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288 lines
11 KiB
C++
288 lines
11 KiB
C++
// Copyright (C) 2000, 2001 Stephen Cleary
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org for updates, documentation, and revision history.
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#ifndef BOOST_OBJECT_POOL_HPP
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#define BOOST_OBJECT_POOL_HPP
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/*!
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\file
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\brief Provides a template type boost::object_pool<T, UserAllocator>
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that can be used for fast and efficient memory allocation of objects of type T.
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It also provides automatic destruction of non-deallocated objects.
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*/
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#include <boost/pool/poolfwd.hpp>
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// boost::pool
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#include <boost/pool/pool.hpp>
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// The following code will be put into Boost.Config in a later revision
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#if defined(BOOST_MSVC) || defined(__KCC)
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# define BOOST_NO_TEMPLATE_CV_REF_OVERLOADS
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#endif
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// The following code might be put into some Boost.Config header in a later revision
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#ifdef __BORLANDC__
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# pragma option push -w-inl
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#endif
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// There are a few places in this file where the expression "this->m" is used.
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// This expression is used to force instantiation-time name lookup, which I am
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// informed is required for strict Standard compliance. It's only necessary
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// if "m" is a member of a base class that is dependent on a template
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// parameter.
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// Thanks to Jens Maurer for pointing this out!
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namespace boost {
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/*! \brief A template class
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that can be used for fast and efficient memory allocation of objects.
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It also provides automatic destruction of non-deallocated objects.
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\details
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<b>T</b> The type of object to allocate/deallocate.
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T must have a non-throwing destructor.
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<b>UserAllocator</b>
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Defines the allocator that the underlying Pool will use to allocate memory from the system.
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See <a href="boost_pool/pool/pooling.html#boost_pool.pool.pooling.user_allocator">User Allocators</a> for details.
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Class object_pool is a template class
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that can be used for fast and efficient memory allocation of objects.
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It also provides automatic destruction of non-deallocated objects.
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When the object pool is destroyed, then the destructor for type T
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is called for each allocated T that has not yet been deallocated. O(N).
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Whenever an object of type ObjectPool needs memory from the system,
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it will request it from its UserAllocator template parameter.
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The amount requested is determined using a doubling algorithm;
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that is, each time more system memory is allocated,
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the amount of system memory requested is doubled.
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Users may control the doubling algorithm by the parameters passed
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to the object_pool's constructor.
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*/
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template <typename T, typename UserAllocator>
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class object_pool: protected pool<UserAllocator>
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{ //!
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public:
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typedef T element_type; //!< ElementType
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typedef UserAllocator user_allocator; //!<
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typedef typename pool<UserAllocator>::size_type size_type; //!< pool<UserAllocator>::size_type
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typedef typename pool<UserAllocator>::difference_type difference_type; //!< pool<UserAllocator>::difference_type
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protected:
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//! \return The underlying boost:: \ref pool storage used by *this.
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pool<UserAllocator> & store()
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{
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return *this;
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}
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//! \return The underlying boost:: \ref pool storage used by *this.
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const pool<UserAllocator> & store() const
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{
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return *this;
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}
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// for the sake of code readability :)
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static void * & nextof(void * const ptr)
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{ //! \returns The next memory block after ptr (for the sake of code readability :)
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return *(static_cast<void **>(ptr));
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}
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public:
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explicit object_pool(const size_type arg_next_size = 32, const size_type arg_max_size = 0)
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:
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pool<UserAllocator>(sizeof(T), arg_next_size, arg_max_size)
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{ //! Constructs a new (empty by default) ObjectPool.
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//! \param next_size Number of chunks to request from the system the next time that object needs to allocate system memory (default 32).
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//! \pre next_size != 0.
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//! \param max_size Maximum number of chunks to ever request from the system - this puts a cap on the doubling algorithm
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//! used by the underlying pool.
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}
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~object_pool();
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// Returns 0 if out-of-memory.
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element_type * malloc BOOST_PREVENT_MACRO_SUBSTITUTION()
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{ //! Allocates memory that can hold one object of type ElementType.
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//!
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//! If out of memory, returns 0.
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//!
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//! Amortized O(1).
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return static_cast<element_type *>(store().ordered_malloc());
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}
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void free BOOST_PREVENT_MACRO_SUBSTITUTION(element_type * const chunk)
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{ //! De-Allocates memory that holds a chunk of type ElementType.
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//!
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//! Note that p may not be 0.\n
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//!
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//! Note that the destructor for p is not called. O(N).
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store().ordered_free(chunk);
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}
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bool is_from(element_type * const chunk) const
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{ /*! \returns true if chunk was allocated from *this or
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may be returned as the result of a future allocation from *this.
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Returns false if chunk was allocated from some other pool or
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may be returned as the result of a future allocation from some other pool.
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Otherwise, the return value is meaningless.
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\note This function may NOT be used to reliably test random pointer values!
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*/
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return store().is_from(chunk);
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}
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element_type * construct()
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{ //! \returns A pointer to an object of type T, allocated in memory from the underlying pool
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//! and default constructed. The returned objected can be freed by a call to \ref destroy.
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//! Otherwise the returned object will be automatically destroyed when *this is destroyed.
