/////////////////////////////////////////////////////////////////////////////// // // Copyright (c) 2015 Microsoft Corporation. All rights reserved. // // This code is licensed under the MIT License (MIT). // // 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 GSL_UTIL_H #define GSL_UTIL_H #include "assert" // for Expects #include <array> #include <cstddef> // for ptrdiff_t, size_t #include <initializer_list> // for initializer_list #include <type_traits> // for is_signed, integral_constant #include <utility> // for exchange, forward #if defined(__has_include) && __has_include(<version>) #include <version> #if defined(__cpp_lib_span) && __cpp_lib_span >= 202002L #include <span> #endif // __cpp_lib_span >= 202002L #endif //__has_include(<version>) #if defined(_MSC_VER) && !defined(__clang__) #pragma warning(push) #pragma warning(disable : 4127) // conditional expression is constant #endif // _MSC_VER #if defined(__cplusplus) && (__cplusplus >= 201703L) #define GSL_NODISCARD [[nodiscard]] #else #define GSL_NODISCARD #endif // defined(__cplusplus) && (__cplusplus >= 201703L) #if defined(__cpp_inline_variables) #define GSL_INLINE inline #else #define GSL_INLINE #endif namespace gsl { // // GSL.util: utilities // // index type for all container indexes/subscripts/sizes using index = std::ptrdiff_t; // final_action allows you to ensure something gets run at the end of a scope template <class F> class final_action { public: static_assert(!std::is_reference<F>::value && !std::is_const<F>::value && !std::is_volatile<F>::value, "Final_action should store its callable by value"); explicit final_action(F f) noexcept : f_(std::move(f)) {} final_action(final_action&& other) noexcept : f_(std::move(other.f_)), invoke_(std::exchange(other.invoke_, false)) {} final_action(const final_action&) = delete; final_action& operator=(const final_action&) = delete; final_action& operator=(final_action&&) = delete; // clang-format off GSL_SUPPRESS(f.6) // NO-FORMAT: attribute // terminate if throws // clang-format on ~final_action() noexcept { if (invoke_) f_(); } private: F f_; bool invoke_{true}; }; // finally() - convenience function to generate a final_action template <class F> GSL_NODISCARD final_action<typename std::remove_cv<typename std::remove_reference<F>::type>::type> finally(F&& f) noexcept { return final_action<typename std::remove_cv<typename std::remove_reference<F>::type>::type>( std::forward<F>(f)); } // narrow_cast(): a searchable way to do narrowing casts of values template <class T, class U> // clang-format off GSL_SUPPRESS(type.1) // NO-FORMAT: attribute // clang-format on constexpr T narrow_cast(U&& u) noexcept { return static_cast<T>(std::forward<U>(u)); } // // at() - Bounds-checked way of accessing builtin arrays, std::array, std::vector // template <class T, std::size_t N> // clang-format off GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute // clang-format on constexpr T& at(T (&arr)[N], const index i) { Expects(i >= 0 && i < narrow_cast<index>(N)); return arr[narrow_cast<std::size_t>(i)]; } template <class Cont> // clang-format off GSL_SUPPRESS(bounds.4) // NO-FORMAT: attribute GSL_SUPPRESS(bounds.2) // NO-FORMAT: attribute // clang-format on constexpr auto at(Cont& cont, const index i) -> decltype(cont[cont.size()]) { Expects(i >= 0 && i < narrow_cast<index>(cont.size())); using size_type = decltype(cont.size()); return cont[narrow_cast<size_type>(i)]; } template <class T> // clang-format off GSL_SUPPRESS(bounds.1) // NO-FORMAT: attribute // clang-format on constexpr T at(const std::initializer_list<T> cont, const index i) { Expects(i >= 0 && i < narrow_cast<index>(cont.size())); return *(cont.begin() + i); } #if defined(__cpp_lib_span) && __cpp_lib_span >= 202002L template <class T, size_t extent = std::dynamic_extent> constexpr auto at(std::span<T, extent> sp, const index i) -> decltype(sp[sp.size()]) { Expects(i >= 0 && i < narrow_cast<index>(sp.size())); return sp[gsl::narrow_cast<size_t>(i)]; } #endif // __cpp_lib_span >= 202002L } // namespace gsl #if defined(_MSC_VER) && !defined(__clang__) #pragma warning(pop) #endif // _MSC_VER #endif // GSL_UTIL_H