting it as JSON array type is safe. + + With the rules described above, the following JSON values cannot be + expressed by an initializer list: + + - the empty array (`[]`): use @ref array(std::initializer_list<basic_json>) + with an empty initializer list in this case + - arrays whose elements satisfy rule 2: use @ref + array(std::initializer_list<basic_json>) with the same initializer list + in this case + + @note When used without parentheses around an empty initializer list, @ref + basic_json() is called instead of this function, yielding the JSON null + value. + + @param[in] init initializer list with JSON values + + @param[in] type_deduction internal parameter; when set to `true`, the type + of the JSON value is deducted from the initializer list @a init; when set + to `false`, the type provided via @a manual_type is forced. This mode is + used by the functions @ref array(std::initializer_list<basic_json>) and + @ref object(std::initializer_list<basic_json>). + + @param[in] manual_type internal parameter; when @a type_deduction is set + to `false`, the created JSON value will use the provided type (only @ref + value_t::array and @ref value_t::object are valid); when @a type_deduction + is set to `true`, this parameter has no effect + + @throw std::domain_error if @a type_deduction is `false`, @a manual_type + is `value_t::object`, but @a init contains an element which is not a pair + whose first element is a string; example: `"cannot create object from + initializer list"` + + @complexity Linear in the size of the initializer list @a init. + + @liveexample{The example below shows how JSON values are created from + initializer lists.,basic_json__list_init_t} + + @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array + value from an initializer list + @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object + value from an initializer list + + @since version 1.0.0 + */ + basic_json(std::initializer_list<basic_json> init, + bool type_deduction = true, + value_t manual_type = value_t::array) + { + // check if each element is an array with two elements whose first + // element is a string + bool is_an_object = std::all_of(init.begin(), init.end(), + [](const basic_json & element) + { + return element.is_array() and element.size() == 2 and element[0].is_string(); + }); + + // adjust type if type deduction is not wanted + if (not type_deduction) + { + // if array is wanted, do not create an object though possible + if (manual_type == value_t::array) + { + is_an_object = false; + } + + // if object is wanted but impossible, throw an exception + if (manual_type == value_t::object and not is_an_object) + { + JSON_THROW(std::domain_error("cannot create object from initializer list")); + } + } + + if (is_an_object) + { + // the initializer list is a list of pairs -> create object + m_type = value_t::object; + m_value = value_t::object; + + std::for_each(init.begin(), init.end(), [this](const basic_json & element) + { + m_value.object->emplace(*(element[0].m_value.string), element[1]); + }); + } + else + { + // the initializer list describes an array -> create array + m_type = value_t::array; + m_value.array = create<array_t>(init); + } + + assert_invariant(); + } + + /*! + @brief explicitly create an array from an initializer list + + Creates a JSON array value from a given initializer list. That is, given a + list of values `a, b, c`, creates the JSON value `[a, b, c]`. If the + initializer list is empty, the empty array `[]` is created. + + @note This function is only needed to express two edge cases that cannot + be realized with the initializer list constructor (@ref + basic_json(std::initializer_list<basic_json>, bool, value_t)). These cases + are: + 1. creating an array whose elements are all pairs whose first element is a + string -- in this case, the initializer list constructor would create an + object, taking the first elements as keys + 2. creating an empty array -- passing the empty initializer list to the + initializer list constructor yields an empty object + + @param[in] init initializer list with JSON values to create an array from + (optional) + + @return JSON array value + + @complexity Linear in the size of @a init. + + @liveexample{The following code shows an example for the `array` + function.,array} + + @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) -- + create a JSON value from an initializer list + @sa @ref object(std::initializer_list<basic_json>) -- create a JSON object + value from an initializer list + + @since version 1.0.0 + */ + static basic_json array(std::initializer_list<basic_json> init = + std::initializer_list<basic_json>()) + { + return basic_json(init, false, value_t::array); + } + + /*! + @brief explicitly create an object from an initializer list + + Creates a JSON object value from a given initializer list. The initializer + lists elements must be pairs, and their first elements must be strings. If + the initializer list is empty, the empty object `{}` is created. + + @note This function is only added for symmetry reasons. In contrast to the + related function @ref array(std::initializer_list<basic_json>), there are + no cases which can only be expressed by this function. That is, any + initializer list @a init can also be passed to the initializer list + constructor @ref basic_json(std::initializer_list<basic_json>, bool, + value_t). + + @param[in] init initializer list to create an object from (optional) + + @return JSON object value + + @throw std::domain_error if @a init is not a pair whose first elements are + strings; thrown by + @ref basic_json(std::initializer_list<basic_json>, bool, value_t) + + @complexity Linear in the size of @a init. + + @liveexample{The following code shows an example for the `object` + function.,object} + + @sa @ref basic_json(std::initializer_list<basic_json>, bool, value_t) -- + create a JSON value from an initializer list + @sa @ref array(std::initializer_list<basic_json>) -- create a JSON array + value from an initializer list + + @since version 1.0.0 + */ + static basic_json object(std::initializer_list<basic_json> init = + std::initializer_list<basic_json>()) + { + return basic_json(init, false, value_t::object); + } + + /*! + @brief construct an array with count copies of given value + + Constructs a JSON array value by creating @a cnt copies of a passed value. + In case @a cnt is `0`, an empty array is created. As postcondition, + `std::distance(begin(),end()) == cnt` holds. + + @param[in] cnt the number of JSON copies of @a val to create + @param[in] val the JSON value to copy + + @complexity Linear in @a cnt. + + @liveexample{The following code shows examples for the @ref + basic_json(size_type\, const basic_json&) + constructor.,basic_json__size_type_basic_json} + + @since version 1.0.0 + */ + basic_json(size_type cnt, const basic_json& val) + : m_type(value_t::array) + { + m_value.array = create<array_t>(cnt, val); + assert_invariant(); + } + + /*! + @brief construct a JSON container given an iterator range + + Constructs the JSON value with the contents of the range `[first, last)`. + The semantics depends on the different types a JSON value can have: + - In case of primitive types (number, boolean, or string), @a first must + be `begin()` and @a last must be `end()`. In this case, the value is + copied. Otherwise, std::out_of_range is thrown. + - In case of structured types (array, object), the constructor behaves as + similar versions for `std::vector`. + - In case of a null type, std::domain_error is thrown. + + @tparam InputIT an input iterator type (@ref iterator or @ref + const_iterator) + + @param[in] first begin of the range to copy from (included) + @param[in] last end of the range to copy from (excluded) + + @pre Iterators @a first and @a last must be initialized. **This + precondition is enforced with an assertion.** + + @throw std::domain_error if iterators are not compatible; that is, do not + belong to the same JSON value; example: `"iterators are not compatible"` + @throw std::out_of_range if iterators are for a primitive type (number, + boolean, or string) where an out of range error can be detected easily; + example: `"iterators out of range"` + @throw std::bad_alloc if allocation for object, array, or string fails + @throw std::domain_error if called with a null value; example: `"cannot + use construct with iterators from null"` + + @complexity Linear in distance between @a first and @a last. + + @liveexample{The example below shows several ways to create JSON values by + specifying a subrange with iterators.,basic_json__InputIt_InputIt} + + @since version 1.0.0 + */ + template<class InputIT, typename std::enable_if< + std::is_same<InputIT, typename basic_json_t::iterator>::value or + std::is_same<InputIT, typename basic_json_t::const_iterator>::value, int>::type = 0> + basic_json(InputIT first, InputIT last) + { + assert(first.m_object != nullptr); + assert(last.m_object != nullptr); + + // make sure iterator fits the current value + if (first.m_object != last.m_object) + { + JSON_THROW(std::domain_error("iterators are not compatible")); + } + + // copy type from first iterator + m_type = first.m_object->m_type; + + // check if iterator range is complete for primitive values + switch (m_type) + { + case value_t::boolean: + case value_t::number_float: + case value_t::number_integer: + case value_t::number_unsigned: + case value_t::string: + { + if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end()) + { + JSON_THROW(std::out_of_range("iterators out of range")); + } + break; + } + + default: + { + break; + } + } + + switch (m_type) + { + case value_t::number_integer: + { + m_value.number_integer = first.m_object->m_value.number_integer; + break; + } + + case value_t::number_unsigned: + { + m_value.number_unsigned = first.m_object->m_value.number_unsigned; + break; + } + + case value_t::number_float: + { + m_value.number_float = first.m_object->m_value.number_float; + break; + } + + case value_t::boolean: + { + m_value.boolean = first.m_object->m_value.boolean; + break; + } + + case value_t::string: + { + m_value = *first.m_object->m_value.string; + break; + } + + case value_t::object: + { + m_value.object = create<object_t>(first.m_it.object_iterator, + last.m_it.object_iterator); + break; + } + + case value_t::array: + { + m_value.array = create<array_t>(first.m_it.array_iterator, + last.m_it.array_iterator); + break; + } + + default: + { + JSON_THROW(std::domain_error("cannot use construct with iterators from " + first.m_object->type_name())); + } + } + + assert_invariant(); + } + + /*! + @brief construct a JSON value given an input stream + + @param[in,out] i stream to read a serialized JSON value from + @param[in] cb a parser callback function of type @ref parser_callback_t + which is used to control the deserialization by filtering unwanted values + (optional) + + @complexity Linear in the length of the input. The parser is a predictive + LL(1) parser. The complexity can be higher if the parser callback function + @a cb has a super-linear complexity. + + @note A UTF-8 byte order mark is silently ignored. + + @deprecated This constructor is deprecated and will be removed in version + 3.0.0 to unify the interface of the library. Deserialization will be + done by stream operators or by calling one of the `parse` functions, + e.g. @ref parse(std::istream&, const parser_callback_t). That is, calls + like `json j(i);` for an input stream @a i need to be replaced by + `json j = json::parse(i);`. See the example below. + + @liveexample{The example below demonstrates constructing a JSON value from + a `std::stringstream` with and without callback + function.,basic_json__istream} + + @since version 2.0.0, deprecated in version 2.0.3, to be removed in + version 3.0.0 + */ + JSON_DEPRECATED + explicit basic_json(std::istream& i, const parser_callback_t cb = nullptr) + { + *this = parser(i, cb).parse(); + assert_invariant(); + } + + /////////////////////////////////////// + // other constructors and destructor // + /////////////////////////////////////// + + /*! + @brief copy constructor + + Creates a copy of a given JSON value. + + @param[in] other the JSON value to copy + + @complexity Linear in the size of @a other. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is linear. + - As postcondition, it holds: `other == basic_json(other)`. + + @throw std::bad_alloc if allocation for object, array, or string fails. + + @liveexample{The following code shows an example for the copy + constructor.,basic_json__basic_json} + + @since version 1.0.0 + */ + basic_json(const basic_json& other) + : m_type(other.m_type) + { + // check of passed value is valid + other.assert_invariant(); + + switch (m_type) + { + case value_t::object: + { + m_value = *other.m_value.object; + break; + } + + case value_t::array: + { + m_value = *other.m_value.array; + break; + } + + case value_t::string: + { + m_value = *other.m_value.string; + break; + } + + case value_t::boolean: + { + m_value = other.m_value.boolean; + break; + } + + case value_t::number_integer: + { + m_value = other.m_value.number_integer; + break; + } + + case value_t::number_unsigned: + { + m_value = other.m_value.number_unsigned; + break; + } + + case value_t::number_float: + { + m_value = other.m_value.number_float; + break; + } + + default: + { + break; + } + } + + assert_invariant(); + } + + /*! + @brief move constructor + + Move constructor. Constructs a JSON value with the contents of the given + value @a other using move semantics. It "steals" the resources from @a + other and leaves it as JSON null value. + + @param[in,out] other value to move to this object + + @post @a other is a JSON null value + + @complexity Constant. + + @liveexample{The code below shows the move constructor explicitly called + via std::move.,basic_json__moveconstructor} + + @since version 1.0.0 + */ + basic_json(basic_json&& other) noexcept + : m_type(std::move(other.m_type)), + m_value(std::move(other.m_value)) + { + // check that passed value is valid + other.assert_invariant(); + + // invalidate payload + other.m_type = value_t::null; + other.m_value = {}; + + assert_invariant(); + } + + /*! + @brief copy assignment + + Copy assignment operator. Copies a JSON value via the "copy and swap" + strategy: It is expressed in terms of the copy constructor, destructor, + and the swap() member function. + + @param[in] other value to copy from + + @complexity Linear. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is linear. + + @liveexample{The code below shows and example for the copy assignment. It + creates a copy of value `a` which is then swapped with `b`. Finally\, the + copy of `a` (which is the null value after the swap) is + destroyed.,basic_json__copyassignment} + + @since version 1.0.0 + */ + reference& operator=(basic_json other) noexcept ( + std::is_nothrow_move_constructible<value_t>::value and + std::is_nothrow_move_assignable<value_t>::value and + std::is_nothrow_move_constructible<json_value>::value and + std::is_nothrow_move_assignable<json_value>::value + ) + { + // check that passed value is valid + other.assert_invariant(); + + using std::swap; + swap(m_type, other.m_type); + swap(m_value, other.m_value); + + assert_invariant(); + return *this; + } + + /*! + @brief destructor + + Destroys the JSON value and frees all allocated memory. + + @complexity Linear. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is linear. + - All stored elements are destroyed and all memory is freed. + + @since version 1.0.0 + */ + ~basic_json() + { + assert_invariant(); + + switch (m_type) + { + case value_t::object: + { + AllocatorType<object_t> alloc; + alloc.destroy(m_value.object); + alloc.deallocate(m_value.object, 1); + break; + } + + case value_t::array: + { + AllocatorType<array_t> alloc; + alloc.destroy(m_value.array); + alloc.deallocate(m_value.array, 1); + break; + } + + case value_t::string: + { + AllocatorType<string_t> alloc; + alloc.destroy(m_value.string); + alloc.deallocate(m_value.string, 1); + break; + } + + default: + { + // all other types need no specific destructor + break; + } + } + } + + /// @} + + public: + /////////////////////// + // object inspection // + /////////////////////// + + /// @name object inspection + /// Functions to inspect the type of a JSON value. + /// @{ + + /*! + @brief serialization + + Serialization function for JSON values. The function tries to mimic + Python's `json.dumps()` function, and currently supports its @a indent + parameter. + + @param[in] indent If indent is nonnegative, then array elements and object + members will be pretty-printed with that indent level. An indent level of + `0` will only insert newlines. `-1` (the default) selects the most compact + representation. + + @return string containing the serialization of the JSON value + + @complexity Linear. + + @liveexample{The following example shows the effect of different @a indent + parameters to the result of the serialization.,dump} + + @see https://docs.python.org/2/library/json.html#json.dump + + @since version 1.0.0 + */ + string_t dump(const int indent = -1) const + { + std::stringstream ss; + + if (indent >= 0) + { + dump(ss, true, static_cast<unsigned int>(indent)); + } + else + { + dump(ss, false, 0); + } + + return ss.str(); + } + + /*! + @brief return the type of the JSON value (explicit) + + Return the type of the JSON value as a value from the @ref value_t + enumeration. + + @return the type of the JSON value + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `type()` for all JSON + types.,type} + + @since version 1.0.0 + */ + constexpr value_t type() const noexcept + { + return m_type; + } + + /*! + @brief return whether type is primitive + + This function returns true iff the JSON type is primitive (string, number, + boolean, or null). + + @return `true` if type is primitive (string, number, boolean, or null), + `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_primitive()` for all JSON + types.,is_primitive} + + @sa @ref is_structured() -- returns whether JSON value is structured + @sa @ref is_null() -- returns whether JSON value is `null` + @sa @ref is_string() -- returns whether JSON value is a string + @sa @ref is_boolean() -- returns whether JSON value is a boolean + @sa @ref is_number() -- returns whether JSON value is a number + + @since version 1.0.0 + */ + constexpr bool is_primitive() const noexcept + { + return is_null() or is_string() or is_boolean() or is_number(); + } + + /*! + @brief return whether type is structured + + This function returns true iff the JSON type is structured (array or + object). + + @return `true` if type is structured (array or object), `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_structured()` for all JSON + types.,is_structured} + + @sa @ref is_primitive() -- returns whether value is primitive + @sa @ref is_array() -- returns whether value is an array + @sa @ref is_object() -- returns whether value is an object + + @since version 1.0.0 + */ + constexpr bool is_structured() const noexcept + { + return is_array() or is_object(); + } + + /*! + @brief return whether value is null + + This function returns true iff the JSON value is null. + + @return `true` if type is null, `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_null()` for all JSON + types.,is_null} + + @since version 1.0.0 + */ + constexpr bool is_null() const noexcept + { + return m_type == value_t::null; + } + + /*! + @brief return whether value is a boolean + + This function returns true iff the JSON value is a boolean. + + @return `true` if type is boolean, `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_boolean()` for all JSON + types.,is_boolean} + + @since version 1.0.0 + */ + constexpr bool is_boolean() const noexcept + { + return m_type == value_t::boolean; + } + + /*! + @brief return whether value is a number + + This function returns true iff the JSON value is a number. This includes + both integer and floating-point values. + + @return `true` if type is number (regardless whether integer, unsigned + integer or floating-type), `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_number()` for all JSON + types.,is_number} + + @sa @ref is_number_integer() -- check if value is an integer or unsigned + integer number + @sa @ref is_number_unsigned() -- check if value is an unsigned integer + number + @sa @ref is_number_float() -- check if value is a floating-point number + + @since version 1.0.0 + */ + constexpr bool is_number() const noexcept + { + return is_number_integer() or is_number_float(); + } + + /*! + @brief return whether value is an integer number + + This function returns true iff the JSON value is an integer or unsigned + integer number. This excludes floating-point values. + + @return `true` if type is an integer or unsigned integer number, `false` + otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_number_integer()` for all + JSON types.,is_number_integer} + + @sa @ref is_number() -- check if value is a number + @sa @ref is_number_unsigned() -- check if value is an unsigned integer + number + @sa @ref is_number_float() -- check if value is a floating-point number + + @since version 1.0.0 + */ + constexpr bool is_number_integer() const noexcept + { + return m_type == value_t::number_integer or m_type == value_t::number_unsigned; + } + + /*! + @brief return whether value is an unsigned integer number + + This function returns true iff the JSON value is an unsigned integer + number. This excludes floating-point and (signed) integer values. + + @return `true` if type is an unsigned integer number, `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_number_unsigned()` for all + JSON types.,is_number_unsigned} + + @sa @ref is_number() -- check if value is a number + @sa @ref is_number_integer() -- check if value is an integer or unsigned + integer number + @sa @ref is_number_float() -- check if value is a floating-point number + + @since version 2.0.0 + */ + constexpr bool is_number_unsigned() const noexcept + { + return m_type == value_t::number_unsigned; + } + + /*! + @brief return whether value is a floating-point number + + This function returns true iff the JSON value is a floating-point number. + This excludes integer and unsigned integer values. + + @return `true` if type is a floating-point number, `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_number_float()` for all + JSON types.,is_number_float} + + @sa @ref is_number() -- check if value is number + @sa @ref is_number_integer() -- check if value is an integer number + @sa @ref is_number_unsigned() -- check if value is an unsigned integer + number + + @since version 1.0.0 + */ + constexpr bool is_number_float() const noexcept + { + return m_type == value_t::number_float; + } + + /*! + @brief return whether value is an object + + This function returns true iff the JSON value is an object. + + @return `true` if type is object, `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_object()` for all JSON + types.,is_object} + + @since version 1.0.0 + */ + constexpr bool is_object() const noexcept + { + return m_type == value_t::object; + } + + /*! + @brief return whether value is an array + + This function returns true iff the JSON value is an array. + + @return `true` if type is array, `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_array()` for all JSON + types.,is_array} + + @since version 1.0.0 + */ + constexpr bool is_array() const noexcept + { + return m_type == value_t::array; + } + + /*! + @brief return whether value is a string + + This function returns true iff the JSON value is a string. + + @return `true` if type is string, `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_string()` for all JSON + types.,is_string} + + @since version 1.0.0 + */ + constexpr bool is_string() const noexcept + { + return m_type == value_t::string; + } + + /*! + @brief return whether value is discarded + + This function returns true iff the JSON value was discarded during parsing + with a callback function (see @ref parser_callback_t). + + @note This function will always be `false` for JSON values after parsing. + That is, discarded values can only occur during parsing, but will be + removed when inside a structured value or replaced by null in other cases. + + @return `true` if type is discarded, `false` otherwise. + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies `is_discarded()` for all JSON + types.,is_discarded} + + @since version 1.0.0 + */ + constexpr bool is_discarded() const noexcept + { + return m_type == value_t::discarded; + } + + /*! + @brief return the type of the JSON value (implicit) + + Implicitly return the type of the JSON value as a value from the @ref + value_t enumeration. + + @return the type of the JSON value + + @complexity Constant. + + @exceptionsafety No-throw guarantee: this member function never throws + exceptions. + + @liveexample{The following code exemplifies the @ref value_t operator for + all JSON types.,operator__value_t} + + @since version 1.0.0 + */ + constexpr operator value_t() const noexcept + { + return m_type; + } + + /// @} + + private: + ////////////////// + // value access // + ////////////////// + + /// get a boolean (explicit) + boolean_t get_impl(boolean_t* /*unused*/) const + { + if (is_boolean()) + { + return m_value.boolean; + } + + JSON_THROW(std::domain_error("type must be boolean, but is " + type_name())); + } + + /// get a pointer to the value (object) + object_t* get_impl_ptr(object_t* /*unused*/) noexcept + { + return is_object() ? m_value.object : nullptr; + } + + /// get a pointer to the value (object) + constexpr const object_t* get_impl_ptr(const object_t* /*unused*/) const noexcept + { + return is_object() ? m_value.object : nullptr; + } + + /// get a pointer to the value (array) + array_t* get_impl_ptr(array_t* /*unused*/) noexcept + { + return is_array() ? m_value.array : nullptr; + } + + /// get a pointer to the value (array) + constexpr const array_t* get_impl_ptr(const array_t* /*unused*/) const noexcept + { + return is_array() ? m_value.array : nullptr; + } + + /// get a pointer to the value (string) + string_t* get_impl_ptr(string_t* /*unused*/) noexcept + { + return is_string() ? m_value.string : nullptr; + } + + /// get a pointer to the value (string) + constexpr const string_t* get_impl_ptr(const string_t* /*unused*/) const noexcept + { + return is_string() ? m_value.string : nullptr; + } + + /// get a pointer to the value (boolean) + boolean_t* get_impl_ptr(boolean_t* /*unused*/) noexcept + { + return is_boolean() ? &m_value.boolean : nullptr; + } + + /// get a pointer to the value (boolean) + constexpr const boolean_t* get_impl_ptr(const boolean_t* /*unused*/) const noexcept + { + return is_boolean() ? &m_value.boolean : nullptr; + } + + /// get a pointer to the value (integer number) + number_integer_t* get_impl_ptr(number_integer_t* /*unused*/) noexcept + { + return is_number_integer() ? &m_value.number_integer : nullptr; + } + + /// get a pointer to the value (integer number) + constexpr const number_integer_t* get_impl_ptr(const number_integer_t* /*unused*/) const noexcept + { + return is_number_integer() ? &m_value.number_integer : nullptr; + } + + /// get a pointer to the value (unsigned number) + number_unsigned_t* get_impl_ptr(number_unsigned_t* /*unused*/) noexcept + { + return is_number_unsigned() ? &m_value.number_unsigned : nullptr; + } + + /// get a pointer to the value (unsigned number) + constexpr const number_unsigned_t* get_impl_ptr(const number_unsigned_t* /*unused*/) const noexcept + { + return is_number_unsigned() ? &m_value.number_unsigned : nullptr; + } + + /// get a pointer to the value (floating-point number) + number_float_t* get_impl_ptr(number_float_t* /*unused*/) noexcept + { + return is_number_float() ? &m_value.number_float : nullptr; + } + + /// get a pointer to the value (floating-point number) + constexpr const number_float_t* get_impl_ptr(const number_float_t* /*unused*/) const noexcept + { + return is_number_float() ? &m_value.number_float : nullptr; + } + + /*! + @brief helper function to implement get_ref() + + This funcion helps to implement get_ref() without code duplication for + const and non-const overloads + + @tparam ThisType will be deduced as `basic_json` or `const basic_json` + + @throw std::domain_error if ReferenceType does not match underlying value + type of the current JSON + */ + template<typename ReferenceType, typename ThisType> + static ReferenceType get_ref_impl(ThisType& obj) + { + // helper type + using PointerType = typename std::add_pointer<ReferenceType>::type; + + // delegate the call to get_ptr<>() + auto ptr = obj.template get_ptr<PointerType>(); + + if (ptr != nullptr) + { + return *ptr; + } + + JSON_THROW(std::domain_error("incompatible ReferenceType for get_ref, actual type is " + + obj.type_name())); + } + + public: + /// @name value access + /// Direct access to the stored value of a JSON value. + /// @{ + + /*! + @brief get special-case overload + + This overloads avoids a lot of template boilerplate, it can be seen as the + identity method + + @tparam BasicJsonType == @ref basic_json + + @return a copy of *this + + @complexity Constant. + + @since version 2.1.0 + */ + template < + typename BasicJsonType, + detail::enable_if_t<std::is_same<typename std::remove_const<BasicJsonType>::type, + basic_json_t>::value, + int> = 0 > + basic_json get() const + { + return *this; + } + + /*! + @brief get a value (explicit) + + Explicit type conversion between the JSON value and a compatible value + which is [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible) + and [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible). + The value is converted by calling the @ref json_serializer<ValueType> + `from_json()` method. + + The function is equivalent to executing + @code {.cpp} + ValueType ret; + JSONSerializer<ValueType>::from_json(*this, ret); + return ret; + @endcode + + This overloads is chosen if: + - @a ValueType is not @ref basic_json, + - @ref json_serializer<ValueType> has a `from_json()` method of the form + `void from_json(const @ref basic_json&, ValueType&)`, and + - @ref json_serializer<ValueType> does not have a `from_json()` method of + the form `ValueType from_json(const @ref basic_json&)` + + @tparam ValueTypeCV the provided value type + @tparam ValueType the returned value type + + @return copy of the JSON value, converted to @a ValueType + + @throw what @ref json_serializer<ValueType> `from_json()` method throws + + @liveexample{The example below shows several conversions from JSON values + to other types. There a few things to note: (1) Floating-point numbers can + be converted to integers\, (2) A JSON array can be converted to a standard + `std::vector<short>`\, (3) A JSON object can be converted to C++ + associative containers such as `std::unordered_map<std::string\, + json>`.,get__ValueType_const} + + @since version 2.1.0 + */ + template < + typename ValueTypeCV, + typename ValueType = detail::uncvref_t<ValueTypeCV>, + detail::enable_if_t < + not std::is_same<basic_json_t, ValueType>::value and + detail::has_from_json<basic_json_t, ValueType>::value and + not detail::has_non_default_from_json<basic_json_t, ValueType>::value, + int > = 0 > + ValueType get() const noexcept(noexcept( + JSONSerializer<ValueType>::from_json(std::declval<const basic_json_t&>(), std::declval<ValueType&>()))) + { + // we cannot static_assert on ValueTypeCV being non-const, because + // there is support for get<const basic_json_t>(), which is why we + // still need the uncvref + static_assert(not std::is_reference<ValueTypeCV>::value, + "get() cannot be used with reference types, you might want to use get_ref()"); + static_assert(std::is_default_constructible<ValueType>::value, + "types must be DefaultConstructible when used with get()"); + + ValueType ret; + JSONSerializer<ValueType>::from_json(*this, ret); + return ret; + } + + /*! + @brief get a value (explicit); special case + + Explicit type conversion between the JSON value and a compatible value + which is **not** [CopyConstructible](http://en.cppreference.com/w/cpp/concept/CopyConstructible) + and **not** [DefaultConstructible](http://en.cppreference.com/w/cpp/concept/DefaultConstructible). + The value is converted by calling the @ref json_serializer<ValueType> + `from_json()` method. + + The function is equivalent to executing + @code {.cpp} + return JSONSerializer<ValueTypeCV>::from_json(*this); + @endcode + + This overloads is chosen if: + - @a ValueType is not @ref basic_json and + - @ref json_serializer<ValueType> has a `from_json()` method of the form + `ValueType from_json(const @ref basic_json&)` + + @note If @ref json_serializer<ValueType> has both overloads of + `from_json()`, this one is chosen. + + @tparam ValueTypeCV the provided value type + @tparam ValueType the returned value type + + @return copy of the JSON value, converted to @a ValueType + + @throw what @ref json_serializer<ValueType> `from_json()` method throws + + @since version 2.1.0 + */ + template < + typename ValueTypeCV, + typename ValueType = detail::uncvref_t<ValueTypeCV>, + detail::enable_if_t<not std::is_same<basic_json_t, ValueType>::value and + detail::has_non_default_from_json<basic_json_t, + ValueType>::value, int> = 0 > + ValueType get() const noexcept(noexcept( + JSONSerializer<ValueTypeCV>::from_json(std::declval<const basic_json_t&>()))) + { + static_assert(not std::is_reference<ValueTypeCV>::value, + "get() cannot be used with reference types, you might want to use get_ref()"); + return JSONSerializer<ValueTypeCV>::from_json(*this); + } + + /*! + @brief get a pointer value (explicit) + + Explicit pointer access to the internally stored JSON value. No copies are + made. + + @warning The pointer becomes