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element_type * const ret = (malloc)();
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if (ret == 0)
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return ret;
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try { new (ret) element_type(); }
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catch (...) { (free)(ret); throw; }
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return ret;
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}
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#if defined(BOOST_DOXYGEN)
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template <class Arg1, ... class ArgN>
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element_type * construct(Arg1&, ... ArgN&)
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{
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//! \returns A pointer to an object of type T, allocated in memory from the underlying pool
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//! and constructed from arguments Arg1 to ArgN. The returned objected can be freed by a call to \ref destroy.
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//! Otherwise the returned object will be automatically destroyed when *this is destroyed.
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//!
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//! \note Since the number and type of arguments to this function is totally arbitrary, a simple system has been
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//! set up to automatically generate template construct functions. This system is based on the macro preprocessor
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//! m4, which is standard on UNIX systems and also available for Win32 systems.\n\n
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//! detail/pool_construct.m4, when run with m4, will create the file detail/pool_construct.ipp, which only defines
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//! the construct functions for the proper number of arguments. The number of arguments may be passed into the
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//! file as an m4 macro, NumberOfArguments; if not provided, it will default to 3.\n\n
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//! For each different number of arguments (1 to NumberOfArguments), a template function is generated. There
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//! are the same number of template parameters as there are arguments, and each argument's type is a reference
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//! to that (possibly cv-qualified) template argument. Each possible permutation of the cv-qualifications is also generated.\n\n
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//! Because each permutation is generated for each possible number of arguments, the included file size grows
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//! exponentially in terms of the number of constructor arguments, not linearly. For the sake of rational
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//! compile times, only use as many arguments as you need.\n\n
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//! detail/pool_construct.bat and detail/pool_construct.sh are also provided to call m4, defining NumberOfArguments
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//! to be their command-line parameter. See these files for more details.
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}
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#else
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// Include automatically-generated file for family of template construct() functions.
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// Copy .inc renamed .ipp to conform to Doxygen include filename expectations, PAB 12 Jan 11.
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// But still get Doxygen warning:
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// I:/boost-sandbox/guild/pool/boost/pool/object_pool.hpp:82:
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// Warning: include file boost/pool/detail/pool_construct.ipp
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// not found, perhaps you forgot to add its directory to INCLUDE_PATH?
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// But the file IS found and referenced OK, but cannot view code.
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// This seems because not at the head of the file
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// But if moved this up, Doxygen is happy, but of course it won't compile,
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// because the many constructors *must* go here.
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#ifndef BOOST_NO_TEMPLATE_CV_REF_OVERLOADS
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# include <boost/pool/detail/pool_construct.ipp>
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#else
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# include <boost/pool/detail/pool_construct_simple.ipp>
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#endif
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#endif
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void destroy(element_type * const chunk)
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{ //! Destroys an object allocated with \ref construct.
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//!
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//! Equivalent to:
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//!
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//! p->~ElementType(); this->free(p);
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//!
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//! \pre p must have been previously allocated from *this via a call to \ref construct.
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chunk->~T();
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(free)(chunk);
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}
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size_type get_next_size() const
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{ //! \returns The number of chunks that will be allocated next time we run out of memory.
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return store().get_next_size();
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}
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void set_next_size(const size_type x)
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{ //! Set a new number of chunks to allocate the next time we run out of memory.
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//! \param x wanted next_size (must not be zero).
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store().set_next_size(x);
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}
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};
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template <typename T, typename UserAllocator>
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object_pool<T, UserAllocator>::~object_pool()
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{
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#ifndef BOOST_POOL_VALGRIND
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// handle trivial case of invalid list.
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if (!this->list.valid())
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return;
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details::PODptr<size_type> iter = this->list;
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details::PODptr<size_type> next = iter;
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// Start 'freed_iter' at beginning of free list
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void * freed_iter = this->first;
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const size_type partition_size = this->alloc_size();
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do
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{
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// increment next
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next = next.next();
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// delete all contained objects that aren't freed.
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// Iterate 'i' through all chunks in the memory block.
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for (char * i = iter.begin(); i != iter.end(); i += partition_size)
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{
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// If this chunk is free,
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if (i == freed_iter)
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{
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// Increment freed_iter to point to next in free list.
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freed_iter = nextof(freed_iter);
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// Continue searching chunks in the memory block.
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continue;
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}
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// This chunk is not free (allocated), so call its destructor,
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static_cast<T *>(static_cast<void *>(i))->~T();
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// and continue searching chunks in the memory block.
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}
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// free storage.
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(UserAllocator::free)(iter.begin());
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// increment iter.
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iter = next;
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} while (iter.valid());
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// Make the block list empty so that the inherited destructor doesn't try to
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// free it again.
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this->list.invalidate();
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#else
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// destruct all used elements:
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for(std::set<void*>::iterator pos = this->used_list.begin(); pos != this->used_list.end(); ++pos)
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{
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static_cast<T*>(*pos)->~T();
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}
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// base class will actually free the memory...
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#endif
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}
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} // namespace boost
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// The following code might be put into some Boost.Config header in a later revision
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#ifdef __BORLANDC__
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# pragma option pop
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#endif
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#endif
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