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construct/include/ircd/buffer/unique_buffer.h

134 lines
3 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
namespace ircd::buffer
{
std::unique_ptr<char, decltype(&std::free)> aligned_alloc(const size_t &align, const size_t &size);
}
/// Like unique_ptr, this template holds ownership of an allocated buffer
///
template<class buffer>
struct ircd::buffer::unique_buffer
:buffer
{
buffer release();
unique_buffer() = default;
unique_buffer(const size_t &size, const size_t &align = 0);
explicit unique_buffer(const buffer &);
explicit 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>
ircd::buffer::unique_buffer<buffer>::unique_buffer(const buffer &src)
:unique_buffer
{
size(src)
}
{
assert(this->begin() != nullptr);
assert(size(src) == size(*this));
const mutable_buffer dst
{
const_cast<char *>(this->begin()), size(src)
};
copy(dst, src);
}
template<class buffer>
ircd::buffer::unique_buffer<buffer>::unique_buffer(const size_t &size,
const size_t &align)
:buffer
{
aligned_alloc(align, size).release(), size
}
{}
template<class buffer>
ircd::buffer::unique_buffer<buffer>::unique_buffer(unique_buffer &&other)
noexcept
:buffer
{
other.release()
}
{
assert(std::get<0>(other) == nullptr);
}
template<class buffer>
ircd::buffer::unique_buffer<buffer> &
ircd::buffer::unique_buffer<buffer>::operator=(unique_buffer &&other)
& noexcept
{
this->~unique_buffer();
static_cast<buffer &>(*this) = other.release();
assert(std::get<0>(other) == nullptr);
return *this;
}
template<class buffer>
ircd::buffer::unique_buffer<buffer>::~unique_buffer()
noexcept
{
std::free(const_cast<char *>(this->begin()));
}
template<class buffer>
buffer
ircd::buffer::unique_buffer<buffer>::release()
{
const buffer ret{*this};
this->begin() = nullptr;
return ret;
}
inline std::unique_ptr<char, decltype(&std::free)>
ircd::buffer::aligned_alloc(const size_t &align,
const size_t &size)
{
static const size_t &align_default{16};
const size_t &alignment
{
align?: align_default
};
int errc;
void *ret;
switch((errc = ::posix_memalign(&ret, alignment, size)))
{
case 0:
break;
case int(std::errc::not_enough_memory):
throw std::bad_alloc{};
default:
throw std::system_error
{
errc, std::system_category()
};
}
return std::unique_ptr<char, decltype(&std::free)>
{
reinterpret_cast<char *>(ret), &std::free
};
}