invalid if the underlying JSON object + changes. + + @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref + object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, + @ref number_unsigned_t, or @ref number_float_t. + + @return pointer to the internally stored JSON value if the requested + pointer type @a PointerType fits to the JSON value; `nullptr` otherwise + + @complexity Constant. + + @liveexample{The example below shows how pointers to internal values of a + JSON value can be requested. Note that no type conversions are made and a + `nullptr` is returned if the value and the requested pointer type does not + match.,get__PointerType} + + @sa @ref get_ptr() for explicit pointer-member access + + @since version 1.0.0 + */ + template<typename PointerType, typename std::enable_if< + std::is_pointer<PointerType>::value, int>::type = 0> + PointerType get() noexcept + { + // delegate the call to get_ptr + return get_ptr<PointerType>(); + } + + /*! + @brief get a pointer value (explicit) + @copydoc get() + */ + template<typename PointerType, typename std::enable_if< + std::is_pointer<PointerType>::value, int>::type = 0> + constexpr const PointerType get() const noexcept + { + // delegate the call to get_ptr + return get_ptr<PointerType>(); + } + + /*! + @brief get a pointer value (implicit) + + Implicit pointer access to the internally stored JSON value. No copies are + made. + + @warning Writing data to the pointee of the result yields an undefined + state. + + @tparam PointerType pointer type; must be a pointer to @ref array_t, @ref + object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, + @ref number_unsigned_t, or @ref number_float_t. Enforced by a static + assertion. + + @return pointer to the internally stored JSON value if the requested + pointer type @a PointerType fits to the JSON value; `nullptr` otherwise + + @complexity Constant. + + @liveexample{The example below shows how pointers to internal values of a + JSON value can be requested. Note that no type conversions are made and a + `nullptr` is returned if the value and the requested pointer type does not + match.,get_ptr} + + @since version 1.0.0 + */ + template<typename PointerType, typename std::enable_if< + std::is_pointer<PointerType>::value, int>::type = 0> + PointerType get_ptr() noexcept + { + // get the type of the PointerType (remove pointer and const) + using pointee_t = typename std::remove_const<typename + std::remove_pointer<typename + std::remove_const<PointerType>::type>::type>::type; + // make sure the type matches the allowed types + static_assert( + std::is_same<object_t, pointee_t>::value + or std::is_same<array_t, pointee_t>::value + or std::is_same<string_t, pointee_t>::value + or std::is_same<boolean_t, pointee_t>::value + or std::is_same<number_integer_t, pointee_t>::value + or std::is_same<number_unsigned_t, pointee_t>::value + or std::is_same<number_float_t, pointee_t>::value + , "incompatible pointer type"); + + // delegate the call to get_impl_ptr<>() + return get_impl_ptr(static_cast<PointerType>(nullptr)); + } + + /*! + @brief get a pointer value (implicit) + @copydoc get_ptr() + */ + template<typename PointerType, typename std::enable_if< + std::is_pointer<PointerType>::value and + std::is_const<typename std::remove_pointer<PointerType>::type>::value, int>::type = 0> + constexpr const PointerType get_ptr() const noexcept + { + // get the type of the PointerType (remove pointer and const) + using pointee_t = typename std::remove_const<typename + std::remove_pointer<typename + std::remove_const<PointerType>::type>::type>::type; + // make sure the type matches the allowed types + static_assert( + std::is_same<object_t, pointee_t>::value + or std::is_same<array_t, pointee_t>::value + or std::is_same<string_t, pointee_t>::value + or std::is_same<boolean_t, pointee_t>::value + or std::is_same<number_integer_t, pointee_t>::value + or std::is_same<number_unsigned_t, pointee_t>::value + or std::is_same<number_float_t, pointee_t>::value + , "incompatible pointer type"); + + // delegate the call to get_impl_ptr<>() const + return get_impl_ptr(static_cast<const PointerType>(nullptr)); + } + + /*! + @brief get a reference value (implicit) + + Implicit reference access to the internally stored JSON value. No copies + are made. + + @warning Writing data to the referee of the result yields an undefined + state. + + @tparam ReferenceType reference type; must be a reference to @ref array_t, + @ref object_t, @ref string_t, @ref boolean_t, @ref number_integer_t, or + @ref number_float_t. Enforced by static assertion. + + @return reference to the internally stored JSON value if the requested + reference type @a ReferenceType fits to the JSON value; throws + std::domain_error otherwise + + @throw std::domain_error in case passed type @a ReferenceType is + incompatible with the stored JSON value + + @complexity Constant. + + @liveexample{The example shows several calls to `get_ref()`.,get_ref} + + @since version 1.1.0 + */ + template<typename ReferenceType, typename std::enable_if< + std::is_reference<ReferenceType>::value, int>::type = 0> + ReferenceType get_ref() + { + // delegate call to get_ref_impl + return get_ref_impl<ReferenceType>(*this); + } + + /*! + @brief get a reference value (implicit) + @copydoc get_ref() + */ + template<typename ReferenceType, typename std::enable_if< + std::is_reference<ReferenceType>::value and + std::is_const<typename std::remove_reference<ReferenceType>::type>::value, int>::type = 0> + ReferenceType get_ref() const + { + // delegate call to get_ref_impl + return get_ref_impl<ReferenceType>(*this); + } + + /*! + @brief get a value (implicit) + + Implicit type conversion between the JSON value and a compatible value. + The call is realized by calling @ref get() const. + + @tparam ValueType non-pointer type compatible to the JSON value, for + instance `int` for JSON integer numbers, `bool` for JSON booleans, or + `std::vector` types for JSON arrays. The character type of @ref string_t + as well as an initializer list of this type is excluded to avoid + ambiguities as these types implicitly convert to `std::string`. + + @return copy of the JSON value, converted to type @a ValueType + + @throw std::domain_error in case passed type @a ValueType is incompatible + to JSON, thrown by @ref get() const + + @complexity Linear in the size of the JSON value. + + @liveexample{The example below shows several conversions from JSON values + to other types. There a few things to note: (1) Floating-point numbers can + be converted to integers\, (2) A JSON array can be converted to a standard + `std::vector<short>`\, (3) A JSON object can be converted to C++ + associative containers such as `std::unordered_map<std::string\, + json>`.,operator__ValueType} + + @since version 1.0.0 + */ + template < typename ValueType, typename std::enable_if < + not std::is_pointer<ValueType>::value and + not std::is_same<ValueType, typename string_t::value_type>::value +#ifndef _MSC_VER // fix for issue #167 operator<< ambiguity under VS2015 + and not std::is_same<ValueType, std::initializer_list<typename string_t::value_type>>::value +#endif + , int >::type = 0 > + operator ValueType() const + { + // delegate the call to get<>() const + return get<ValueType>(); + } + + /// @} + + + //////////////////// + // element access // + //////////////////// + + /// @name element access + /// Access to the JSON value. + /// @{ + + /*! + @brief access specified array element with bounds checking + + Returns a reference to the element at specified location @a idx, with + bounds checking. + + @param[in] idx index of the element to access + + @return reference to the element at index @a idx + + @throw std::domain_error if the JSON value is not an array; example: + `"cannot use at() with string"` + @throw std::out_of_range if the index @a idx is out of range of the array; + that is, `idx >= size()`; example: `"array index 7 is out of range"` + + @complexity Constant. + + @liveexample{The example below shows how array elements can be read and + written using `at()`.,at__size_type} + + @since version 1.0.0 + */ + reference at(size_type idx) + { + // at only works for arrays + if (is_array()) + { + JSON_TRY + { + return m_value.array->at(idx); + } + JSON_CATCH (std::out_of_range&) + { + // create better exception explanation + JSON_THROW(std::out_of_range("array index " + std::to_string(idx) + " is out of range")); + } + } + else + { + JSON_THROW(std::domain_error("cannot use at() with " + type_name())); + } + } + + /*! + @brief access specified array element with bounds checking + + Returns a const reference to the element at specified location @a idx, + with bounds checking. + + @param[in] idx index of the element to access + + @return const reference to the element at index @a idx + + @throw std::domain_error if the JSON value is not an array; example: + `"cannot use at() with string"` + @throw std::out_of_range if the index @a idx is out of range of the array; + that is, `idx >= size()`; example: `"array index 7 is out of range"` + + @complexity Constant. + + @liveexample{The example below shows how array elements can be read using + `at()`.,at__size_type_const} + + @since version 1.0.0 + */ + const_reference at(size_type idx) const + { + // at only works for arrays + if (is_array()) + { + JSON_TRY + { + return m_value.array->at(idx); + } + JSON_CATCH (std::out_of_range&) + { + // create better exception explanation + JSON_THROW(std::out_of_range("array index " + std::to_string(idx) + " is out of range")); + } + } + else + { + JSON_THROW(std::domain_error("cannot use at() with " + type_name())); + } + } + + /*! + @brief access specified object element with bounds checking + + Returns a reference to the element at with specified key @a key, with + bounds checking. + + @param[in] key key of the element to access + + @return reference to the element at key @a key + + @throw std::domain_error if the JSON value is not an object; example: + `"cannot use at() with boolean"` + @throw std::out_of_range if the key @a key is is not stored in the object; + that is, `find(key) == end()`; example: `"key "the fast" not found"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be read and + written using `at()`.,at__object_t_key_type} + + @sa @ref operator[](const typename object_t::key_type&) for unchecked + access by reference + @sa @ref value() for access by value with a default value + + @since version 1.0.0 + */ + reference at(const typename object_t::key_type& key) + { + // at only works for objects + if (is_object()) + { + JSON_TRY + { + return m_value.object->at(key); + } + JSON_CATCH (std::out_of_range&) + { + // create better exception explanation + JSON_THROW(std::out_of_range("key '" + key + "' not found")); + } + } + else + { + JSON_THROW(std::domain_error("cannot use at() with " + type_name())); + } + } + + /*! + @brief access specified object element with bounds checking + + Returns a const reference to the element at with specified key @a key, + with bounds checking. + + @param[in] key key of the element to access + + @return const reference to the element at key @a key + + @throw std::domain_error if the JSON value is not an object; example: + `"cannot use at() with boolean"` + @throw std::out_of_range if the key @a key is is not stored in the object; + that is, `find(key) == end()`; example: `"key "the fast" not found"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be read using + `at()`.,at__object_t_key_type_const} + + @sa @ref operator[](const typename object_t::key_type&) for unchecked + access by reference + @sa @ref value() for access by value with a default value + + @since version 1.0.0 + */ + const_reference at(const typename object_t::key_type& key) const + { + // at only works for objects + if (is_object()) + { + JSON_TRY + { + return m_value.object->at(key); + } + JSON_CATCH (std::out_of_range&) + { + // create better exception explanation + JSON_THROW(std::out_of_range("key '" + key + "' not found")); + } + } + else + { + JSON_THROW(std::domain_error("cannot use at() with " + type_name())); + } + } + + /*! + @brief access specified array element + + Returns a reference to the element at specified location @a idx. + + @note If @a idx is beyond the range of the array (i.e., `idx >= size()`), + then the array is silently filled up with `null` values to make `idx` a + valid reference to the last stored element. + + @param[in] idx index of the element to access + + @return reference to the element at index @a idx + + @throw std::domain_error if JSON is not an array or null; example: + `"cannot use operator[] with string"` + + @complexity Constant if @a idx is in the range of the array. Otherwise + linear in `idx - size()`. + + @liveexample{The example below shows how array elements can be read and + written using `[]` operator. Note the addition of `null` + values.,operatorarray__size_type} + + @since version 1.0.0 + */ + reference operator[](size_type idx) + { + // implicitly convert null value to an empty array + if (is_null()) + { + m_type = value_t::array; + m_value.array = create<array_t>(); + assert_invariant(); + } + + // operator[] only works for arrays + if (is_array()) + { + // fill up array with null values if given idx is outside range + if (idx >= m_value.array->size()) + { + m_value.array->insert(m_value.array->end(), + idx - m_value.array->size() + 1, + basic_json()); + } + + return m_value.array->operator[](idx); + } + + JSON_THROW(std::domain_error("cannot use operator[] with " + type_name())); + } + + /*! + @brief access specified array element + + Returns a const reference to the element at specified location @a idx. + + @param[in] idx index of the element to access + + @return const reference to the element at index @a idx + + @throw std::domain_error if JSON is not an array; example: `"cannot use + operator[] with null"` + + @complexity Constant. + + @liveexample{The example below shows how array elements can be read using + the `[]` operator.,operatorarray__size_type_const} + + @since version 1.0.0 + */ + const_reference operator[](size_type idx) const + { + // const operator[] only works for arrays + if (is_array()) + { + return m_value.array->operator[](idx); + } + + JSON_THROW(std::domain_error("cannot use operator[] with " + type_name())); + } + + /*! + @brief access specified object element + + Returns a reference to the element at with specified key @a key. + + @note If @a key is not found in the object, then it is silently added to + the object and filled with a `null` value to make `key` a valid reference. + In case the value was `null` before, it is converted to an object. + + @param[in] key key of the element to access + + @return reference to the element at key @a key + + @throw std::domain_error if JSON is not an object or null; example: + `"cannot use operator[] with string"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be read and + written using the `[]` operator.,operatorarray__key_type} + + @sa @ref at(const typename object_t::key_type&) for access by reference + with range checking + @sa @ref value() for access by value with a default value + + @since version 1.0.0 + */ + reference operator[](const typename object_t::key_type& key) + { + // implicitly convert null value to an empty object + if (is_null()) + { + m_type = value_t::object; + m_value.object = create<object_t>(); + assert_invariant(); + } + + // operator[] only works for objects + if (is_object()) + { + return m_value.object->operator[](key); + } + + JSON_THROW(std::domain_error("cannot use operator[] with " + type_name())); + } + + /*! + @brief read-only access specified object element + + Returns a const reference to the element at with specified key @a key. No + bounds checking is performed. + + @warning If the element with key @a key does not exist, the behavior is + undefined. + + @param[in] key key of the element to access + + @return const reference to the element at key @a key + + @pre The element with key @a key must exist. **This precondition is + enforced with an assertion.** + + @throw std::domain_error if JSON is not an object; example: `"cannot use + operator[] with null"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be read using + the `[]` operator.,operatorarray__key_type_const} + + @sa @ref at(const typename object_t::key_type&) for access by reference + with range checking + @sa @ref value() for access by value with a default value + + @since version 1.0.0 + */ + const_reference operator[](const typename object_t::key_type& key) const + { + // const operator[] only works for objects + if (is_object()) + { + assert(m_value.object->find(key) != m_value.object->end()); + return m_value.object->find(key)->second; + } + + JSON_THROW(std::domain_error("cannot use operator[] with " + type_name())); + } + + /*! + @brief access specified object element + + Returns a reference to the element at with specified key @a key. + + @note If @a key is not found in the object, then it is silently added to + the object and filled with a `null` value to make `key` a valid reference. + In case the value was `null` before, it is converted to an object. + + @param[in] key key of the element to access + + @return reference to the element at key @a key + + @throw std::domain_error if JSON is not an object or null; example: + `"cannot use operator[] with string"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be read and + written using the `[]` operator.,operatorarray__key_type} + + @sa @ref at(const typename object_t::key_type&) for access by reference + with range checking + @sa @ref value() for access by value with a default value + + @since version 1.0.0 + */ + template<typename T, std::size_t n> + reference operator[](T * (&key)[n]) + { + return operator[](static_cast<const T>(key)); + } + + /*! + @brief read-only access specified object element + + Returns a const reference to the element at with specified key @a key. No + bounds checking is performed. + + @warning If the element with key @a key does not exist, the behavior is + undefined. + + @note This function is required for compatibility reasons with Clang. + + @param[in] key key of the element to access + + @return const reference to the element at key @a key + + @throw std::domain_error if JSON is not an object; example: `"cannot use + operator[] with null"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be read using + the `[]` operator.,operatorarray__key_type_const} + + @sa @ref at(const typename object_t::key_type&) for access by reference + with range checking + @sa @ref value() for access by value with a default value + + @since version 1.0.0 + */ + template<typename T, std::size_t n> + const_reference operator[](T * (&key)[n]) const + { + return operator[](static_cast<const T>(key)); + } + + /*! + @brief access specified object element + + Returns a reference to the element at with specified key @a key. + + @note If @a key is not found in the object, then it is silently added to + the object and filled with a `null` value to make `key` a valid reference. + In case the value was `null` before, it is converted to an object. + + @param[in] key key of the element to access + + @return reference to the element at key @a key + + @throw std::domain_error if JSON is not an object or null; example: + `"cannot use operator[] with string"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be read and + written using the `[]` operator.,operatorarray__key_type} + + @sa @ref at(const typename object_t::key_type&) for access by reference + with range checking + @sa @ref value() for access by value with a default value + + @since version 1.1.0 + */ + template<typename T> + reference operator[](T* key) + { + // implicitly convert null to object + if (is_null()) + { + m_type = value_t::object; + m_value = value_t::object; + assert_invariant(); + } + + // at only works for objects + if (is_object()) + { + return m_value.object->operator[](key); + } + + JSON_THROW(std::domain_error("cannot use operator[] with " + type_name())); + } + + /*! + @brief read-only access specified object element + + Returns a const reference to the element at with specified key @a key. No + bounds checking is performed. + + @warning If the element with key @a key does not exist, the behavior is + undefined. + + @param[in] key key of the element to access + + @return const reference to the element at key @a key + + @pre The element with key @a key must exist. **This precondition is + enforced with an assertion.** + + @throw std::domain_error if JSON is not an object; example: `"cannot use + operator[] with null"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be read using + the `[]` operator.,operatorarray__key_type_const} + + @sa @ref at(const typename object_t::key_type&) for access by reference + with range checking + @sa @ref value() for access by value with a default value + + @since version 1.1.0 + */ + template<typename T> + const_reference operator[](T* key) const + { + // at only works for objects + if (is_object()) + { + assert(m_value.object->find(key) != m_value.object->end()); + return m_value.object->find(key)->second; + } + + JSON_THROW(std::domain_error("cannot use operator[] with " + type_name())); + } + + /*! + @brief access specified object element with default value + + Returns either a copy of an object's element at the specified key @a key + or a given default value if no element with key @a key exists. + + The function is basically equivalent to executing + @code {.cpp} + try { + return at(key); + } catch(std::out_of_range) { + return default_value; + } + @endcode + + @note Unlike @ref at(const typename object_t::key_type&), this function + does not throw if the given key @a key was not found. + + @note Unlike @ref operator[](const typename object_t::key_type& key), this + function does not implicitly add an element to the position defined by @a + key. This function is furthermore also applicable to const objects. + + @param[in] key key of the element to access + @param[in] default_value the value to return if @a key is not found + + @tparam ValueType type compatible to JSON values, for instance `int` for + JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for + JSON arrays. Note the type of the expected value at @a key and the default + value @a default_value must be compatible. + + @return copy of the element at key @a key or @a default_value if @a key + is not found + + @throw std::domain_error if JSON is not an object; example: `"cannot use + value() with null"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be queried + with a default value.,basic_json__value} + + @sa @ref at(const typename object_t::key_type&) for access by reference + with range checking + @sa @ref operator[](const typename object_t::key_type&) for unchecked + access by reference + + @since version 1.0.0 + */ + template<class ValueType, typename std::enable_if< + std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0> + ValueType value(const typename object_t::key_type& key, ValueType default_value) const + { + // at only works for objects + if (is_object()) + { + // if key is found, return value and given default value otherwise + const auto it = find(key); + if (it != end()) + { + return *it; + } + + return default_value; + } + else + { + JSON_THROW(std::domain_error("cannot use value() with " + type_name())); + } + } + + /*! + @brief overload for a default value of type const char* + @copydoc basic_json::value(const typename object_t::key_type&, ValueType) const + */ + string_t value(const typename object_t::key_type& key, const char* default_value) const + { + return value(key, string_t(default_value)); + } + + /*! + @brief access specified object element via JSON Pointer with default value + + Returns either a copy of an object's element at the specified key @a key + or a given default value if no element with key @a key exists. + + The function is basically equivalent to executing + @code {.cpp} + try { + return at(ptr); + } catch(std::out_of_range) { + return default_value; + } + @endcode + + @note Unlike @ref at(const json_pointer&), this function does not throw + if the given key @a key was not found. + + @param[in] ptr a JSON pointer to the element to access + @param[in] default_value the value to return if @a ptr found no value + + @tparam ValueType type compatible to JSON values, for instance `int` for + JSON integer numbers, `bool` for JSON booleans, or `std::vector` types for + JSON arrays. Note the type of the expected value at @a key and the default + value @a default_value must be compatible. + + @return copy of the element at key @a key or @a default_value if @a key + is not found + + @throw std::domain_error if JSON is not an object; example: `"cannot use + value() with null"` + + @complexity Logarithmic in the size of the container. + + @liveexample{The example below shows how object elements can be queried + with a default value.,basic_json__value_ptr} + + @sa @ref operator[](const json_pointer&) for unchecked access by reference + + @since version 2.0.2 + */ + template<class ValueType, typename std::enable_if< + std::is_convertible<basic_json_t, ValueType>::value, int>::type = 0> + ValueType value(const json_pointer& ptr, ValueType default_value) const + { + // at only works for objects + if (is_object()) + { + // if pointer resolves a value, return it or use default value + JSON_TRY + { + return ptr.get_checked(this); + } + JSON_CATCH (std::out_of_range&) + { + return default_value; + } + } + + JSON_THROW(std::domain_error("cannot use value() with " + type_name())); + } + + /*! + @brief overload for a default value of type const char* + @copydoc basic_json::value(const json_pointer&, ValueType) const + */ + string_t value(const json_pointer& ptr, const char* default_value) const + { + return value(ptr, string_t(default_value)); + } + + /*! + @brief access the first element + + Returns a reference to the first element in the container. For a JSON + container `c`, the expression `c.front()` is equivalent to `*c.begin()`. + + @return In case of a structured type (array or object), a reference to the + first element is returned. In case of number, string, or boolean values, a + reference to the value is returned. + + @complexity Constant. + + @pre The JSON value must not be `null` (would throw `std::out_of_range`) + or an empty array or object (undefined behavior, **guarded by + assertions**). + @post The JSON value remains unchanged. + + @throw std::out_of_range when called on `null` value + + @liveexample{The following code shows an example for `front()`.,front} + + @sa @ref back() -- access the last element + + @since version 1.0.0 + */ + reference front() + { + return *begin(); + } + + /*! + @copydoc basic_json::front() + */ + const_reference front() const + { + return *cbegin(); + } + + /*! + @brief access the last element + + Returns a reference to the last element in the container. For a JSON + container `c`, the expression `c.back()` is equivalent to + @code {.cpp} + auto tmp = c.end(); + --tmp; + return *tmp; + @endcode + + @return In case of a structured type (array or object), a reference to the + last element is returned. In case of number, string, or boolean values, a + reference to the value is returned. + + @complexity Constant. + + @pre The JSON value must not be `null` (would throw `std::out_of_range`) + or an empty array or object (undefined behavior, **guarded by + assertions**). + @post The JSON value remains unchanged. + + @throw std::out_of_range when called on `null` value. + + @liveexample{The following code shows an example for `back()`.,back} + + @sa @ref front() -- access the first element + + @since version 1.0.0 + */ + reference back() + { + auto tmp = end(); + --tmp; + return *tmp; + } + + /*! + @copydoc basic_json::back() + */ + const_reference back() const + { + auto tmp = cend(); + --tmp; + return *tmp; + } + + /*! + @brief remove element given an iterator + + Removes the element specified by iterator @a pos. The iterator @a pos must + be valid and dereferenceable. Thus the `end()` iterator (which is valid, + but is not dereferenceable) cannot be used as a value for @a pos. + + If called on a primitive type other than `null`, the resulting JSON value + will be `null`. + + @param[in] pos iterator to the element to remove + @return Iterator following the last removed element. If the iterator @a + pos refers to the last element, the `end()` iterator is returned. + + @tparam IteratorType an @ref iterator or @ref const_iterator + + @post Invalidates iterators and references at or after the point of the + erase, including the `end()` iterator. + + @throw std::domain_error if called on a `null` value; example: `"cannot + use erase() with null"` + @throw std::domain_error if called on an iterator which does not belong to + the current JSON value; example: `"iterator does not fit current value"` + @throw std::out_of_range if called on a primitive type with invalid + iterator (i.e., any iterator which is not `begin()`); example: `"iterator + out of range"` + + @complexity The complexity depends on the type: + - objects: amortized constant + - arrays: linear in distance between @a pos and the end of the container + - strings: linear in the length of the string + - other types: constant + + @liveexample{The example shows the result of `erase()` for different JSON + types.,erase__IteratorType} + + @sa @ref erase(IteratorType, IteratorType) -- removes the elements in + the given range + @sa @ref erase(const typename object_t::key_type&) -- removes the element + from an object at the given key + @sa @ref erase(const size_type) -- removes the element from an array at + the given index + + @since version 1.0.0 + */ + template<class IteratorType, typename std::enable_if< + std::is_same<IteratorType, typename basic_json_t::iterator>::value or + std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type + = 0> + IteratorType erase(IteratorType pos) + { + // make sure iterator fits the current value + if (this != pos.m_object) + { + JSON_THROW(std::domain_error("iterator does not fit current value")); + } + + IteratorType result = end(); + + switch (m_type) + { + case value_t::boolean: + case value_t::number_float: + case value_t::number_integer: + case value_t::number_unsigned: + case value_t::string: + { + if (not pos.m_it.primitive_iterator.is_begin()) + { + JSON_THROW(std::out_of_range("iterator out of range")); + } + + if (is_string()) + { + AllocatorType<string_t> alloc; + alloc.destroy(m_value.string); + alloc.deallocate(m_value.string, 1); + m_value.string = nullptr; + } + + m_type = value_t::null; + assert_invariant(); + break; + } + + case value_t::object: + { + result.m_it.object_iterator = m_value.object->erase(pos.m_it.object_iterator); + break; + } + + case value_t::array: + { + result.m_it.array_iterator = m_value.array->erase(pos.m_it.array_iterator); + break; + } + + default: + { + JSON_THROW(std::domain_error("cannot use erase() with " + type_name())); + } + } + + return result; + } + + /*! + @brief remove elements given an iterator range + + Removes the element specified by the range `[first; last)`. The iterator + @a first does not need to be dereferenceable if `first == last`: erasing + an empty range is a no-op. + + If called on a primitive type other than `null`, the resulting JSON value + will be `null`. + + @param[in] first iterator to the beginning of the range to remove + @param[in] last iterator past the end of the range to remove + @return Iterator following the last removed element. If the iterator @a + second refers to the last element, the `end()` iterator is returned. + + @tparam IteratorType an @ref iterator or @ref const_iterator + + @post Invalidates iterators and references at or after the point of the + erase, including the `end()` iterator. + + @throw std::domain_error if called on a `null` value; example: `"cannot + use erase() with null"` + @throw std::domain_error if called on iterators which does not belong to + the current JSON value; example: `"iterators do not fit current value"` + @throw std::out_of_range if called on a primitive type with invalid + iterators (i.e., if `first != begin()` and `last != end()`); example: + `"iterators out of range"` + + @complexity The complexity depends on the type: + - objects: `log(size()) + std::distance(first, last)` + - arrays: linear in the distance between @a first and @a last, plus linear + in the distance between @a last and end of the container + - strings: linear in the length of the string + - other types: constant + + @liveexample{The example shows the result of `erase()` for different JSON + types.,erase__IteratorType_IteratorType} + + @sa @ref erase(IteratorType) -- removes the element at a given position + @sa @ref erase(const typename object_t::key_type&) -- removes the element + from an object at the given key + @sa @ref erase(const size_type) -- removes the element from an array at + the given index + + @since version 1.0.0 + */ + template<class IteratorType, typename std::enable_if< + std::is_same<IteratorType, typename basic_json_t::iterator>::value or + std::is_same<IteratorType, typename basic_json_t::const_iterator>::value, int>::type + = 0> + IteratorType erase(IteratorType first, IteratorType last) + { + // make sure iterator fits the current value + if (this != first.m_object or this != last.m_object) + { + JSON_THROW(std::domain_error("iterators do not fit current value")); + } + + IteratorType result = end(); + + switch (m_type) + { + case value_t::boolean: + case value_t::number_float: + case value_t::number_integer: + case value_t::number_unsigned: + case value_t::string: + { + if (not first.m_it.primitive_iterator.is_begin() or not last.m_it.primitive_iterator.is_end()) + { + JSON_THROW(std::out_of_range("iterators