1//===- SwapByteOrder.h - Generic and optimized byte swaps -------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file declares generic and optimized functions to swap the byte order of 11// an integral type. 12// 13//===----------------------------------------------------------------------===// 14 15#ifndef LLVM_SYSTEM_SWAP_BYTE_ORDER_H 16#define LLVM_SYSTEM_SWAP_BYTE_ORDER_H 17 18#include "llvm/Support/DataTypes.h" 19#include <cstddef> 20#include <limits> 21 22namespace llvm { 23namespace sys { 24 25/// SwapByteOrder_16 - This function returns a byte-swapped representation of 26/// the 16-bit argument. 27inline uint16_t SwapByteOrder_16(uint16_t value) { 28#if defined(_MSC_VER) && !defined(_DEBUG) 29 // The DLL version of the runtime lacks these functions (bug!?), but in a 30 // release build they're replaced with BSWAP instructions anyway. 31 return _byteswap_ushort(value); 32#else 33 uint16_t Hi = value << 8; 34 uint16_t Lo = value >> 8; 35 return Hi | Lo; 36#endif 37} 38 39/// SwapByteOrder_32 - This function returns a byte-swapped representation of 40/// the 32-bit argument. 41inline uint32_t SwapByteOrder_32(uint32_t value) { 42#if defined(__llvm__) || \ 43(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__ICC) 44 return __builtin_bswap32(value); 45#elif defined(_MSC_VER) && !defined(_DEBUG) 46 return _byteswap_ulong(value); 47#else 48 uint32_t Byte0 = value & 0x000000FF; 49 uint32_t Byte1 = value & 0x0000FF00; 50 uint32_t Byte2 = value & 0x00FF0000; 51 uint32_t Byte3 = value & 0xFF000000; 52 return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24); 53#endif 54} 55 56/// SwapByteOrder_64 - This function returns a byte-swapped representation of 57/// the 64-bit argument. 58inline uint64_t SwapByteOrder_64(uint64_t value) { 59#if defined(__llvm__) || \ 60(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__ICC) 61 return __builtin_bswap64(value); 62#elif defined(_MSC_VER) && !defined(_DEBUG) 63 return _byteswap_uint64(value); 64#else 65 uint64_t Hi = SwapByteOrder_32(uint32_t(value)); 66 uint32_t Lo = SwapByteOrder_32(uint32_t(value >> 32)); 67 return (Hi << 32) | Lo; 68#endif 69} 70 71inline unsigned char SwapByteOrder(unsigned char C) { return C; } 72inline signed char SwapByteOrder(signed char C) { return C; } 73inline char SwapByteOrder(char C) { return C; } 74 75inline unsigned short SwapByteOrder(unsigned short C) { return SwapByteOrder_16(C); } 76inline signed short SwapByteOrder( signed short C) { return SwapByteOrder_16(C); } 77 78inline unsigned int SwapByteOrder(unsigned int C) { return SwapByteOrder_32(C); } 79inline signed int SwapByteOrder( signed int C) { return SwapByteOrder_32(C); } 80 81#if __LONG_MAX__ == __INT_MAX__ 82inline unsigned long SwapByteOrder(unsigned long C) { return SwapByteOrder_32(C); } 83inline signed long SwapByteOrder( signed long C) { return SwapByteOrder_32(C); } 84#elif __LONG_MAX__ == __LONG_LONG_MAX__ 85inline unsigned long SwapByteOrder(unsigned long C) { return SwapByteOrder_64(C); } 86inline signed long SwapByteOrder( signed long C) { return SwapByteOrder_64(C); } 87#else 88#error "Unknown long size!" 89#endif 90 91inline unsigned long long SwapByteOrder(unsigned long long C) { 92 return SwapByteOrder_64(C); 93} 94inline signed long long SwapByteOrder(signed long long C) { 95 return SwapByteOrder_64(C); 96} 97 98} // end namespace sys 99} // end namespace llvm 100 101#endif 102