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construct/include/ircd/buffer/unique_buffer.h

130 lines
2.9 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_BUFFER_UNIQUE_BUFFER_H
/// Like unique_ptr, this template holds ownership of an allocated buffer
///
template<class buffer,
uint alignment>
struct ircd::buffer::unique_buffer
:buffer
{
static char *allocate(const size_t &size);
buffer release();
unique_buffer(const size_t &size);
explicit unique_buffer(const buffer &);
unique_buffer();
unique_buffer(unique_buffer &&) noexcept;
unique_buffer(const unique_buffer &) = delete;
unique_buffer &operator=(unique_buffer &&) noexcept;
unique_buffer &operator=(const unique_buffer &) = delete;
~unique_buffer() noexcept;
};
template<class buffer,
uint alignment>
ircd::buffer::unique_buffer<buffer, alignment>::unique_buffer()
:buffer
{
nullptr, nullptr
}
{}
template<class buffer,
uint alignment>
ircd::buffer::unique_buffer<buffer, alignment>::unique_buffer(const buffer &src)
:unique_buffer
{
size(src)
}
{
const mutable_buffer dst
{
const_cast<char *>(data(*this)), size(*this)
};
copy(dst, src);
}
template<class buffer,
uint alignment>
ircd::buffer::unique_buffer<buffer, alignment>::unique_buffer(const size_t &size)
:buffer
{
allocate(size), size
}
{
}
template<class buffer,
uint alignment>
ircd::buffer::unique_buffer<buffer, alignment>::unique_buffer(unique_buffer &&other)
noexcept
:buffer
{
std::move(static_cast<buffer &>(other))
}
{
get<0>(other) = nullptr;
}
template<class buffer,
uint alignment>
ircd::buffer::unique_buffer<buffer, alignment> &
ircd::buffer::unique_buffer<buffer, alignment>::operator=(unique_buffer &&other)
noexcept
{
this->~unique_buffer();
static_cast<buffer &>(*this) = std::move(static_cast<buffer &>(other));
get<0>(other) = nullptr;
return *this;
}
template<class buffer,
uint alignment>
ircd::buffer::unique_buffer<buffer, alignment>::~unique_buffer()
noexcept
{
std::free(const_cast<char *>(data(*this)));
}
template<class buffer,
uint alignment>
buffer
ircd::buffer::unique_buffer<buffer, alignment>::release()
{
const buffer ret{static_cast<buffer>(*this)};
static_cast<buffer &>(*this) = buffer{};
return ret;
}
template<class buffer,
uint alignment>
char *
ircd::buffer::unique_buffer<buffer, alignment>::allocate(const size_t &size)
{
int errc;
void *ret;
if(unlikely((errc = ::posix_memalign(&ret, alignment, size)) != 0))
throw std::system_error
{
errc, std::system_category()
};
assert(errc == 0);
assert(ret != nullptr);
return reinterpret_cast<char *>(ret);
}