out of range")); + } + + if (is_string()) + { + AllocatorType<string_t> alloc; + alloc.destroy(m_value.string); + alloc.deallocate(m_value.string, 1); + m_value.string = nullptr; + } + + m_type = value_t::null; + assert_invariant(); + break; + } + + case value_t::object: + { + result.m_it.object_iterator = m_value.object->erase(first.m_it.object_iterator, + last.m_it.object_iterator); + break; + } + + case value_t::array: + { + result.m_it.array_iterator = m_value.array->erase(first.m_it.array_iterator, + last.m_it.array_iterator); + break; + } + + default: + { + JSON_THROW(std::domain_error("cannot use erase() with " + type_name())); + } + } + + return result; + } + + /*! + @brief remove element from a JSON object given a key + + Removes elements from a JSON object with the key value @a key. + + @param[in] key value of the elements to remove + + @return Number of elements removed. If @a ObjectType is the default + `std::map` type, the return value will always be `0` (@a key was not + found) or `1` (@a key was found). + + @post References and iterators to the erased elements are invalidated. + Other references and iterators are not affected. + + @throw std::domain_error when called on a type other than JSON object; + example: `"cannot use erase() with null"` + + @complexity `log(size()) + count(key)` + + @liveexample{The example shows the effect of `erase()`.,erase__key_type} + + @sa @ref erase(IteratorType) -- removes the element at a given position + @sa @ref erase(IteratorType, IteratorType) -- removes the elements in + the given range + @sa @ref erase(const size_type) -- removes the element from an array at + the given index + + @since version 1.0.0 + */ + size_type erase(const typename object_t::key_type& key) + { + // this erase only works for objects + if (is_object()) + { + return m_value.object->erase(key); + } + + JSON_THROW(std::domain_error("cannot use erase() with " + type_name())); + } + + /*! + @brief remove element from a JSON array given an index + + Removes element from a JSON array at the index @a idx. + + @param[in] idx index of the element to remove + + @throw std::domain_error when called on a type other than JSON array; + example: `"cannot use erase() with null"` + @throw std::out_of_range when `idx >= size()`; example: `"array index 17 + is out of range"` + + @complexity Linear in distance between @a idx and the end of the container. + + @liveexample{The example shows the effect of `erase()`.,erase__size_type} + + @sa @ref erase(IteratorType) -- removes the element at a given position + @sa @ref erase(IteratorType, IteratorType) -- removes the elements in + the given range + @sa @ref erase(const typename object_t::key_type&) -- removes the element + from an object at the given key + + @since version 1.0.0 + */ + void erase(const size_type idx) + { + // this erase only works for arrays + if (is_array()) + { + if (idx >= size()) + { + JSON_THROW(std::out_of_range("array index " + std::to_string(idx) + " is out of range")); + } + + m_value.array->erase(m_value.array->begin() + static_cast<difference_type>(idx)); + } + else + { + JSON_THROW(std::domain_error("cannot use erase() with " + type_name())); + } + } + + /// @} + + + //////////// + // lookup // + //////////// + + /// @name lookup + /// @{ + + /*! + @brief find an element in a JSON object + + Finds an element in a JSON object with key equivalent to @a key. If the + element is not found or the JSON value is not an object, end() is + returned. + + @note This method always returns @ref end() when executed on a JSON type + that is not an object. + + @param[in] key key value of the element to search for + + @return Iterator to an element with key equivalent to @a key. If no such + element is found or the JSON value is not an object, past-the-end (see + @ref end()) iterator is returned. + + @complexity Logarithmic in the size of the JSON object. + + @liveexample{The example shows how `find()` is used.,find__key_type} + + @since version 1.0.0 + */ + iterator find(typename object_t::key_type key) + { + auto result = end(); + + if (is_object()) + { + result.m_it.object_iterator = m_value.object->find(key); + } + + return result; + } + + /*! + @brief find an element in a JSON object + @copydoc find(typename object_t::key_type) + */ + const_iterator find(typename object_t::key_type key) const + { + auto result = cend(); + + if (is_object()) + { + result.m_it.object_iterator = m_value.object->find(key); + } + + return result; + } + + /*! + @brief returns the number of occurrences of a key in a JSON object + + Returns the number of elements with key @a key. If ObjectType is the + default `std::map` type, the return value will always be `0` (@a key was + not found) or `1` (@a key was found). + + @note This method always returns `0` when executed on a JSON type that is + not an object. + + @param[in] key key value of the element to count + + @return Number of elements with key @a key. If the JSON value is not an + object, the return value will be `0`. + + @complexity Logarithmic in the size of the JSON object. + + @liveexample{The example shows how `count()` is used.,count} + + @since version 1.0.0 + */ + size_type count(typename object_t::key_type key) const + { + // return 0 for all nonobject types + return is_object() ? m_value.object->count(key) : 0; + } + + /// @} + + + /////////////// + // iterators // + /////////////// + + /// @name iterators + /// @{ + + /*! + @brief returns an iterator to the first element + + Returns an iterator to the first element. + + @image html range-begin-end.svg "Illustration from cppreference.com" + + @return iterator to the first element + + @complexity Constant. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is constant. + + @liveexample{The following code shows an example for `begin()`.,begin} + + @sa @ref cbegin() -- returns a const iterator to the beginning + @sa @ref end() -- returns an iterator to the end + @sa @ref cend() -- returns a const iterator to the end + + @since version 1.0.0 + */ + iterator begin() noexcept + { + iterator result(this); + result.set_begin(); + return result; + } + + /*! + @copydoc basic_json::cbegin() + */ + const_iterator begin() const noexcept + { + return cbegin(); + } + + /*! + @brief returns a const iterator to the first element + + Returns a const iterator to the first element. + + @image html range-begin-end.svg "Illustration from cppreference.com" + + @return const iterator to the first element + + @complexity Constant. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is constant. + - Has the semantics of `const_cast<const basic_json&>(*this).begin()`. + + @liveexample{The following code shows an example for `cbegin()`.,cbegin} + + @sa @ref begin() -- returns an iterator to the beginning + @sa @ref end() -- returns an iterator to the end + @sa @ref cend() -- returns a const iterator to the end + + @since version 1.0.0 + */ + const_iterator cbegin() const noexcept + { + const_iterator result(this); + result.set_begin(); + return result; + } + + /*! + @brief returns an iterator to one past the last element + + Returns an iterator to one past the last element. + + @image html range-begin-end.svg "Illustration from cppreference.com" + + @return iterator one past the last element + + @complexity Constant. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is constant. + + @liveexample{The following code shows an example for `end()`.,end} + + @sa @ref cend() -- returns a const iterator to the end + @sa @ref begin() -- returns an iterator to the beginning + @sa @ref cbegin() -- returns a const iterator to the beginning + + @since version 1.0.0 + */ + iterator end() noexcept + { + iterator result(this); + result.set_end(); + return result; + } + + /*! + @copydoc basic_json::cend() + */ + const_iterator end() const noexcept + { + return cend(); + } + + /*! + @brief returns a const iterator to one past the last element + + Returns a const iterator to one past the last element. + + @image html range-begin-end.svg "Illustration from cppreference.com" + + @return const iterator one past the last element + + @complexity Constant. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is constant. + - Has the semantics of `const_cast<const basic_json&>(*this).end()`. + + @liveexample{The following code shows an example for `cend()`.,cend} + + @sa @ref end() -- returns an iterator to the end + @sa @ref begin() -- returns an iterator to the beginning + @sa @ref cbegin() -- returns a const iterator to the beginning + + @since version 1.0.0 + */ + const_iterator cend() const noexcept + { + const_iterator result(this); + result.set_end(); + return result; + } + + /*! + @brief returns an iterator to the reverse-beginning + + Returns an iterator to the reverse-beginning; that is, the last element. + + @image html range-rbegin-rend.svg "Illustration from cppreference.com" + + @complexity Constant. + + @requirement This function helps `basic_json` satisfying the + [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) + requirements: + - The complexity is constant. + - Has the semantics of `reverse_iterator(end())`. + + @liveexample{The following code shows an example for `rbegin()`.,rbegin} + + @sa @ref crbegin() -- returns a const reverse iterator to the beginning + @sa @ref rend() -- returns a reverse iterator to the end + @sa @ref crend() -- returns a const reverse iterator to the end + + @since version 1.0.0 + */ + reverse_iterator rbegin() noexcept + { + return reverse_iterator(end()); + } + + /*! + @copydoc basic_json::crbegin() + */ + const_reverse_iterator rbegin() const noexcept + { + return crbegin(); + } + + /*! + @brief returns an iterator to the reverse-end + + Returns an iterator to the reverse-end; that is, one before the first + element. + + @image html range-rbegin-rend.svg "Illustration from cppreference.com" + + @complexity Constant. + + @requirement This function helps `basic_json` satisfying the + [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) + requirements: + - The complexity is constant. + - Has the semantics of `reverse_iterator(begin())`. + + @liveexample{The following code shows an example for `rend()`.,rend} + + @sa @ref crend() -- returns a const reverse iterator to the end + @sa @ref rbegin() -- returns a reverse iterator to the beginning + @sa @ref crbegin() -- returns a const reverse iterator to the beginning + + @since version 1.0.0 + */ + reverse_iterator rend() noexcept + { + return reverse_iterator(begin()); + } + + /*! + @copydoc basic_json::crend() + */ + const_reverse_iterator rend() const noexcept + { + return crend(); + } + + /*! + @brief returns a const reverse iterator to the last element + + Returns a const iterator to the reverse-beginning; that is, the last + element. + + @image html range-rbegin-rend.svg "Illustration from cppreference.com" + + @complexity Constant. + + @requirement This function helps `basic_json` satisfying the + [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) + requirements: + - The complexity is constant. + - Has the semantics of `const_cast<const basic_json&>(*this).rbegin()`. + + @liveexample{The following code shows an example for `crbegin()`.,crbegin} + + @sa @ref rbegin() -- returns a reverse iterator to the beginning + @sa @ref rend() -- returns a reverse iterator to the end + @sa @ref crend() -- returns a const reverse iterator to the end + + @since version 1.0.0 + */ + const_reverse_iterator crbegin() const noexcept + { + return const_reverse_iterator(cend()); + } + + /*! + @brief returns a const reverse iterator to one before the first + + Returns a const reverse iterator to the reverse-end; that is, one before + the first element. + + @image html range-rbegin-rend.svg "Illustration from cppreference.com" + + @complexity Constant. + + @requirement This function helps `basic_json` satisfying the + [ReversibleContainer](http://en.cppreference.com/w/cpp/concept/ReversibleContainer) + requirements: + - The complexity is constant. + - Has the semantics of `const_cast<const basic_json&>(*this).rend()`. + + @liveexample{The following code shows an example for `crend()`.,crend} + + @sa @ref rend() -- returns a reverse iterator to the end + @sa @ref rbegin() -- returns a reverse iterator to the beginning + @sa @ref crbegin() -- returns a const reverse iterator to the beginning + + @since version 1.0.0 + */ + const_reverse_iterator crend() const noexcept + { + return const_reverse_iterator(cbegin()); + } + + private: + // forward declaration + template<typename IteratorType> class iteration_proxy; + + public: + /*! + @brief wrapper to access iterator member functions in range-based for + + This function allows to access @ref iterator::key() and @ref + iterator::value() during range-based for loops. In these loops, a + reference to the JSON values is returned, so there is no access to the + underlying iterator. + + @note The name of this function is not yet final and may change in the + future. + */ + static iteration_proxy<iterator> iterator_wrapper(reference cont) + { + return iteration_proxy<iterator>(cont); + } + + /*! + @copydoc iterator_wrapper(reference) + */ + static iteration_proxy<const_iterator> iterator_wrapper(const_reference cont) + { + return iteration_proxy<const_iterator>(cont); + } + + /// @} + + + ////////////// + // capacity // + ////////////// + + /// @name capacity + /// @{ + + /*! + @brief checks whether the container is empty + + Checks if a JSON value has no elements. + + @return The return value depends on the different types and is + defined as follows: + Value type | return value + ----------- | ------------- + null | `true` + boolean | `false` + string | `false` + number | `false` + object | result of function `object_t::empty()` + array | result of function `array_t::empty()` + + @note This function does not return whether a string stored as JSON value + is empty - it returns whether the JSON container itself is empty which is + false in the case of a string. + + @complexity Constant, as long as @ref array_t and @ref object_t satisfy + the Container concept; that is, their `empty()` functions have constant + complexity. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is constant. + - Has the semantics of `begin() == end()`. + + @liveexample{The following code uses `empty()` to check if a JSON + object contains any elements.,empty} + + @sa @ref size() -- returns the number of elements + + @since version 1.0.0 + */ + bool empty() const noexcept + { + switch (m_type) + { + case value_t::null: + { + // null values are empty + return true; + } + + case value_t::array: + { + // delegate call to array_t::empty() + return m_value.array->empty(); + } + + case value_t::object: + { + // delegate call to object_t::empty() + return m_value.object->empty(); + } + + default: + { + // all other types are nonempty + return false; + } + } + } + + /*! + @brief returns the number of elements + + Returns the number of elements in a JSON value. + + @return The return value depends on the different types and is + defined as follows: + Value type | return value + ----------- | ------------- + null | `0` + boolean | `1` + string | `1` + number | `1` + object | result of function object_t::size() + array | result of function array_t::size() + + @note This function does not return the length of a string stored as JSON + value - it returns the number of elements in the JSON value which is 1 in + the case of a string. + + @complexity Constant, as long as @ref array_t and @ref object_t satisfy + the Container concept; that is, their size() functions have constant + complexity. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is constant. + - Has the semantics of `std::distance(begin(), end())`. + + @liveexample{The following code calls `size()` on the different value + types.,size} + + @sa @ref empty() -- checks whether the container is empty + @sa @ref max_size() -- returns the maximal number of elements + + @since version 1.0.0 + */ + size_type size() const noexcept + { + switch (m_type) + { + case value_t::null: + { + // null values are empty + return 0; + } + + case value_t::array: + { + // delegate call to array_t::size() + return m_value.array->size(); + } + + case value_t::object: + { + // delegate call to object_t::size() + return m_value.object->size(); + } + + default: + { + // all other types have size 1 + return 1; + } + } + } + + /*! + @brief returns the maximum possible number of elements + + Returns the maximum number of elements a JSON value is able to hold due to + system or library implementation limitations, i.e. `std::distance(begin(), + end())` for the JSON value. + + @return The return value depends on the different types and is + defined as follows: + Value type | return value + ----------- | ------------- + null | `0` (same as `size()`) + boolean | `1` (same as `size()`) + string | `1` (same as `size()`) + number | `1` (same as `size()`) + object | result of function `object_t::max_size()` + array | result of function `array_t::max_size()` + + @complexity Constant, as long as @ref array_t and @ref object_t satisfy + the Container concept; that is, their `max_size()` functions have constant + complexity. + + @requirement This function helps `basic_json` satisfying the + [Container](http://en.cppreference.com/w/cpp/concept/Container) + requirements: + - The complexity is constant. + - Has the semantics of returning `b.size()` where `b` is the largest + possible JSON value. + + @liveexample{The following code calls `max_size()` on the different value + types. Note the output is implementation specific.,max_size} + + @sa @ref size() -- returns the number of elements + + @since version 1.0.0 + */ + size_type max_size() const noexcept + { + switch (m_type) + { + case value_t::array: + { + // delegate call to array_t::max_size() + return m_value.array->max_size(); + } + + case value_t::object: + { + // delegate call to object_t::max_size() + return m_value.object->max_size(); + } + + default: + { + // all other types have max_size() == size() + return size(); + } + } + } + + /// @} + + + /////////////// + // modifiers // + /////////////// + + /// @name modifiers + /// @{ + + /*! + @brief clears the contents + + Clears the content of a JSON value and resets it to the default value as + if @ref basic_json(value_t) would have been called: + + Value type | initial value + ----------- | ------------- + null | `null` + boolean | `false` + string | `""` + number | `0` + object | `{}` + array | `[]` + + @complexity Linear in the size of the JSON value. + + @liveexample{The example below shows the effect of `clear()` to different + JSON types.,clear} + + @since version 1.0.0 + */ + void clear() noexcept + { + switch (m_type) + { + case value_t::number_integer: + { + m_value.number_integer = 0; + break; + } + + case value_t::number_unsigned: + { + m_value.number_unsigned = 0; + break; + } + + case value_t::number_float: + { + m_value.number_float = 0.0; + break; + } + + case value_t::boolean: + { + m_value.boolean = false; + break; + } + + case value_t::string: + { + m_value.string->clear(); + break; + } + + case value_t::array: + { + m_value.array->clear(); + break; + } + + case value_t::object: + { + m_value.object->clear(); + break; + } + + default: + { + break; + } + } + } + + /*! + @brief add an object to an array + + Appends the given element @a val to the end of the JSON value. If the + function is called on a JSON null value, an empty array is created before + appending @a val. + + @param[in] val the value to add to the JSON array + + @throw std::domain_error when called on a type other than JSON array or + null; example: `"cannot use push_back() with number"` + + @complexity Amortized constant. + + @liveexample{The example shows how `push_back()` and `+=` can be used to + add elements to a JSON array. Note how the `null` value was silently + converted to a JSON array.,push_back} + + @since version 1.0.0 + */ + void push_back(basic_json&& val) + { + // push_back only works for null objects or arrays + if (not(is_null() or is_array())) + { + JSON_THROW(std::domain_error("cannot use push_back() with " + type_name())); + } + + // transform null object into an array + if (is_null()) + { + m_type = value_t::array; + m_value = value_t::array; + assert_invariant(); + } + + // add element to array (move semantics) + m_value.array->push_back(std::move(val)); + // invalidate object + val.m_type = value_t::null; + } + + /*! + @brief add an object to an array + @copydoc push_back(basic_json&&) + */ + reference operator+=(basic_json&& val) + { + push_back(std::move(val)); + return *this; + } + + /*! + @brief add an object to an array + @copydoc push_back(basic_json&&) + */ + void push_back(const basic_json& val) + { + // push_back only works for null objects or arrays + if (not(is_null() or is_array())) + { + JSON_THROW(std::domain_error("cannot use push_back() with " + type_name())); + } + + // transform null object into an array + if (is_null()) + { + m_type = value_t::array; + m_value = value_t::array; + assert_invariant(); + } + + // add element to array + m_value.array->push_back(val); + } + + /*! + @brief add an object to an array + @copydoc push_back(basic_json&&) + */ + reference operator+=(const basic_json& val) + { + push_back(val); + return *this; + } + + /*! + @brief add an object to an object + + Inserts the given element @a val to the JSON object. If the function is + called on a JSON null value, an empty object is created before inserting + @a val. + + @param[in] val the value to add to the JSON object + + @throw std::domain_error when called on a type other than JSON object or + null; example: `"cannot use push_back() with number"` + + @complexity Logarithmic in the size of the container, O(log(`size()`)). + + @liveexample{The example shows how `push_back()` and `+=` can be used to + add elements to a JSON object. Note how the `null` value was silently + converted to a JSON object.,push_back__object_t__value} + + @since version 1.0.0 + */ + void push_back(const typename object_t::value_type& val) + { + // push_back only works for null objects or objects + if (not(is_null() or is_object())) + { + JSON_THROW(std::domain_error("cannot use push_back() with " + type_name())); + } + + // transform null object into an object + if (is_null()) + { + m_type = value_t::object; + m_value = value_t::object; + assert_invariant(); + } + + // add element to array + m_value.object->insert(val); + } + + /*! + @brief add an object to an object + @copydoc push_back(const typename object_t::value_type&) + */ + reference operator+=(const typename object_t::value_type& val) + { + push_back(val); + return *this; + } + + /*! + @brief add an object to an object + + This function allows to use `push_back` with an initializer list. In case + + 1. the current value is an object, + 2. the initializer list @a init contains only two elements, and + 3. the first element of @a init is a string, + + @a init is converted into an object element and added using + @ref push_back(const typename object_t::value_type&). Otherwise, @a init + is converted to a JSON value and added using @ref push_back(basic_json&&). + + @param init an initializer list + + @complexity Linear in the size of the initializer list @a init. + + @note This function is required to resolve an ambiguous overload error, + because pairs like `{"key", "value"}` can be both interpreted as + `object_t::value_type` or `std::initializer_list<basic_json>`, see + https://github.com/nlohmann/json/issues/235 for more information. + + @liveexample{The example shows how initializer lists are treated as + objects when possible.,push_back__initializer_list} + */ + void push_back(std::initializer_list<basic_json> init) + { + if (is_object() and init.size() == 2 and init.begin()->is_string()) + { + const string_t key = *init.begin(); + push_back(typename object_t::value_type(key, *(init.begin() + 1))); + } + else + { + push_back(basic_json(init)); + } + } + + /*! + @brief add an object to an object + @copydoc push_back(std::initializer_list<basic_json>) + */ + reference operator+=(std::initializer_list<basic_json> init) + { + push_back(init); + return *this; + } + + /*! + @brief add an object to an array + + Creates a JSON value from the passed parameters @a args to the end of the + JSON value. If the function is called on a JSON null value, an empty array + is created before appending the value created from @a args. + + @param[in] args arguments to forward to a constructor of @ref basic_json + @tparam Args compatible types to create a @ref basic_json object + + @throw std::domain_error when called on a type other than JSON array or + null; example: `"cannot use emplace_back() with number"` + + @complexity Amortized constant. + + @liveexample{The example shows how `push_back()` can be used to add + elements to a JSON array. Note how the `null` value was silently converted + to a JSON array.,emplace_back} + + @since version 2.0.8 + */ + template<class... Args> + void emplace_back(Args&& ... args) + { + // emplace_back only works for null objects or arrays + if (not(is_null() or is_array())) + { + JSON_THROW(std::domain_error("cannot use emplace_back() with " + type_name())); + } + + // transform null object into an array + if (is_null()) + { + m_type = value_t::array; + m_value = value_t::array; + assert_invariant(); + } + + // add element to array (perfect forwarding) + m_value.array->emplace_back(std::forward<Args>(args)...); + } + + /*! + @brief add an object to an object if key does not exist + + Inserts a new element into a JSON object constructed in-place with the + given @a args if there is no element with the key in the container. If the + function is called on a JSON null value, an empty object is created before + appending the value created from @a args. + + @param[in] args arguments to forward to a constructor of @ref basic_json + @tparam Args compatible types to create a @ref basic_json object + + @return a pair consisting of an iterator to the inserted element, or the + already-existing element if no insertion happened, and a bool + denoting whether the insertion took place. + + @throw std::domain_error when called on a type other than JSON object or + null; example: `"cannot use emplace() with number"` + + @complexity Logarithmic in the size of the container, O(log(`size()`)). + + @liveexample{The example shows how `emplace()` can be used to add elements + to a JSON object. Note how the `null` value was silently converted to a + JSON object. Further note how no value is added if there was already one + value stored with the same key.,emplace} + + @since version 2.0.8 + */ + template<class... Args> + std::pair<iterator, bool> emplace(Args&& ... args) + { + // emplace only works for null objects or arrays + if (not(is_null() or is_object())) + { + JSON_THROW(std::domain_error("cannot use emplace() with " + type_name())); + } + + // transform null object into an object + if (is_null()) + { + m_type = value_t::object; + m_value = value_t::object; + assert_invariant(); + } + + // add element to array (perfect forwarding) + auto res = m_value.object->emplace(std::forward<Args>(args)...); + // create result iterator and set iterator to the result of emplace + auto it = begin(); + it.m_it.object_iterator = res.first; + + // return pair of iterator and boolean + return {it, res.second}; + } + + /*! + @brief inserts element + + Inserts element @a val before iterator @a pos. + + @param[in] pos iterator before which the content will be inserted; may be + the end() iterator + @param[in] val element to insert + @return iterator pointing to the inserted @a val. + + @throw std::domain_error if called on JSON values other than arrays; + example: `"cannot use insert() with string"` + @throw std::domain_error if @a pos is not an iterator of *this; example: + `"iterator does not fit current value"` + + @complexity Constant plus linear in the distance between @a pos and end of + the container. + + @liveexample{The example shows how `insert()` is used.,insert} + + @since version 1.0.0 + */ + iterator insert(const_iterator pos, const basic_json& val) + { + // insert only works for arrays + if (is_array()) + { + // check if iterator pos fits to this JSON value + if (pos.m_object != this) + { + JSON_THROW(std::domain_error("iterator does not fit current value")); + } + + // insert to array and return iterator + iterator result(this); + result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, val); + return result; + } + + JSON_THROW(std::domain_error("cannot use insert() with " + type_name())); + } + + /*! + @brief inserts element + @copydoc insert(const_iterator, const basic_json&) + */ + iterator insert(const_iterator pos, basic_json&& val) + { + return insert(pos, val); + } + + /*! + @brief inserts elements + + Inserts @a cnt copies of @a val before iterator @a pos. + + @param[in] pos iterator before which the content will be inserted; may be + the end() iterator + @param[in] cnt number of copies of @a val to insert + @param[in] val element to insert + @return iterator pointing to the first element inserted, or @a pos if + `cnt==0` + + @throw std::domain_error if called on JSON values other than arrays; + example: `"cannot use insert() with string"` + @throw std::domain_error if @a pos is not an iterator of *this; example: + `"iterator does not fit current value"` + + @complexity Linear in @a cnt plus linear in the distance between @a pos + and end of the container. + + @liveexample{The example shows how `insert()` is used.,insert__count} + + @since version 1.0.0 + */ + iterator insert(const_iterator pos, size_type cnt, const basic_json& val) + { + // insert only works for arrays + if (is_array()) + { + // check if iterator pos fits to this JSON value + if (pos.m_object != this) + { + JSON_THROW(std::domain_error("iterator does not fit current value")); + } + + // insert to array and return iterator + iterator result(this); + result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, cnt, val); + return result; + } + + JSON_THROW(std::domain_error("cannot use insert() with " + type_name())); + } + + /*! + @brief inserts elements + + Inserts elements from range `[first, last)` before iterator @a pos. + + @param[in] pos iterator before which the content will be inserted; may be + the end() iterator + @param[in] first begin of the range of elements to insert + @param[in] last end of the range of elements to insert + + @throw std::domain_error if called on JSON values other than arrays; + example: `"cannot use insert() with string"` + @throw std::domain_error if @a pos is not an iterator of *this; example: + `"iterator does not fit current value"` + @throw std::domain_error if @a first and @a last do not belong to the same + JSON value; example: `"iterators do not fit"` + @throw std::domain_error if @a first or @a last are iterators into + container for which insert is called; example: `"passed iterators may not + belong to container"` + + @return iterator pointing to the first element inserted, or @a pos if + `first==last` + + @complexity Linear in `std::distance(first, last)` plus linear in the + distance between @a pos and end of the container. + + @liveexample{The example shows how `insert()` is used.,insert__range} + + @since version 1.0.0 + */ + iterator insert(const_iterator pos, const_iterator first, const_iterator last) + { + // insert only works for arrays + if (not is_array()) + { + JSON_THROW(std::domain_error("cannot use insert() with " + type_name())); + } + + // check if iterator pos fits to this JSON value + if (pos.m_object != this) + { + JSON_THROW(std::domain_error("iterator does not fit current value")); + } + + // check if range iterators belong to the same JSON object + if (first.m_object != last.m_object) + { + JSON_THROW(std::domain_error("iterators do not fit")); + } + + if (first.m_object == this or last.m_object == this) + { + JSON_THROW(std::domain_error("passed iterators may not belong to container")); + } + + // insert to array and return iterator + iterator result(this); + result.m_it.array_iterator = m_value.array->insert( + pos.m_it.array_iterator, + first.m_it.array_iterator, + last.m_it.array_iterator); + return result; + } + + /*! + @brief inserts elements + + Inserts elements from initializer list @a ilist before iterator @a pos. + + @param[in] pos iterator before which the content will be inserted; may be + the end() iterator + @param[in] ilist initializer list to insert the values from + + @throw std::domain_error if called on JSON values other than arrays; + example: `"cannot use insert() with string"` + @throw std::domain_error if @a pos is not an iterator of *this; example: + `"iterator does not fit current value"` + + @return iterator pointing to the first element inserted, or @a pos if + `ilist` is empty + + @complexity Linear in `ilist.size()` plus linear in the distance between + @a pos and end of the container. + + @liveexample{The example shows how `insert()` is used.,insert__ilist} + + @since version 1.0.0 + */ + iterator insert(const_iterator pos, std::initializer_list<basic_json> ilist) + { + // insert only works for arrays + if (not is_array()) + { + JSON_THROW(std::domain_error("cannot use insert() with " + type_name())); + } + + // check if iterator pos fits to this JSON value + if (pos.m_object != this) + { + JSON_THROW(std::domain_error("iterator does not fit current value")); + } + + // insert to array and return iterator + iterator result(this); + result.m_it.array_iterator = m_value.array->insert(pos.m_it.array_iterator, ilist); + return result; + } + + /*! + @brief exchanges the values + + Exchanges the contents of the JSON value with those of @a other. Does not + invoke any move, copy, or swap operations on individual elements. All + iterators and references