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_SUPPORT_SWAPBYTEORDER_H 16#define LLVM_SUPPORT_SWAPBYTEORDER_H 17 18#include "llvm/Support/Compiler.h" 19#include "llvm/Support/DataTypes.h" 20#include <cstddef> 21#if defined(_MSC_VER) && !defined(_DEBUG) 22#include <stdlib.h> 23#endif 24 25namespace llvm { 26namespace sys { 27 28/// SwapByteOrder_16 - This function returns a byte-swapped representation of 29/// the 16-bit argument. 30inline uint16_t SwapByteOrder_16(uint16_t value) { 31#if defined(_MSC_VER) && !defined(_DEBUG) 32 // The DLL version of the runtime lacks these functions (bug!?), but in a 33 // release build they're replaced with BSWAP instructions anyway. 34 return _byteswap_ushort(value); 35#else 36 uint16_t Hi = value << 8; 37 uint16_t Lo = value >> 8; 38 return Hi | Lo; 39#endif 40} 41 42/// SwapByteOrder_32 - This function returns a byte-swapped representation of 43/// the 32-bit argument. 44inline uint32_t SwapByteOrder_32(uint32_t value) { 45#if defined(__llvm__) || (LLVM_GNUC_PREREQ(4, 3, 0) && !defined(__ICC)) 46 return __builtin_bswap32(value); 47#elif defined(_MSC_VER) && !defined(_DEBUG) 48 return _byteswap_ulong(value); 49#else 50 uint32_t Byte0 = value & 0x000000FF; 51 uint32_t Byte1 = value & 0x0000FF00; 52 uint32_t Byte2 = value & 0x00FF0000; 53 uint32_t Byte3 = value & 0xFF000000; 54 return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24); 55#endif 56} 57 58/// SwapByteOrder_64 - This function returns a byte-swapped representation of 59/// the 64-bit argument. 60inline uint64_t SwapByteOrder_64(uint64_t value) { 61#if defined(__llvm__) || (LLVM_GNUC_PREREQ(4, 3, 0) && !defined(__ICC)) 62 return __builtin_bswap64(value); 63#elif defined(_MSC_VER) && !defined(_DEBUG) 64 return _byteswap_uint64(value); 65#else 66 uint64_t Hi = SwapByteOrder_32(uint32_t(value)); 67 uint32_t Lo = SwapByteOrder_32(uint32_t(value >> 32)); 68 return (Hi << 32) | Lo; 69#endif 70} 71 72inline unsigned char getSwappedBytes(unsigned char C) { return C; } 73inline signed char getSwappedBytes(signed char C) { return C; } 74inline char getSwappedBytes(char C) { return C; } 75 76inline unsigned short getSwappedBytes(unsigned short C) { return SwapByteOrder_16(C); } 77inline signed short getSwappedBytes( signed short C) { return SwapByteOrder_16(C); } 78 79inline unsigned int getSwappedBytes(unsigned int C) { return SwapByteOrder_32(C); } 80inline signed int getSwappedBytes( signed int C) { return SwapByteOrder_32(C); } 81 82#if __LONG_MAX__ == __INT_MAX__ 83inline unsigned long getSwappedBytes(unsigned long C) { return SwapByteOrder_32(C); } 84inline signed long getSwappedBytes( signed long C) { return SwapByteOrder_32(C); } 85#elif __LONG_MAX__ == __LONG_LONG_MAX__ 86inline unsigned long getSwappedBytes(unsigned long C) { return SwapByteOrder_64(C); } 87inline signed long getSwappedBytes( signed long C) { return SwapByteOrder_64(C); } 88#else 89#error "Unknown long size!" 90#endif 91 92inline unsigned long long getSwappedBytes(unsigned long long C) { 93 return SwapByteOrder_64(C); 94} 95inline signed long long getSwappedBytes(signed long long C) { 96 return SwapByteOrder_64(C); 97} 98 99inline float getSwappedBytes(float C) { 100 union { 101 uint32_t i; 102 float f; 103 } in, out; 104 in.f = C; 105 out.i = SwapByteOrder_32(in.i); 106 return out.f; 107} 108 109inline double getSwappedBytes(double C) { 110 union { 111 uint64_t i; 112 double d; 113 } in, out; 114 in.d = C; 115 out.i = SwapByteOrder_64(in.i); 116 return out.d; 117} 118 119template<typename T> 120inline void swapByteOrder(T &Value) { 121 Value = getSwappedBytes(Value); 122} 123 124} // end namespace sys 125} // end namespace llvm 126 127#endif 128