// Copyright 2016 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef BASE_BIT_CAST_H_ #define BASE_BIT_CAST_H_ #include #include "base/compiler_specific.h" #if !HAS_BUILTIN(__builtin_bit_cast) #include // memcpy #endif namespace base { // This is C++20's std::bit_cast<>(). It morally does what // `*reinterpret_cast(&source)` does, but the cast/deref pair is // undefined behavior, while bit_cast<>() isn't. template #if HAS_BUILTIN(__builtin_bit_cast) constexpr #else inline #endif Dest bit_cast(const Source& source) { #if HAS_BUILTIN(__builtin_bit_cast) // TODO(thakis): Keep only this codepath once nacl is gone or updated. return __builtin_bit_cast(Dest, source); #else static_assert(sizeof(Dest) == sizeof(Source), "bit_cast requires source and destination to be the same size"); static_assert(std::is_trivially_copyable_v, "bit_cast requires the destination type to be copyable"); static_assert(std::is_trivially_copyable_v, "bit_cast requires the source type to be copyable"); Dest dest; memcpy(&dest, &source, sizeof(dest)); return dest; #endif } } // namespace base #endif // BASE_BIT_CAST_H_