remain valid. The past-the-end iterator is + invalidated. + + @param[in,out] other JSON value to exchange the contents with + + @complexity Constant. + + @liveexample{The example below shows how JSON values can be swapped with + `swap()`.,swap__reference} + + @since version 1.0.0 + */ + void swap(reference other) noexcept ( + std::is_nothrow_move_constructible<value_t>::value and + std::is_nothrow_move_assignable<value_t>::value and + std::is_nothrow_move_constructible<json_value>::value and + std::is_nothrow_move_assignable<json_value>::value + ) + { + std::swap(m_type, other.m_type); + std::swap(m_value, other.m_value); + assert_invariant(); + } + + /*! + @brief exchanges the values + + Exchanges the contents of a JSON array with those of @a other. Does not + invoke any move, copy, or swap operations on individual elements. All + iterators and references remain valid. The past-the-end iterator is + invalidated. + + @param[in,out] other array to exchange the contents with + + @throw std::domain_error when JSON value is not an array; example: + `"cannot use swap() with string"` + + @complexity Constant. + + @liveexample{The example below shows how arrays can be swapped with + `swap()`.,swap__array_t} + + @since version 1.0.0 + */ + void swap(array_t& other) + { + // swap only works for arrays + if (is_array()) + { + std::swap(*(m_value.array), other); + } + else + { + JSON_THROW(std::domain_error("cannot use swap() with " + type_name())); + } + } + + /*! + @brief exchanges the values + + Exchanges the contents of a JSON object with those of @a other. Does not + invoke any move, copy, or swap operations on individual elements. All + iterators and references remain valid. The past-the-end iterator is + invalidated. + + @param[in,out] other object to exchange the contents with + + @throw std::domain_error when JSON value is not an object; example: + `"cannot use swap() with string"` + + @complexity Constant. + + @liveexample{The example below shows how objects can be swapped with + `swap()`.,swap__object_t} + + @since version 1.0.0 + */ + void swap(object_t& other) + { + // swap only works for objects + if (is_object()) + { + std::swap(*(m_value.object), other); + } + else + { + JSON_THROW(std::domain_error("cannot use swap() with " + type_name())); + } + } + + /*! + @brief exchanges the values + + Exchanges the contents of a JSON string with those of @a other. Does not + invoke any move, copy, or swap operations on individual elements. All + iterators and references remain valid. The past-the-end iterator is + invalidated. + + @param[in,out] other string to exchange the contents with + + @throw std::domain_error when JSON value is not a string; example: `"cannot + use swap() with boolean"` + + @complexity Constant. + + @liveexample{The example below shows how strings can be swapped with + `swap()`.,swap__string_t} + + @since version 1.0.0 + */ + void swap(string_t& other) + { + // swap only works for strings + if (is_string()) + { + std::swap(*(m_value.string), other); + } + else + { + JSON_THROW(std::domain_error("cannot use swap() with " + type_name())); + } + } + + /// @} + + public: + ////////////////////////////////////////// + // lexicographical comparison operators // + ////////////////////////////////////////// + + /// @name lexicographical comparison operators + /// @{ + + /*! + @brief comparison: equal + + Compares two JSON values for equality according to the following rules: + - Two JSON values are equal if (1) they are from the same type and (2) + their stored values are the same. + - Integer and floating-point numbers are automatically converted before + comparison. Floating-point numbers are compared indirectly: two + floating-point numbers `f1` and `f2` are considered equal if neither + `f1 > f2` nor `f2 > f1` holds. + - Two JSON null values are equal. + + @param[in] lhs first JSON value to consider + @param[in] rhs second JSON value to consider + @return whether the values @a lhs and @a rhs are equal + + @complexity Linear. + + @liveexample{The example demonstrates comparing several JSON + types.,operator__equal} + + @since version 1.0.0 + */ + friend bool operator==(const_reference lhs, const_reference rhs) noexcept + { + const auto lhs_type = lhs.type(); + const auto rhs_type = rhs.type(); + + if (lhs_type == rhs_type) + { + switch (lhs_type) + { + case value_t::array: + { + return *lhs.m_value.array == *rhs.m_value.array; + } + case value_t::object: + { + return *lhs.m_value.object == *rhs.m_value.object; + } + case value_t::null: + { + return true; + } + case value_t::string: + { + return *lhs.m_value.string == *rhs.m_value.string; + } + case value_t::boolean: + { + return lhs.m_value.boolean == rhs.m_value.boolean; + } + case value_t::number_integer: + { + return lhs.m_value.number_integer == rhs.m_value.number_integer; + } + case value_t::number_unsigned: + { + return lhs.m_value.number_unsigned == rhs.m_value.number_unsigned; + } + case value_t::number_float: + { + return lhs.m_value.number_float == rhs.m_value.number_float; + } + default: + { + return false; + } + } + } + else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float) + { + return static_cast<number_float_t>(lhs.m_value.number_integer) == rhs.m_value.number_float; + } + else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer) + { + return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_integer); + } + else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float) + { + return static_cast<number_float_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_float; + } + else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned) + { + return lhs.m_value.number_float == static_cast<number_float_t>(rhs.m_value.number_unsigned); + } + else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer) + { + return static_cast<number_integer_t>(lhs.m_value.number_unsigned) == rhs.m_value.number_integer; + } + else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned) + { + return lhs.m_value.number_integer == static_cast<number_integer_t>(rhs.m_value.number_unsigned); + } + + return false; + } + + /*! + @brief comparison: equal + @copydoc operator==(const_reference, const_reference) + */ + template<typename ScalarType, typename std::enable_if< + std::is_scalar<ScalarType>::value, int>::type = 0> + friend bool operator==(const_reference lhs, const ScalarType rhs) noexcept + { + return (lhs == basic_json(rhs)); + } + + /*! + @brief comparison: equal + @copydoc operator==(const_reference, const_reference) + */ + template<typename ScalarType, typename std::enable_if< + std::is_scalar<ScalarType>::value, int>::type = 0> + friend bool operator==(const ScalarType lhs, const_reference rhs) noexcept + { + return (basic_json(lhs) == rhs); + } + + /*! + @brief comparison: not equal + + Compares two JSON values for inequality by calculating `not (lhs == rhs)`. + + @param[in] lhs first JSON value to consider + @param[in] rhs second JSON value to consider + @return whether the values @a lhs and @a rhs are not equal + + @complexity Linear. + + @liveexample{The example demonstrates comparing several JSON + types.,operator__notequal} + + @since version 1.0.0 + */ + friend bool operator!=(const_reference lhs, const_reference rhs) noexcept + { + return not (lhs == rhs); + } + + /*! + @brief comparison: not equal + @copydoc operator!=(const_reference, const_reference) + */ + template<typename ScalarType, typename std::enable_if< + std::is_scalar<ScalarType>::value, int>::type = 0> + friend bool operator!=(const_reference lhs, const ScalarType rhs) noexcept + { + return (lhs != basic_json(rhs)); + } + + /*! + @brief comparison: not equal + @copydoc operator!=(const_reference, const_reference) + */ + template<typename ScalarType, typename std::enable_if< + std::is_scalar<ScalarType>::value, int>::type = 0> + friend bool operator!=(const ScalarType lhs, const_reference rhs) noexcept + { + return (basic_json(lhs) != rhs); + } + + /*! + @brief comparison: less than + + Compares whether one JSON value @a lhs is less than another JSON value @a + rhs according to the following rules: + - If @a lhs and @a rhs have the same type, the values are compared using + the default `<` operator. + - Integer and floating-point numbers are automatically converted before + comparison + - In case @a lhs and @a rhs have different types, the values are ignored + and the order of the types is considered, see + @ref operator<(const value_t, const value_t). + + @param[in] lhs first JSON value to consider + @param[in] rhs second JSON value to consider + @return whether @a lhs is less than @a rhs + + @complexity Linear. + + @liveexample{The example demonstrates comparing several JSON + types.,operator__less} + + @since version 1.0.0 + */ + friend bool operator<(const_reference lhs, const_reference rhs) noexcept + { + const auto lhs_type = lhs.type(); + const auto rhs_type = rhs.type(); + + if (lhs_type == rhs_type) + { + switch (lhs_type) + { + case value_t::array: + { + return *lhs.m_value.array < *rhs.m_value.array; + } + case value_t::object: + { + return *lhs.m_value.object < *rhs.m_value.object; + } + case value_t::null: + { + return false; + } + case value_t::string: + { + return *lhs.m_value.string < *rhs.m_value.string; + } + case value_t::boolean: + { + return lhs.m_value.boolean < rhs.m_value.boolean; + } + case value_t::number_integer: + { + return lhs.m_value.number_integer < rhs.m_value.number_integer; + } + case value_t::number_unsigned: + { + return lhs.m_value.number_unsigned < rhs.m_value.number_unsigned; + } + case value_t::number_float: + { + return lhs.m_value.number_float < rhs.m_value.number_float; + } + default: + { + return false; + } + } + } + else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_float) + { + return static_cast<number_float_t>(lhs.m_value.number_integer) < rhs.m_value.number_float; + } + else if (lhs_type == value_t::number_float and rhs_type == value_t::number_integer) + { + return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_integer); + } + else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_float) + { + return static_cast<number_float_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_float; + } + else if (lhs_type == value_t::number_float and rhs_type == value_t::number_unsigned) + { + return lhs.m_value.number_float < static_cast<number_float_t>(rhs.m_value.number_unsigned); + } + else if (lhs_type == value_t::number_integer and rhs_type == value_t::number_unsigned) + { + return lhs.m_value.number_integer < static_cast<number_integer_t>(rhs.m_value.number_unsigned); + } + else if (lhs_type == value_t::number_unsigned and rhs_type == value_t::number_integer) + { + return static_cast<number_integer_t>(lhs.m_value.number_unsigned) < rhs.m_value.number_integer; + } + + // We only reach this line if we cannot compare values. In that case, + // we compare types. Note we have to call the operator explicitly, + // because MSVC has problems otherwise. + return operator<(lhs_type, rhs_type); + } + + /*! + @brief comparison: less than or equal + + Compares whether one JSON value @a lhs is less than or equal to another + JSON value by calculating `not (rhs < lhs)`. + + @param[in] lhs first JSON value to consider + @param[in] rhs second JSON value to consider + @return whether @a lhs is less than or equal to @a rhs + + @complexity Linear. + + @liveexample{The example demonstrates comparing several JSON + types.,operator__greater} + + @since version 1.0.0 + */ + friend bool operator<=(const_reference lhs, const_reference rhs) noexcept + { + return not (rhs < lhs); + } + + /*! + @brief comparison: greater than + + Compares whether one JSON value @a lhs is greater than another + JSON value by calculating `not (lhs <= rhs)`. + + @param[in] lhs first JSON value to consider + @param[in] rhs second JSON value to consider + @return whether @a lhs is greater than to @a rhs + + @complexity Linear. + + @liveexample{The example demonstrates comparing several JSON + types.,operator__lessequal} + + @since version 1.0.0 + */ + friend bool operator>(const_reference lhs, const_reference rhs) noexcept + { + return not (lhs <= rhs); + } + + /*! + @brief comparison: greater than or equal + + Compares whether one JSON value @a lhs is greater than or equal to another + JSON value by calculating `not (lhs < rhs)`. + + @param[in] lhs first JSON value to consider + @param[in] rhs second JSON value to consider + @return whether @a lhs is greater than or equal to @a rhs + + @complexity Linear. + + @liveexample{The example demonstrates comparing several JSON + types.,operator__greaterequal} + + @since version 1.0.0 + */ + friend bool operator>=(const_reference lhs, const_reference rhs) noexcept + { + return not (lhs < rhs); + } + + /// @} + + + /////////////////// + // serialization // + /////////////////// + + /// @name serialization + /// @{ + + /*! + @brief serialize to stream + + Serialize the given JSON value @a j to the output stream @a o. The JSON + value will be serialized using the @ref dump member function. The + indentation of the output can be controlled with the member variable + `width` of the output stream @a o. For instance, using the manipulator + `std::setw(4)` on @a o sets the indentation level to `4` and the + serialization result is the same as calling `dump(4)`. + + @param[in,out] o stream to serialize to + @param[in] j JSON value to serialize + + @return the stream @a o + + @complexity Linear. + + @liveexample{The example below shows the serialization with different + parameters to `width` to adjust the indentation level.,operator_serialize} + + @since version 1.0.0 + */ + friend std::ostream& operator<<(std::ostream& o, const basic_json& j) + { + // read width member and use it as indentation parameter if nonzero + const bool pretty_print = (o.width() > 0); + const auto indentation = (pretty_print ? o.width() : 0); + + // reset width to 0 for subsequent calls to this stream + o.width(0); + + // do the actual serialization + j.dump(o, pretty_print, static_cast<unsigned int>(indentation)); + + return o; + } + + /*! + @brief serialize to stream + @copydoc operator<<(std::ostream&, const basic_json&) + */ + friend std::ostream& operator>>(const basic_json& j, std::ostream& o) + { + return o << j; + } + + /// @} + + + ///////////////////// + // deserialization // + ///////////////////// + + /// @name deserialization + /// @{ + + /*! + @brief deserialize from an array + + This function reads from an array of 1-byte values. + + @pre Each element of the container has a size of 1 byte. Violating this + precondition yields undefined behavior. **This precondition is enforced + with a static assertion.** + + @param[in] array array to read from + @param[in] cb a parser callback function of type @ref parser_callback_t + which is used to control the deserialization by filtering unwanted values + (optional) + + @return result of the deserialization + + @complexity Linear in the length of the input. The parser is a predictive + LL(1) parser. The complexity can be higher if the parser callback function + @a cb has a super-linear complexity. + + @note A UTF-8 byte order mark is silently ignored. + + @liveexample{The example below demonstrates the `parse()` function reading + from an array.,parse__array__parser_callback_t} + + @since version 2.0.3 + */ + template<class T, std::size_t N> + static basic_json parse(T (&array)[N], + const parser_callback_t cb = nullptr) + { + // delegate the call to the iterator-range parse overload + return parse(std::begin(array), std::end(array), cb); + } + + /*! + @brief deserialize from string literal + + @tparam CharT character/literal type with size of 1 byte + @param[in] s string literal to read a serialized JSON value from + @param[in] cb a parser callback function of type @ref parser_callback_t + which is used to control the deserialization by filtering unwanted values + (optional) + + @return result of the deserialization + + @complexity Linear in the length of the input. The parser is a predictive + LL(1) parser. The complexity can be higher if the parser callback function + @a cb has a super-linear complexity. + + @note A UTF-8 byte order mark is silently ignored. + @note String containers like `std::string` or @ref string_t can be parsed + with @ref parse(const ContiguousContainer&, const parser_callback_t) + + @liveexample{The example below demonstrates the `parse()` function with + and without callback function.,parse__string__parser_callback_t} + + @sa @ref parse(std::istream&, const parser_callback_t) for a version that + reads from an input stream + + @since version 1.0.0 (originally for @ref string_t) + */ + template<typename CharT, typename std::enable_if< + std::is_pointer<CharT>::value and + std::is_integral<typename std::remove_pointer<CharT>::type>::value and + sizeof(typename std::remove_pointer<CharT>::type) == 1, int>::type = 0> + static basic_json parse(const CharT s, + const parser_callback_t cb = nullptr) + { + return parser(reinterpret_cast<const char*>(s), cb).parse(); + } + + /*! + @brief deserialize from stream + + @param[in,out] i stream to read a serialized JSON value from + @param[in] cb a parser callback function of type @ref parser_callback_t + which is used to control the deserialization by filtering unwanted values + (optional) + + @return result of the deserialization + + @complexity Linear in the length of the input. The parser is a predictive + LL(1) parser. The complexity can be higher if the parser callback function + @a cb has a super-linear complexity. + + @note A UTF-8 byte order mark is silently ignored. + + @liveexample{The example below demonstrates the `parse()` function with + and without callback function.,parse__istream__parser_callback_t} + + @sa @ref parse(const CharT, const parser_callback_t) for a version + that reads from a string + + @since version 1.0.0 + */ + static basic_json parse(std::istream& i, + const parser_callback_t cb = nullptr) + { + return parser(i, cb).parse(); + } + + /*! + @copydoc parse(std::istream&, const parser_callback_t) + */ + static basic_json parse(std::istream&& i, + const parser_callback_t cb = nullptr) + { + return parser(i, cb).parse(); + } + + /*! + @brief deserialize from an iterator range with contiguous storage + + This function reads from an iterator range of a container with contiguous + storage of 1-byte values. Compatible container types include + `std::vector`, `std::string`, `std::array`, `std::valarray`, and + `std::initializer_list`. Furthermore, C-style arrays can be used with + `std::begin()`/`std::end()`. User-defined containers can be used as long + as they implement random-access iterators and a contiguous storage. + + @pre The iterator range is contiguous. Violating this precondition yields + undefined behavior. **This precondition is enforced with an assertion.** + @pre Each element in the range has a size of 1 byte. Violating this + precondition yields undefined behavior. **This precondition is enforced + with a static assertion.** + + @warning There is no way to enforce all preconditions at compile-time. If + the function is called with noncompliant iterators and with + assertions switched off, the behavior is undefined and will most + likely yield segmentation violation. + + @tparam IteratorType iterator of container with contiguous storage + @param[in] first begin of the range to parse (included) + @param[in] last end of the range to parse (excluded) + @param[in] cb a parser callback function of type @ref parser_callback_t + which is used to control the deserialization by filtering unwanted values + (optional) + + @return result of the deserialization + + @complexity Linear in the length of the input. The parser is a predictive + LL(1) parser. The complexity can be higher if the parser callback function + @a cb has a super-linear complexity. + + @note A UTF-8 byte order mark is silently ignored. + + @liveexample{The example below demonstrates the `parse()` function reading + from an iterator range.,parse__iteratortype__parser_callback_t} + + @since version 2.0.3 + */ + template<class IteratorType, typename std::enable_if< + std::is_base_of< + std::random_access_iterator_tag, + typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0> + static basic_json parse(IteratorType first, IteratorType last, + const parser_callback_t cb = nullptr) + { + // assertion to check that the iterator range is indeed contiguous, + // see http://stackoverflow.com/a/35008842/266378 for more discussion + assert(std::accumulate(first, last, std::pair<bool, int>(true, 0), + [&first](std::pair<bool, int> res, decltype(*first) val) + { + res.first &= (val == *(std::next(std::addressof(*first), res.second++))); + return res; + }).first); + + // assertion to check that each element is 1 byte long + static_assert(sizeof(typename std::iterator_traits<IteratorType>::value_type) == 1, + "each element in the iterator range must have the size of 1 byte"); + + // if iterator range is empty, create a parser with an empty string + // to generate "unexpected EOF" error message + if (std::distance(first, last) <= 0) + { + return parser("").parse(); + } + + return parser(first, last, cb).parse(); + } + + /*! + @brief deserialize from a container with contiguous storage + + This function reads from a container with contiguous storage of 1-byte + values. Compatible container types include `std::vector`, `std::string`, + `std::array`, and `std::initializer_list`. User-defined containers can be + used as long as they implement random-access iterators and a contiguous + storage. + + @pre The container storage is contiguous. Violating this precondition + yields undefined behavior. **This precondition is enforced with an + assertion.** + @pre Each element of the container has a size of 1 byte. Violating this + precondition yields undefined behavior. **This precondition is enforced + with a static assertion.** + + @warning There is no way to enforce all preconditions at compile-time. If + the function is called with a noncompliant container and with + assertions switched off, the behavior is undefined and will most + likely yield segmentation violation. + + @tparam ContiguousContainer container type with contiguous storage + @param[in] c container to read from + @param[in] cb a parser callback function of type @ref parser_callback_t + which is used to control the deserialization by filtering unwanted values + (optional) + + @return result of the deserialization + + @complexity Linear in the length of the input. The parser is a predictive + LL(1) parser. The complexity can be higher if the parser callback function + @a cb has a super-linear complexity. + + @note A UTF-8 byte order mark is silently ignored. + + @liveexample{The example below demonstrates the `parse()` function reading + from a contiguous container.,parse__contiguouscontainer__parser_callback_t} + + @since version 2.0.3 + */ + template<class ContiguousContainer, typename std::enable_if< + not std::is_pointer<ContiguousContainer>::value and + std::is_base_of< + std::random_access_iterator_tag, + typename std::iterator_traits<decltype(std::begin(std::declval<ContiguousContainer const>()))>::iterator_category>::value + , int>::type = 0> + static basic_json parse(const ContiguousContainer& c, + const parser_callback_t cb = nullptr) + { + // delegate the call to the iterator-range parse overload + return parse(std::begin(c), std::end(c), cb); + } + + /*! + @brief deserialize from stream + + Deserializes an input stream to a JSON value. + + @param[in,out] i input stream to read a serialized JSON value from + @param[in,out] j JSON value to write the deserialized input to + + @throw std::invalid_argument in case of parse errors + + @complexity Linear in the length of the input. The parser is a predictive + LL(1) parser. + + @note A UTF-8 byte order mark is silently ignored. + + @liveexample{The example below shows how a JSON value is constructed by + reading a serialization from a stream.,operator_deserialize} + + @sa parse(std::istream&, const parser_callback_t) for a variant with a + parser callback function to filter values while parsing + + @since version 1.0.0 + */ + friend std::istream& operator<<(basic_json& j, std::istream& i) + { + j = parser(i).parse(); + return i; + } + + /*! + @brief deserialize from stream + @copydoc operator<<(basic_json&, std::istream&) + */ + friend std::istream& operator>>(std::istream& i, basic_json& j) + { + j = parser(i).parse(); + return i; + } + + /// @} + + ////////////////////////////////////////// + // binary serialization/deserialization // + ////////////////////////////////////////// + + /// @name binary serialization/deserialization support + /// @{ + + private: + /*! + @note Some code in the switch cases has been copied, because otherwise + copilers would complain about implicit fallthrough and there is no + portable attribute to mute such warnings. + */ + template<typename T> + static void add_to_vector(std::vector<uint8_t>& vec, size_t bytes, const T number) + { + assert(bytes == 1 or bytes == 2 or bytes == 4 or bytes == 8); + + switch (bytes) + { + case 8: + { + vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 070) & 0xff)); + vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 060) & 0xff)); + vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 050) & 0xff)); + vec.push_back(static_cast<uint8_t>((static_cast<uint64_t>(number) >> 040) & 0xff)); + vec.push_back(static_cast<uint8_t>((number >> 030) & 0xff)); + vec.push_back(static_cast<uint8_t>((number >> 020) & 0xff)); + vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff)); + vec.push_back(static_cast<uint8_t>(number & 0xff)); + break; + } + + case 4: + { + vec.push_back(static_cast<uint8_t>((number >> 030) & 0xff)); + vec.push_back(static_cast<uint8_t>((number >> 020) & 0xff)); + vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff)); + vec.push_back(static_cast<uint8_t>(number & 0xff)); + break; + } + + case 2: + { + vec.push_back(static_cast<uint8_t>((number >> 010) & 0xff)); + vec.push_back(static_cast<uint8_t>(number & 0xff)); + break; + } + + case 1: + { + vec.push_back(static_cast<uint8_t>(number & 0xff)); + break; + } + } + } + + /*! + @brief take sufficient bytes from a vector to fill an integer variable + + In the context of binary serialization formats, we need to read several + bytes from a byte vector and combine them to multi-byte integral data + types. + + @param[in] vec byte vector to read from + @param[in] current_index the position in the vector after which to read + + @return the next sizeof(T) bytes from @a vec, in reverse order as T + + @tparam T the integral return type + + @throw std::out_of_range if there are less than sizeof(T)+1 bytes in the + vector @a vec to read + + In the for loop, the bytes from the vector are copied in reverse order into + the return value. In the figures below, let sizeof(T)=4 and `i` be the loop + variable. + + Precondition: + + vec: | | | a | b | c | d | T: | | | | | + ^ ^ ^ ^ + current_index i ptr sizeof(T) + + Postcondition: + + vec: | | | a | b | c | d | T: | d | c | b | a | + ^ ^ ^ + | i ptr + current_index + + @sa Code adapted from <http://stackoverflow.com/a/41031865/266378>. + */ + template<typename T> + static T get_from_vector(const std::vector<uint8_t>& vec, const size_t current_index) + { + if (current_index + sizeof(T) + 1 > vec.size()) + { + JSON_THROW(std::out_of_range("cannot read " + std::to_string(sizeof(T)) + " bytes from vector")); + } + + T result; + auto* ptr = reinterpret_cast<uint8_t*>(&result); + for (size_t i = 0; i < sizeof(T); ++i) + { + *ptr++ = vec[current_index + sizeof(T) - i]; + } + return result; + } + + /*! + @brief create a MessagePack serialization of a given JSON value + + This is a straightforward implementation of the MessagePack specification. + + @param[in] j JSON value to serialize + @param[in,out] v byte vector to write the serialization to + + @sa https://github.com/msgpack/msgpack/blob/master/spec.md + */ + static void to_msgpack_internal(const basic_json& j, std::vector<uint8_t>& v) + { + switch (j.type()) + { + case value_t::null: + { + // nil + v.push_back(0xc0); + break; + } + + case value_t::boolean: + { + // true and false + v.push_back(j.m_value.boolean ? 0xc3 : 0xc2); + break; + } + + case value_t::number_integer: + { + if (j.m_value.number_integer >= 0) + { + // MessagePack does not differentiate between positive + // signed integers and unsigned integers. Therefore, we + // used the code from the value_t::number_unsigned case + // here. + if (j.m_value.number_unsigned < 128) + { + // positive fixnum + add_to_vector(v, 1, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= std::numeric_limits<uint8_t>::max()) + { + // uint 8 + v.push_back(0xcc); + add_to_vector(v, 1, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= std::numeric_limits<uint16_t>::max()) + { + // uint 16 + v.push_back(0xcd); + add_to_vector(v, 2, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= std::numeric_limits<uint32_t>::max()) + { + // uint 32 + v.push_back(0xce); + add_to_vector(v, 4, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= std::numeric_limits<uint64_t>::max()) + { + // uint 64 + v.push_back(0xcf); + add_to_vector(v, 8, j.m_value.number_unsigned); + } + } + else + { + if (j.m_value.number_integer >= -32) + { + // negative fixnum + add_to_vector(v, 1, j.m_value.number_integer); + } + else if (j.m_value.number_integer >= std::numeric_limits<int8_t>::min() and j.m_value.number_integer <= std::numeric_limits<int8_t>::max()) + { + // int 8 + v.push_back(0xd0); + add_to_vector(v, 1, j.m_value.number_integer); + } + else if (j.m_value.number_integer >= std::numeric_limits<int16_t>::min() and j.m_value.number_integer <= std::numeric_limits<int16_t>::max()) + { + // int 16 + v.push_back(0xd1); + add_to_vector(v, 2, j.m_value.number_integer); + } + else if (j.m_value.number_integer >= std::numeric_limits<int32_t>::min() and j.m_value.number_integer <= std::numeric_limits<int32_t>::max()) + { + // int 32 + v.push_back(0xd2); + add_to_vector(v, 4, j.m_value.number_integer); + } + else if (j.m_value.number_integer >= std::numeric_limits<int64_t>::min() and j.m_value.number_integer <= std::numeric_limits<int64_t>::max()) + { + // int 64 + v.push_back(0xd3); + add_to_vector(v, 8, j.m_value.number_integer); + } + } + break; + } + + case value_t::number_unsigned: + { + if (j.m_value.number_unsigned < 128) + { + // positive fixnum + add_to_vector(v, 1, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= std::numeric_limits<uint8_t>::max()) + { + // uint 8 + v.push_back(0xcc); + add_to_vector(v, 1, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= std::numeric_limits<uint16_t>::max()) + { + // uint 16 + v.push_back(0xcd); + add_to_vector(v, 2, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= std::numeric_limits<uint32_t>::max()) + { + // uint 32 + v.push_back(0xce); + add_to_vector(v, 4, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= std::numeric_limits<uint64_t>::max()) + { + // uint 64 + v.push_back(0xcf); + add_to_vector(v, 8, j.m_value.number_unsigned); + } + break; + } + + case value_t::number_float: + { + // float 64 + v.push_back(0xcb); + const auto* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float)); + for (size_t i = 0; i < 8; ++i) + { + v.push_back(helper[7 - i]); + } + break; + } + + case value_t::string: + { + const auto N = j.m_value.string->size(); + if (N <= 31) + { + // fixstr + v.push_back(static_cast<uint8_t>(0xa0 | N)); + } + else if (N <= 255) + { + // str 8 + v.push_back(0xd9); + add_to_vector(v, 1, N); + } + else if (N <= 65535) + { + // str 16 + v.push_back(0xda); + add_to_vector(v, 2, N); + } + else if (N <= 4294967295) + { + // str 32 + v.push_back(0xdb); + add_to_vector(v, 4, N); + } + + // append string + std::copy(j.m_value.string->begin(), j.m_value.string->end(), + std::back_inserter(v)); + break; + } + + case value_t::array: + { + const auto N = j.m_value.array->size(); + if (N <= 15) + { + // fixarray + v.push_back(static_cast<uint8_t>(0x90 | N)); + } + else if (N <= 0xffff) + { + // array 16 + v.push_back(0xdc); + add_to_vector(v, 2, N); + } + else if (N <= 0xffffffff) + { + // array 32 + v.push_back(0xdd); + add_to_vector(v, 4, N); + } + + // append each element + for (const auto& el : *j.m_value.array) + { + to_msgpack_internal(el, v); + } + break; + } + + case value_t::object: + { + const auto N = j.m_value.object->size(); + if (N <= 15) + { + // fixmap + v.push_back(static_cast<uint8_t>(0x80 | (N & 0xf))); + } + else if (N <= 65535) + { + // map 16 + v.push_back(0xde); + add_to_vector(v, 2, N); + } + else if (N <= 4294967295) + { + // map 32 + v.push_back(0xdf); + add_to_vector(v, 4, N); + } + + // append each element + for (const auto& el : *j.m_value.object) + { + to_msgpack_internal(el.first, v); + to_msgpack_internal(el.second, v); + } + break; + } + + default: + { + break; + } + } + } + + /*! + @brief create a CBOR serialization of a given JSON value + + This is a straightforward implementation of the CBOR specification. + + @param[in] j JSON value to serialize + @param[in,out] v byte vector to write the serialization to + + @sa https://tools.ietf.org/html/rfc7049 + */ + static void to_cbor_internal(const basic_json& j, std::vector<uint8_t>& v) + { + switch (j.type()) + { + case value_t::null: + { + v.push_back(0xf6); + break; + } + + case value_t::boolean: + { + v.push_back(j.m_value.boolean ? 