85 lines
2.3 KiB
C++
85 lines
2.3 KiB
C++
#ifndef PROTOZERO_BYTESWAP_HPP
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#define PROTOZERO_BYTESWAP_HPP
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/*****************************************************************************
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protozero - Minimalistic protocol buffer decoder and encoder in C++.
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This file is from https://github.com/mapbox/protozero where you can find more
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documentation.
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*****************************************************************************/
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/**
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* @file byteswap.hpp
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*
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* @brief Contains functions to swap bytes in values (for different endianness).
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*/
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#include <cassert>
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#include <cstdint>
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#include <protozero/config.hpp>
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namespace protozero {
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namespace detail {
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inline uint32_t byteswap_impl(uint32_t value) noexcept {
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#ifdef PROTOZERO_USE_BUILTIN_BSWAP
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return __builtin_bswap32(value);
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#else
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return ((value & 0xff000000) >> 24) |
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((value & 0x00ff0000) >> 8) |
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((value & 0x0000ff00) << 8) |
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((value & 0x000000ff) << 24);
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#endif
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}
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inline uint64_t byteswap_impl(uint64_t value) noexcept {
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#ifdef PROTOZERO_USE_BUILTIN_BSWAP
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return __builtin_bswap64(value);
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#else
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return ((value & 0xff00000000000000ULL) >> 56) |
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((value & 0x00ff000000000000ULL) >> 40) |
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((value & 0x0000ff0000000000ULL) >> 24) |
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((value & 0x000000ff00000000ULL) >> 8) |
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((value & 0x00000000ff000000ULL) << 8) |
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((value & 0x0000000000ff0000ULL) << 24) |
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((value & 0x000000000000ff00ULL) << 40) |
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((value & 0x00000000000000ffULL) << 56);
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#endif
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}
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inline void byteswap_inplace(uint32_t* ptr) noexcept {
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*ptr = byteswap_impl(*ptr);
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}
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inline void byteswap_inplace(uint64_t* ptr) noexcept {
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*ptr = byteswap_impl(*ptr);
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}
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inline void byteswap_inplace(int32_t* ptr) noexcept {
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auto bptr = reinterpret_cast<uint32_t*>(ptr);
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*bptr = byteswap_impl(*bptr);
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}
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inline void byteswap_inplace(int64_t* ptr) noexcept {
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auto bptr = reinterpret_cast<uint64_t*>(ptr);
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*bptr = byteswap_impl(*bptr);
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}
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inline void byteswap_inplace(float* ptr) noexcept {
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auto bptr = reinterpret_cast<uint32_t*>(ptr);
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*bptr = byteswap_impl(*bptr);
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}
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inline void byteswap_inplace(double* ptr) noexcept {
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auto bptr = reinterpret_cast<uint64_t*>(ptr);
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*bptr = byteswap_impl(*bptr);
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}
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} // end namespace detail
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} // end namespace protozero
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#endif // PROTOZERO_BYTESWAP_HPP
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