base/sys_byteorder.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // This header defines cross-platform ByteSwap() implementations for 16, 32 and
   6 // 64-bit values, and NetToHostXX() / HostToNextXX() functions equivalent to
   7 // the traditional ntohX() and htonX() functions.
   8 // Use the functions defined here rather than using the platform-specific
   9 // functions directly.
  10
  11 #ifndef BASE_SYS_BYTEORDER_H_
  12 #define BASE_SYS_BYTEORDER_H_
  13
  14 #include "base/basictypes.h"
  15 #include "build/build_config.h"
  16
  17 #if defined(OS_WIN)
  18 #include <winsock2.h>
  19 #else
  20 #include <arpa/inet.h>
  21 #endif
  22
  23 // Include headers to provide byteswap for all platforms.
  24 #if defined(COMPILER_MSVC)
  25 #include <stdlib.h>
  26 #elif defined(OS_MACOSX)
  27 #include <libkern/OSByteOrder.h>
  28 #elif defined(OS_OPENBSD)
  29 #include <sys/endian.h>
  30 #else
  31 #include <byteswap.h>
  32 #endif
  33
  34
  35 namespace base {
  36
  37 // Returns a value with all bytes in |x| swapped, i.e. reverses the endianness.
  38 inline uint16 ByteSwap(uint16 x) {
  39 #if defined(COMPILER_MSVC)
  40   return _byteswap_ushort(x);
  41 #elif defined(OS_MACOSX)
  42   return OSSwapInt16(x);
  43 #elif defined(OS_OPENBSD)
  44   return swap16(x);
  45 #else
  46   return bswap_16(x);
  47 #endif
  48 }
  49 inline uint32 ByteSwap(uint32 x) {
  50 #if defined(COMPILER_MSVC)
  51   return _byteswap_ulong(x);
  52 #elif defined(OS_MACOSX)
  53   return OSSwapInt32(x);
  54 #elif defined(OS_OPENBSD)
  55   return swap32(x);
  56 #else
  57   return bswap_32(x);
  58 #endif
  59 }
  60 inline uint64 ByteSwap(uint64 x) {
  61 #if defined(COMPILER_MSVC)
  62   return _byteswap_uint64(x);
  63 #elif defined(OS_MACOSX)
  64   return OSSwapInt64(x);
  65 #elif defined(OS_OPENBSD)
  66   return swap64(x);
  67 #else
  68   return bswap_64(x);
  69 #endif
  70 }
  71
  72 // Converts the bytes in |x| from host order (endianness) to little endian, and
  73 // returns the result.
  74 inline uint16 ByteSwapToLE16(uint16 x) {
  75 #if defined(ARCH_CPU_LITTLE_ENDIAN)
  76   return x;
  77 #else
  78   return ByteSwap(x);
  79 #endif
  80 }
  81 inline uint32 ByteSwapToLE32(uint32 x) {
  82 #if defined(ARCH_CPU_LITTLE_ENDIAN)
  83   return x;
  84 #else
  85   return ByteSwap(x);
  86 #endif
  87 }
  88 inline uint64 ByteSwapToLE64(uint64 x) {
  89 #if defined(ARCH_CPU_LITTLE_ENDIAN)
  90   return x;
  91 #else
  92   return ByteSwap(x);
  93 #endif
  94 }
  95
  96 // Converts the bytes in |x| from network to host order (endianness), and
  97 // returns the result.
  98 inline uint16 NetToHost16(uint16 x) {
  99 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 100   return ByteSwap(x);
 101 #else
 102   return x;
 103 #endif
 104 }
 105 inline uint32 NetToHost32(uint32 x) {
 106 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 107   return ByteSwap(x);
 108 #else
 109   return x;
 110 #endif
 111 }
 112 inline uint64 NetToHost64(uint64 x) {
 113 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 114   return ByteSwap(x);
 115 #else
 116   return x;
 117 #endif
 118 }
 119
 120 // Converts the bytes in |x| from host to network order (endianness), and
 121 // returns the result.
 122 inline uint16 HostToNet16(uint16 x) {
 123 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 124   return ByteSwap(x);
 125 #else
 126   return x;
 127 #endif
 128 }
 129 inline uint32 HostToNet32(uint32 x) {
 130 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 131   return ByteSwap(x);
 132 #else
 133   return x;
 134 #endif
 135 }
 136 inline uint64 HostToNet64(uint64 x) {
 137 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 138   return ByteSwap(x);
 139 #else
 140   return x;
 141 #endif
 142 }
 143
 144 }  // namespace base
 145
 146
 147 #endif  // BASE_SYS_BYTEORDER_H_