| // -*- C++ -*- |
| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP___BIT_BYTESWAP_H |
| #define _LIBCPP___BIT_BYTESWAP_H |
| |
| #include <__concepts/arithmetic.h> |
| #include <__config> |
| #include <cstdint> |
| #include <cstdlib> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_CONCEPTS) |
| |
| template <integral _Tp> |
| _LIBCPP_HIDE_FROM_ABI constexpr _Tp byteswap(_Tp __val) noexcept { |
| |
| if constexpr (sizeof(_Tp) == 1) { |
| return __val; |
| } else if constexpr (sizeof(_Tp) == 2) { |
| return __builtin_bswap16(__val); |
| } else if constexpr (sizeof(_Tp) == 4) { |
| return __builtin_bswap32(__val); |
| } else if constexpr (sizeof(_Tp) == 8) { |
| return __builtin_bswap64(__val); |
| #ifndef _LIBCPP_HAS_NO_INT128 |
| } else if constexpr (sizeof(_Tp) == 16) { |
| #if __has_builtin(__builtin_bswap128) |
| return __builtin_bswap128(__val); |
| #else |
| return static_cast<_Tp>(byteswap(static_cast<uint64_t>(__val))) << 64 | |
| static_cast<_Tp>(byteswap(static_cast<uint64_t>(__val >> 64))); |
| #endif // __has_builtin(__builtin_bswap128) |
| #endif // _LIBCPP_HAS_NO_INT128 |
| } else { |
| static_assert(sizeof(_Tp) == 0, "byteswap is unimplemented for integral types of this size"); |
| } |
| } |
| |
| #endif // _LIBCPP_STD_VER > 20 && !defined(_LIBCPP_HAS_NO_CONCEPTS) |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___BIT_BYTESWAP_H |
