137 lines
3.2 KiB
C++
137 lines
3.2 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// This header defines cross-platform ByteSwap() implementations for 16, 32 and
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// 64-bit values, and NetToHostXX() / HostToNextXX() functions equivalent to
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// the traditional ntohX() and htonX() functions.
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// Use the functions defined here rather than using the platform-specific
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// functions directly.
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#ifndef BASE_SYS_BYTEORDER_H_
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#define BASE_SYS_BYTEORDER_H_
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#include <stdint.h>
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#include "build/build_config.h"
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#if defined(COMPILER_MSVC)
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#include <stdlib.h>
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#endif
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namespace base {
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// Returns a value with all bytes in |x| swapped, i.e. reverses the endianness.
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inline uint16_t ByteSwap(uint16_t x) {
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#if defined(COMPILER_MSVC)
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return _byteswap_ushort(x);
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#else
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return __builtin_bswap16(x);
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#endif
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}
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inline uint32_t ByteSwap(uint32_t x) {
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#if defined(COMPILER_MSVC)
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return _byteswap_ulong(x);
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#else
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return __builtin_bswap32(x);
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#endif
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}
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inline uint64_t ByteSwap(uint64_t x) {
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#if defined(COMPILER_MSVC)
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return _byteswap_uint64(x);
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#else
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return __builtin_bswap64(x);
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#endif
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}
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inline uintptr_t ByteSwapUintPtrT(uintptr_t x) {
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// We do it this way because some build configurations are ILP32 even when
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// defined(ARCH_CPU_64_BITS). Unfortunately, we can't use sizeof in #ifs. But,
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// because these conditionals are constexprs, the irrelevant branches will
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// likely be optimized away, so this construction should not result in code
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// bloat.
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static_assert(sizeof(uintptr_t) == 4 || sizeof(uintptr_t) == 8,
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"Unsupported uintptr_t size");
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if (sizeof(uintptr_t) == 4)
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return ByteSwap(static_cast<uint32_t>(x));
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return ByteSwap(static_cast<uint64_t>(x));
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}
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// Converts the bytes in |x| from host order (endianness) to little endian, and
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// returns the result.
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inline uint16_t ByteSwapToLE16(uint16_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return x;
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#else
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return ByteSwap(x);
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#endif
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}
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inline uint32_t ByteSwapToLE32(uint32_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return x;
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#else
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return ByteSwap(x);
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#endif
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}
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inline uint64_t ByteSwapToLE64(uint64_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return x;
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#else
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return ByteSwap(x);
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#endif
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}
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// Converts the bytes in |x| from network to host order (endianness), and
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// returns the result.
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inline uint16_t NetToHost16(uint16_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return ByteSwap(x);
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#else
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return x;
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#endif
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}
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inline uint32_t NetToHost32(uint32_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return ByteSwap(x);
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#else
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return x;
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#endif
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}
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inline uint64_t NetToHost64(uint64_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return ByteSwap(x);
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#else
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return x;
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#endif
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}
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// Converts the bytes in |x| from host to network order (endianness), and
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// returns the result.
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inline uint16_t HostToNet16(uint16_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return ByteSwap(x);
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#else
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return x;
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#endif
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}
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inline uint32_t HostToNet32(uint32_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return ByteSwap(x);
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#else
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return x;
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#endif
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}
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inline uint64_t HostToNet64(uint64_t x) {
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#if defined(ARCH_CPU_LITTLE_ENDIAN)
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return ByteSwap(x);
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#else
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return x;
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#endif
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}
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} // namespace base
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#endif // BASE_SYS_BYTEORDER_H_
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