byteswap.hpp
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#ifndef PROTOZERO_BYTESWAP_HPP
#define PROTOZERO_BYTESWAP_HPP
/*****************************************************************************
protozero - Minimalistic protocol buffer decoder and encoder in C++.
This file is from https://github.com/mapbox/protozero where you can find more
documentation.
*****************************************************************************/
#include "config.hpp"
#include <cstdint>
#include <cstring>
namespace protozero {
namespace detail {
inline uint32_t byteswap_impl(uint32_t value) noexcept {
#ifdef PROTOZERO_USE_BUILTIN_BSWAP
return __builtin_bswap32(value);
#else
return ((value & 0xff000000U) >> 24U) |
((value & 0x00ff0000U) >> 8U) |
((value & 0x0000ff00U) << 8U) |
((value & 0x000000ffU) << 24U);
#endif
}
inline uint64_t byteswap_impl(uint64_t value) noexcept {
#ifdef PROTOZERO_USE_BUILTIN_BSWAP
return __builtin_bswap64(value);
#else
return ((value & 0xff00000000000000ULL) >> 56U) |
((value & 0x00ff000000000000ULL) >> 40U) |
((value & 0x0000ff0000000000ULL) >> 24U) |
((value & 0x000000ff00000000ULL) >> 8U) |
((value & 0x00000000ff000000ULL) << 8U) |
((value & 0x0000000000ff0000ULL) << 24U) |
((value & 0x000000000000ff00ULL) << 40U) |
((value & 0x00000000000000ffULL) << 56U);
#endif
}
} // end namespace detail
inline void byteswap_inplace(uint32_t* ptr) noexcept {
*ptr = detail::byteswap_impl(*ptr);
}
inline void byteswap_inplace(uint64_t* ptr) noexcept {
*ptr = detail::byteswap_impl(*ptr);
}
inline void byteswap_inplace(int32_t* ptr) noexcept {
auto* bptr = reinterpret_cast<uint32_t*>(ptr);
*bptr = detail::byteswap_impl(*bptr);
}
inline void byteswap_inplace(int64_t* ptr) noexcept {
auto* bptr = reinterpret_cast<uint64_t*>(ptr);
*bptr = detail::byteswap_impl(*bptr);
}
inline void byteswap_inplace(float* ptr) noexcept {
static_assert(sizeof(float) == 4, "Expecting four byte float");
uint32_t tmp = 0;
std::memcpy(&tmp, ptr, 4);
tmp = detail::byteswap_impl(tmp); // uint32 overload
std::memcpy(ptr, &tmp, 4);
}
inline void byteswap_inplace(double* ptr) noexcept {
static_assert(sizeof(double) == 8, "Expecting eight byte double");
uint64_t tmp = 0;
std::memcpy(&tmp, ptr, 8);
tmp = detail::byteswap_impl(tmp); // uint64 overload
std::memcpy(ptr, &tmp, 8);
}
namespace detail {
// Added for backwards compatibility with any code that might use this
// function (even if it shouldn't have). Will be removed in a later
// version of protozero.
using ::protozero::byteswap_inplace;
} // end namespace detail
} // end namespace protozero
#endif // PROTOZERO_BYTESWAP_HPP
config.hpp
Contains macro checks for different configurations.
protozero
All parts of the protozero header-only library are in this namespace.
Definition: basic_pbf_builder.hpp:24
protozero::byteswap_inplace
void byteswap_inplace(uint32_t *ptr) noexcept
byteswap the data pointed to by ptr in-place.
Definition: byteswap.hpp:56
protozero::byteswap_inplace
void byteswap_inplace(double *ptr) noexcept
byteswap the data pointed to by ptr in-place.
Definition: byteswap.hpp:88