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      1 /*
      2  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef WEBRTC_BASE_BYTEORDER_H_
     12 #define WEBRTC_BASE_BYTEORDER_H_
     13 
     14 #if defined(WEBRTC_POSIX) && !defined(__native_client__)
     15 #include <arpa/inet.h>
     16 #endif
     17 
     18 #if defined(WEBRTC_WIN)
     19 #include <stdlib.h>
     20 #endif
     21 
     22 #include "webrtc/base/basictypes.h"
     23 
     24 namespace rtc {
     25 
     26 // Reading and writing of little and big-endian numbers from memory
     27 // TODO: Optimized versions, with direct read/writes of
     28 // integers in host-endian format, when the platform supports it.
     29 
     30 inline void Set8(void* memory, size_t offset, uint8_t v) {
     31   static_cast<uint8_t*>(memory)[offset] = v;
     32 }
     33 
     34 inline uint8_t Get8(const void* memory, size_t offset) {
     35   return static_cast<const uint8_t*>(memory)[offset];
     36 }
     37 
     38 inline void SetBE16(void* memory, uint16_t v) {
     39   Set8(memory, 0, static_cast<uint8_t>(v >> 8));
     40   Set8(memory, 1, static_cast<uint8_t>(v >> 0));
     41 }
     42 
     43 inline void SetBE32(void* memory, uint32_t v) {
     44   Set8(memory, 0, static_cast<uint8_t>(v >> 24));
     45   Set8(memory, 1, static_cast<uint8_t>(v >> 16));
     46   Set8(memory, 2, static_cast<uint8_t>(v >> 8));
     47   Set8(memory, 3, static_cast<uint8_t>(v >> 0));
     48 }
     49 
     50 inline void SetBE64(void* memory, uint64_t v) {
     51   Set8(memory, 0, static_cast<uint8_t>(v >> 56));
     52   Set8(memory, 1, static_cast<uint8_t>(v >> 48));
     53   Set8(memory, 2, static_cast<uint8_t>(v >> 40));
     54   Set8(memory, 3, static_cast<uint8_t>(v >> 32));
     55   Set8(memory, 4, static_cast<uint8_t>(v >> 24));
     56   Set8(memory, 5, static_cast<uint8_t>(v >> 16));
     57   Set8(memory, 6, static_cast<uint8_t>(v >> 8));
     58   Set8(memory, 7, static_cast<uint8_t>(v >> 0));
     59 }
     60 
     61 inline uint16_t GetBE16(const void* memory) {
     62   return static_cast<uint16_t>((Get8(memory, 0) << 8) | (Get8(memory, 1) << 0));
     63 }
     64 
     65 inline uint32_t GetBE32(const void* memory) {
     66   return (static_cast<uint32_t>(Get8(memory, 0)) << 24) |
     67          (static_cast<uint32_t>(Get8(memory, 1)) << 16) |
     68          (static_cast<uint32_t>(Get8(memory, 2)) << 8) |
     69          (static_cast<uint32_t>(Get8(memory, 3)) << 0);
     70 }
     71 
     72 inline uint64_t GetBE64(const void* memory) {
     73   return (static_cast<uint64_t>(Get8(memory, 0)) << 56) |
     74          (static_cast<uint64_t>(Get8(memory, 1)) << 48) |
     75          (static_cast<uint64_t>(Get8(memory, 2)) << 40) |
     76          (static_cast<uint64_t>(Get8(memory, 3)) << 32) |
     77          (static_cast<uint64_t>(Get8(memory, 4)) << 24) |
     78          (static_cast<uint64_t>(Get8(memory, 5)) << 16) |
     79          (static_cast<uint64_t>(Get8(memory, 6)) << 8) |
     80          (static_cast<uint64_t>(Get8(memory, 7)) << 0);
     81 }
     82 
     83 inline void SetLE16(void* memory, uint16_t v) {
