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author | wanglu <wang_lu@dl.cn.nexty-ele.com> | 2019-03-25 09:42:49 +0800 |
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committer | wanglu <wang_lu@dl.cn.nexty-ele.com> | 2019-03-25 09:52:02 +0800 |
commit | 4a8b7a6301e4b093c99329d0a16fbee6c535f312 (patch) | |
tree | fe9f589e1723e8f173b50dfa617374042f4cf7a7 /include/mapbox/optional.hpp | |
parent | fb539bbd9f7b36d26cd56fe09b804e18b3b3d984 (diff) |
This is a application for display turn by run navigation information.halibut_8.0.0halibut_7.99.3halibut_7.99.2halibut_7.99.1halibut/8.0.0halibut/7.99.3halibut/7.99.2halibut/7.99.18.0.07.99.37.99.27.99.1
Change-Id: I0866a7d9ffa347c0935b4d00259ad1a74cd00d6e
Signed-off-by: wanglu <wang_lu@dl.cn.nexty-ele.com>
Diffstat (limited to 'include/mapbox/optional.hpp')
-rw-r--r-- | include/mapbox/optional.hpp | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/include/mapbox/optional.hpp b/include/mapbox/optional.hpp new file mode 100644 index 0000000..d84705c --- /dev/null +++ b/include/mapbox/optional.hpp @@ -0,0 +1,74 @@ +#ifndef MAPBOX_UTIL_OPTIONAL_HPP +#define MAPBOX_UTIL_OPTIONAL_HPP + +#pragma message("This implementation of optional is deprecated. See https://github.com/mapbox/variant/issues/64.") + +#include <type_traits> +#include <utility> + +#include <mapbox/variant.hpp> + +namespace mapbox { +namespace util { + +template <typename T> +class optional +{ + static_assert(!std::is_reference<T>::value, "optional doesn't support references"); + + struct none_type + { + }; + + variant<none_type, T> variant_; + +public: + optional() = default; + + optional(optional const& rhs) + { + if (this != &rhs) + { // protect against invalid self-assignment + variant_ = rhs.variant_; + } + } + + optional(T const& v) { variant_ = v; } + + explicit operator bool() const noexcept { return variant_.template is<T>(); } + + T const& get() const { return variant_.template get<T>(); } + T& get() { return variant_.template get<T>(); } + + T const& operator*() const { return this->get(); } + T operator*() { return this->get(); } + + optional& operator=(T const& v) + { + variant_ = v; + return *this; + } + + optional& operator=(optional const& rhs) + { + if (this != &rhs) + { + variant_ = rhs.variant_; + } + return *this; + } + + template <typename... Args> + void emplace(Args&&... args) + { + variant_ = T{std::forward<Args>(args)...}; + } + + void reset() { variant_ = none_type{}; } + +}; // class optional + +} // namespace util +} // namespace mapbox + +#endif // MAPBOX_UTIL_OPTIONAL_HPP |