1 //===- SwapByteOrder.h - Generic and optimized byte swaps -------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares generic and optimized functions to swap the byte order of
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_SUPPORT_SWAPBYTEORDER_H
16 #define LLVM_SUPPORT_SWAPBYTEORDER_H
18 #include "llvm/Support/Compiler.h"
19 #include "llvm/Support/DataTypes.h"
21 #if defined(_MSC_VER) && !defined(_DEBUG)
28 /// SwapByteOrder_16 - This function returns a byte-swapped representation of
29 /// the 16-bit argument.
30 inline 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);
36 uint16_t Hi = value << 8;
37 uint16_t Lo = value >> 8;
42 /// SwapByteOrder_32 - This function returns a byte-swapped representation of
43 /// the 32-bit argument.
44 inline 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);
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);
58 /// SwapByteOrder_64 - This function returns a byte-swapped representation of
59 /// the 64-bit argument.
60 inline 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);
66 uint64_t Hi = SwapByteOrder_32(uint32_t(value));
67 uint32_t Lo = SwapByteOrder_32(uint32_t(value >> 32));
68 return (Hi << 32) | Lo;
72 inline unsigned char getSwappedBytes(unsigned char C) { return C; }
73 inline signed char getSwappedBytes(signed char C) { return C; }
74 inline char getSwappedBytes(char C) { return C; }
76 inline unsigned short getSwappedBytes(unsigned short C) { return SwapByteOrder_16(C); }
77 inline signed short getSwappedBytes( signed short C) { return SwapByteOrder_16(C); }
79 inline unsigned int getSwappedBytes(unsigned int C) { return SwapByteOrder_32(C); }
80 inline signed int getSwappedBytes( signed int C) { return SwapByteOrder_32(C); }
82 #if __LONG_MAX__ == __INT_MAX__
83 inline unsigned long getSwappedBytes(unsigned long C) { return SwapByteOrder_32(C); }
84 inline signed long getSwappedBytes( signed long C) { return SwapByteOrder_32(C); }
85 #elif __LONG_MAX__ == __LONG_LONG_MAX__
86 inline unsigned long getSwappedBytes(unsigned long C) { return SwapByteOrder_64(C); }
87 inline signed long getSwappedBytes( signed long C) { return SwapByteOrder_64(C); }
89 #error "Unknown long size!"
92 inline unsigned long long getSwappedBytes(unsigned long long C) {
93 return SwapByteOrder_64(C);
95 inline signed long long getSwappedBytes(signed long long C) {
96 return SwapByteOrder_64(C);
99 inline float getSwappedBytes(float C) {
105 out.i = SwapByteOrder_32(in.i);
109 inline double getSwappedBytes(double C) {
115 out.i = SwapByteOrder_64(in.i);
120 inline void swapByteOrder(T &Value) {
121 Value = getSwappedBytes(Value);
124 } // end namespace sys
125 } // end namespace llvm