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 "third_party/base/logging.h" 17 #include "third_party/build/build_config.h" 18 19 #if defined(COMPILER_MSVC) 20 #include <stdlib.h> 21 #endif 22 23 namespace pdfium { 24 namespace base { 25 26 // Returns a value with all bytes in |x| swapped, i.e. reverses the endianness. 27 inline uint16_t ByteSwap(uint16_t x) { 28 #if defined(COMPILER_MSVC) 29 return _byteswap_ushort(x); 30 #else 31 return __builtin_bswap16(x); 32 #endif 33 } 34 35 inline uint32_t ByteSwap(uint32_t x) { 36 #if defined(COMPILER_MSVC) 37 return _byteswap_ulong(x); 38 #else 39 return __builtin_bswap32(x); 40 #endif 41 } 42 43 inline uint64_t ByteSwap(uint64_t x) { 44 #if defined(COMPILER_MSVC) 45 return _byteswap_uint64(x); 46 #else 47 return __builtin_bswap64(x); 48 #endif 49 } 50 51 inline uintptr_t ByteSwapUintPtrT(uintptr_t x) { 52 // We do it this way because some build configurations are ILP32 even when 53 // defined(ARCH_CPU_64_BITS). Unfortunately, we can't use sizeof in #ifs. But, 54 // because these conditionals are constexprs, the irrelevant branches will 55 // likely be optimized away, so this construction should not result in code 56 // bloat. 57 if (sizeof(uintptr_t) == 4) { 58 return ByteSwap(static_cast<uint32_t>(x)); 59 } else if (sizeof(uintptr_t) == 8) { 60 return ByteSwap(static_cast<uint64_t>(x)); 61 } else { 62 NOTREACHED(); 63 } 64 } 65 66 // Converts the bytes in |x| from host order (endianness) to little endian, and 67 // returns the result. 68 inline uint16_t ByteSwapToLE16(uint16_t x) { 69 #if defined(ARCH_CPU_LITTLE_ENDIAN) 70 return x; 71 #else 72 return ByteSwap(x); 73 #endif 74 } 75 inline uint32_t ByteSwapToLE32(uint32_t x) { 76 #if defined(ARCH_CPU_LITTLE_ENDIAN) 77 return x; 78 #else 79 return ByteSwap(x); 80 #endif 81 } 82 inline uint64_t ByteSwapToLE64(uint64_t x) { 83 #if defined(ARCH_CPU_LITTLE_ENDIAN) 84 return x; 85 #else 86 return ByteSwap(x); 87 #endif 88 } 89 90 // Converts the bytes in |x| from network to host order (endianness), and 91 // returns the result. 92 inline uint16_t NetToHost16(uint16_t x) { 93 #if defined(ARCH_CPU_LITTLE_ENDIAN) 94 return ByteSwap(x); 95 #else 96 return x; 97 #endif 98 } 99 inline uint32_t NetToHost32(uint32_t x) { 100 #if defined(ARCH_CPU_LITTLE_ENDIAN) 101 return ByteSwap(x); 102 #else 103 return x; 104 #endif 105 } 106 inline uint64_t NetToHost64(uint64_t x) { 107 #if defined(ARCH_CPU_LITTLE_ENDIAN) 108 return ByteSwap(x); 109 #else 110 return x; 111 #endif 112 } 113 114 // Converts the bytes in |x| from host to network order (endianness), and 115 // returns the result. 116 inline uint16_t HostToNet16(uint16_t x) { 117 #if defined(ARCH_CPU_LITTLE_ENDIAN) 118 return ByteSwap(x); 119 #else 120 return x; 121 #endif 122 } 123 inline uint32_t HostToNet32(uint32_t x) { 124 #if defined(ARCH_CPU_LITTLE_ENDIAN) 125 return ByteSwap(x); 126 #else 127 return x; 128 #endif 129 } 130 inline uint64_t HostToNet64(uint64_t x) { 131 #if defined(ARCH_CPU_LITTLE_ENDIAN) 132 return ByteSwap(x); 133 #else 134 return x; 135 #endif 136 } 137 138 } // namespace base 139 } // namespace pdfium 140 141 #endif // BASE_SYS_BYTEORDER_H_ 142