0xf5 : 0xf4); + break; + } + + case value_t::number_integer: + { + if (j.m_value.number_integer >= 0) + { + // CBOR does not differentiate between positive signed + // integers and unsigned integers. Therefore, we used the + // code from the value_t::number_unsigned case here. + if (j.m_value.number_integer <= 0x17) + { + add_to_vector(v, 1, j.m_value.number_integer); + } + else if (j.m_value.number_integer <= std::numeric_limits<uint8_t>::max()) + { + v.push_back(0x18); + // one-byte uint8_t + add_to_vector(v, 1, j.m_value.number_integer); + } + else if (j.m_value.number_integer <= std::numeric_limits<uint16_t>::max()) + { + v.push_back(0x19); + // two-byte uint16_t + add_to_vector(v, 2, j.m_value.number_integer); + } + else if (j.m_value.number_integer <= std::numeric_limits<uint32_t>::max()) + { + v.push_back(0x1a); + // four-byte uint32_t + add_to_vector(v, 4, j.m_value.number_integer); + } + else + { + v.push_back(0x1b); + // eight-byte uint64_t + add_to_vector(v, 8, j.m_value.number_integer); + } + } + else + { + // The conversions below encode the sign in the first + // byte, and the value is converted to a positive number. + const auto positive_number = -1 - j.m_value.number_integer; + if (j.m_value.number_integer >= -24) + { + v.push_back(static_cast<uint8_t>(0x20 + positive_number)); + } + else if (positive_number <= std::numeric_limits<uint8_t>::max()) + { + // int 8 + v.push_back(0x38); + add_to_vector(v, 1, positive_number); + } + else if (positive_number <= std::numeric_limits<uint16_t>::max()) + { + // int 16 + v.push_back(0x39); + add_to_vector(v, 2, positive_number); + } + else if (positive_number <= std::numeric_limits<uint32_t>::max()) + { + // int 32 + v.push_back(0x3a); + add_to_vector(v, 4, positive_number); + } + else + { + // int 64 + v.push_back(0x3b); + add_to_vector(v, 8, positive_number); + } + } + break; + } + + case value_t::number_unsigned: + { + if (j.m_value.number_unsigned <= 0x17) + { + v.push_back(static_cast<uint8_t>(j.m_value.number_unsigned)); + } + else if (j.m_value.number_unsigned <= 0xff) + { + v.push_back(0x18); + // one-byte uint8_t + add_to_vector(v, 1, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= 0xffff) + { + v.push_back(0x19); + // two-byte uint16_t + add_to_vector(v, 2, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= 0xffffffff) + { + v.push_back(0x1a); + // four-byte uint32_t + add_to_vector(v, 4, j.m_value.number_unsigned); + } + else if (j.m_value.number_unsigned <= 0xffffffffffffffff) + { + v.push_back(0x1b); + // eight-byte uint64_t + add_to_vector(v, 8, j.m_value.number_unsigned); + } + break; + } + + case value_t::number_float: + { + // Double-Precision Float + v.push_back(0xfb); + const auto* helper = reinterpret_cast<const uint8_t*>(&(j.m_value.number_float)); + for (size_t i = 0; i < 8; ++i) + { + v.push_back(helper[7 - i]); + } + break; + } + + case value_t::string: + { + const auto N = j.m_value.string->size(); + if (N <= 0x17) + { + v.push_back(0x60 + static_cast<uint8_t>(N)); // 1 byte for string + size + } + else if (N <= 0xff) + { + v.push_back(0x78); // one-byte uint8_t for N + add_to_vector(v, 1, N); + } + else if (N <= 0xffff) + { + v.push_back(0x79); // two-byte uint16_t for N + add_to_vector(v, 2, N); + } + else if (N <= 0xffffffff) + { + v.push_back(0x7a); // four-byte uint32_t for N + add_to_vector(v, 4, N); + } + // LCOV_EXCL_START + else if (N <= 0xffffffffffffffff) + { + v.push_back(0x7b); // eight-byte uint64_t for N + add_to_vector(v, 8, N); + } + // LCOV_EXCL_STOP + + // append string + std::copy(j.m_value.string->begin(), j.m_value.string->end(), + std::back_inserter(v)); + break; + } + + case value_t::array: + { + const auto N = j.m_value.array->size(); + if (N <= 0x17) + { + v.push_back(0x80 + static_cast<uint8_t>(N)); // 1 byte for array + size + } + else if (N <= 0xff) + { + v.push_back(0x98); // one-byte uint8_t for N + add_to_vector(v, 1, N); + } + else if (N <= 0xffff) + { + v.push_back(0x99); // two-byte uint16_t for N + add_to_vector(v, 2, N); + } + else if (N <= 0xffffffff) + { + v.push_back(0x9a); // four-byte uint32_t for N + add_to_vector(v, 4, N); + } + // LCOV_EXCL_START + else if (N <= 0xffffffffffffffff) + { + v.push_back(0x9b); // eight-byte uint64_t for N + add_to_vector(v, 8, N); + } + // LCOV_EXCL_STOP + + // append each element + for (const auto& el : *j.m_value.array) + { + to_cbor_internal(el, v); + } + break; + } + + case value_t::object: + { + const auto N = j.m_value.object->size(); + if (N <= 0x17) + { + v.push_back(0xa0 + static_cast<uint8_t>(N)); // 1 byte for object + size + } + else if (N <= 0xff) + { + v.push_back(0xb8); + add_to_vector(v, 1, N); // one-byte uint8_t for N + } + else if (N <= 0xffff) + { + v.push_back(0xb9); + add_to_vector(v, 2, N); // two-byte uint16_t for N + } + else if (N <= 0xffffffff) + { + v.push_back(0xba); + add_to_vector(v, 4, N); // four-byte uint32_t for N + } + // LCOV_EXCL_START + else if (N <= 0xffffffffffffffff) + { + v.push_back(0xbb); + add_to_vector(v, 8, N); // eight-byte uint64_t for N + } + // LCOV_EXCL_STOP + + // append each element + for (const auto& el : *j.m_value.object) + { + to_cbor_internal(el.first, v); + to_cbor_internal(el.second, v); + } + break; + } + + default: + { + break; + } + } + } + + + /* + @brief checks if given lengths do not exceed the size of a given vector + + To secure the access to the byte vector during CBOR/MessagePack + deserialization, bytes are copied from the vector into buffers. This + function checks if the number of bytes to copy (@a len) does not exceed + the size @s size of the vector. Additionally, an @a offset is given from + where to start reading the bytes. + + This function checks whether reading the bytes is safe; that is, offset is + a valid index in the vector, offset+len + + @param[in] size size of the byte vector + @param[in] len number of bytes to read + @param[in] offset offset where to start reading + + vec: x x x x x X X X X X + ^ ^ ^ + 0 offset len + + @throws out_of_range if `len > v.size()` + */ + static void check_length(const size_t size, const size_t len, const size_t offset) + { + // simple case: requested length is greater than the vector's length + if (len > size or offset > size) + { + JSON_THROW(std::out_of_range("len out of range")); + } + + // second case: adding offset would result in overflow + if ((size > (std::numeric_limits<size_t>::max() - offset))) + { + JSON_THROW(std::out_of_range("len+offset out of range")); + } + + // last case: reading past the end of the vector + if (len + offset > size) + { + JSON_THROW(std::out_of_range("len+offset out of range")); + } + } + + /*! + @brief create a JSON value from a given MessagePack vector + + @param[in] v MessagePack serialization + @param[in] idx byte index to start reading from @a v + + @return deserialized JSON value + + @throw std::invalid_argument if unsupported features from MessagePack were + used in the given vector @a v or if the input is not valid MessagePack + @throw std::out_of_range if the given vector ends prematurely + + @sa https://github.com/msgpack/msgpack/blob/master/spec.md + */ + static basic_json from_msgpack_internal(const std::vector<uint8_t>& v, size_t& idx) + { + // make sure reading 1 byte is safe + check_length(v.size(), 1, idx); + + // store and increment index + const size_t current_idx = idx++; + + if (v[current_idx] <= 0xbf) + { + if (v[current_idx] <= 0x7f) // positive fixint + { + return v[current_idx]; + } + if (v[current_idx] <= 0x8f) // fixmap + { + basic_json result = value_t::object; + const size_t len = v[current_idx] & 0x0f; + for (size_t i = 0; i < len; ++i) + { + std::string key = from_msgpack_internal(v, idx); + result[key] = from_msgpack_internal(v, idx); + } + return result; + } + else if (v[current_idx] <= 0x9f) // fixarray + { + basic_json result = value_t::array; + const size_t len = v[current_idx] & 0x0f; + for (size_t i = 0; i < len; ++i) + { + result.push_back(from_msgpack_internal(v, idx)); + } + return result; + } + else // fixstr + { + const size_t len = v[current_idx] & 0x1f; + const size_t offset = current_idx + 1; + idx += len; // skip content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + } + else if (v[current_idx] >= 0xe0) // negative fixint + { + return static_cast<int8_t>(v[current_idx]); + } + else + { + switch (v[current_idx]) + { + case 0xc0: // nil + { + return value_t::null; + } + + case 0xc2: // false + { + return false; + } + + case 0xc3: // true + { + return true; + } + + case 0xca: // float 32 + { + // copy bytes in reverse order into the double variable + float res; + for (size_t byte = 0; byte < sizeof(float); ++byte) + { + reinterpret_cast<uint8_t*>(&res)[sizeof(float) - byte - 1] = v.at(current_idx + 1 + byte); + } + idx += sizeof(float); // skip content bytes + return res; + } + + case 0xcb: // float 64 + { + // copy bytes in reverse order into the double variable + double res; + for (size_t byte = 0; byte < sizeof(double); ++byte) + { + reinterpret_cast<uint8_t*>(&res)[sizeof(double) - byte - 1] = v.at(current_idx + 1 + byte); + } + idx += sizeof(double); // skip content bytes + return res; + } + + case 0xcc: // uint 8 + { + idx += 1; // skip content byte + return get_from_vector<uint8_t>(v, current_idx); + } + + case 0xcd: // uint 16 + { + idx += 2; // skip 2 content bytes + return get_from_vector<uint16_t>(v, current_idx); + } + + case 0xce: // uint 32 + { + idx += 4; // skip 4 content bytes + return get_from_vector<uint32_t>(v, current_idx); + } + + case 0xcf: // uint 64 + { + idx += 8; // skip 8 content bytes + return get_from_vector<uint64_t>(v, current_idx); + } + + case 0xd0: // int 8 + { + idx += 1; // skip content byte + return get_from_vector<int8_t>(v, current_idx); + } + + case 0xd1: // int 16 + { + idx += 2; // skip 2 content bytes + return get_from_vector<int16_t>(v, current_idx); + } + + case 0xd2: // int 32 + { + idx += 4; // skip 4 content bytes + return get_from_vector<int32_t>(v, current_idx); + } + + case 0xd3: // int 64 + { + idx += 8; // skip 8 content bytes + return get_from_vector<int64_t>(v, current_idx); + } + + case 0xd9: // str 8 + { + const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx)); + const size_t offset = current_idx + 2; + idx += len + 1; // skip size byte + content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + + case 0xda: // str 16 + { + const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx)); + const size_t offset = current_idx + 3; + idx += len + 2; // skip 2 size bytes + content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + + case 0xdb: // str 32 + { + const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx)); + const size_t offset = current_idx + 5; + idx += len + 4; // skip 4 size bytes + content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + + case 0xdc: // array 16 + { + basic_json result = value_t::array; + const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx)); + idx += 2; // skip 2 size bytes + for (size_t i = 0; i < len; ++i) + { + result.push_back(from_msgpack_internal(v, idx)); + } + return result; + } + + case 0xdd: // array 32 + { + basic_json result = value_t::array; + const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx)); + idx += 4; // skip 4 size bytes + for (size_t i = 0; i < len; ++i) + { + result.push_back(from_msgpack_internal(v, idx)); + } + return result; + } + + case 0xde: // map 16 + { + basic_json result = value_t::object; + const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx)); + idx += 2; // skip 2 size bytes + for (size_t i = 0; i < len; ++i) + { + std::string key = from_msgpack_internal(v, idx); + result[key] = from_msgpack_internal(v, idx); + } + return result; + } + + case 0xdf: // map 32 + { + basic_json result = value_t::object; + const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx)); + idx += 4; // skip 4 size bytes + for (size_t i = 0; i < len; ++i) + { + std::string key = from_msgpack_internal(v, idx); + result[key] = from_msgpack_internal(v, idx); + } + return result; + } + + default: + { + JSON_THROW(std::invalid_argument("error parsing a msgpack @ " + std::to_string(current_idx) + ": " + std::to_string(static_cast<int>(v[current_idx])))); + } + } + } + } + + /*! + @brief create a JSON value from a given CBOR vector + + @param[in] v CBOR serialization + @param[in] idx byte index to start reading from @a v + + @return deserialized JSON value + + @throw std::invalid_argument if unsupported features from CBOR were used in + the given vector @a v or if the input is not valid CBOR + @throw std::out_of_range if the given vector ends prematurely + + @sa https://tools.ietf.org/html/rfc7049 + */ + static basic_json from_cbor_internal(const std::vector<uint8_t>& v, size_t& idx) + { + // store and increment index + const size_t current_idx = idx++; + + switch (v.at(current_idx)) + { + // Integer 0x00..0x17 (0..23) + case 0x00: + case 0x01: + case 0x02: + case 0x03: + case 0x04: + case 0x05: + case 0x06: + case 0x07: + case 0x08: + case 0x09: + case 0x0a: + case 0x0b: + case 0x0c: + case 0x0d: + case 0x0e: + case 0x0f: + case 0x10: + case 0x11: + case 0x12: + case 0x13: + case 0x14: + case 0x15: + case 0x16: + case 0x17: + { + return v[current_idx]; + } + + case 0x18: // Unsigned integer (one-byte uint8_t follows) + { + idx += 1; // skip content byte + return get_from_vector<uint8_t>(v, current_idx); + } + + case 0x19: // Unsigned integer (two-byte uint16_t follows) + { + idx += 2; // skip 2 content bytes + return get_from_vector<uint16_t>(v, current_idx); + } + + case 0x1a: // Unsigned integer (four-byte uint32_t follows) + { + idx += 4; // skip 4 content bytes + return get_from_vector<uint32_t>(v, current_idx); + } + + case 0x1b: // Unsigned integer (eight-byte uint64_t follows) + { + idx += 8; // skip 8 content bytes + return get_from_vector<uint64_t>(v, current_idx); + } + + // Negative integer -1-0x00..-1-0x17 (-1..-24) + case 0x20: + case 0x21: + case 0x22: + case 0x23: + case 0x24: + case 0x25: + case 0x26: + case 0x27: + case 0x28: + case 0x29: + case 0x2a: + case 0x2b: + case 0x2c: + case 0x2d: + case 0x2e: + case 0x2f: + case 0x30: + case 0x31: + case 0x32: + case 0x33: + case 0x34: + case 0x35: + case 0x36: + case 0x37: + { + return static_cast<int8_t>(0x20 - 1 - v[current_idx]); + } + + case 0x38: // Negative integer (one-byte uint8_t follows) + { + idx += 1; // skip content byte + // must be uint8_t ! + return static_cast<number_integer_t>(-1) - get_from_vector<uint8_t>(v, current_idx); + } + + case 0x39: // Negative integer -1-n (two-byte uint16_t follows) + { + idx += 2; // skip 2 content bytes + return static_cast<number_integer_t>(-1) - get_from_vector<uint16_t>(v, current_idx); + } + + case 0x3a: // Negative integer -1-n (four-byte uint32_t follows) + { + idx += 4; // skip 4 content bytes + return static_cast<number_integer_t>(-1) - get_from_vector<uint32_t>(v, current_idx); + } + + case 0x3b: // Negative integer -1-n (eight-byte uint64_t follows) + { + idx += 8; // skip 8 content bytes + return static_cast<number_integer_t>(-1) - static_cast<number_integer_t>(get_from_vector<uint64_t>(v, current_idx)); + } + + // UTF-8 string (0x00..0x17 bytes follow) + case 0x60: + case 0x61: + case 0x62: + case 0x63: + case 0x64: + case 0x65: + case 0x66: + case 0x67: + case 0x68: + case 0x69: + case 0x6a: + case 0x6b: + case 0x6c: + case 0x6d: + case 0x6e: + case 0x6f: + case 0x70: + case 0x71: + case 0x72: + case 0x73: + case 0x74: + case 0x75: + case 0x76: + case 0x77: + { + const auto len = static_cast<size_t>(v[current_idx] - 0x60); + const size_t offset = current_idx + 1; + idx += len; // skip content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + + case 0x78: // UTF-8 string (one-byte uint8_t for n follows) + { + const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx)); + const size_t offset = current_idx + 2; + idx += len + 1; // skip size byte + content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + + case 0x79: // UTF-8 string (two-byte uint16_t for n follow) + { + const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx)); + const size_t offset = current_idx + 3; + idx += len + 2; // skip 2 size bytes + content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + + case 0x7a: // UTF-8 string (four-byte uint32_t for n follow) + { + const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx)); + const size_t offset = current_idx + 5; + idx += len + 4; // skip 4 size bytes + content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + + case 0x7b: // UTF-8 string (eight-byte uint64_t for n follow) + { + const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx)); + const size_t offset = current_idx + 9; + idx += len + 8; // skip 8 size bytes + content bytes + check_length(v.size(), len, offset); + return std::string(reinterpret_cast<const char*>(v.data()) + offset, len); + } + + case 0x7f: // UTF-8 string (indefinite length) + { + std::string result; + while (v.at(idx) != 0xff) + { + string_t s = from_cbor_internal(v, idx); + result += s; + } + // skip break byte (0xFF) + idx += 1; + return result; + } + + // array (0x00..0x17 data items follow) + case 0x80: + case 0x81: + case 0x82: + case 0x83: + case 0x84: + case 0x85: + case 0x86: + case 0x87: + case 0x88: + case 0x89: + case 0x8a: + case 0x8b: + case 0x8c: + case 0x8d: + case 0x8e: + case 0x8f: + case 0x90: + case 0x91: + case 0x92: + case 0x93: + case 0x94: + case 0x95: + case 0x96: + case 0x97: + { + basic_json result = value_t::array; + const auto len = static_cast<size_t>(v[current_idx] - 0x80); + for (size_t i = 0; i < len; ++i) + { + result.push_back(from_cbor_internal(v, idx)); + } + return result; + } + + case 0x98: // array (one-byte uint8_t for n follows) + { + basic_json result = value_t::array; + const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx)); + idx += 1; // skip 1 size byte + for (size_t i = 0; i < len; ++i) + { + result.push_back(from_cbor_internal(v, idx)); + } + return result; + } + + case 0x99: // array (two-byte uint16_t for n follow) + { + basic_json result = value_t::array; + const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx)); + idx += 2; // skip 4 size bytes + for (size_t i = 0; i < len; ++i) + { + result.push_back(from_cbor_internal(v, idx)); + } + return result; + } + + case 0x9a: // array (four-byte uint32_t for n follow) + { + basic_json result = value_t::array; + const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx)); + idx += 4; // skip 4 size bytes + for (size_t i = 0; i < len; ++i) + { + result.push_back(from_cbor_internal(v, idx)); + } + return result; + } + + case 0x9b: // array (eight-byte uint64_t for n follow) + { + basic_json result = value_t::array; + const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx)); + idx += 8; // skip 8 size bytes + for (size_t i = 0; i < len; ++i) + { + result.push_back(from_cbor_internal(v, idx)); + } + return result; + } + + case 0x9f: // array (indefinite length) + { + basic_json result = value_t::array; + while (v.at(idx) != 0xff) + { + result.push_back(from_cbor_internal(v, idx)); + } + // skip break byte (0xFF) + idx += 1; + return result; + } + + // map (0x00..0x17 pairs of data items follow) + case 0xa0: + case 0xa1: + case 0xa2: + case 0xa3: + case 0xa4: + case 0xa5: + case 0xa6: + case 0xa7: + case 0xa8: + case 0xa9: + case 0xaa: + case 0xab: + case 0xac: + case 0xad: + case 0xae: + case 0xaf: + case 0xb0: + case 0xb1: + case 0xb2: + case 0xb3: + case 0xb4: + case 0xb5: + case 0xb6: + case 0xb7: + { + basic_json result = value_t::object; + const auto len = static_cast<size_t>(v[current_idx] - 0xa0); + for (size_t i = 0; i < len; ++i) + { + std::string key = from_cbor_internal(v, idx); + result[key] = from_cbor_internal(v, idx); + } + return result; + } + + case 0xb8: // map (one-byte uint8_t for n follows) + { + basic_json result = value_t::object; + const auto len = static_cast<size_t>(get_from_vector<uint8_t>(v, current_idx)); + idx += 1; // skip 1 size byte + for (size_t i = 0; i < len; ++i) + { + std::string key = from_cbor_internal(v, idx); + result[key] = from_cbor_internal(v, idx); + } + return result; + } + + case 0xb9: // map (two-byte uint16_t for n follow) + { + basic_json result = value_t::object; + const auto len = static_cast<size_t>(get_from_vector<uint16_t>(v, current_idx)); + idx += 2; // skip 2 size bytes + for (size_t i = 0; i < len; ++i) + { + std::string key = from_cbor_internal(v, idx); + result[key] = from_cbor_internal(v, idx); + } + return result; + } + + case 0xba: // map (four-byte uint32_t for n follow) + { + basic_json result = value_t::object; + const auto len = static_cast<size_t>(get_from_vector<uint32_t>(v, current_idx)); + idx += 4; // skip 4 size bytes + for (size_t i = 0; i < len; ++i) + { + std::string key = from_cbor_internal(v, idx); + result[key] = from_cbor_internal(v, idx); + } + return result; + } + + case 0xbb: // map (eight-byte uint64_t for n follow) + { + basic_json result = value_t::object; + const auto len = static_cast<size_t>(get_from_vector<uint64_t>(v, current_idx)); + idx += 8; // skip 8 size bytes + for (size_t i = 0; i < len; ++i) + { + std::string key = from_cbor_internal(v, idx); + result[key] = from_cbor_internal(v, idx); + } + return result; + } + + case 0xbf: // map (indefinite length) + { + basic_json result = value_t::object; + while (v.at(idx) != 0xff) + { + std::string key = from_cbor_internal(v, idx); + result[key] = from_cbor_internal(v, idx); + } + // skip break byte (0xFF) + idx += 1; + return result; + } + + case 0xf4: // false + { + return false; + } + + case 0xf5: // true + { + return true; + } + + case 0xf6: // null + { + return value_t::null; + } + + case 0xf9: // Half-Precision Float (two-byte IEEE 754) + { + idx += 2; // skip two content bytes + + // code from RFC 7049, Appendix D, Figure 3: + // As half-precision floating-point numbers were only added to + // IEEE 754 in 2008, today's programming platforms often still + // only have limited support for them. It is very easy to + // include at least decoding support for them even without such + // support. An example of a small decoder for half-precision + // floating-point numbers in the C language is shown in Fig. 3. + const int half = (v.at(current_idx + 1) << 8) + v.at(current_idx + 2); + const int exp = (half >> 10) & 0x1f; + const int mant = half & 0x3ff; + double val; + if (exp == 0) + { + val = std::ldexp(mant, -24); + } + else if (exp != 31) + { + val = std::ldexp(mant + 1024, exp - 25); + } + else + { + val = mant == 0 + ? std::numeric_limits<double>::infinity() + : std::numeric_limits<double>::quiet_NaN(); + } + return (half & 0x8000) != 0 ? -val : val; + } + + case 0xfa: // Single-Precision Float (four-byte IEEE 754) + { + // copy bytes in reverse order into the float variable + float res; + for (size_t byte = 0; byte < sizeof(float); ++byte) + { + reinterpret_cast<uint8_t*>(&res)[sizeof(float) - byte - 1] = v.at(current_idx + 1 + byte); + } + idx += sizeof(float); // skip content bytes + return res; + } + + case 0xfb: // Double-Precision Float (eight-byte IEEE 754) + { + // copy bytes in reverse order into the double variable + double res; + for (size_t byte = 0; byte < sizeof(double); ++byte) + { + reinterpret_cast<uint8_t*>(&res)[sizeof(double) - byte - 1] = v.at(current_idx + 1 + byte); + } + idx += sizeof(double); // skip content bytes + return res; + } + + default: // anything else (0xFF is handled inside the other types) + { + JSON_THROW(std::invalid_argument("error parsing a CBOR @ " + std::to_string(current_idx) + ": " + std::to_string(static_cast<int>(v[current_idx])))); + } + } + } + + public: + /*! + @brief create a MessagePack serialization of a given JSON value + + Serializes a given JSON value @a j to a byte vector using the MessagePack + serialization format. MessagePack is a binary serialization format which + aims to be more compact than JSON itself, yet more efficient to parse. + + @param[in] j JSON value to serialize + @return MessagePack serialization as byte vector + + @complexity Linear in the size of the JSON value @a j. + + @liveexample{The example shows the serialization of a JSON value to a byte + vector in MessagePack format.,to_msgpack} + + @sa http://msgpack.org + @sa @ref from_msgpack(const std::vector<uint8_t>&, const size_t) for the + analogous deserialization + @sa @ref to_cbor(const basic_json& for the related CBOR format + + @since version 2.0.9 + */ + static std::vector<uint8_t> to_msgpack(const basic_json& j) + { + std::vector<uint8_t> result; + to_msgpack_internal(j, result); + return result; + } + + /*! + @brief create a JSON value from a byte vector in MessagePack format + + Deserializes a given byte vector @a v to a JSON value using the MessagePack + serialization format. + + @param[in] v a byte vector in MessagePack format + @param[in] start_index the index to start reading from @a v (0 by default) + @return deserialized JSON value + + @throw std::invalid_argument if unsupported features from MessagePack were + used in the given vector @a v or if the input is not valid MessagePack + @throw std::out_of_range if the given vector ends prematurely + + @complexity Linear in the size of the byte vector @a v. + + @liveexample{The example shows the deserialization of a byte vector in + MessagePack format to a JSON value.,from_msgpack} + + @sa http://msgpack.org + @sa @ref to_msgpack(const basic_json&) for the analogous serialization + @sa @ref from_cbor(const std::vector<uint8_t>&, const size_t) for the + related CBOR format + + @since version 2.0.9, parameter @a start_index since 2.1.1 + */ + static basic_json from_msgpack(const std::vector<uint8_t>& v, + const size_t start_index = 0) + { + size_t i = start_index; + return from_msgpack_internal(v, i); + } + + /*! + @brief create a MessagePack serialization of a given JSON value + + Serializes a given JSON value @a j to a byte vector using the CBOR (Concise + Binary Object Representation) serialization format. CBOR is a binary + serialization format which aims to be more compact than JSON itself, yet + more efficient to parse. + + @param[in] j JSON value to serialize + @return MessagePack serialization as byte vector + + @complexity Linear in the size of the JSON value @a j. + + @liveexample{The example shows the serialization of a JSON value to a byte + vector in CBOR format.,to_cbor} + + @sa http://cbor.io + @sa @ref from_cbor(const std::vector<uint8_t>&, const size_t) for the + analogous deserialization + @sa @ref to_msgpack(const basic_json& for the related MessagePack format + + @since version 2.0.9 + */ + static std::vector<uint8_t> to_cbor(const basic_json& j) + { + std::vector<uint8_t> result; + to_cbor_internal(j, result); + return result; + } + + /*! + @brief create a JSON value from a byte vector in CBOR format + + Deserializes a given byte vector @a v to a JSON value using the CBOR + (Concise Binary Object Representation) serialization format. + + @param[in] v a byte vector in CBOR format + @param[in] start_index the index to start reading from @a v (0 by default) + @return deserialized JSON value + + @throw std::invalid_argument if unsupported features from CBOR were used in + the given vector @a v or if the input is not valid MessagePack + @throw std::out_of_range if the given vector ends prematurely + + @complexity Linear in the size of the byte vector @a v. + + @liveexample{The example shows the deserialization of a byte vector in CBOR + format to a JSON value.,from_cbor} + + @sa http://cbor.io + @sa @ref to_cbor(const basic_json&) for the analogous serialization + @sa @ref from_msgpack(const std::vector<uint8_t>&, const size_t) for the + related MessagePack format + + @since version 2.0.9, parameter @a start_index since 2.1.1 + */ + static basic_json from_cbor(const std::vector<uint8_t>& v, + const size_t start_index = 0) + { + size_t i = start_index; + return from_cbor_internal(v, i); + } + + /// @} + + /////////////////////////// + // convenience functions // + /////////////////////////// + + /*! + @brief return the type as string + + Returns the type name as string to be used in error messages - usually to + indicate that a function was called on a wrong JSON type. + + @return basically a string representation of a the @a m_type member + + @complexity Constant. + + @liveexample{The following code exemplifies `type_name()` for all JSON + types.,type_name} + + @since version 1.0.0, public since 2.1.0 + */ + std::string type_name() const + { + { + switch (m_type) + { + case value_t::null: + return "null"; + case value_t::object: + return "object"; + case value_t::array: + return "array"; + case value_t::string: + return "string"; + case value_t::boolean: + return "boolean"; + case value_t::discarded: + return "discarded"; + default: + return "number"; + } + } + } + + private: + /*! + @brief calculates the extra space to escape a JSON string + + @param[in] s the string to escape + @return the number of characters required to escape string @a s + + @complexity Linear in the length of string @a s. + */ + static std::size_t extra_space(const string_t& s) noexcept + { + return std::accumulate(s.begin(), s.end(), size_t{}, + [](size_t res, typename string_t::value_type c) + { + switch (c) + { + case '"': + case '\\': + case '\b': + case '\f': + case '\n': + case '\r': + case '\t': + { + // from c (1 byte) to \x (2 bytes) + return res + 1; + } + + default: + { + if (c >= 0x00 and c <= 0x1f) + { + // from c (1 byte) to \uxxxx (6 bytes) + return res + 5; + } + + return res; + } + } + }); + } + + /*! + @brief escape a string + + Escape a string by replacing certain special characters by a sequence of + an escape character (backslash) and another character and other control + characters by a sequence of "\u" followed by a four-digit hex + representation. + + @param[in] s the string to escape + @return the escaped string + + @complexity Linear in the length of string @a s. + */ + static string_t escape_string(const string_t& s) + { + const auto space = extra_space(s); + if (space == 0) + { + return s; + } + + // create a result string of necessary size + string_t result(s.size() + space, '\\'); + std::size_t pos = 0; + + for (const auto& c : s) + { + switch (c) + { + // quotation mark (0x22) + case '"': + { + result[pos + 1] = '"'; + pos += 2; + break; + } + + // reverse solidus (0x5c) + case '\\': + { + // nothing to change + pos += 2; + break; + } + + // backspace (0x08) + case '\b': + { + result[pos + 1] = 'b'; + pos += 2; + break; + } + + // formfeed (0x0c) + case '\f': + { + result[pos + 1] = 'f'; + pos += 2; + break; + } + + // newline (0x0a) + case '\n': + { + result[pos + 1] = 'n'; + pos += 2; + break; + } + + // carriage return (0x0d) + case '\r': + { + result[pos + 1] = 'r'; + pos += 2; + break; + } + + // horizontal tab (0x09) + case '\t': + { + result[pos + 1] = 't'; + pos += 2; + break; + } + + default: + { + if (c >= 0x00 and c <= 0x1f) + { + // convert a number 0..15 to its hex representation + // (0..f) + static const char hexify[16] = + { + '0', '1', '2', '3', '4', '5', '6', '7', + '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' + }; + + // print character c as \uxxxx + for (const char m : + { 'u', '0', '0', hexify[c >> 4], hexify[c & 0x0f] + }) + { + result[++pos] = m; + } + + ++pos; + } + else + { + // all other characters are added as-is + result[pos++] = c; + } + break; + } + } + } + + return result; + } + + + /*! + @brief locale-independent serialization for built-in arithmetic types + */ + struct numtostr + { + public: + template<typename NumberType> + numtostr(NumberType value) + { + x_write(value, std::is_integral<NumberType>()); + } + + const char* c_str() const + { + return m_buf.data(); + } + + private: + /// a (hopefully) large enough character buffer + std::array < char, 64 > m_buf{{}}; + + template<typename NumberType> + void x_write(NumberType x, /*is_integral=*/std::true_type) + { + // special case for "0" + if (x == 0) + { + m_buf[0] = '0'; + return; + } + + const bool is_negative = x < 0; + size_t i = 0; + + // spare 1 byte for '\0' + while (x != 0 and i < m_buf.size() - 1) + { + const auto digit = std::labs(static_cast<long>(x % 10)); + m_buf[i++] = static_cast<char>('0' + digit); + x /= 10; + } + + // make sure the number has been processed completely + assert(x == 0); + + if (is_negative) + { + // make sure there is capacity for the '-' + assert(i < m_buf.size() - 2); + m_buf[i++] = '-'; + } + + std::reverse(m_buf.begin(), m_buf.begin() + i); + } + + template<typename NumberType> + void x_write(NumberType x, /*is_integral=*/std::false_type) + { + // special case for 0.0 and -0.0 + if (x == 0) + { + size_t i = 0; + if (std::signbit(x)) + { + m_buf[i++] = '-'; + } + m_buf[i++] = '0'; + m_buf[i++] = '.'; + m_buf[i] = '0'; + return; + } + + // get number of digits for a text -> float -> text round-trip + static constexpr auto d = std::numeric_limits<NumberType>::digits10; + + // the actual conversion + const auto written_bytes = snprintf(m_buf.data(), m_buf.size(), "%.