| ////////////////////////////////////////////////////////////////////////////// |
| // |
| // (C) Copyright Ion Gaztanaga 2015-2015. 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) |
| // |
| // See http://www.boost.org/libs/container for documentation. |
| // |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| #ifndef BOOST_CONTAINER_PMR_UNSYNCHRONIZED_POOL_RESOURCE_HPP |
| #define BOOST_CONTAINER_PMR_UNSYNCHRONIZED_POOL_RESOURCE_HPP |
| |
| #if defined (_MSC_VER) |
| # pragma once |
| #endif |
| |
| #include <boost/container/detail/config_begin.hpp> |
| #include <boost/container/detail/workaround.hpp> |
| #include <boost/container/detail/auto_link.hpp> |
| #include <boost/container/pmr/memory_resource.hpp> |
| #include <boost/container/detail/pool_resource.hpp> |
| |
| #include <cstddef> |
| |
| namespace boost { |
| namespace container { |
| namespace pmr { |
| |
| //! A unsynchronized_pool_resource is a general-purpose memory resources having |
| //! the following qualities: |
| //! |
| //! - Each resource owns the allocated memory, and frees it on destruction, |
| //! even if deallocate has not been called for some of the allocated blocks. |
| //! |
| //! - A pool resource consists of a collection of pools, serving |
| //! requests for different block sizes. Each individual pool manages a |
| //! collection of chunks that are in turn divided into blocks of uniform size, |
| //! returned via calls to do_allocate. Each call to do_allocate(size, alignment) |
| //! is dispatched to the pool serving the smallest blocks accommodating at |
| //! least size bytes. |
| //! |
| //! - When a particular pool is exhausted, allocating a block from that pool |
| //! results in the allocation of an additional chunk of memory from the upstream |
| //! allocator (supplied at construction), thus replenishing the pool. With |
| //! each successive replenishment, the chunk size obtained increases |
| //! geometrically. [ Note: By allocating memory in chunks, the pooling strategy |
| //! increases the chance that consecutive allocations will be close together |
| //! in memory. - end note ] |
| //! |
| //! - Allocation requests that exceed the largest block size of any pool are |
| //! fulfilled directly from the upstream allocator. |
| //! |
| //! - A pool_options struct may be passed to the pool resource constructors to |
| //! tune the largest block size and the maximum chunk size. |
| //! |
| //! An unsynchronized_pool_resource class may not be accessed from multiple threads |
| //! simultaneously and thus avoids the cost of synchronization entirely in |
| //! single-threaded applications. |
| class BOOST_CONTAINER_DECL unsynchronized_pool_resource |
| : public memory_resource |
| { |
| pool_resource m_resource; |
| |
| public: |
| |
| //! <b>Requires</b>: `upstream` is the address of a valid memory resource. |
| //! |
| //! <b>Effects</b>: Constructs a pool resource object that will obtain memory |
| //! from upstream whenever the pool resource is unable to satisfy a memory |
| //! request from its own internal data structures. The resulting object will hold |
| //! a copy of upstream, but will not own the resource to which upstream points. |
| //! [ Note: The intention is that calls to upstream->allocate() will be |
| //! substantially fewer than calls to this->allocate() in most cases. - end note |
| //! The behavior of the pooling mechanism is tuned according to the value of |
| //! the opts argument. |
| //! |
| //! <b>Throws</b>: Nothing unless upstream->allocate() throws. It is unspecified if |
| //! or under what conditions this constructor calls upstream->allocate(). |
| unsynchronized_pool_resource(const pool_options& opts, memory_resource* upstream) BOOST_NOEXCEPT; |
| |
| //! <b>Effects</b>: Same as |
| //! `unsynchronized_pool_resource(pool_options(), get_default_resource())`. |
| unsynchronized_pool_resource() BOOST_NOEXCEPT; |
| |
| //! <b>Effects</b>: Same as |
| //! `unsynchronized_pool_resource(pool_options(), upstream)`. |
| explicit unsynchronized_pool_resource(memory_resource* upstream) BOOST_NOEXCEPT; |
| |
| //! <b>Effects</b>: Same as |
| //! `unsynchronized_pool_resource(opts, get_default_resource())`. |
| explicit unsynchronized_pool_resource(const pool_options& opts) BOOST_NOEXCEPT; |
| |
| #if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) || defined(BOOST_CONTAINER_DOXYGEN_INVOKED) |
