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 //////////////////////////////////////////////////////////////////////////////
 //
 // (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.
    virtual 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.
    virtual 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)`.
    virtual 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

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