llvm/Support/SwapByteOrder.h

0001 //===- SwapByteOrder.h - Generic and optimized byte swaps -------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008 //
0009 // This file declares generic and optimized functions to swap the byte order of
0010 // an integral type.
0011 //
0012 //===----------------------------------------------------------------------===//
0013
0014 #ifndef LLVM_SUPPORT_SWAPBYTEORDER_H
0015 #define LLVM_SUPPORT_SWAPBYTEORDER_H
0016
0017 #include "llvm/ADT/STLForwardCompat.h"
0018 #include "llvm/ADT/bit.h"
0019 #include <cstdint>
0020 #include <type_traits>
0021
0022 namespace llvm {
0023
0024 namespace sys {
0025
0026 constexpr bool IsBigEndianHost =
0027     llvm::endianness::native == llvm::endianness::big;
0028
0029 static const bool IsLittleEndianHost = !IsBigEndianHost;
0030
0031 inline unsigned char      getSwappedBytes(unsigned char      C) { return llvm::byteswap(C); }
0032 inline   signed char      getSwappedBytes( signed  char      C) { return llvm::byteswap(C); }
0033 inline          char      getSwappedBytes(         char      C) { return llvm::byteswap(C); }
0034
0035 inline unsigned short     getSwappedBytes(unsigned short     C) { return llvm::byteswap(C); }
0036 inline   signed short     getSwappedBytes(  signed short     C) { return llvm::byteswap(C); }
0037
0038 inline unsigned int       getSwappedBytes(unsigned int       C) { return llvm::byteswap(C); }
0039 inline   signed int       getSwappedBytes(  signed int       C) { return llvm::byteswap(C); }
0040
0041 inline unsigned long      getSwappedBytes(unsigned long      C) { return llvm::byteswap(C); }
0042 inline   signed long      getSwappedBytes(  signed long      C) { return llvm::byteswap(C); }
0043
0044 inline unsigned long long getSwappedBytes(unsigned long long C) { return llvm::byteswap(C); }
0045 inline   signed long long getSwappedBytes(  signed long long C) { return llvm::byteswap(C); }
0046
0047 inline float getSwappedBytes(float C) {
0048   return llvm::bit_cast<float>(llvm::byteswap(llvm::bit_cast<uint32_t>(C)));
0049 }
0050
0051 inline double getSwappedBytes(double C) {
0052   return llvm::bit_cast<double>(llvm::byteswap(llvm::bit_cast<uint64_t>(C)));
0053 }
0054
0055 template <typename T>
0056 inline std::enable_if_t<std::is_enum_v<T>, T> getSwappedBytes(T C) {
0057   return static_cast<T>(llvm::byteswap(llvm::to_underlying(C)));
0058 }
0059
0060 template<typename T>
0061 inline void swapByteOrder(T &Value) {
0062   Value = getSwappedBytes(Value);
0063 }
0064
0065 } // end namespace sys
0066 } // end namespace llvm
0067
0068 #endif