Files
scylladb/utils/bit_cast.hh

53 lines
1.5 KiB
C++

/*
* Copyright (C) 2021-present ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <cstring>
#include <cstddef>
#include <type_traits>
template <class T> concept Trivial = std::is_trivial_v<T>;
template <class T> concept TriviallyCopyable = std::is_trivially_copyable_v<T>;
// C++20 has std::bit_cast, which does the same thing,
// (but better, because it supports constexpr through compiler magic)
// but it hasn't made its way to our libstdc++ yet.
template <Trivial To, TriviallyCopyable From>
requires (sizeof(To) == sizeof(From))
To bit_cast(const From& src) noexcept {
To dst;
std::memcpy(&dst, &src, sizeof(To));
return dst;
}
template <Trivial To>
To read_unaligned(const void* src) {
To dst;
std::memcpy(&dst, src, sizeof(To));
return dst;
}
template <TriviallyCopyable From>
void write_unaligned(void* dst, const From& src) {
std::memcpy(dst, &src, sizeof(From));
}