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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2026
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#pragma once
#include "td/utils/type_traits.h"
#include <cstring>
#include <type_traits>
namespace td {
namespace detail {
template <class T>
class As {
public:
explicit As(void *ptr) : ptr_(ptr) {
}
As(const As &) = delete;
As &operator=(const As &) = delete;
As(As &&) = default;
As &operator=(As &&other) && noexcept {
std::memcpy(ptr_, other.ptr_, sizeof(T));
return *this;
}
~As() = default;
As &operator=(const T &other) && {
std::memcpy(ptr_, &other, sizeof(T));
return *this;
}
operator T() const {
T res;
std::memcpy(&res, ptr_, sizeof(T));
return res;
}
bool operator==(const As &other) const {
return this->operator T() == other.operator T();
}
private:
void *ptr_;
};
template <class T>
class ConstAs {
public:
explicit ConstAs(const void *ptr) : ptr_(ptr) {
}
operator T() const {
T res;
std::memcpy(&res, ptr_, sizeof(T));
return res;
}
private:
const void *ptr_;
};
} // namespace detail
template <class ToT, class FromT,
std::enable_if_t<TD_IS_TRIVIALLY_COPYABLE(ToT) && TD_IS_TRIVIALLY_COPYABLE(FromT), int> = 0>
detail::As<ToT> as(FromT *from) {
return detail::As<ToT>(from);
}
template <class ToT, class FromT,
std::enable_if_t<TD_IS_TRIVIALLY_COPYABLE(ToT) && TD_IS_TRIVIALLY_COPYABLE(FromT), int> = 0>
detail::ConstAs<ToT> as(const FromT *from) {
return detail::ConstAs<ToT>(from);
}
} // namespace td
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