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_BSD)
  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 #elif defined(OS_FREEBSD)
  46   return bswap16(x);
  47 #else
  48   return bswap_16(x);
  49 #endif
  50 }
  51 inline uint32 ByteSwap(uint32 x) {
  52 #if defined(COMPILER_MSVC)
  53   return _byteswap_ulong(x);
  54 #elif defined(OS_MACOSX)
  55   return OSSwapInt32(x);
  56 #elif defined(OS_OPENBSD)
  57   return swap32(x);
  58 #elif defined(OS_FREEBSD)
  59   return bswap32(x);
  60 #else
  61   return bswap_32(x);
  62 #endif
  63 }
  64 inline uint64 ByteSwap(uint64 x) {
  65 #if defined(COMPILER_MSVC)
  66   return _byteswap_uint64(x);
  67 #elif defined(OS_MACOSX)
  68   return OSSwapInt64(x);
  69 #elif defined(OS_OPENBSD)
  70   return swap64(x);
  71 #elif defined(OS_FREEBSD)
  72   return bswap64(x);
  73 #else
  74   return bswap_64(x);
  75 #endif
  76 }
  77
  78 // Converts the bytes in |x| from host order (endianness) to little endian, and
  79 // returns the result.
  80 inline uint16 ByteSwapToLE16(uint16 x) {
  81 #if defined(ARCH_CPU_LITTLE_ENDIAN)
  82   return x;
  83 #else
  84   return ByteSwap(x);
  85 #endif
  86 }
  87 inline uint32 ByteSwapToLE32(uint32 x) {
  88 #if defined(ARCH_CPU_LITTLE_ENDIAN)
  89   return x;
  90 #else
  91   return ByteSwap(x);
  92 #endif
  93 }
  94 inline uint64 ByteSwapToLE64(uint64 x) {
  95 #if defined(ARCH_CPU_LITTLE_ENDIAN)
  96   return x;
  97 #else
  98   return ByteSwap(x);
  99 #endif
 100 }
 101
 102 // Converts the bytes in |x| from network to host order (endianness), and
 103 // returns the result.
 104 inline uint16 NetToHost16(uint16 x) {
 105 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 106   return ByteSwap(x);
 107 #else
 108   return x;
 109 #endif
 110 }
 111 inline uint32 NetToHost32(uint32 x) {
 112 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 113   return ByteSwap(x);
 114 #else
 115   return x;
 116 #endif
 117 }
 118 inline uint64 NetToHost64(uint64 x) {
 119 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 120   return ByteSwap(x);
 121 #else
 122   return x;
 123 #endif
 124 }
 125
 126 // Converts the bytes in |x| from host to network order (endianness), and
 127 // returns the result.
 128 inline uint16 HostToNet16(uint16 x) {
 129 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 130   return ByteSwap(x);
 131 #else
 132   return x;
 133 #endif
 134 }
 135 inline uint32 HostToNet32(uint32 x) {
 136 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 137   return ByteSwap(x);
 138 #else
 139   return x;
 140 #endif
 141 }
 142 inline uint64 HostToNet64(uint64 x) {
 143 #if defined(ARCH_CPU_LITTLE_ENDIAN)
 144   return ByteSwap(x);
 145 #else
 146   return x;
 147 #endif
 148 }
 149
 150 }  // namespace base
 151
 152
 153 #endif  // BASE_SYS_BYTEORDER_H_