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 <stdint.h> 15 16 #include "build/build_config.h" 17 18 namespace base { 19 20 // Returns a value with all bytes in |x| swapped, i.e. reverses the endianness. ByteSwap(uint16_t x)21inline uint16_t ByteSwap(uint16_t x) { 22 return ((x & 0x00ff) << 8) | ((x & 0xff00) >> 8); 23 } 24 ByteSwap(uint32_t x)25inline uint32_t ByteSwap(uint32_t x) { 26 return ((x & 0x000000fful) << 24) | ((x & 0x0000ff00ul) << 8) | 27 ((x & 0x00ff0000ul) >> 8) | ((x & 0xff000000ul) >> 24); 28 } 29 ByteSwap(uint64_t x)30inline uint64_t ByteSwap(uint64_t x) { 31 return ((x & 0x00000000000000ffull) << 56) | 32 ((x & 0x000000000000ff00ull) << 40) | 33 ((x & 0x0000000000ff0000ull) << 24) | 34 ((x & 0x00000000ff000000ull) << 8) | 35 ((x & 0x000000ff00000000ull) >> 8) | 36 ((x & 0x0000ff0000000000ull) >> 24) | 37 ((x & 0x00ff000000000000ull) >> 40) | 38 ((x & 0xff00000000000000ull) >> 56); 39 } 40 41 // Converts the bytes in |x| from host order (endianness) to little endian, and 42 // returns the result. ByteSwapToLE16(uint16_t x)43inline uint16_t ByteSwapToLE16(uint16_t x) { 44 #if defined(ARCH_CPU_LITTLE_ENDIAN) 45 return x; 46 #else 47 return ByteSwap(x); 48 #endif 49 } ByteSwapToLE32(uint32_t x)50inline uint32_t ByteSwapToLE32(uint32_t x) { 51 #if defined(ARCH_CPU_LITTLE_ENDIAN) 52 return x; 53 #else 54 return ByteSwap(x); 55 #endif 56 } ByteSwapToLE64(uint64_t x)57inline uint64_t ByteSwapToLE64(uint64_t x) { 58 #if defined(ARCH_CPU_LITTLE_ENDIAN) 59 return x; 60 #else 61 return ByteSwap(x); 62 #endif 63 } 64 65 // Converts the bytes in |x| from network to host order (endianness), and 66 // returns the result. NetToHost16(uint16_t x)67inline uint16_t NetToHost16(uint16_t x) { 68 #if defined(ARCH_CPU_LITTLE_ENDIAN) 69 return ByteSwap(x); 70 #else 71 return x; 72 #endif 73 } NetToHost32(uint32_t x)74inline uint32_t NetToHost32(uint32_t x) { 75 #if defined(ARCH_CPU_LITTLE_ENDIAN) 76 return ByteSwap(x); 77 #else 78 return x; 79 #endif 80 } NetToHost64(uint64_t x)81inline uint64_t NetToHost64(uint64_t x) { 82 #if defined(ARCH_CPU_LITTLE_ENDIAN) 83 return ByteSwap(x); 84 #else 85 return x; 86 #endif 87 } 88 89 // Converts the bytes in |x| from host to network order (endianness), and 90 // returns the result. HostToNet16(uint16_t x)91inline uint16_t HostToNet16(uint16_t x) { 92 #if defined(ARCH_CPU_LITTLE_ENDIAN) 93 return ByteSwap(x); 94 #else 95 return x; 96 #endif 97 } HostToNet32(uint32_t x)98inline uint32_t HostToNet32(uint32_t x) { 99 #if defined(ARCH_CPU_LITTLE_ENDIAN) 100 return ByteSwap(x); 101 #else 102 return x; 103 #endif 104 } HostToNet64(uint64_t x)105inline uint64_t HostToNet64(uint64_t x) { 106 #if defined(ARCH_CPU_LITTLE_ENDIAN) 107 return ByteSwap(x); 108 #else 109 return x; 110 #endif 111 } 112 113 } // namespace base 114 115 #endif // BASE_SYS_BYTEORDER_H_ 116