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      1 /*
      2  * libjingle
      3  * Copyright 2004--2005, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #ifndef TALK_BASE_BYTEORDER_H__
     29 #define TALK_BASE_BYTEORDER_H__
     30 
     31 #ifdef POSIX
     32 #include <arpa/inet.h>
     33 #endif
     34 
     35 #ifdef WIN32
     36 #include <winsock2.h>
     37 #endif
     38 
     39 #include "talk/base/basictypes.h"
     40 
     41 namespace talk_base {
     42 
     43 // Reading and writing of little and big-endian numbers from memory
     44 // TODO: Add HostEndian #defines (HE)
     45 // TODO: Consider NetworkEndian as synonym for BigEndian, for clarity in use.
     46 // TODO: Consider creating optimized versions, such as direct read/writes of
     47 // integers in host-endian format, when the platform supports it.
     48 
     49 inline void Set8(void* memory, size_t offset, uint8 v) {
     50   static_cast<uint8*>(memory)[offset] = v;
     51 }
     52 inline uint8 Get8(const void* memory, size_t offset) {
     53   return static_cast<const uint8*>(memory)[offset];
     54 }
     55 
     56 inline void SetBE16(void* memory, uint16 v) {
     57   Set8(memory, 0, static_cast<uint8>(v >>  8));
     58   Set8(memory, 1, static_cast<uint8>(v >>  0));
     59 }
     60 inline void SetBE32(void* memory, uint32 v) {
     61   Set8(memory, 0, static_cast<uint8>(v >> 24));
     62   Set8(memory, 1, static_cast<uint8>(v >> 16));
     63   Set8(memory, 2, static_cast<uint8>(v >>  8));
     64   Set8(memory, 3, static_cast<uint8>(v >>  0));
     65 }
     66 inline void SetBE64(void* memory, uint64 v) {
     67   Set8(memory, 0, static_cast<uint8>(v >> 56));
     68   Set8(memory, 1, static_cast<uint8>(v >> 48));
     69   Set8(memory, 2, static_cast<uint8>(v >> 40));
     70   Set8(memory, 3, static_cast<uint8>(v >> 32));
     71   Set8(memory, 4, static_cast<uint8>(v >> 24));
     72   Set8(memory, 5, static_cast<uint8>(v >> 16));
     73   Set8(memory, 6, static_cast<uint8>(v >>  8));
     74   Set8(memory, 7, static_cast<uint8>(v >>  0));
     75 }
     76 inline uint16 GetBE16(const void* memory) {
     77   return (static_cast<uint16>(Get8(memory, 0)) << 8)
     78        | (static_cast<uint16>(Get8(memory, 1)) << 0);
     79 }
     80 inline uint32 GetBE32(const void* memory) {
     81   return (static_cast<uint32>(Get8(memory, 0)) << 24)
     82        | (static_cast<uint32>(Get8(memory, 1)) << 16)
     83        | (static_cast<uint32>(Get8(memory, 2)) <<  8)
     84        | (static_cast<uint32>(Get8(memory, 3)) <<  0);
     85 }
     86 inline uint64 GetBE64(const void* memory) {
     87   return (static_cast<uint64>(Get8(memory, 0)) << 56)
     88        | (static_cast<uint64>(Get8(memory, 1)) << 48)
     89        | (static_cast<uint64>(Get8(memory, 2)) << 40)
     90        | (static_cast<uint64>(Get8(memory, 3)) << 32)
     91        | (static_cast<uint64>(Get8(memory, 4)) << 24)
     92        | (static_cast<uint64>(Get8(memory, 5)) << 16)
     93        | (static_cast<uint64>(Get8(memory, 6)) <<  8)
     94        | (static_cast<uint64>(Get8(memory, 7)) <<  0);
     95 }
     96 
     97 inline void SetLE16(void* memory, uint16 v) {
     98   Set8(memory, 1, static_cast<uint8>(v >>  8));
     99   Set8(memory, 0, static_cast<uint8>(v >>  0));
    100 }
    101 inline void SetLE32(void* memory, uint32 v) {
    102   Set8(memory, 3, static_cast<uint8>(v >> 24));
    103   Set8(memory, 2, static_cast<uint8>(v >> 16));
    104   Set8(memory, 1, static_cast<uint8>(v >>  8));
    105   Set8(memory, 0, static_cast<uint8>(v >>  0));
    106 }
    107 inline void SetLE64(void* memory, uint64 v) {
    108   Set8(memory, 7, static_cast<uint8>(v >> 56));
    109   Set8(memory, 6, static_cast<uint8>(v >> 48));
    110   Set8(memory, 5, static_cast<uint8>(v >> 40));
    111   Set8(memory, 4, static_cast<uint8>(v >> 32));
    112   Set8(memory, 3, static_cast<uint8>(v >> 24));
    113   Set8(memory, 2, static_cast<uint8>(v >> 16));
    114   Set8(memory, 1, static_cast<uint8>(v >>  8));
    115   Set8(memory, 0, static_cast<uint8>(v >>  0));
    116 }
    117 inline uint16 GetLE16(const void* memory) {
    118   return (static_cast<uint16>(Get8(memory, 1)) << 8)
    119        | (static_cast<uint16>(Get8(memory, 0)) << 0);
    120 }
    121 inline uint32 GetLE32(const void* memory) {
    122   return (static_cast<uint32>(Get8(memory, 3)) << 24)
    123        | (static_cast<uint32>(Get8(memory, 2)) << 16)
    124        | (static_cast<uint32>(Get8(memory, 1)) <<  8)
    125        | (static_cast<uint32>(Get8(memory, 0)) <<  0);
    126 }
    127 inline uint64 GetLE64(const void* memory) {
    128   return (static_cast<uint64>(Get8(memory, 7)) << 56)
    129        | (static_cast<uint64>(Get8(memory, 6)) << 48)
    130        | (static_cast<uint64>(Get8(memory, 5)) << 40)
    131        | (static_cast<uint64>(Get8(memory, 4)) << 32)
    132        | (static_cast<uint64>(Get8(memory, 3)) << 24)
    133        | (static_cast<uint64>(Get8(memory, 2)) << 16)
    134        | (static_cast<uint64>(Get8(memory, 1)) <<  8)
    135        | (static_cast<uint64>(Get8(memory, 0)) <<  0);
    136 }
    137 
    138 // Check if the current host is big endian.
    139 inline bool IsHostBigEndian() {
    140   static const int number = 1;
    141   return (0 == *reinterpret_cast<const char*>(&number));
    142 }
    143 
    144 inline uint16 HostToNetwork16(uint16 n) {
    145   return htons(n);
    146 }
    147 
    148 inline uint32 HostToNetwork32(uint32 n) {
    149   return htonl(n);
    150 }
    151 
    152 inline uint64 HostToNetwork64(uint64 n) {
    153   // If the host is little endian, GetBE64 converts n to big network endian.
    154   return IsHostBigEndian() ? n : GetBE64(&n);
    155 }
    156 
    157 inline uint16 NetworkToHost16(uint16 n) {
    158   return ntohs(n);
    159 }
    160 
    161 inline uint32 NetworkToHost32(uint32 n) {
    162   return ntohl(n);
    163 }
    164 
    165 inline uint64 NetworkToHost64(uint64 n) {
    166   // If the host is little endian, GetBE64 converts n to little endian.
    167   return IsHostBigEndian() ? n : GetBE64(&n);
    168 }
    169 
    170 }  // namespace talk_base
    171 
    172 #endif  // TALK_BASE_BYTEORDER_H__
    173