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#ifndef MAPBOX_UTIL_RECURSIVE_WRAPPER_HPP
#define MAPBOX_UTIL_RECURSIVE_WRAPPER_HPP
// Based on variant/recursive_wrapper.hpp from boost.
//
// Original license:
//
// Copyright (c) 2002-2003
// Eric Friedman, Itay Maman
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#include <cassert>
#include <utility>
namespace mapbox {
namespace util {
template <typename T>
class recursive_wrapper
{
T* p_;
void assign(T const& rhs)
{
this->get() = rhs;
}
public:
using type = T;
/**
* Default constructor default initializes the internally stored value.
* For POD types this means nothing is done and the storage is
* uninitialized.
*
* @throws std::bad_alloc if there is insufficient memory for an object
* of type T.
* @throws any exception thrown by the default constructur of T.
*/
recursive_wrapper()
: p_(new T){}
~recursive_wrapper() noexcept { delete p_; }
recursive_wrapper(recursive_wrapper const& operand)
: p_(new T(operand.get())) {}
recursive_wrapper(T const& operand)
: p_(new T(operand)) {}
recursive_wrapper(recursive_wrapper&& operand)
: p_(new T(std::move(operand.get()))) {}
recursive_wrapper(T&& operand)
: p_(new T(std::move(operand))) {}
inline recursive_wrapper& operator=(recursive_wrapper const& rhs)
{
assign(rhs.get());
return *this;
}
inline recursive_wrapper& operator=(T const& rhs)
{
assign(rhs);
return *this;
}
inline void swap(recursive_wrapper& operand) noexcept
{
T* temp = operand.p_;
operand.p_ = p_;
p_ = temp;
}
recursive_wrapper& operator=(recursive_wrapper&& rhs) noexcept
{
swap(rhs);
return *this;
}
recursive_wrapper& operator=(T&& rhs)
{
get() = std::move(rhs);
return *this;
}
T& get()
{
assert(p_);
return *get_pointer();
}
T const& get() const
{
assert(p_);
return *get_pointer();
}
T* get_pointer() { return p_; }
const T* get_pointer() const { return p_; }
operator T const&() const { return this->get(); }
operator T&() { return this->get(); }
}; // class recursive_wrapper
template <typename T>
inline void swap(recursive_wrapper<T>& lhs, recursive_wrapper<T>& rhs) noexcept
{
lhs.swap(rhs);
}
} // namespace util
} // namespace mapbox
#endif // MAPBOX_UTIL_RECURSIVE_WRAPPER_HPP
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