*g", d, x); + + // negative value indicates an error + assert(written_bytes > 0); + // check if buffer was large enough + assert(static_cast<size_t>(written_bytes) < m_buf.size()); + + // read information from locale + const auto loc = localeconv(); + assert(loc != nullptr); + const char thousands_sep = !loc->thousands_sep ? '\0' + : loc->thousands_sep[0]; + + const char decimal_point = !loc->decimal_point ? '\0' + : loc->decimal_point[0]; + + // erase thousands separator + if (thousands_sep != '\0') + { + const auto end = std::remove(m_buf.begin(), m_buf.begin() + written_bytes, thousands_sep); + std::fill(end, m_buf.end(), '\0'); + } + + // convert decimal point to '.' + if (decimal_point != '\0' and decimal_point != '.') + { + for (auto& c : m_buf) + { + if (c == decimal_point) + { + c = '.'; + break; + } + } + } + + // determine if need to append ".0" + size_t i = 0; + bool value_is_int_like = true; + for (i = 0; i < m_buf.size(); ++i) + { + // break when end of number is reached + if (m_buf[i] == '\0') + { + break; + } + + // check if we find non-int character + value_is_int_like = value_is_int_like and m_buf[i] != '.' and + m_buf[i] != 'e' and m_buf[i] != 'E'; + } + + if (value_is_int_like) + { + // there must be 2 bytes left for ".0" + assert((i + 2) < m_buf.size()); + // we write to the end of the number + assert(m_buf[i] == '\0'); + assert(m_buf[i - 1] != '\0'); + + // add ".0" + m_buf[i] = '.'; + m_buf[i + 1] = '0'; + + // the resulting string is properly terminated + assert(m_buf[i + 2] == '\0'); + } + } + }; + + + /*! + @brief internal implementation of the serialization function + + This function is called by the public member function dump and organizes + the serialization internally. The indentation level is propagated as + additional parameter. In case of arrays and objects, the function is + called recursively. Note that + + - strings and object keys are escaped using `escape_string()` + - integer numbers are converted implicitly via `operator<<` + - floating-point numbers are converted to a string using `"%g"` format + + @param[out] o stream to write to + @param[in] pretty_print whether the output shall be pretty-printed + @param[in] indent_step the indent level + @param[in] current_indent the current indent level (only used internally) + */ + void dump(std::ostream& o, + const bool pretty_print, + const unsigned int indent_step, + const unsigned int current_indent = 0) const + { + // variable to hold indentation for recursive calls + unsigned int new_indent = current_indent; + + switch (m_type) + { + case value_t::object: + { + if (m_value.object->empty()) + { + o << "{}"; + return; + } + + o << "{"; + + // increase indentation + if (pretty_print) + { + new_indent += indent_step; + o << "\n"; + } + + for (auto i = m_value.object->cbegin(); i != m_value.object->cend(); ++i) + { + if (i != m_value.object->cbegin()) + { + o << (pretty_print ? ",\n" : ","); + } + o << string_t(new_indent, ' ') << "\"" + << escape_string(i->first) << "\":" + << (pretty_print ? " " : ""); + i->second.dump(o, pretty_print, indent_step, new_indent); + } + + // decrease indentation + if (pretty_print) + { + new_indent -= indent_step; + o << "\n"; + } + + o << string_t(new_indent, ' ') + "}"; + return; + } + + case value_t::array: + { + if (m_value.array->empty()) + { + o << "[]"; + return; + } + + o << "["; + + // increase indentation + if (pretty_print) + { + new_indent += indent_step; + o << "\n"; + } + + for (auto i = m_value.array->cbegin(); i != m_value.array->cend(); ++i) + { + if (i != m_value.array->cbegin()) + { + o << (pretty_print ? ",\n" : ","); + } + o << string_t(new_indent, ' '); + i->dump(o, pretty_print, indent_step, new_indent); + } + + // decrease indentation + if (pretty_print) + { + new_indent -= indent_step; + o << "\n"; + } + + o << string_t(new_indent, ' ') << "]"; + return; + } + + case value_t::string: + { + o << string_t("\"") << escape_string(*m_value.string) << "\""; + return; + } + + case value_t::boolean: + { + o << (m_value.boolean ? "true" : "false"); + return; + } + + case value_t::number_integer: + { + o << numtostr(m_value.number_integer).c_str(); + return; + } + + case value_t::number_unsigned: + { + o << numtostr(m_value.number_unsigned).c_str(); + return; + } + + case value_t::number_float: + { + o << numtostr(m_value.number_float).c_str(); + return; + } + + case value_t::discarded: + { + o << "<discarded>"; + return; + } + + case value_t::null: + { + o << "null"; + return; + } + } + } + + private: + ////////////////////// + // member variables // + ////////////////////// + + /// the type of the current element + value_t m_type = value_t::null; + + /// the value of the current element + json_value m_value = {}; + + + private: + /////////////// + // iterators // + /////////////// + + /*! + @brief an iterator for primitive JSON types + + This class models an iterator for primitive JSON types (boolean, number, + string). It's only purpose is to allow the iterator/const_iterator classes + to "iterate" over primitive values. Internally, the iterator is modeled by + a `difference_type` variable. Value begin_value (`0`) models the begin, + end_value (`1`) models past the end. + */ + class primitive_iterator_t + { + public: + + difference_type get_value() const noexcept + { + return m_it; + } + /// set iterator to a defined beginning + void set_begin() noexcept + { + m_it = begin_value; + } + + /// set iterator to a defined past the end + void set_end() noexcept + { + m_it = end_value; + } + + /// return whether the iterator can be dereferenced + constexpr bool is_begin() const noexcept + { + return (m_it == begin_value); + } + + /// return whether the iterator is at end + constexpr bool is_end() const noexcept + { + return (m_it == end_value); + } + + friend constexpr bool operator==(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept + { + return lhs.m_it == rhs.m_it; + } + + friend constexpr bool operator!=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept + { + return !(lhs == rhs); + } + + friend constexpr bool operator<(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept + { + return lhs.m_it < rhs.m_it; + } + + friend constexpr bool operator<=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept + { + return lhs.m_it <= rhs.m_it; + } + + friend constexpr bool operator>(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept + { + return lhs.m_it > rhs.m_it; + } + + friend constexpr bool operator>=(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept + { + return lhs.m_it >= rhs.m_it; + } + + primitive_iterator_t operator+(difference_type i) + { + auto result = *this; + result += i; + return result; + } + + friend constexpr difference_type operator-(primitive_iterator_t lhs, primitive_iterator_t rhs) noexcept + { + return lhs.m_it - rhs.m_it; + } + + friend std::ostream& operator<<(std::ostream& os, primitive_iterator_t it) + { + return os << it.m_it; + } + + primitive_iterator_t& operator++() + { + ++m_it; + return *this; + } + + primitive_iterator_t operator++(int) + { + auto result = *this; + m_it++; + return result; + } + + primitive_iterator_t& operator--() + { + --m_it; + return *this; + } + + primitive_iterator_t operator--(int) + { + auto result = *this; + m_it--; + return result; + } + + primitive_iterator_t& operator+=(difference_type n) + { + m_it += n; + return *this; + } + + primitive_iterator_t& operator-=(difference_type n) + { + m_it -= n; + return *this; + } + + private: + static constexpr difference_type begin_value = 0; + static constexpr difference_type end_value = begin_value + 1; + + /// iterator as signed integer type + difference_type m_it = std::numeric_limits<std::ptrdiff_t>::denorm_min(); + }; + + /*! + @brief an iterator value + + @note This structure could easily be a union, but MSVC currently does not + allow unions members with complex constructors, see + https://github.com/nlohmann/json/pull/105. + */ + struct internal_iterator + { + /// iterator for JSON objects + typename object_t::iterator object_iterator; + /// iterator for JSON arrays + typename array_t::iterator array_iterator; + /// generic iterator for all other types + primitive_iterator_t primitive_iterator; + + /// create an uninitialized internal_iterator + internal_iterator() noexcept + : object_iterator(), array_iterator(), primitive_iterator() + {} + }; + + /// proxy class for the iterator_wrapper functions + template<typename IteratorType> + class iteration_proxy + { + private: + /// helper class for iteration + class iteration_proxy_internal + { + private: + /// the iterator + IteratorType anchor; + /// an index for arrays (used to create key names) + size_t array_index = 0; + + public: + explicit iteration_proxy_internal(IteratorType it) noexcept + : anchor(it) + {} + + /// dereference operator (needed for range-based for) + iteration_proxy_internal& operator*() + { + return *this; + } + + /// increment operator (needed for range-based for) + iteration_proxy_internal& operator++() + { + ++anchor; + ++array_index; + + return *this; + } + + /// inequality operator (needed for range-based for) + bool operator!= (const iteration_proxy_internal& o) const + { + return anchor != o.anchor; + } + + /// return key of the iterator + typename basic_json::string_t key() const + { + assert(anchor.m_object != nullptr); + + switch (anchor.m_object->type()) + { + // use integer array index as key + case value_t::array: + { + return std::to_string(array_index); + } + + // use key from the object + case value_t::object: + { + return anchor.key(); + } + + // use an empty key for all primitive types + default: + { + return ""; + } + } + } + + /// return value of the iterator + typename IteratorType::reference value() const + { + return anchor.value(); + } + }; + + /// the container to iterate + typename IteratorType::reference container; + + public: + /// construct iteration proxy from a container + explicit iteration_proxy(typename IteratorType::reference cont) + : container(cont) + {} + + /// return iterator begin (needed for range-based for) + iteration_proxy_internal begin() noexcept + { + return iteration_proxy_internal(container.begin()); + } + + /// return iterator end (needed for range-based for) + iteration_proxy_internal end() noexcept + { + return iteration_proxy_internal(container.end()); + } + }; + + public: + /*! + @brief a template for a random access iterator for the @ref basic_json class + + This class implements a both iterators (iterator and const_iterator) for the + @ref basic_json class. + + @note An iterator is called *initialized* when a pointer to a JSON value + has been set (e.g., by a constructor or a copy assignment). If the + iterator is default-constructed, it is *uninitialized* and most + methods are undefined. **The library uses assertions to detect calls + on uninitialized iterators.** + + @requirement The class satisfies the following concept requirements: + - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator): + The iterator that can be moved to point (forward and backward) to any + element in constant time. + + @since version 1.0.0, simplified in version 2.0.9 + */ + template<typename U> + class iter_impl : public std::iterator<std::random_access_iterator_tag, U> + { + /// allow basic_json to access private members + friend class basic_json; + + // make sure U is basic_json or const basic_json + static_assert(std::is_same<U, basic_json>::value + or std::is_same<U, const basic_json>::value, + "iter_impl only accepts (const) basic_json"); + + public: + /// the type of the values when the iterator is dereferenced + using value_type = typename basic_json::value_type; + /// a type to represent differences between iterators + using difference_type = typename basic_json::difference_type; + /// defines a pointer to the type iterated over (value_type) + using pointer = typename std::conditional<std::is_const<U>::value, + typename basic_json::const_pointer, + typename basic_json::pointer>::type; + /// defines a reference to the type iterated over (value_type) + using reference = typename std::conditional<std::is_const<U>::value, + typename basic_json::const_reference, + typename basic_json::reference>::type; + /// the category of the iterator + using iterator_category = std::bidirectional_iterator_tag; + + /// default constructor + iter_impl() = default; + + /*! + @brief constructor for a given JSON instance + @param[in] object pointer to a JSON object for this iterator + @pre object != nullptr + @post The iterator is initialized; i.e. `m_object != nullptr`. + */ + explicit iter_impl(pointer object) noexcept + : m_object(object) + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + m_it.object_iterator = typename object_t::iterator(); + break; + } + + case basic_json::value_t::array: + { + m_it.array_iterator = typename array_t::iterator(); + break; + } + + default: + { + m_it.primitive_iterator = primitive_iterator_t(); + break; + } + } + } + + /* + Use operator `const_iterator` instead of `const_iterator(const iterator& + other) noexcept` to avoid two class definitions for @ref iterator and + @ref const_iterator. + + This function is only called if this class is an @ref iterator. If this + class is a @ref const_iterator this function is not called. + */ + operator const_iterator() const + { + const_iterator ret; + + if (m_object) + { + ret.m_object = m_object; + ret.m_it = m_it; + } + + return ret; + } + + /*! + @brief copy constructor + @param[in] other iterator to copy from + @note It is not checked whether @a other is initialized. + */ + iter_impl(const iter_impl& other) noexcept + : m_object(other.m_object), m_it(other.m_it) + {} + + /*! + @brief copy assignment + @param[in,out] other iterator to copy from + @note It is not checked whether @a other is initialized. + */ + iter_impl& operator=(iter_impl other) noexcept( + std::is_nothrow_move_constructible<pointer>::value and + std::is_nothrow_move_assignable<pointer>::value and + std::is_nothrow_move_constructible<internal_iterator>::value and + std::is_nothrow_move_assignable<internal_iterator>::value + ) + { + std::swap(m_object, other.m_object); + std::swap(m_it, other.m_it); + return *this; + } + + private: + /*! + @brief set the iterator to the first value + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + void set_begin() noexcept + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + m_it.object_iterator = m_object->m_value.object->begin(); + break; + } + + case basic_json::value_t::array: + { + m_it.array_iterator = m_object->m_value.array->begin(); + break; + } + + case basic_json::value_t::null: + { + // set to end so begin()==end() is true: null is empty + m_it.primitive_iterator.set_end(); + break; + } + + default: + { + m_it.primitive_iterator.set_begin(); + break; + } + } + } + + /*! + @brief set the iterator past the last value + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + void set_end() noexcept + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + m_it.object_iterator = m_object->m_value.object->end(); + break; + } + + case basic_json::value_t::array: + { + m_it.array_iterator = m_object->m_value.array->end(); + break; + } + + default: + { + m_it.primitive_iterator.set_end(); + break; + } + } + } + + public: + /*! + @brief return a reference to the value pointed to by the iterator + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + reference operator*() const + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + assert(m_it.object_iterator != m_object->m_value.object->end()); + return m_it.object_iterator->second; + } + + case basic_json::value_t::array: + { + assert(m_it.array_iterator != m_object->m_value.array->end()); + return *m_it.array_iterator; + } + + case basic_json::value_t::null: + { + JSON_THROW(std::out_of_range("cannot get value")); + } + + default: + { + if (m_it.primitive_iterator.is_begin()) + { + return *m_object; + } + + JSON_THROW(std::out_of_range("cannot get value")); + } + } + } + + /*! + @brief dereference the iterator + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + pointer operator->() const + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + assert(m_it.object_iterator != m_object->m_value.object->end()); + return &(m_it.object_iterator->second); + } + + case basic_json::value_t::array: + { + assert(m_it.array_iterator != m_object->m_value.array->end()); + return &*m_it.array_iterator; + } + + default: + { + if (m_it.primitive_iterator.is_begin()) + { + return m_object; + } + + JSON_THROW(std::out_of_range("cannot get value")); + } + } + } + + /*! + @brief post-increment (it++) + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + iter_impl operator++(int) + { + auto result = *this; + ++(*this); + return result; + } + + /*! + @brief pre-increment (++it) + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + iter_impl& operator++() + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + std::advance(m_it.object_iterator, 1); + break; + } + + case basic_json::value_t::array: + { + std::advance(m_it.array_iterator, 1); + break; + } + + default: + { + ++m_it.primitive_iterator; + break; + } + } + + return *this; + } + + /*! + @brief post-decrement (it--) + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + iter_impl operator--(int) + { + auto result = *this; + --(*this); + return result; + } + + /*! + @brief pre-decrement (--it) + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + iter_impl& operator--() + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + std::advance(m_it.object_iterator, -1); + break; + } + + case basic_json::value_t::array: + { + std::advance(m_it.array_iterator, -1); + break; + } + + default: + { + --m_it.primitive_iterator; + break; + } + } + + return *this; + } + + /*! + @brief comparison: equal + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + bool operator==(const iter_impl& other) const + { + // if objects are not the same, the comparison is undefined + if (m_object != other.m_object) + { + JSON_THROW(std::domain_error("cannot compare iterators of different containers")); + } + + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + return (m_it.object_iterator == other.m_it.object_iterator); + } + + case basic_json::value_t::array: + { + return (m_it.array_iterator == other.m_it.array_iterator); + } + + default: + { + return (m_it.primitive_iterator == other.m_it.primitive_iterator); + } + } + } + + /*! + @brief comparison: not equal + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + bool operator!=(const iter_impl& other) const + { + return not operator==(other); + } + + /*! + @brief comparison: smaller + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + bool operator<(const iter_impl& other) const + { + // if objects are not the same, the comparison is undefined + if (m_object != other.m_object) + { + JSON_THROW(std::domain_error("cannot compare iterators of different containers")); + } + + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + JSON_THROW(std::domain_error("cannot compare order of object iterators")); + } + + case basic_json::value_t::array: + { + return (m_it.array_iterator < other.m_it.array_iterator); + } + + default: + { + return (m_it.primitive_iterator < other.m_it.primitive_iterator); + } + } + } + + /*! + @brief comparison: less than or equal + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + bool operator<=(const iter_impl& other) const + { + return not other.operator < (*this); + } + + /*! + @brief comparison: greater than + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + bool operator>(const iter_impl& other) const + { + return not operator<=(other); + } + + /*! + @brief comparison: greater than or equal + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + bool operator>=(const iter_impl& other) const + { + return not operator<(other); + } + + /*! + @brief add to iterator + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + iter_impl& operator+=(difference_type i) + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + JSON_THROW(std::domain_error("cannot use offsets with object iterators")); + } + + case basic_json::value_t::array: + { + std::advance(m_it.array_iterator, i); + break; + } + + default: + { + m_it.primitive_iterator += i; + break; + } + } + + return *this; + } + + /*! + @brief subtract from iterator + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + iter_impl& operator-=(difference_type i) + { + return operator+=(-i); + } + + /*! + @brief add to iterator + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + iter_impl operator+(difference_type i) + { + auto result = *this; + result += i; + return result; + } + + /*! + @brief subtract from iterator + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + iter_impl operator-(difference_type i) + { + auto result = *this; + result -= i; + return result; + } + + /*! + @brief return difference + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + difference_type operator-(const iter_impl& other) const + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + JSON_THROW(std::domain_error("cannot use offsets with object iterators")); + } + + case basic_json::value_t::array: + { + return m_it.array_iterator - other.m_it.array_iterator; + } + + default: + { + return m_it.primitive_iterator - other.m_it.primitive_iterator; + } + } + } + + /*! + @brief access to successor + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + reference operator[](difference_type n) const + { + assert(m_object != nullptr); + + switch (m_object->m_type) + { + case basic_json::value_t::object: + { + JSON_THROW(std::domain_error("cannot use operator[] for object iterators")); + } + + case basic_json::value_t::array: + { + return *std::next(m_it.array_iterator, n); + } + + case basic_json::value_t::null: + { + JSON_THROW(std::out_of_range("cannot get value")); + } + + default: + { + if (m_it.primitive_iterator.get_value() == -n) + { + return *m_object; + } + + JSON_THROW(std::out_of_range("cannot get value")); + } + } + } + + /*! + @brief return the key of an object iterator + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + typename object_t::key_type key() const + { + assert(m_object != nullptr); + + if (m_object->is_object()) + { + return m_it.object_iterator->first; + } + + JSON_THROW(std::domain_error("cannot use key() for non-object iterators")); + } + + /*! + @brief return the value of an iterator + @pre The iterator is initialized; i.e. `m_object != nullptr`. + */ + reference value() const + { + return operator*(); + } + + private: + /// associated JSON instance + pointer m_object = nullptr; + /// the actual iterator of the associated instance + internal_iterator m_it = internal_iterator(); + }; + + /*! + @brief a template for a reverse iterator class + + @tparam Base the base iterator type to reverse. Valid types are @ref + iterator (to create @ref reverse_iterator) and @ref const_iterator (to + create @ref const_reverse_iterator). + + @requirement The class satisfies the following concept requirements: + - [RandomAccessIterator](http://en.cppreference.com/w/cpp/concept/RandomAccessIterator): + The iterator that can be moved to point (forward and backward) to any + element in constant time. + - [OutputIterator](http://en.cppreference.com/w/cpp/concept/OutputIterator): + It is possible to write to the pointed-to element (only if @a Base is + @ref iterator). + + @since version 1.0.0 + */ + template<typename Base> + class json_reverse_iterator : public std::reverse_iterator<Base> + { + public: + /// shortcut to the reverse iterator adaptor + using base_iterator = std::reverse_iterator<Base>; + /// the reference type for the pointed-to element + using reference = typename Base::reference; + + /// create reverse iterator from iterator + json_reverse_iterator(const typename base_iterator::iterator_type& it) noexcept + : base_iterator(it) + {} + + /// create reverse iterator from base class + json_reverse_iterator(const base_iterator& it) noexcept + : base_iterator(it) + {} + + /// post-increment (it++) + json_reverse_iterator operator++(int) + { + return base_iterator::operator++(1); + } + + /// pre-increment (++it) + json_reverse_iterator& operator++() + { + base_iterator::operator++(); + return *this; + } + + /// post-decrement (it--) + json_reverse_iterator operator--(int) + { + return base_iterator::operator--(1); + } + + /// pre-decrement (--it) + json_reverse_iterator& operator--() + { + base_iterator::operator--(); + return *this; + } + + /// add to iterator + json_reverse_iterator& operator+=(difference_type i) + { + base_iterator::operator+=(i); + return *this; + } + + /// add to iterator + json_reverse_iterator operator+(difference_type i) const + { + auto result = *this; + result += i; + return result; + } + + /// subtract from iterator + json_reverse_iterator operator-(difference_type i) const + { + auto result = *this; + result -= i; + return result; + } + + /// return difference + difference_type operator-(const json_reverse_iterator& other) const + { + return this->base() - other.base(); + } + + /// access to successor + reference operator[](difference_type n) const + { + return *(this->operator+(n)); + } + + /// return the key of an object iterator + typename object_t::key_type key() const + { + auto it = --this->base(); + return it.key(); + } + + /// return the value of an iterator + reference value() const + { + auto it = --this->base(); + return it.operator * (); + } + }; + + + private: + ////////////////////// + // lexer and parser // + ////////////////////// + + /*! + @brief lexical analysis + + This class organizes the lexical analysis during JSON deserialization. The + core of it is a scanner generated by [re2c](http://re2c.org) that + processes a buffer and recognizes tokens according to RFC 7159. + */ + class lexer + { + public: + /// token types for the parser + enum class token_type + { + uninitialized, ///< indicating the scanner is uninitialized + literal_true, ///< the `true` literal + literal_false, ///< the `false` literal + literal_null, ///< the `null` literal + value_string, ///< a string -- use get_string() for actual value + value_unsigned, ///< an unsigned integer -- use get_number() for actual value + value_integer, ///< a signed integer -- use get_number() for actual value + value_float, ///< an floating point number -- use get_number() for actual value + begin_array, ///< the character for array begin `[` + begin_object, ///< the character for object begin `{` + end_array, ///< the character for array end `]` + end_object, ///< the character for object end `}` + name_separator, ///< the name separator `:` + value_separator, ///< the value separator `,` + parse_error, ///< indicating a parse error + end_of_input ///< indicating the end of the input buffer + }; + + /// the char type to use in the lexer + using lexer_char_t = unsigned char; + + /// a lexer from a buffer with given length + lexer(const lexer_char_t* buff, const size_t len) noexcept + : m_content(buff) + { + assert(m_content != nullptr); + m_start = m_cursor = m_content; + m_limit = m_content + len; + } + + /// a lexer from an input stream + explicit lexer(std::istream& s) + : m_stream(&s), m_line_buffer() + { + // immediately abort if stream is erroneous + if (s.fail()) + { + JSON_THROW(std::invalid_argument("stream error")); + } + + // fill buffer + fill_line_buffer(); + + // skip UTF-8 byte-order mark + if (m_line_buffer.size() >= 3 and m_line_buffer.substr(0, 3) == "\xEF\xBB\xBF") + { + m_line_buffer[0] = ' '; + m_line_buffer[1] = ' '; + m_line_buffer[2] = ' '; + } + } + + // switch off unwanted functions (due to pointer members) + lexer() = delete; + lexer(const lexer&) = delete; + lexer operator=(const lexer&) = delete; + + /*! + @brief create a string from one or two Unicode code points + + There are two cases: (1) @a codepoint1 is in the Basic Multilingual + Plane (U+0000 through U+FFFF) and @a codepoint2 is 0, or (2) + @a codepoint1 and @a codepoint2 are a UTF-16 surrogate pair to + represent a code point above U+FFFF. + + @param[in] codepoint1 the code point (can be high surrogate) + @param[in] codepoint2 the code point (can be low surrogate or 0) + + @return string representation of the code point; the length of the + result string is between 1 and 4 characters. + + @throw std::out_of_range if code point is > 0x10ffff; example: `"code + points above 0x10FFFF are invalid"` + @throw std::invalid_argument if the low surrogate is invalid; example: + `""missing or wrong low surrogate""` + + @complexity Constant. + + @see <http://en.wikipedia.org/wiki/UTF-8#Sample_code> + */ + static string_t to_unicode(const std::size_t codepoint1, + const std::size_t codepoint2 = 0) + { + // calculate the code point from the given code points + std::size_t codepoint = codepoint1; + + // check if codepoint1 is a high surrogate + if (codepoint1 >= 0xD800 and codepoint1 <= 0xDBFF) + { + // check if codepoint2 is a low surrogate + if (codepoint2 >= 0xDC00 and codepoint2 <= 0xDFFF) + { + codepoint = + // high surrogate occupies the most significant 22 bits + (codepoint1 << 10) + // low surrogate occupies the least significant 15 bits + + codepoint2 + // there is still the 0xD800, 0xDC00 and 0x10000 noise + // in the result so we have to subtract with: + // (0xD800 << 10) + DC00 - 0x10000 = 0x35FDC00 + - 0x35FDC00; + } + else + { + JSON_THROW(std::invalid_argument("missing or wrong low surrogate")); + } + } + + string_t result; + + if (codepoint < 0x80) + { + // 1-byte characters: 0xxxxxxx (ASCII) + result.append(1, static_cast<typename string_t::value_type>(codepoint)); + } + else if (codepoint <= 0x7ff) + { + // 2-byte characters: 110xxxxx 10xxxxxx + result.append(1, static_cast<typename string_t::value_type>(0xC0 | ((codepoint >> 6) & 0x1F))); + result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F))); + } + else if (codepoint <= 0xffff) + { + // 3-byte characters: 1110xxxx 10xxxxxx 10xxxxxx + result.append(1, static_cast<typename string_t::value_type>(0xE0 | ((codepoint >> 12) & 0x0F))); + result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F))); + result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F))); + } + else if (codepoint <= 0x10ffff) + { + // 4-byte characters: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx + result.append(1, static_cast<typename string_t::value_type>(0xF0 | ((codepoint >> 18) & 0x07))); + result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 12) & 0x3F))); + result.append(1, static_cast<typename string_t::value_type>(0x80 | ((codepoint >> 6) & 0x3F))); + result.append(1, static_cast<typename string_t::value_type>(0x80 | (codepoint & 0x3F))); + } + else + { + JSON_THROW(std::out_of_range("code points above 0x10FFFF are invalid")); + } + + return result; + } + + /// return name of values of type token_type (only used for errors) + static std::string token_type_name(const token_type t) + { + switch (t) + { + case token_type::uninitialized: + return "<uninitialized>"; + case token_type::literal_true: + return "true literal"; + case token_type::literal_false: + return "false literal"; + case token_type::literal_null: + return "null literal"; + case token_type::value_string: + return "string literal"; + case lexer::token_type::value_unsigned: + case lexer::token_type::value_integer: + case lexer::token_type::value_float: + return "number literal"; + case token_type::begin_array: + return "'['"; + case token_type::begin_object: + return "'{'"; + case token_type::end_array: + return "']'"; + case token_type::end_object: + return "'}'"; + case token_type::name_separator: + return "':'"; + case token_type::value_separator: + return "','"; + case token_type::parse_error: + return "<parse error>"; + case token_type::end_of_input: + return "end of input"; + default: + { + // catch non-enum values + return "unknown token"; // LCOV_EXCL_LINE + } + } + } + + /*! + This function implements a scanner for JSON. It is specified using + regular expressions that try to follow RFC 7159 as close as possible. + These regular expressions are then translated into a minimized + deterministic finite automaton (DFA) by the tool + [re2c](http://re2c.org). As a result, the translated code for this + function consists of a large block of code with `goto` jumps. + + @return the class of the next token read from the buffer + + @complexity Linear in the length of the input.\n + + Proposition: The loop below will always terminate for finite input.