| unsynchronized_pool_resource(const unsynchronized_pool_resource&) = delete; |
| unsynchronized_pool_resource operator=(const unsynchronized_pool_resource&) = delete; |
| #else |
| private: |
| unsynchronized_pool_resource (const unsynchronized_pool_resource&); |
| unsynchronized_pool_resource operator=(const unsynchronized_pool_resource&); |
| public: |
| #endif |
| |
| //! <b>Effects</b>: Calls |
| //! `this->release()`. |
| ~unsynchronized_pool_resource() BOOST_OVERRIDE; |
| |
| //! <b>Effects</b>: Calls Calls `upstream_resource()->deallocate()` as necessary |
| //! to release all allocated memory. [ Note: memory is released back to |
| //! `upstream_resource()` even if deallocate has not been called for some |
| //! of the allocated blocks. - end note ] |
| void release(); |
| |
| //! <b>Returns</b>: The value of the upstream argument provided to the |
| //! constructor of this object. |
| memory_resource* upstream_resource() const; |
| |
| //! <b>Returns</b>: The options that control the pooling behavior of this resource. |
| //! The values in the returned struct may differ from those supplied to the pool |
| //! resource constructor in that values of zero will be replaced with |
| //! implementation-defined defaults and sizes may be rounded to unspecified granularity. |
| pool_options options() const; |
| |
| protected: |
| |
| //! <b>Returns</b>: A pointer to allocated storage with a size of at least `bytes`. |
| //! The size and alignment of the allocated memory shall meet the requirements for |
| //! a class derived from `memory_resource`. |
| //! |
| //! <b>Effects</b>: If the pool selected for a block of size bytes is unable to |
| //! satisfy the memory request from its own internal data structures, it will call |
| //! `upstream_resource()->allocate()` to obtain more memory. If `bytes` is larger |
| //! than that which the largest pool can handle, then memory will be allocated |
| //! using `upstream_resource()->allocate()`. |
| //! |
| //! <b>Throws</b>: Nothing unless `upstream_resource()->allocate()` throws. |
| void* do_allocate(std::size_t bytes, std::size_t alignment) BOOST_OVERRIDE; |
| |
| //! <b>Effects</b>: Return the memory at p to the pool. It is unspecified if or under |
| //! what circumstances this operation will result in a call to |
| //! `upstream_resource()->deallocate()`. |
| //! |
| //! <b>Throws</b>: Nothing. |
| void do_deallocate(void* p, std::size_t bytes, std::size_t alignment) BOOST_OVERRIDE; |
| |
| //! <b>Returns</b>: |
| //! `this == dynamic_cast<const unsynchronized_pool_resource*>(&other)`. |
| bool do_is_equal(const memory_resource& other) const BOOST_NOEXCEPT BOOST_OVERRIDE; |
| |
| //Non-standard observers |
| public: |
| //! <b>Returns</b>: The number of pools that will be used in the pool resource. |
| //! |
| //! <b>Note</b>: Non-standard extension. |
| std::size_t pool_count() const; |
| |
| //! <b>Returns</b>: The index of the pool that will be used to serve the allocation of `bytes`. |
| //! Returns `pool_count()` if `bytes` is bigger |
| //! than `options().largest_required_pool_block` (no pool will be used to serve this). |
| //! |
| //! <b>Note</b>: Non-standard extension. |
| std::size_t pool_index(std::size_t bytes) const; |
| |
| //! <b>Requires</b>: `pool_idx < pool_index()` |
| //! |
| //! <b>Returns</b>: The number blocks that will be allocated in the next chunk |
| //! from the pool specified by `pool_idx`. |
| //! |
| //! <b>Note</b>: Non-standard extension. |
| std::size_t pool_next_blocks_per_chunk(std::size_t pool_idx) const; |
| |
| //! <b>Requires</b>: `pool_idx < pool_index()` |
| //! |
| //! <b>Returns</b>: The number of bytes of the block that the specified `pool_idx` pool manages. |
| //! |
| //! <b>Note</b>: Non-standard extension. |
| std::size_t pool_block(std::size_t pool_idx) const; |
| |
| //! <b>Requires</b>: `pool_idx < pool_index()` |
| //! |
| //! <b>Returns</b>: The number of blocks that the specified `pool_idx` pool has cached |
| //! and will be served without calling the upstream_allocator. |
| //! |
| //! <b>Note</b>: Non-standard extension. |
| std::size_t pool_cached_blocks(std::size_t pool_idx) const; |
| }; |
| |
| } //namespace pmr { |
| } //namespace container { |
| } //namespace boost { |
| |
| #include <boost/container/detail/config_end.hpp> |
| |
| #endif //BOOST_CONTAINER_PMR_UNSYNCHRONIZED_POOL_RESOURCE_HPP |