base/sys_byteorder.h

   1 // Copyright (c) 2011 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 is a convenience header to pull in the platform-specific
   6 // headers that define functions for byte-order conversion,
   7 // particularly: ntohs(), htons(), ntohl(), htonl(). Prefer including
   8 // this file instead of directly writing the #if / #else, since it
   9 // avoids duplicating the platform-specific selections.
  10 // This header also provides ntohll() and htonll() for byte-order conversion
  11 // for 64-bit integers.
  12
  13 #ifndef BASE_SYS_BYTEORDER_H_
  14 #define BASE_SYS_BYTEORDER_H_
  15
  16 #include "base/basictypes.h"
  17 #include "build/build_config.h"
  18
  19 #if defined(OS_WIN)
  20 #include <winsock2.h>
  21 #else
  22 #include <arpa/inet.h>
  23 #endif
  24
  25 // Include headers to provide byteswap for all platforms.
  26 #if defined(COMPILER_MSVC)
  27 #include <stdlib.h>
  28 #elif defined(OS_MACOSX)
  29 #include <libkern/OSByteOrder.h>
  30 #elif defined(OS_OPENBSD)
  31 #include <sys/endian.h>
  32 #else
  33 #include <byteswap.h>
  34 #endif
  35
  36
  37 namespace base {
  38
  39 // Returns a value with all bytes in |x| swapped, i.e. reverses the endianness.
  40 inline uint64 ByteSwap(uint64 x) {
  41 #if defined(COMPILER_MSVC)
  42   return _byteswap_uint64(x);
  43 #elif defined(OS_MACOSX)
  44   return OSSwapInt64(x);
  45 #elif defined(OS_OPENBSD)
  46   return swap64(x);
  47 #else
  48   return bswap_64(x);
  49 #endif
  50 }
  51
  52 // Converts the bytes in |x| from network to host order (endianness), and
  53 // returns the result.
  54 inline uint64 ntohll(uint64 x) {
  55 #if defined(ARCH_CPU_LITTLE_ENDIAN)
  56   return ByteSwap(x);
  57 #else
  58   return x;
  59 #endif
  60 }
  61
  62 // Converts the bytes in |x| from host to network order (endianness), and
  63 // returns the result.
  64 inline uint64 htonll(uint64 x) {
  65 #if defined(ARCH_CPU_LITTLE_ENDIAN)
  66   return ByteSwap(x);
  67 #else
  68   return x;
  69 #endif
  70 }
  71
  72 }  // namespace base
  73
  74
  75 #endif  // BASE_SYS_BYTEORDER_H_