\n + + Proof (by contradiction): Assume a finite input. To loop forever, the + loop must never hit code with a `break` statement. The only code + snippets without a `break` statement are the continue statements for + whitespace and byte-order-marks. To loop forever, the input must be an + infinite sequence of whitespace or byte-order-marks. This contradicts + the assumption of finite input, q.e.d. + */ + token_type scan() + { + while (true) + { + // pointer for backtracking information + m_marker = nullptr; + + // remember the begin of the token + m_start = m_cursor; + assert(m_start != nullptr); + + + { + lexer_char_t yych; + unsigned int yyaccept = 0; + static const unsigned char yybm[] = + { + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 32, 32, 0, 0, 32, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 160, 128, 0, 128, 128, 128, 128, 128, + 128, 128, 128, 128, 128, 128, 128, 128, + 192, 192, 192, 192, 192, 192, 192, 192, + 192, 192, 128, 128, 128, 128, 128, 128, + 128, 128, 128, 128, 128, 128, 128, 128, + 128, 128, 128, 128, 128, 128, 128, 128, + 128, 128, 128, 128, 128, 128, 128, 128, + 128, 128, 128, 128, 0, 128, 128, 128, + 128, 128, 128, 128, 128, 128, 128, 128, + 128, 128, 128, 128, 128, 128, 128, 128, + 128, 128, 128, 128, 128, 128, 128, 128, + 128, 128, 128, 128, 128, 128, 128, 128, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, + }; + if ((m_limit - m_cursor) < 5) + { + fill_line_buffer(5); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yybm[0 + yych] & 32) + { + goto basic_json_parser_6; + } + if (yych <= '[') + { + if (yych <= '-') + { + if (yych <= '"') + { + if (yych <= 0x00) + { + goto basic_json_parser_2; + } + if (yych <= '!') + { + goto basic_json_parser_4; + } + goto basic_json_parser_9; + } + else + { + if (yych <= '+') + { + goto basic_json_parser_4; + } + if (yych <= ',') + { + goto basic_json_parser_10; + } + goto basic_json_parser_12; + } + } + else + { + if (yych <= '9') + { + if (yych <= '/') + { + goto basic_json_parser_4; + } + if (yych <= '0') + { + goto basic_json_parser_13; + } + goto basic_json_parser_15; + } + else + { + if (yych <= ':') + { + goto basic_json_parser_17; + } + if (yych <= 'Z') + { + goto basic_json_parser_4; + } + goto basic_json_parser_19; + } + } + } + else + { + if (yych <= 'n') + { + if (yych <= 'e') + { + if (yych == ']') + { + goto basic_json_parser_21; + } + goto basic_json_parser_4; + } + else + { + if (yych <= 'f') + { + goto basic_json_parser_23; + } + if (yych <= 'm') + { + goto basic_json_parser_4; + } + goto basic_json_parser_24; + } + } + else + { + if (yych <= 'z') + { + if (yych == 't') + { + goto basic_json_parser_25; + } + goto basic_json_parser_4; + } + else + { + if (yych <= '{') + { + goto basic_json_parser_26; + } + if (yych == '}') + { + goto basic_json_parser_28; + } + goto basic_json_parser_4; + } + } + } +basic_json_parser_2: + ++m_cursor; + { + last_token_type = token_type::end_of_input; + break; + } +basic_json_parser_4: + ++m_cursor; +basic_json_parser_5: + { + last_token_type = token_type::parse_error; + break; + } +basic_json_parser_6: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yybm[0 + yych] & 32) + { + goto basic_json_parser_6; + } + { + continue; + } +basic_json_parser_9: + yyaccept = 0; + yych = *(m_marker = ++m_cursor); + if (yych <= 0x1F) + { + goto basic_json_parser_5; + } + if (yych <= 0x7F) + { + goto basic_json_parser_31; + } + if (yych <= 0xC1) + { + goto basic_json_parser_5; + } + if (yych <= 0xF4) + { + goto basic_json_parser_31; + } + goto basic_json_parser_5; +basic_json_parser_10: + ++m_cursor; + { + last_token_type = token_type::value_separator; + break; + } +basic_json_parser_12: + yych = *++m_cursor; + if (yych <= '/') + { + goto basic_json_parser_5; + } + if (yych <= '0') + { + goto basic_json_parser_43; + } + if (yych <= '9') + { + goto basic_json_parser_45; + } + goto basic_json_parser_5; +basic_json_parser_13: + yyaccept = 1; + yych = *(m_marker = ++m_cursor); + if (yych <= '9') + { + if (yych == '.') + { + goto basic_json_parser_47; + } + if (yych >= '0') + { + goto basic_json_parser_48; + } + } + else + { + if (yych <= 'E') + { + if (yych >= 'E') + { + goto basic_json_parser_51; + } + } + else + { + if (yych == 'e') + { + goto basic_json_parser_51; + } + } + } +basic_json_parser_14: + { + last_token_type = token_type::value_unsigned; + break; + } +basic_json_parser_15: + yyaccept = 1; + m_marker = ++m_cursor; + if ((m_limit - m_cursor) < 3) + { + fill_line_buffer(3); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yybm[0 + yych] & 64) + { + goto basic_json_parser_15; + } + if (yych <= 'D') + { + if (yych == '.') + { + goto basic_json_parser_47; + } + goto basic_json_parser_14; + } + else + { + if (yych <= 'E') + { + goto basic_json_parser_51; + } + if (yych == 'e') + { + goto basic_json_parser_51; + } + goto basic_json_parser_14; + } +basic_json_parser_17: + ++m_cursor; + { + last_token_type = token_type::name_separator; + break; + } +basic_json_parser_19: + ++m_cursor; + { + last_token_type = token_type::begin_array; + break; + } +basic_json_parser_21: + ++m_cursor; + { + last_token_type = token_type::end_array; + break; + } +basic_json_parser_23: + yyaccept = 0; + yych = *(m_marker = ++m_cursor); + if (yych == 'a') + { + goto basic_json_parser_52; + } + goto basic_json_parser_5; +basic_json_parser_24: + yyaccept = 0; + yych = *(m_marker = ++m_cursor); + if (yych == 'u') + { + goto basic_json_parser_53; + } + goto basic_json_parser_5; +basic_json_parser_25: + yyaccept = 0; + yych = *(m_marker = ++m_cursor); + if (yych == 'r') + { + goto basic_json_parser_54; + } + goto basic_json_parser_5; +basic_json_parser_26: + ++m_cursor; + { + last_token_type = token_type::begin_object; + break; + } +basic_json_parser_28: + ++m_cursor; + { + last_token_type = token_type::end_object; + break; + } +basic_json_parser_30: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; +basic_json_parser_31: + if (yybm[0 + yych] & 128) + { + goto basic_json_parser_30; + } + if (yych <= 0xE0) + { + if (yych <= '\\') + { + if (yych <= 0x1F) + { + goto basic_json_parser_32; + } + if (yych <= '"') + { + goto basic_json_parser_33; + } + goto basic_json_parser_35; + } + else + { + if (yych <= 0xC1) + { + goto basic_json_parser_32; + } + if (yych <= 0xDF) + { + goto basic_json_parser_36; + } + goto basic_json_parser_37; + } + } + else + { + if (yych <= 0xEF) + { + if (yych == 0xED) + { + goto basic_json_parser_39; + } + goto basic_json_parser_38; + } + else + { + if (yych <= 0xF0) + { + goto basic_json_parser_40; + } + if (yych <= 0xF3) + { + goto basic_json_parser_41; + } + if (yych <= 0xF4) + { + goto basic_json_parser_42; + } + } + } +basic_json_parser_32: + m_cursor = m_marker; + if (yyaccept <= 1) + { + if (yyaccept == 0) + { + goto basic_json_parser_5; + } + else + { + goto basic_json_parser_14; + } + } + else + { + if (yyaccept == 2) + { + goto basic_json_parser_44; + } + else + { + goto basic_json_parser_58; + } + } +basic_json_parser_33: + ++m_cursor; + { + last_token_type = token_type::value_string; + break; + } +basic_json_parser_35: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 'e') + { + if (yych <= '/') + { + if (yych == '"') + { + goto basic_json_parser_30; + } + if (yych <= '.') + { + goto basic_json_parser_32; + } + goto basic_json_parser_30; + } + else + { + if (yych <= '\\') + { + if (yych <= '[') + { + goto basic_json_parser_32; + } + goto basic_json_parser_30; + } + else + { + if (yych == 'b') + { + goto basic_json_parser_30; + } + goto basic_json_parser_32; + } + } + } + else + { + if (yych <= 'q') + { + if (yych <= 'f') + { + goto basic_json_parser_30; + } + if (yych == 'n') + { + goto basic_json_parser_30; + } + goto basic_json_parser_32; + } + else + { + if (yych <= 's') + { + if (yych <= 'r') + { + goto basic_json_parser_30; + } + goto basic_json_parser_32; + } + else + { + if (yych <= 't') + { + goto basic_json_parser_30; + } + if (yych <= 'u') + { + goto basic_json_parser_55; + } + goto basic_json_parser_32; + } + } + } +basic_json_parser_36: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 0x7F) + { + goto basic_json_parser_32; + } + if (yych <= 0xBF) + { + goto basic_json_parser_30; + } + goto basic_json_parser_32; +basic_json_parser_37: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 0x9F) + { + goto basic_json_parser_32; + } + if (yych <= 0xBF) + { + goto basic_json_parser_36; + } + goto basic_json_parser_32; +basic_json_parser_38: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 0x7F) + { + goto basic_json_parser_32; + } + if (yych <= 0xBF) + { + goto basic_json_parser_36; + } + goto basic_json_parser_32; +basic_json_parser_39: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 0x7F) + { + goto basic_json_parser_32; + } + if (yych <= 0x9F) + { + goto basic_json_parser_36; + } + goto basic_json_parser_32; +basic_json_parser_40: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 0x8F) + { + goto basic_json_parser_32; + } + if (yych <= 0xBF) + { + goto basic_json_parser_38; + } + goto basic_json_parser_32; +basic_json_parser_41: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 0x7F) + { + goto basic_json_parser_32; + } + if (yych <= 0xBF) + { + goto basic_json_parser_38; + } + goto basic_json_parser_32; +basic_json_parser_42: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 0x7F) + { + goto basic_json_parser_32; + } + if (yych <= 0x8F) + { + goto basic_json_parser_38; + } + goto basic_json_parser_32; +basic_json_parser_43: + yyaccept = 2; + yych = *(m_marker = ++m_cursor); + if (yych <= '9') + { + if (yych == '.') + { + goto basic_json_parser_47; + } + if (yych >= '0') + { + goto basic_json_parser_48; + } + } + else + { + if (yych <= 'E') + { + if (yych >= 'E') + { + goto basic_json_parser_51; + } + } + else + { + if (yych == 'e') + { + goto basic_json_parser_51; + } + } + } +basic_json_parser_44: + { + last_token_type = token_type::value_integer; + break; + } +basic_json_parser_45: + yyaccept = 2; + m_marker = ++m_cursor; + if ((m_limit - m_cursor) < 3) + { + fill_line_buffer(3); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= '9') + { + if (yych == '.') + { + goto basic_json_parser_47; + } + if (yych <= '/') + { + goto basic_json_parser_44; + } + goto basic_json_parser_45; + } + else + { + if (yych <= 'E') + { + if (yych <= 'D') + { + goto basic_json_parser_44; + } + goto basic_json_parser_51; + } + else + { + if (yych == 'e') + { + goto basic_json_parser_51; + } + goto basic_json_parser_44; + } + } +basic_json_parser_47: + yych = *++m_cursor; + if (yych <= '/') + { + goto basic_json_parser_32; + } + if (yych <= '9') + { + goto basic_json_parser_56; + } + goto basic_json_parser_32; +basic_json_parser_48: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= '/') + { + goto basic_json_parser_50; + } + if (yych <= '9') + { + goto basic_json_parser_48; + } +basic_json_parser_50: + { + last_token_type = token_type::parse_error; + break; + } +basic_json_parser_51: + yych = *++m_cursor; + if (yych <= ',') + { + if (yych == '+') + { + goto basic_json_parser_59; + } + goto basic_json_parser_32; + } + else + { + if (yych <= '-') + { + goto basic_json_parser_59; + } + if (yych <= '/') + { + goto basic_json_parser_32; + } + if (yych <= '9') + { + goto basic_json_parser_60; + } + goto basic_json_parser_32; + } +basic_json_parser_52: + yych = *++m_cursor; + if (yych == 'l') + { + goto basic_json_parser_62; + } + goto basic_json_parser_32; +basic_json_parser_53: + yych = *++m_cursor; + if (yych == 'l') + { + goto basic_json_parser_63; + } + goto basic_json_parser_32; +basic_json_parser_54: + yych = *++m_cursor; + if (yych == 'u') + { + goto basic_json_parser_64; + } + goto basic_json_parser_32; +basic_json_parser_55: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= '@') + { + if (yych <= '/') + { + goto basic_json_parser_32; + } + if (yych <= '9') + { + goto basic_json_parser_65; + } + goto basic_json_parser_32; + } + else + { + if (yych <= 'F') + { + goto basic_json_parser_65; + } + if (yych <= '`') + { + goto basic_json_parser_32; + } + if (yych <= 'f') + { + goto basic_json_parser_65; + } + goto basic_json_parser_32; + } +basic_json_parser_56: + yyaccept = 3; + m_marker = ++m_cursor; + if ((m_limit - m_cursor) < 3) + { + fill_line_buffer(3); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= 'D') + { + if (yych <= '/') + { + goto basic_json_parser_58; + } + if (yych <= '9') + { + goto basic_json_parser_56; + } + } + else + { + if (yych <= 'E') + { + goto basic_json_parser_51; + } + if (yych == 'e') + { + goto basic_json_parser_51; + } + } +basic_json_parser_58: + { + last_token_type = token_type::value_float; + break; + } +basic_json_parser_59: + yych = *++m_cursor; + if (yych <= '/') + { + goto basic_json_parser_32; + } + if (yych >= ':') + { + goto basic_json_parser_32; + } +basic_json_parser_60: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= '/') + { + goto basic_json_parser_58; + } + if (yych <= '9') + { + goto basic_json_parser_60; + } + goto basic_json_parser_58; +basic_json_parser_62: + yych = *++m_cursor; + if (yych == 's') + { + goto basic_json_parser_66; + } + goto basic_json_parser_32; +basic_json_parser_63: + yych = *++m_cursor; + if (yych == 'l') + { + goto basic_json_parser_67; + } + goto basic_json_parser_32; +basic_json_parser_64: + yych = *++m_cursor; + if (yych == 'e') + { + goto basic_json_parser_69; + } + goto basic_json_parser_32; +basic_json_parser_65: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= '@') + { + if (yych <= '/') + { + goto basic_json_parser_32; + } + if (yych <= '9') + { + goto basic_json_parser_71; + } + goto basic_json_parser_32; + } + else + { + if (yych <= 'F') + { + goto basic_json_parser_71; + } + if (yych <= '`') + { + goto basic_json_parser_32; + } + if (yych <= 'f') + { + goto basic_json_parser_71; + } + goto basic_json_parser_32; + } +basic_json_parser_66: + yych = *++m_cursor; + if (yych == 'e') + { + goto basic_json_parser_72; + } + goto basic_json_parser_32; +basic_json_parser_67: + ++m_cursor; + { + last_token_type = token_type::literal_null; + break; + } +basic_json_parser_69: + ++m_cursor; + { + last_token_type = token_type::literal_true; + break; + } +basic_json_parser_71: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= '@') + { + if (yych <= '/') + { + goto basic_json_parser_32; + } + if (yych <= '9') + { + goto basic_json_parser_74; + } + goto basic_json_parser_32; + } + else + { + if (yych <= 'F') + { + goto basic_json_parser_74; + } + if (yych <= '`') + { + goto basic_json_parser_32; + } + if (yych <= 'f') + { + goto basic_json_parser_74; + } + goto basic_json_parser_32; + } +basic_json_parser_72: + ++m_cursor; + { + last_token_type = token_type::literal_false; + break; + } +basic_json_parser_74: + ++m_cursor; + if (m_limit <= m_cursor) + { + fill_line_buffer(1); // LCOV_EXCL_LINE + } + yych = *m_cursor; + if (yych <= '@') + { + if (yych <= '/') + { + goto basic_json_parser_32; + } + if (yych <= '9') + { + goto basic_json_parser_30; + } + goto basic_json_parser_32; + } + else + { + if (yych <= 'F') + { + goto basic_json_parser_30; + } + if (yych <= '`') + { + goto basic_json_parser_32; + } + if (yych <= 'f') + { + goto basic_json_parser_30; + } + goto basic_json_parser_32; + } + } + + } + + return last_token_type; + } + + /*! + @brief append data from the stream to the line buffer + + This function is called by the scan() function when the end of the + buffer (`m_limit`) is reached and the `m_cursor` pointer cannot be + incremented without leaving the limits of the line buffer. Note re2c + decides when to call this function. + + If the lexer reads from contiguous storage, there is no trailing null + byte. Therefore, this function must make sure to add these padding + null bytes. + + If the lexer reads from an input stream, this function reads the next + line of the input. + + @pre + p p p p p p u u u u u x . . . . . . + ^ ^ ^ ^ + m_content m_start | m_limit + m_cursor + + @post + u u u u u x x x x x x x . . . . . . + ^ ^ ^ + | m_cursor m_limit + m_start + m_content + */ + void fill_line_buffer(size_t n = 0) + { + // if line buffer is used, m_content points to its data + assert(m_line_buffer.empty() + or m_content == reinterpret_cast<const lexer_char_t*>(m_line_buffer.data())); + + // if line buffer is used, m_limit is set past the end of its data + assert(m_line_buffer.empty() + or m_limit == m_content + m_line_buffer.size()); + + // pointer relationships + assert(m_content <= m_start); + assert(m_start <= m_cursor); + assert(m_cursor <= m_limit); + assert(m_marker == nullptr or m_marker <= m_limit); + + // number of processed characters (p) + const auto num_processed_chars = static_cast<size_t>(m_start - m_content); + // offset for m_marker wrt. to m_start + const auto offset_marker = (m_marker == nullptr) ? 0 : m_marker - m_start; + // number of unprocessed characters (u) + const auto offset_cursor = m_cursor - m_start; + + // no stream is used or end of file is reached + if (m_stream == nullptr or m_stream->eof()) + { + // m_start may or may not be pointing into m_line_buffer at + // this point. We trust the standard library to do the right + // thing. See http://stackoverflow.com/q/28142011/266378 + m_line_buffer.assign(m_start, m_limit); + + // append n characters to make sure that there is sufficient + // space between m_cursor and m_limit + m_line_buffer.append(1, '\x00'); + if (n > 0) + { + m_line_buffer.append(n - 1, '\x01'); + } + } + else + { + // delete processed characters from line buffer + m_line_buffer.erase(0, num_processed_chars); + // read next line from input stream + m_line_buffer_tmp.clear(); + std::getline(*m_stream, m_line_buffer_tmp, '\n'); + + // add line with newline symbol to the line buffer + m_line_buffer += m_line_buffer_tmp; + m_line_buffer.push_back('\n'); + } + + // set pointers + m_content = reinterpret_cast<const lexer_char_t*>(m_line_buffer.data()); + assert(m_content != nullptr); + m_start = m_content; + m_marker = m_start + offset_marker; + m_cursor = m_start + offset_cursor; + m_limit = m_start + m_line_buffer.size(); + } + + /// return string representation of last read token + string_t get_token_string() const + { + assert(m_start != nullptr); + return string_t(reinterpret_cast<typename string_t::const_pointer>(m_start), + static_cast<size_t>(m_cursor - m_start)); + } + + /*! + @brief return string value for string tokens + + The function iterates the characters between the opening and closing + quotes of the string value. The complete string is the range + [m_start,m_cursor). Consequently, we iterate from m_start+1 to + m_cursor-1. + + We differentiate two cases: + + 1. Escaped characters. In this case, a new character is constructed + according to the nature of the escape. Some escapes create new + characters (e.g., `"\\n"` is replaced by `"\n"`), some are copied + as is (e.g., `"\\\\"`). Furthermore, Unicode escapes of the shape + `"\\uxxxx"` need special care. In this case, to_unicode takes care + of the construction of the values. + 2. Unescaped characters are copied as is. + + @pre `m_cursor - m_start >= 2`, meaning the length of the last token + is at least 2 bytes which is trivially true for any string (which + consists of at least two quotes). + + " c1 c2 c3 ... " + ^ ^ + m_start m_cursor + + @complexity Linear in the length of the string.\n + + Lemma: The loop body will always terminate.\n + + Proof (by contradiction): Assume the loop body does not terminate. As + the loop body does not contain another loop, one of the called + functions must never return. The called functions are `std::strtoul` + and to_unicode. Neither function can loop forever, so the loop body + will never loop forever which contradicts the assumption that the loop + body does not terminate, q.e.d.\n + + Lemma: The loop condition for the for loop is eventually false.\n + + Proof (by contradiction): Assume the loop does not terminate. Due to + the above lemma, this can only be due to a tautological loop + condition; that is, the loop condition i < m_cursor - 1 must always be + true. Let x be the change of i for any loop iteration. Then + m_start + 1 + x < m_cursor - 1 must hold to loop indefinitely. This + can be rephrased to m_cursor - m_start - 2 > x. With the + precondition, we x <= 0, meaning that the loop condition holds + indefinitely if i is always decreased. However, observe that the value + of i is strictly increasing with each iteration, as it is incremented + by 1 in the iteration expression and never decremented inside the loop + body. Hence, the loop condition will eventually be false which + contradicts the assumption that the loop condition is a tautology, + q.e.d. + + @return string value of current token without opening and closing + quotes + @throw std::out_of_range if to_unicode fails + */ + string_t get_string() const + { + assert(m_cursor - m_start >= 2); + + string_t result; + result.reserve(static_cast<size_t>(m_cursor - m_start - 2)); + + // iterate the result between the quotes + for (const lexer_char_t* i = m_start + 1; i < m_cursor - 1; ++i) + { + // find next escape character + auto e = std::find(i, m_cursor - 1, '\\'); + if (e != i) + { + // see https://github.com/nlohmann/json/issues/365#issuecomment-262874705 + for (auto k = i; k < e; k++) + { + result.push_back(static_cast<typename string_t::value_type>(*k)); + } + i = e - 1; // -1 because of ++i + } + else + { + // processing escaped character + // read next character + ++i; + + switch (*i) + { + // the default escapes + case 't': + { + result += "\t"; + break; + } + case 'b': + { + result += "\b"; + break; + } + case 'f': + { + result += "\f"; + break; + } + case 'n': + { + result += "\n"; + break; + } + case 'r': + { + result += "\r"; + break; + } + case '\\': + { + result += "\\"; + break; + } + case '/': + { + result += "/"; + break; + } + case '"': + { + result += "\""; + break; + } + + // unicode + case 'u': + { + // get code xxxx from uxxxx + auto codepoint = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer>(i + 1), + 4).c_str(), nullptr, 16); + + // check if codepoint is a high surrogate + if (codepoint >= 0xD800 and codepoint <= 0xDBFF) + { + // make sure there is a subsequent unicode + if ((i + 6 >= m_limit) or * (i + 5) != '\\' or * (i + 6) != 'u') + { + JSON_THROW(std::invalid_argument("missing low surrogate")); + } + + // get code yyyy from uxxxx\uyyyy + auto codepoint2 = std::strtoul(std::string(reinterpret_cast<typename string_t::const_pointer> + (i + 7), 4).c_str(), nullptr, 16); + result += to_unicode(codepoint, codepoint2); + // skip the next 10 characters (xxxx\uyyyy) + i += 10; + } + else if (codepoint >= 0xDC00 and codepoint <= 0xDFFF) + { + // we found a lone low surrogate + JSON_THROW(std::invalid_argument("missing high surrogate")); + } + else + { + // add unicode character(s) + result += to_unicode(codepoint); + // skip the next four characters (xxxx) + i += 4; + } + break; + } + } + } + } + + return result; + } + + + /*! + @brief parse string into a built-in arithmetic type as if the current + locale is POSIX. + + @note in floating-point case strtod may parse past the token's end - + this is not an error + + @note any leading blanks are not handled + */ + struct strtonum + { + public: + strtonum(const char* start, const char* end) + : m_start(start), m_end(end) + {} + + /*! + @return true iff parsed successfully as number of type T + + @param[in,out] val shall contain parsed value, or undefined value + if could not parse + */ + template<typename T, typename = typename std::enable_if<std::is_arithmetic<T>::value>::type> + bool to(T& val) const + { + return parse(val, std::is_integral<T>()); + } + + private: + const char* const m_start = nullptr; + const char* const m_end = nullptr; + + // floating-point conversion + + // overloaded wrappers for strtod/strtof/strtold + // that will be called from parse<floating_point_t> + static void strtof(float& f, const char* str, char** endptr) + { + f = std::strtof(str, endptr); + } + + static void strtof(double& f, const char* str, char** endptr) + { + f = std::strtod(str, endptr); + } + + static void strtof(long double& f, const char* str, char** endptr) + { + f = std::strtold(str, endptr); + } + + template<typename T> + bool parse(T& value, /*is_integral=*/std::false_type) const + { + // replace decimal separator with locale-specific version, + // when necessary; data will point to either the original + // string, or buf, or tempstr containing the fixed string. + std::string tempstr; + std::array<char, 64> buf; + const size_t len = static_cast<size_t>(m_end - m_start); + + // lexer will reject empty numbers + assert(len > 0); + + // since dealing with strtod family of functions, we're + // getting the decimal point char from the C locale facilities + // instead of C++'s numpunct facet of the current std::locale + const auto loc = localeconv(); + assert(loc != nullptr); + const char decimal_point_char = (loc->decimal_point == nullptr) ? '.' : loc->decimal_point[0]; + + const char* data = m_start; + + if (decimal_point_char != '.') + { + const size_t ds_pos = static_cast<size_t>(std::find(m_start, m_end, '.') - m_start); + + if (ds_pos != len) + { + // copy the data into the local buffer or tempstr, if + // buffer is too small; replace decimal separator, and + // update data to point to the modified bytes + if ((len + 1) < buf.size()) + { + std::copy(m_start, m_end, buf.begin()); + buf[len] = 0; + buf[ds_pos] = decimal_point_char; + data = buf.data(); + } + else + { + tempstr.assign(m_start, m_end); + tempstr[ds_pos] = decimal_point_char; + data = tempstr.c_str(); + } + } + } + + char* endptr = nullptr; + value = 0; + // this calls appropriate overload depending on T + strtof(value, data, &endptr); + + // parsing was successful iff strtof parsed exactly the number + // of characters determined by the lexer (len) + const bool ok = (endptr == (data + len)); + + if (ok and (value == static_cast<T>(0.0)) and (*data == '-')) + { + // some implementations forget to negate the zero + value = -0.0; + } + + return ok; + } + + // integral conversion + + signed long long parse_integral(char** endptr, /*is_signed*/std::true_type) const + { + return std::strtoll(m_start, endptr, 10); + } + + unsigned long long parse_integral(char** endptr, /*is_signed*/std::false_type) const + { + return std::strtoull(m_start, endptr, 10); + } + + template<typename T> + bool parse(T& value, /*is_integral=*/std::true_type) const + { + char* endptr = nullptr; + errno = 0; // these are thread-local + const auto x = parse_integral(&endptr, std::is_signed<T>()); + + // called right overload? + static_assert(std::is_signed<T>() == std::is_signed<decltype(x)>(), ""); + + value = static_cast<T>(x); + + return (x == static_cast<decltype(x)>(value)) // x fits into destination T + and (x < 0) == (value < 0) // preserved sign + //and ((x != 0) or is_integral()) // strto[u]ll did nto fail + and (errno == 0) // strto[u]ll did not overflow + and (m_start < m_end) // token was not empty + and (endptr == m_end); // parsed entire token exactly + } + }; + + /*! + @brief return number value for number tokens + + This function translates the last token into the most appropriate + number type (either integer, unsigned integer or floating point), + which is passed back to the caller via the result parameter. + + integral numbers that don't fit into the the range of the respective + type are parsed as number_float_t + + floating-point values do not satisfy std::isfinite predicate + are converted to value_t::null + + throws if the entire string [m_start .. m_cursor) cannot be + interpreted as a number + + @param[out] result @ref basic_json object to receive the number. + @param[in] token the type of the number token + */ + bool get_number(basic_json& result, const token_type token) const + { + assert(m_start != nullptr); + assert(m_start < m_cursor); + assert((token == token_type::value_unsigned) or + (token == token_type::value_integer) or + (token == token_type::value_float)); + + strtonum num_converter(reinterpret_cast<const char*>(m_start), + reinterpret_cast<const char*>(m_cursor)); + + switch (token) + { + case lexer::token_type::value_unsigned: + { + number_unsigned_t val; + if (num_converter.to(val)) + { + // parsing successful + result.m_type = value_t::number_unsigned; + result.m_value = val; + return true; + } + break; + } + + case lexer::token_type::value_integer: + { + number_integer_t val; + if (num_converter.to(val)) + { + // parsing successful + result.m_type = value_t::number_integer; + result.m_value = val; + return true; + } + break; + } + + default: + { + break; + } + } + + // parse float (either explicitly or because a previous conversion + // failed) + number_float_t val; + if (num_converter.to(val)) + { + // parsing successful + result.m_type = value_t::number_float; + result.m_value = val; + + // replace infinity and NAN by null + if (not std::isfinite(result.m_value.number_float)) + { + result.m_type = value_t::null; + result.m_value = basic_json::json_value(); + } + + return true; + } + + // couldn't parse number in any format + return false; + } + + private: + /// optional input stream + std::istream* m_stream = nullptr; + /// line buffer buffer for m_stream + string_t m_line_buffer {}; + /// used for filling m_line_buffer + string_t m_line_buffer_tmp {}; + /// the buffer pointer + const lexer_char_t* m_content = nullptr; + /// pointer to the beginning of the current symbol + const lexer_char_t* m_start = nullptr; + /// pointer for backtracking information + const lexer_char_t* m_marker = nullptr; + /// pointer to the current symbol + const lexer_char_t* m_cursor = nullptr; + /// pointer to the end of the buffer + const lexer_char_t* m_limit = nullptr; + /// the last token type + token_type last_token_type = token_type::end_of_input; + }; + + /*! + @brief syntax analysis + + This class implements a recursive decent parser. + */ + class parser + { + public: + /// a parser reading from a string literal + parser(const char* buff, const parser_callback_t cb = nullptr) + : callback(cb), + m_lexer(reinterpret_cast<const typename lexer::lexer_char_t*>(buff), std::strlen(buff)) + {} + + /// a parser reading from an input stream + parser(std::istream& is, const parser_callback_t cb = nullptr) + : callback(cb), m_lexer(is) + {} + + /// a parser reading from an iterator range with contiguous storage + template<class IteratorType, typename std::enable_if< + std::is_same<typename std::iterator_traits<IteratorType>::iterator_category, std::random_access_iterator_tag>::value + , int>::type + = 0> + parser(IteratorType first, IteratorType last, const parser_callback_t cb = nullptr) + : callback(cb), + m_lexer(reinterpret_cast<const typename lexer::lexer_char_t*>(&(*first)), + static_cast<size_t>(std::distance(first, last))) + {} + + /// public parser interface + basic_json parse() + { + // read first token + get_token(); + + basic_json result = parse_internal(true); + result.assert_invariant(); + + expect(lexer::token_type::end_of_input); + + // return parser result and replace it with null in case the + // top-level value was discarded by the callback function + return result.is_discarded() ? basic_json() : std::move(result); + } + + private: + /// the actual parser + basic_json parse_internal(bool keep) + { + auto result = basic_json(value_t::discarded); + + switch (last_token) + { + case lexer::token_type::begin_object: + { + if (keep and (not callback + or ((keep = callback(depth++, parse_event_t::object_start, result)) != 0))) + { + // explicitly set result to object to cope with {} + result.m_type = value_t::object; + result.m_value = value_t::object; + } + + // read next token + get_token(); + + // closing } -> we are done + if (last_token == lexer::token_type::end_object) + { + get_token(); + if (keep and callback and not callback(--depth, parse_event_t::object_end, result)) + { + result = basic_json(value_t::discarded); + } + return result; + } + + // no comma is expected here + unexpect(lexer::token_type::value_separator); + + // otherwise: parse key-value pairs + do + { + // ugly, but could be fixed with loop reorganization + if (last_token == lexer::token_type::value_separator) + { + get_token(); + } + + // store key + expect(lexer::token_type::value_string); + const auto key = m_lexer.get_string(); + + bool keep_tag = false; + if (keep) + { + if (callback) + { + basic_json k(key); + keep_tag = callback(depth, parse_event_t::key, k); + } + else + { + keep_tag = true; + } + } + + // parse separator (:) + get_token(); + expect(lexer::token_type::name_separator); + + // parse and add value + get_token(); + auto value = parse_internal(keep); + if (keep and keep_tag and not value.is_discarded()) + { + result[key] = std::move(value); + } + } + while (last_token == lexer::token_type::value_separator); + + // closing } + expect(lexer::token_type::end_object); + get_token(); + if (keep and callback and not callback(--depth, parse_event_t::object_end, result)) + { + result = basic_json(value_t::discarded); + } + + return result; + } + + case lexer::token_type::begin_array: + { + if (keep and (not callback + or ((keep = callback(depth++, parse_event_t::array_start, result)) != 0))) + { + // explicitly set result to object to cope with [] + result.m_type = value_t::array; + result.m_value = value_t::array; + } + + // read next token + get_token(); + + // closing ] -> we are done + if (last_token == lexer::token_type::end_array) + { + get_token(); + if (callback and not callback(--depth, parse_event_t::array_end, result)) + { + result = basic_json(value_t::discarded); + } + return result; + } + + // no comma is expected here + unexpect(lexer::token_type::value_separator); + + // otherwise: parse values + do + { + // ugly, but could be fixed with loop reorganization + if (last_token == lexer::token_type::value_separator) + { + get_token(); + } + + // parse value + auto value = parse_internal(keep); + if (keep and not value.is_discarded()) + { + result.push_back(std::move(value)); + } + } + while (last_token == lexer::token_type::value_separator); + + // closing ] + expect(lexer::token_type::end_array); + get_token(); + if (keep and callback and not callback(--depth, parse_event_t::array_end, result)) + { + result = basic_json(value_t::discarded); + } + + return result; + } + + case lexer::token_type::literal_null: + { + get_token(); + result.m_type = value_t::null; + break; + } + + case lexer::token_type::value_string: + { + const auto s = m_lexer.get_string(); + get_token(); + result = basic_json(s); + break; + } + + case lexer::token_type::literal_true: + { + get_token(); + result.m_type = value_t::boolean; + result.m_value = true; + break; + } + + case lexer::token_type::literal_false: + { + get_token(); + result.m_type = value_t::boolean; + result.m_value = false; + break; + } + + case lexer::token_type::value_unsigned: + case lexer::token_type::value_integer: + case lexer::token_type::value_float: + { + m_lexer.get_number(result, last_token); + get_token(); + break; + } + + default: + { + // the last token was unexpected + unexpect(last_token); + } + } + + if (keep and callback and not callback(depth, parse_event_t::value, result)) + { + result = basic_json(value_t::discarded); + } + return result; + } + + /// get next token from lexer + typename lexer::token_type get_token() + { + last_token = m_lexer.scan(); + return last_token; + } + + void expect(typename lexer::token_type t) const + { + if (t != last_token) + { + std::string error_msg = "parse error - unexpected "; + error_msg += (last_token == lexer::token_type::parse_error ? ("'" + m_lexer.get_token_string() + + "'") : + lexer::token_type_name(last_token)); + error_msg += "; expected " + lexer::token_type_name(t); + JSON_THROW(std::invalid_argument(error_msg)); + } + } + + void unexpect(typename lexer::token_type t) const + { + if (t == last_token) + { + std::string error_msg = "parse error - unexpected "; + error_msg += (last_token == lexer::token_type::parse_error ? ("'" + m_lexer.get_token_string() + + "'") : + lexer::token_type_name(last_token)); + JSON_THROW(std::invalid_argument(error_msg)); + } + } + + private: + /// current level of recursion + int depth = 0; + /// callback function + const parser_callback_t callback = nullptr; + /// the type of the last read token + typename lexer::token_type last_token = lexer::token_type::uninitialized; + /// the lexer + lexer m_lexer; + }; + + public: + /*! + @brief JSON Pointer + + A JSON pointer defines