cpp-ipc/include/libpmr/monotonic_buffer_resource.h

63 lines
1.9 KiB
C++

/**
* \file libpmr/monotonic_buffer_resource.h
* \author mutouyun (orz@orzz.org)
* \brief A special-purpose the `allocator` that releases the allocated memory only when the resource is destroyed.
* \date 2023-09-16
*/
#pragma once
#include <cstddef> // std::size_t, std::max_align_t
#include "libimp/export.h"
#include "libimp/span.h"
#include "libimp/byte.h"
#include "libpmr/def.h"
#include "libpmr/allocator.h"
LIBPMR_NAMESPACE_BEG_
/**
* \class LIBIMP_EXPORT monotonic_buffer_resource
* \brief A special-purpose memory resource class
* that releases the allocated memory only when the resource is destroyed.
* \see https://en.cppreference.com/w/cpp/memory/monotonic_buffer_resource
*/
class LIBIMP_EXPORT monotonic_buffer_resource {
allocator upstream_;
struct node {
node *next;
std::size_t size;
} *free_list_;
::LIBIMP::byte *head_;
::LIBIMP::byte *tail_;
std::size_t next_size_;
::LIBIMP::byte * const initial_buffer_;
std::size_t const initial_size_;
public:
monotonic_buffer_resource() noexcept;
explicit monotonic_buffer_resource(allocator upstream) noexcept;
explicit monotonic_buffer_resource(std::size_t initial_size) noexcept;
monotonic_buffer_resource(std::size_t initial_size, allocator upstream) noexcept;
monotonic_buffer_resource(::LIBIMP::span<::LIBIMP::byte> buffer) noexcept;
monotonic_buffer_resource(::LIBIMP::span<::LIBIMP::byte> buffer, allocator upstream) noexcept;
~monotonic_buffer_resource() noexcept;
monotonic_buffer_resource(monotonic_buffer_resource const &) = delete;
monotonic_buffer_resource &operator=(monotonic_buffer_resource const &) = delete;
allocator upstream_resource() const noexcept;
void release() noexcept;
void *allocate(std::size_t bytes, std::size_t alignment = alignof(std::max_align_t)) noexcept;
void deallocate(void *p, std::size_t bytes, std::size_t alignment = alignof(std::max_align_t)) noexcept;
};
LIBPMR_NAMESPACE_END_