     84   Set8(memory, 0, static_cast<uint8_t>(v >> 0));
     85   Set8(memory, 1, static_cast<uint8_t>(v >> 8));
     86 }
     87 
     88 inline void SetLE32(void* memory, uint32_t v) {
     89   Set8(memory, 0, static_cast<uint8_t>(v >> 0));
     90   Set8(memory, 1, static_cast<uint8_t>(v >> 8));
     91   Set8(memory, 2, static_cast<uint8_t>(v >> 16));
     92   Set8(memory, 3, static_cast<uint8_t>(v >> 24));
     93 }
     94 
     95 inline void SetLE64(void* memory, uint64_t v) {
     96   Set8(memory, 0, static_cast<uint8_t>(v >> 0));
     97   Set8(memory, 1, static_cast<uint8_t>(v >> 8));
     98   Set8(memory, 2, static_cast<uint8_t>(v >> 16));
     99   Set8(memory, 3, static_cast<uint8_t>(v >> 24));
    100   Set8(memory, 4, static_cast<uint8_t>(v >> 32));
    101   Set8(memory, 5, static_cast<uint8_t>(v >> 40));
    102   Set8(memory, 6, static_cast<uint8_t>(v >> 48));
    103   Set8(memory, 7, static_cast<uint8_t>(v >> 56));
    104 }
    105 
    106 inline uint16_t GetLE16(const void* memory) {
    107   return static_cast<uint16_t>((Get8(memory, 0) << 0) | (Get8(memory, 1) << 8));
    108 }
    109 
    110 inline uint32_t GetLE32(const void* memory) {
    111   return (static_cast<uint32_t>(Get8(memory, 0)) << 0) |
    112          (static_cast<uint32_t>(Get8(memory, 1)) << 8) |
    113          (static_cast<uint32_t>(Get8(memory, 2)) << 16) |
    114          (static_cast<uint32_t>(Get8(memory, 3)) << 24);
    115 }
    116 
    117 inline uint64_t GetLE64(const void* memory) {
    118   return (static_cast<uint64_t>(Get8(memory, 0)) << 0) |
    119          (static_cast<uint64_t>(Get8(memory, 1)) << 8) |
    120          (static_cast<uint64_t>(Get8(memory, 2)) << 16) |
    121          (static_cast<uint64_t>(Get8(memory, 3)) << 24) |
    122          (static_cast<uint64_t>(Get8(memory, 4)) << 32) |
    123          (static_cast<uint64_t>(Get8(memory, 5)) << 40) |
    124          (static_cast<uint64_t>(Get8(memory, 6)) << 48) |
    125          (static_cast<uint64_t>(Get8(memory, 7)) << 56);
    126 }
    127 
    128 // Check if the current host is big endian.
    129 inline bool IsHostBigEndian() {
    130   static const int number = 1;
    131   return 0 == *reinterpret_cast<const char*>(&number);
    132 }
    133 
    134 inline uint16_t HostToNetwork16(uint16_t n) {
    135   uint16_t result;
    136   SetBE16(&result, n);
    137   return result;
    138 }
    139 
    140 inline uint32_t HostToNetwork32(uint32_t n) {
    141   uint32_t result;
    142   SetBE32(&result, n);
    143   return result;
    144 }
    145 
    146 inline uint64_t HostToNetwork64(uint64_t n) {
    147   uint64_t result;
    148   SetBE64(&result, n);
    149   return result;
    150 }
    151 
    152 inline uint16_t NetworkToHost16(uint16_t n) {
    153   return GetBE16(&n);
    154 }
    155 
    156 inline uint32_t NetworkToHost32(uint32_t n) {
    157   return GetBE32(&n);
    158 }
    159 
    160 inline uint64_t NetworkToHost64(uint64_t n) {
    161   return GetBE64(&n);
    162 }
    163 
    164 }  // namespace rtc
    165 
    166 #endif  // WEBRTC_BASE_BYTEORDER_H_
    167