a string syntax for identifying a specific value + within a JSON document. It can be used with functions `at` and + `operator[]`. Furthermore, JSON pointers are the base for JSON patches. + + @sa [RFC 6901](https://tools.ietf.org/html/rfc6901) + + @since version 2.0.0 + */ + class json_pointer + { + /// allow basic_json to access private members + friend class basic_json; + + public: + /*! + @brief create JSON pointer + + Create a JSON pointer according to the syntax described in + [Section 3 of RFC6901](https://tools.ietf.org/html/rfc6901#section-3). + + @param[in] s string representing the JSON pointer; if omitted, the + empty string is assumed which references the whole JSON + value + + @throw std::domain_error if reference token is nonempty and does not + begin with a slash (`/`); example: `"JSON pointer must be empty or + begin with /"` + @throw std::domain_error if a tilde (`~`) is not followed by `0` + (representing `~`) or `1` (representing `/`); example: `"escape error: + ~ must be followed with 0 or 1"` + + @liveexample{The example shows the construction several valid JSON + pointers as well as the exceptional behavior.,json_pointer} + + @since version 2.0.0 + */ + explicit json_pointer(const std::string& s = "") + : reference_tokens(split(s)) + {} + + /*! + @brief return a string representation of the JSON pointer + + @invariant For each JSON pointer `ptr`, it holds: + @code {.cpp} + ptr == json_pointer(ptr.to_string()); + @endcode + + @return a string representation of the JSON pointer + + @liveexample{The example shows the result of `to_string`., + json_pointer__to_string} + + @since version 2.0.0 + */ + std::string to_string() const noexcept + { + return std::accumulate(reference_tokens.begin(), + reference_tokens.end(), std::string{}, + [](const std::string & a, const std::string & b) + { + return a + "/" + escape(b); + }); + } + + /// @copydoc to_string() + operator std::string() const + { + return to_string(); + } + + private: + /// remove and return last reference pointer + std::string pop_back() + { + if (is_root()) + { + JSON_THROW(std::domain_error("JSON pointer has no parent")); + } + + auto last = reference_tokens.back(); + reference_tokens.pop_back(); + return last; + } + + /// return whether pointer points to the root document + bool is_root() const + { + return reference_tokens.empty(); + } + + json_pointer top() const + { + if (is_root()) + { + JSON_THROW(std::domain_error("JSON pointer has no parent")); + } + + json_pointer result = *this; + result.reference_tokens = {reference_tokens[0]}; + return result; + } + + /*! + @brief create and return a reference to the pointed to value + + @complexity Linear in the number of reference tokens. + */ + reference get_and_create(reference j) const + { + pointer result = &j; + + // in case no reference tokens exist, return a reference to the + // JSON value j which will be overwritten by a primitive value + for (const auto& reference_token : reference_tokens) + { + switch (result->m_type) + { + case value_t::null: + { + if (reference_token == "0") + { + // start a new array if reference token is 0 + result = &result->operator[](0); + } + else + { + // start a new object otherwise + result = &result->operator[](reference_token); + } + break; + } + + case value_t::object: + { + // create an entry in the object + result = &result->operator[](reference_token); + break; + } + + case value_t::array: + { + // create an entry in the array + result = &result->operator[](static_cast<size_type>(std::stoi(reference_token))); + break; + } + + /* + The following code is only reached if there exists a + reference token _and_ the current value is primitive. In + this case, we have an error situation, because primitive + values may only occur as single value; that is, with an + empty list of reference tokens. + */ + default: + { + JSON_THROW(std::domain_error("invalid value to unflatten")); + } + } + } + + return *result; + } + + /*! + @brief return a reference to the pointed to value + + @note This version does not throw if a value is not present, but tries + to create nested values instead. For instance, calling this function + with pointer `"/this/that"` on a null value is equivalent to calling + `operator[]("this").operator[]("that")` on that value, effectively + changing the null value to an object. + + @param[in] ptr a JSON value + + @return reference to the JSON value pointed to by the JSON pointer + + @complexity Linear in the length of the JSON pointer. + + @throw std::out_of_range if the JSON pointer can not be resolved + @throw std::domain_error if an array index begins with '0' + @throw std::invalid_argument if an array index was not a number + */ + reference get_unchecked(pointer ptr) const + { + for (const auto& reference_token : reference_tokens) + { + // convert null values to arrays or objects before continuing + if (ptr->m_type == value_t::null) + { + // check if reference token is a number + const bool nums = std::all_of(reference_token.begin(), + reference_token.end(), + [](const char x) + { + return std::isdigit(x); + }); + + // change value to array for numbers or "-" or to object + // otherwise + if (nums or reference_token == "-") + { + *ptr = value_t::array; + } + else + { + *ptr = value_t::object; + } + } + + switch (ptr->m_type) + { + case value_t::object: + { + // use unchecked object access + ptr = &ptr->operator[](reference_token); + break; + } + + case value_t::array: + { + // error condition (cf. RFC 6901, Sect. 4) + if (reference_token.size() > 1 and reference_token[0] == '0') + { + JSON_THROW(std::domain_error("array index must not begin with '0'")); + } + + if (reference_token == "-") + { + // explicitly treat "-" as index beyond the end + ptr = &ptr->operator[](ptr->m_value.array->size()); + } + else + { + // convert array index to number; unchecked access + ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token))); + } + break; + } + + default: + { + JSON_THROW(std::out_of_range("unresolved reference token '" + reference_token + "'")); + } + } + } + + return *ptr; + } + + reference get_checked(pointer ptr) const + { + for (const auto& reference_token : reference_tokens) + { + switch (ptr->m_type) + { + case value_t::object: + { + // note: at performs range check + ptr = &ptr->at(reference_token); + break; + } + + case value_t::array: + { + if (reference_token == "-") + { + // "-" always fails the range check + JSON_THROW(std::out_of_range("array index '-' (" + + std::to_string(ptr->m_value.array->size()) + + ") is out of range")); + } + + // error condition (cf. RFC 6901, Sect. 4) + if (reference_token.size() > 1 and reference_token[0] == '0') + { + JSON_THROW(std::domain_error("array index must not begin with '0'")); + } + + // note: at performs range check + ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token))); + break; + } + + default: + { + JSON_THROW(std::out_of_range("unresolved reference token '" + reference_token + "'")); + } + } + } + + return *ptr; + } + + /*! + @brief return a const reference to the pointed to value + + @param[in] ptr a JSON value + + @return const reference to the JSON value pointed to by the JSON + pointer + */ + const_reference get_unchecked(const_pointer ptr) const + { + for (const auto& reference_token : reference_tokens) + { + switch (ptr->m_type) + { + case value_t::object: + { + // use unchecked object access + ptr = &ptr->operator[](reference_token); + break; + } + + case value_t::array: + { + if (reference_token == "-") + { + // "-" cannot be used for const access + JSON_THROW(std::out_of_range("array index '-' (" + + std::to_string(ptr->m_value.array->size()) + + ") is out of range")); + } + + // error condition (cf. RFC 6901, Sect. 4) + if (reference_token.size() > 1 and reference_token[0] == '0') + { + JSON_THROW(std::domain_error("array index must not begin with '0'")); + } + + // use unchecked array access + ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token))); + break; + } + + default: + { + JSON_THROW(std::out_of_range("unresolved reference token '" + reference_token + "'")); + } + } + } + + return *ptr; + } + + const_reference get_checked(const_pointer ptr) const + { + for (const auto& reference_token : reference_tokens) + { + switch (ptr->m_type) + { + case value_t::object: + { + // note: at performs range check + ptr = &ptr->at(reference_token); + break; + } + + case value_t::array: + { + if (reference_token == "-") + { + // "-" always fails the range check + JSON_THROW(std::out_of_range("array index '-' (" + + std::to_string(ptr->m_value.array->size()) + + ") is out of range")); + } + + // error condition (cf. RFC 6901, Sect. 4) + if (reference_token.size() > 1 and reference_token[0] == '0') + { + JSON_THROW(std::domain_error("array index must not begin with '0'")); + } + + // note: at performs range check + ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token))); + break; + } + + default: + { + JSON_THROW(std::out_of_range("unresolved reference token '" + reference_token + "'")); + } + } + } + + return *ptr; + } + + /// split the string input to reference tokens + static std::vector<std::string> split(const std::string& reference_string) + { + std::vector<std::string> result; + + // special case: empty reference string -> no reference tokens + if (reference_string.empty()) + { + return result; + } + + // check if nonempty reference string begins with slash + if (reference_string[0] != '/') + { + JSON_THROW(std::domain_error("JSON pointer must be empty or begin with '/'")); + } + + // extract the reference tokens: + // - slash: position of the last read slash (or end of string) + // - start: position after the previous slash + for ( + // search for the first slash after the first character + size_t slash = reference_string.find_first_of('/', 1), + // set the beginning of the first reference token + start = 1; + // we can stop if start == string::npos+1 = 0 + start != 0; + // set the beginning of the next reference token + // (will eventually be 0 if slash == std::string::npos) + start = slash + 1, + // find next slash + slash = reference_string.find_first_of('/', start)) + { + // use the text between the beginning of the reference token + // (start) and the last slash (slash). + auto reference_token = reference_string.substr(start, slash - start); + + // check reference tokens are properly escaped + for (size_t pos = reference_token.find_first_of('~'); + pos != std::string::npos; + pos = reference_token.find_first_of('~', pos + 1)) + { + assert(reference_token[pos] == '~'); + + // ~ must be followed by 0 or 1 + if (pos == reference_token.size() - 1 or + (reference_token[pos + 1] != '0' and + reference_token[pos + 1] != '1')) + { + JSON_THROW(std::domain_error("escape error: '~' must be followed with '0' or '1'")); + } + } + + // finally, store the reference token + unescape(reference_token); + result.push_back(reference_token); + } + + return result; + } + + private: + /*! + @brief replace all occurrences of a substring by another string + + @param[in,out] s the string to manipulate; changed so that all + occurrences of @a f are replaced with @a t + @param[in] f the substring to replace with @a t + @param[in] t the string to replace @a f + + @pre The search string @a f must not be empty. + + @since version 2.0.0 + */ + static void replace_substring(std::string& s, + const std::string& f, + const std::string& t) + { + assert(not f.empty()); + + for ( + size_t pos = s.find(f); // find first occurrence of f + pos != std::string::npos; // make sure f was found + s.replace(pos, f.size(), t), // replace with t + pos = s.find(f, pos + t.size()) // find next occurrence of f + ); + } + + /// escape tilde and slash + static std::string escape(std::string s) + { + // escape "~"" to "~0" and "/" to "~1" + replace_substring(s, "~", "~0"); + replace_substring(s, "/", "~1"); + return s; + } + + /// unescape tilde and slash + static void unescape(std::string& s) + { + // first transform any occurrence of the sequence '~1' to '/' + replace_substring(s, "~1", "/"); + // then transform any occurrence of the sequence '~0' to '~' + replace_substring(s, "~0", "~"); + } + + /*! + @param[in] reference_string the reference string to the current value + @param[in] value the value to consider + @param[in,out] result the result object to insert values to + + @note Empty objects or arrays are flattened to `null`. + */ + static void flatten(const std::string& reference_string, + const basic_json& value, + basic_json& result) + { + switch (value.m_type) + { + case value_t::array: + { + if (value.m_value.array->empty()) + { + // flatten empty array as null + result[reference_string] = nullptr; + } + else + { + // iterate array and use index as reference string + for (size_t i = 0; i < value.m_value.array->size(); ++i) + { + flatten(reference_string + "/" + std::to_string(i), + value.m_value.array->operator[](i), result); + } + } + break; + } + + case value_t::object: + { + if (value.m_value.object->empty()) + { + // flatten empty object as null + result[reference_string] = nullptr; + } + else + { + // iterate object and use keys as reference string + for (const auto& element : *value.m_value.object) + { + flatten(reference_string + "/" + escape(element.first), + element.second, result); + } + } + break; + } + + default: + { + // add primitive value with its reference string + result[reference_string] = value; + break; + } + } + } + + /*! + @param[in] value flattened JSON + + @return unflattened JSON + */ + static basic_json unflatten(const basic_json& value) + { + if (not value.is_object()) + { + JSON_THROW(std::domain_error("only objects can be unflattened")); + } + + basic_json result; + + // iterate the JSON object values + for (const auto& element : *value.m_value.object) + { + if (not element.second.is_primitive()) + { + JSON_THROW(std::domain_error("values in object must be primitive")); + } + + // assign value to reference pointed to by JSON pointer; Note + // that if the JSON pointer is "" (i.e., points to the whole + // value), function get_and_create returns a reference to + // result itself. An assignment will then create a primitive + // value. + json_pointer(element.first).get_and_create(result) = element.second; + } + + return result; + } + + private: + friend bool operator==(json_pointer const& lhs, + json_pointer const& rhs) noexcept + { + return lhs.reference_tokens == rhs.reference_tokens; + } + + friend bool operator!=(json_pointer const& lhs, + json_pointer const& rhs) noexcept + { + return !(lhs == rhs); + } + + /// the reference tokens + std::vector<std::string> reference_tokens {}; + }; + + ////////////////////////// + // JSON Pointer support // + ////////////////////////// + + /// @name JSON Pointer functions + /// @{ + + /*! + @brief access specified element via JSON Pointer + + Uses a JSON pointer to retrieve a reference to the respective JSON value. + No bound checking is performed. Similar to @ref operator[](const typename + object_t::key_type&), `null` values are created in arrays and objects if + necessary. + + In particular: + - If the JSON pointer points to an object key that does not exist, it + is created an filled with a `null` value before a reference to it + is returned. + - If the JSON pointer points to an array index that does not exist, it + is created an filled with a `null` value before a reference to it + is returned. All indices between the current maximum and the given + index are also filled with `null`. + - The special value `-` is treated as a synonym for the index past the + end. + + @param[in] ptr a JSON pointer + + @return reference to the element pointed to by @a ptr + + @complexity Constant. + + @throw std::out_of_range if the JSON pointer can not be resolved + @throw std::domain_error if an array index begins with '0' + @throw std::invalid_argument if an array index was not a number + + @liveexample{The behavior is shown in the example.,operatorjson_pointer} + + @since version 2.0.0 + */ + reference operator[](const json_pointer& ptr) + { + return ptr.get_unchecked(this); + } + + /*! + @brief access specified element via JSON Pointer + + Uses a JSON pointer to retrieve a reference to the respective JSON value. + No bound checking is performed. The function does not change the JSON + value; no `null` values are created. In particular, the the special value + `-` yields an exception. + + @param[in] ptr JSON pointer to the desired element + + @return const reference to the element pointed to by @a ptr + + @complexity Constant. + + @throw std::out_of_range if the JSON pointer can not be resolved + @throw std::domain_error if an array index begins with '0' + @throw std::invalid_argument if an array index was not a number + + @liveexample{The behavior is shown in the example.,operatorjson_pointer_const} + + @since version 2.0.0 + */ + const_reference operator[](const json_pointer& ptr) const + { + return ptr.get_unchecked(this); + } + + /*! + @brief access specified element via JSON Pointer + + Returns a reference to the element at with specified JSON pointer @a ptr, + with bounds checking. + + @param[in] ptr JSON pointer to the desired element + + @return reference to the element pointed to by @a ptr + + @complexity Constant. + + @throw std::out_of_range if the JSON pointer can not be resolved + @throw std::domain_error if an array index begins with '0' + @throw std::invalid_argument if an array index was not a number + + @liveexample{The behavior is shown in the example.,at_json_pointer} + + @since version 2.0.0 + */ + reference at(const json_pointer& ptr) + { + return ptr.get_checked(this); + } + + /*! + @brief access specified element via JSON Pointer + + Returns a const reference to the element at with specified JSON pointer @a + ptr, with bounds checking. + + @param[in] ptr JSON pointer to the desired element + + @return reference to the element pointed to by @a ptr + + @complexity Constant. + + @throw std::out_of_range if the JSON pointer can not be resolved + @throw std::domain_error if an array index begins with '0' + @throw std::invalid_argument if an array index was not a number + + @liveexample{The behavior is shown in the example.,at_json_pointer_const} + + @since version 2.0.0 + */ + const_reference at(const json_pointer& ptr) const + { + return ptr.get_checked(this); + } + + /*! + @brief return flattened JSON value + + The function creates a JSON object whose keys are JSON pointers (see [RFC + 6901](https://tools.ietf.org/html/rfc6901)) and whose values are all + primitive. The original JSON value can be restored using the @ref + unflatten() function. + + @return an object that maps JSON pointers to primitive values + + @note Empty objects and arrays are flattened to `null` and will not be + reconstructed correctly by the @ref unflatten() function. + + @complexity Linear in the size the JSON value. + + @liveexample{The following code shows how a JSON object is flattened to an + object whose keys consist of JSON pointers.,flatten} + + @sa @ref unflatten() for the reverse function + + @since version 2.0.0 + */ + basic_json flatten() const + { + basic_json result(value_t::object); + json_pointer::flatten("", *this, result); + return result; + } + + /*! + @brief unflatten a previously flattened JSON value + + The function restores the arbitrary nesting of a JSON value that has been + flattened before using the @ref flatten() function. The JSON value must + meet certain constraints: + 1. The value must be an object. + 2. The keys must be JSON pointers (see + [RFC 6901](https://tools.ietf.org/html/rfc6901)) + 3. The mapped values must be primitive JSON types. + + @return the original JSON from a flattened version + + @note Empty objects and arrays are flattened by @ref flatten() to `null` + values and can not unflattened to their original type. Apart from + this example, for a JSON value `j`, the following is always true: + `j == j.flatten().unflatten()`. + + @complexity Linear in the size the JSON value. + + @liveexample{The following code shows how a flattened JSON object is + unflattened into the original nested JSON object.,unflatten} + + @sa @ref flatten() for the reverse function + + @since version 2.0.0 + */ + basic_json unflatten() const + { + return json_pointer::unflatten(*this); + } + + /// @} + + ////////////////////////// + // JSON Patch functions // + ////////////////////////// + + /// @name JSON Patch functions + /// @{ + + /*! + @brief applies a JSON patch + + [JSON Patch](http://jsonpatch.com) defines a JSON document structure for + expressing a sequence of operations to apply to a JSON) document. With + this function, a JSON Patch is applied to the current JSON value by + executing all operations from the patch. + + @param[in] json_patch JSON patch document + @return patched document + + @note The application of a patch is atomic: Either all operations succeed + and the patched document is returned or an exception is thrown. In + any case, the original value is not changed: the patch is applied + to a copy of the value. + + @throw std::out_of_range if a JSON pointer inside the patch could not + be resolved successfully in the current JSON value; example: `"key baz + not found"` + @throw invalid_argument if the JSON patch is malformed (e.g., mandatory + attributes are missing); example: `"operation add must have member path"` + + @complexity Linear in the size of the JSON value and the length of the + JSON patch. As usually only a fraction of the JSON value is affected by + the patch, the complexity can usually be neglected. + + @liveexample{The following code shows how a JSON patch is applied to a + value.,patch} + + @sa @ref diff -- create a JSON patch by comparing two JSON values + + @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902) + @sa [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901) + + @since version 2.0.0 + */ + basic_json patch(const basic_json& json_patch) const + { + // make a working copy to apply the patch to + basic_json result = *this; + + // the valid JSON Patch operations + enum class patch_operations {add, remove, replace, move, copy, test, invalid}; + + const auto get_op = [](const std::string op) + { + if (op == "add") + { + return patch_operations::add; + } + if (op == "remove") + { + return patch_operations::remove; + } + if (op == "replace") + { + return patch_operations::replace; + } + if (op == "move") + { + return patch_operations::move; + } + if (op == "copy") + { + return patch_operations::copy; + } + if (op == "test") + { + return patch_operations::test; + } + + return patch_operations::invalid; + }; + + // wrapper for "add" operation; add value at ptr + const auto operation_add = [&result](json_pointer & ptr, basic_json val) + { + // adding to the root of the target document means replacing it + if (ptr.is_root()) + { + result = val; + } + else + { + // make sure the top element of the pointer exists + json_pointer top_pointer = ptr.top(); + if (top_pointer != ptr) + { + result.at(top_pointer); + } + + // get reference to parent of JSON pointer ptr + const auto last_path = ptr.pop_back(); + basic_json& parent = result[ptr]; + + switch (parent.m_type) + { + case value_t::null: + case value_t::object: + { + // use operator[] to add value + parent[last_path] = val; + break; + } + + case value_t::array: + { + if (last_path == "-") + { + // special case: append to back + parent.push_back(val); + } + else + { + const auto idx = std::stoi(last_path); + if (static_cast<size_type>(idx) > parent.size()) + { + // avoid undefined behavior + JSON_THROW(std::out_of_range("array index " + std::to_string(idx) + " is out of range")); + } + else + { + // default case: insert add offset + parent.insert(parent.begin() + static_cast<difference_type>(idx), val); + } + } + break; + } + + default: + { + // if there exists a parent it cannot be primitive + assert(false); // LCOV_EXCL_LINE + } + } + } + }; + + // wrapper for "remove" operation; remove value at ptr + const auto operation_remove = [&result](json_pointer & ptr) + { + // get reference to parent of JSON pointer ptr + const auto last_path = ptr.pop_back(); + basic_json& parent = result.at(ptr); + + // remove child + if (parent.is_object()) + { + // perform range check + auto it = parent.find(last_path); + if (it != parent.end()) + { + parent.erase(it); + } + else + { + JSON_THROW(std::out_of_range("key '" + last_path + "' not found")); + } + } + else if (parent.is_array()) + { + // note erase performs range check + parent.erase(static_cast<size_type>(std::stoi(last_path))); + } + }; + + // type check + if (not json_patch.is_array()) + { + // a JSON patch must be an array of objects + JSON_THROW(std::invalid_argument("JSON patch must be an array of objects")); + } + + // iterate and apply the operations + for (const auto& val : json_patch) + { + // wrapper to get a value for an operation + const auto get_value = [&val](const std::string & op, + const std::string & member, + bool string_type) -> basic_json& + { + // find value + auto it = val.m_value.object->find(member); + + // context-sensitive error message + const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'"; + + // check if desired value is present + if (it == val.m_value.object->end()) + { + JSON_THROW(std::invalid_argument(error_msg + " must have member '" + member + "'")); + } + + // check if result is of type string + if (string_type and not it->second.is_string()) + { + JSON_THROW(std::invalid_argument(error_msg + " must have string member '" + member + "'")); + } + + // no error: return value + return it->second; + }; + + // type check + if (not val.is_object()) + { + JSON_THROW(std::invalid_argument("JSON patch must be an array of objects")); + } + + // collect mandatory members + const std::string op = get_value("op", "op", true); + const std::string path = get_value(op, "path", true); + json_pointer ptr(path); + + switch (get_op(op)) + { + case patch_operations::add: + { + operation_add(ptr, get_value("add", "value", false)); + break; + } + + case patch_operations::remove: + { + operation_remove(ptr); + break; + } + + case patch_operations::replace: + { + // the "path" location must exist - use at() + result.at(ptr) = get_value("replace", "value", false); + break; + } + + case patch_operations::move: + { + const std::string from_path = get_value("move", "from", true); + json_pointer from_ptr(from_path); + + // the "from" location must exist - use at() + basic_json v = result.at(from_ptr); + + // The move operation is functionally identical to a + // "remove" operation on the "from" location, followed + // immediately by an "add" operation at the target + // location with the value that was just removed. + operation_remove(from_ptr); + operation_add(ptr, v); + break; + } + + case patch_operations::copy: + { + const std::string from_path = get_value("copy", "from", true);; + const json_pointer from_ptr(from_path); + + // the "from" location must exist - use at() + result[ptr] = result.at(from_ptr); + break; + } + + case patch_operations::test: + { + bool success = false; + JSON_TRY + { + // check if "value" matches the one at "path" + // the "path" location must exist - use at() + success = (result.at(ptr) == get_value("test", "value", false)); + } + JSON_CATCH (std::out_of_range&) + { + // ignore out of range errors: success remains false + } + + // throw an exception if test fails + if (not success) + { + JSON_THROW(std::domain_error("unsuccessful: " + val.dump())); + } + + break; + } + + case patch_operations::invalid: + { + // op must be "add", "remove", "replace", "move", "copy", or + // "test" + JSON_THROW(std::invalid_argument("operation value '" + op + "' is invalid")); + } + } + } + + return result; + } + + /*! + @brief creates a diff as a JSON patch + + Creates a [JSON Patch](http://jsonpatch.com) so that value @a source can + be changed into the value @a target by calling @ref patch function. + + @invariant For two JSON values @a source and @a target, the following code + yields always `true`: + @code {.cpp} + source.patch(diff(source, target)) == target; + @endcode + + @note Currently, only `remove`, `add`, and `replace` operations are + generated. + + @param[in] source JSON value to compare from + @param[in] target JSON value to compare against + @param[in] path helper value to create JSON pointers + + @return a JSON patch to convert the @a source to @a target + + @complexity Linear in the lengths of @a source and @a target. + + @liveexample{The following code shows how a JSON patch is created as a + diff for two JSON values.,diff} + + @sa @ref patch -- apply a JSON patch + + @sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902) + + @since version 2.0.0 + */ + static basic_json diff(const basic_json& source, + const basic_json& target, + const std::string& path = "") + { + // the patch + basic_json result(value_t::array); + + // if the values are the same, return empty patch + if (source == target) + { + return result; + } + + if (source.type() != target.type()) + { + // different types: replace value + result.push_back( + { + {"op", "replace"}, + {"path", path}, + {"value", target} + }); + } + else + { + switch (source.type()) + { + case value_t::array: + { + // first pass: traverse common elements + size_t i = 0; + while (i < source.size() and i < target.size()) + { + // recursive call to compare array values at index i + auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i)); + result.insert(result.end(), temp_diff.begin(), temp_diff.end()); + ++i; + } + + // i now reached the end of at least one array + // in a second pass, traverse the remaining elements + + // remove my remaining elements + const auto end_index = static_cast<difference_type>(result.size()); + while (i < source.size()) + { + // add operations in reverse order to avoid invalid + // indices + result.insert(result.begin() + end_index, object( + { + {"op", "remove"}, + {"path", path + "/" + std::to_string(i)} + })); + ++i; + } + + // add other remaining elements + while (i < target.size()) + { + result.push_back( + { + {"op", "add"}, + {"path", path + "/" + std::to_string(i)}, + {"value", target[i]} + }); + ++i; + } + + break; + } + + case value_t::object: + { + // first pass: traverse this object's elements + for (auto it = source.begin(); it != source.end(); ++it) + { + // escape the key name to be used in a JSON patch + const auto key = json_pointer::escape(it.key()); + + if (target.find(it.key()) != target.end()) + { + // recursive call to compare object values at key it + auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key); + result.insert(result.end(), temp_diff.begin(), temp_diff.end()); + } + else + { + // found a key that is not in o -> remove it + result.push_back(object( + { + {"op", "remove"}, + {"path", path + "/" + key} + })); + } + } + + // second pass: traverse other object's elements + for (auto it = target.begin(); it != target.end(); ++it) + { + if (source.find(it.key()) == source.end()) + { + // found a key that is not in this -> add it + const auto key = json_pointer::escape(it.key()); + result.push_back( + { + {"op", "add"}, + {"path", path + "/" + key}, + {"value", it.value()} + }); + } + } + + break; + } + + default: + { + // both primitive type: replace value + result.push_back( + { + {"op", "replace"}, + {"path", path}, + {"value", target} + }); + break; + } + } + } + + return result; + } + + /// @} +}; + +///////////// +// presets // +///////////// + +/*! +@brief default JSON class + +This type is the default specialization of the @ref basic_json class which +uses the standard template types. + +@since version 1.0.0 +*/ +using json = basic_json<>; +} // namespace nlohmann + + +/////////////////////// +// nonmember support // +/////////////////////// + +// specialization of std::swap, and std::hash +namespace std +{ +/*! +@brief exchanges the values of two JSON objects + +@since version 1.0.0 +*/ +template<> +inline void swap(nlohmann::json& j1, + nlohmann::json& j2) noexcept( + is_nothrow_move_constructible<nlohmann::json>::value and + is_nothrow_move_assignable<nlohmann::json>::value + ) +{ + j1.swap(j2); +} + +/// hash value for JSON objects +template<> +struct hash<nlohmann::json> +{ + /*! + @brief return a hash value for a JSON object + + @since version 1.0.0 + */ + std::size_t operator()(const nlohmann::json& j) const + { + // a naive hashing via the string representation + const auto& h = hash<nlohmann::json::string_t>(); + return h(j.dump()); + } +}; +} // namespace std + +/*! +@brief user-defined string literal for JSON values + +This operator implements a user-defined string literal for JSON objects. It +can be used by adding `"_json"` to a string literal and returns a JSON object +if no parse error occurred. + +@param[in] s a string representation of a JSON object +@param[in] n the length of string @a s +@return a JSON object + +@since version 1.0.0 +*/ +inline nlohmann::json operator "" _json(const char* s, std::size_t n) +{ + return nlohmann::json::parse(s, s + n); +} + +/*! +@brief user-defined string literal for JSON pointer + +This operator implements a user-defined string literal for JSON Pointers. It +can be used by adding `"_json_pointer"` to a string literal and returns a JSON pointer +object if no parse error occurred. + +@param[in] s a string representation of a JSON Pointer +@param[in] n the length of string @a s +@return a JSON pointer object + +@since version 2.0.0 +*/ +inline nlohmann::json::json_pointer operator "" _json_pointer(const char* s, std::size_t n) +{ + return nlohmann::json::json_pointer(std::string(s, n)); +} + +// restore GCC/clang diagnostic settings +#if defined(__clang__) || defined(__GNUC__) || defined(__GNUG__) + #pragma GCC diagnostic pop +#endif + +// clean up +#undef JSON_CATCH +#undef JSON_DEPRECATED +#undef JSON_THROW +#undef JSON_TRY + +#endif |