Files
clang-p2996/libcxx/include/__bit/byteswap.h
Louis Dionne 9783f28cbb [libc++] Format the code base (#74334)
This patch runs clang-format on all of libcxx/include and libcxx/src, in
accordance with the RFC discussed at [1]. Follow-up patches will format
the benchmarks, the test suite and remaining parts of the code. I'm
splitting this one into its own patch so the diff is a bit easier to
review.

This patch was generated with:

   find libcxx/include libcxx/src -type f \
      | grep -v 'module.modulemap.in' \
      | grep -v 'CMakeLists.txt' \
      | grep -v 'README.txt' \
      | grep -v 'libcxx.imp' \
      | grep -v '__config_site.in' \
      | xargs clang-format -i

A Git merge driver is available in libcxx/utils/clang-format-merge-driver.sh
to help resolve merge and rebase issues across these formatting changes.

[1]: https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
2023-12-18 14:01:33 -05:00

54 lines
1.6 KiB
C++

// -*- 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>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 23
template <integral _Tp>
_LIBCPP_NODISCARD_EXT _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 >= 23
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___BIT_BYTESWAP_H