talk/base/byteorder.h

/*
 * libjingle
 * Copyright 2004--2005, Google Inc.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright notice, 
 *     this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright notice,
 *     this list of conditions and the following disclaimer in the documentation
 *     and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products 
 *     derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef TALK_BASE_BYTEORDER_H__
#define TALK_BASE_BYTEORDER_H__

#ifdef POSIX
#include <arpa/inet.h>
#endif

#ifdef WIN32
#include <winsock2.h>
#endif

#include "talk/base/basictypes.h"

namespace talk_base {

// Reading and writing of little and big-endian numbers from memory
// TODO: Add HostEndian #defines (HE)
// TODO: Consider NetworkEndian as synonym for BigEndian, for clarity in use.
// TODO: Consider creating optimized versions, such as direct read/writes of
// integers in host-endian format, when the platform supports it.

inline void Set8(void* memory, size_t offset, uint8 v) {
  static_cast<uint8*>(memory)[offset] = v;
}
inline uint8 Get8(const void* memory, size_t offset) {
  return static_cast<const uint8*>(memory)[offset];
}

inline void SetBE16(void* memory, uint16 v) {
  Set8(memory, 0, static_cast<uint8>(v >>  8));
  Set8(memory, 1, static_cast<uint8>(v >>  0));
}
inline void SetBE32(void* memory, uint32 v) {
  Set8(memory, 0, static_cast<uint8>(v >> 24));
  Set8(memory, 1, static_cast<uint8>(v >> 16));
  Set8(memory, 2, static_cast<uint8>(v >>  8));
  Set8(memory, 3, static_cast<uint8>(v >>  0));
}
inline void SetBE64(void* memory, uint64 v) {
  Set8(memory, 0, static_cast<uint8>(v >> 56));
  Set8(memory, 1, static_cast<uint8>(v >> 48));
  Set8(memory, 2, static_cast<uint8>(v >> 40));
  Set8(memory, 3, static_cast<uint8>(v >> 32));
  Set8(memory, 4, static_cast<uint8>(v >> 24));
  Set8(memory, 5, static_cast<uint8>(v >> 16));
  Set8(memory, 6, static_cast<uint8>(v >>  8));
  Set8(memory, 7, static_cast<uint8>(v >>  0));
}
inline uint16 GetBE16(const void* memory) {
  return (static_cast<uint16>(Get8(memory, 0)) << 8)
       | (static_cast<uint16>(Get8(memory, 1)) << 0);
}
inline uint32 GetBE32(const void* memory) {
  return (static_cast<uint32>(Get8(memory, 0)) << 24)
       | (static_cast<uint32>(Get8(memory, 1)) << 16)
       | (static_cast<uint32>(Get8(memory, 2)) <<  8)
       | (static_cast<uint32>(Get8(memory, 3)) <<  0);
}
inline uint64 GetBE64(const void* memory) {
  return (static_cast<uint64>(Get8(memory, 0)) << 56)
       | (static_cast<uint64>(Get8(memory, 1)) << 48)
       | (static_cast<uint64>(Get8(memory, 2)) << 40)
       | (static_cast<uint64>(Get8(memory, 3)) << 32)
       | (static_cast<uint64>(Get8(memory, 4)) << 24)
       | (static_cast<uint64>(Get8(memory, 5)) << 16)
       | (static_cast<uint64>(Get8(memory, 6)) <<  8)
       | (static_cast<uint64>(Get8(memory, 7)) <<  0);
}

inline void SetLE16(void* memory, uint16 v) {
  Set8(memory, 1, static_cast<uint8>(v >>  8));
  Set8(memory, 0, static_cast<uint8>(v >>  0));
}
inline void SetLE32(void* memory, uint32 v) {
  Set8(memory, 3, static_cast<uint8>(v >> 24));
  Set8(memory, 2, static_cast<uint8>(v >> 16));
  Set8(memory, 1, static_cast<uint8>(v >>  8));
  Set8(memory, 0, static_cast<uint8>(v >>  0));
}
inline void SetLE64(void* memory, uint64 v) {
  Set8(memory, 7, static_cast<uint8>(v >> 56));
  Set8(memory, 6, static_cast<uint8>(v >> 48));
  Set8(memory, 5, static_cast<uint8>(v >> 40));
  Set8(memory, 4, static_cast<uint8>(v >> 32));
  Set8(memory, 3, static_cast<uint8>(v >> 24));
  Set8(memory, 2, static_cast<uint8>(v >> 16));
  Set8(memory, 1, static_cast<uint8>(v >>  8));
  Set8(memory, 0, static_cast<uint8>(v >>  0));
}
inline uint16 GetLE16(const void* memory) {
  return (static_cast<uint16>(Get8(memory, 1)) << 8)
       | (static_cast<uint16>(Get8(memory, 0)) << 0);
}
inline uint32 GetLE32(const void* memory) {
  return (static_cast<uint32>(Get8(memory, 3)) << 24)
       | (static_cast<uint32>(Get8(memory, 2)) << 16)
       | (static_cast<uint32>(Get8(memory, 1)) <<  8)
       | (static_cast<uint32>(Get8(memory, 0)) <<  0);
}
inline uint64 GetLE64(const void* memory) {
  return (static_cast<uint64>(Get8(memory, 7)) << 56)
       | (static_cast<uint64>(Get8(memory, 6)) << 48)
       | (static_cast<uint64>(Get8(memory, 5)) << 40)
       | (static_cast<uint64>(Get8(memory, 4)) << 32)
       | (static_cast<uint64>(Get8(memory, 3)) << 24)
       | (static_cast<uint64>(Get8(memory, 2)) << 16)
       | (static_cast<uint64>(Get8(memory, 1)) <<  8)
       | (static_cast<uint64>(Get8(memory, 0)) <<  0);
}

// Check if the current host is big endian.
inline bool IsHostBigEndian() {
  static const int number = 1;
  return (0 == *reinterpret_cast<const char*>(&number));
}

inline uint16 HostToNetwork16(uint16 n) {
  return htons(n);
}

inline uint32 HostToNetwork32(uint32 n) {
  return htonl(n);
}

inline uint64 HostToNetwork64(uint64 n) {
  // If the host is little endian, GetBE64 converts n to big network endian.
  return IsHostBigEndian() ? n : GetBE64(&n);
}

inline uint16 NetworkToHost16(uint16 n) {
  return ntohs(n);
}

inline uint32 NetworkToHost32(uint32 n) {
  return ntohl(n);
}

inline uint64 NetworkToHost64(uint64 n) {
  // If the host is little endian, GetBE64 converts n to little endian.
  return IsHostBigEndian() ? n : GetBE64(&n);
}

}  // namespace talk_base

#endif  // TALK_BASE_BYTEORDER_H__