C++ Boost

object_pool - Boost Object Pool Allocator

Introduction

object_pool.hpp provides a template type that can be used for fast and efficient memory allocation. It also provides automatic destruction of non-deallocated objects. For information on other pool-based interfaces, see the other pool interfaces.

Synopsis

template <typename ElementType, typename UserAllocator = default_user_allocator_new_delete>
class object_pool
{
  private:
    object_pool(const object_pool &);
    void operator=(const object_pool &);

  public:
    typedef ElementType element_type;
    typedef UserAllocator user_allocator;
    typedef typename pool<UserAllocator>::size_type size_type;
    typedef typename pool<UserAllocator>::difference_type difference_type;

    object_pool();
    ~object_pool();

    element_type * malloc();
    void free(element_type * p);
    bool is_from(element_type * p) const;

    element_type * construct();
    // other construct() functions
    void destroy(element_type * p);
};

Template Parameters

ElementType

The template parameter is the type of object to allocate/deallocate. It must have a non-throwing destructor.

UserAllocator

Defines the method that the underlying Pool will use to allocate memory from the system. See User Allocators for details.

Semantics

Symbol Table
SymbolMeaning
ObjectPoolobject_pool<ElementType, UserAllocator>
tvalue of type ObjectPool
uvalue of type const ObjectPool
pvalue of type ElementType *

Typedefs
ExpressionType
ObjectPool::element_typeElementType
ObjectPool::user_allocatorUserAllocator
ObjectPool::size_typepool<UserAllocator>::size_type
ObjectPool::difference_typepool<UserAllocator>::difference_type

Constructors, Destructors, and Testing
ExpressionReturn TypeNotes
ObjectPool()not usedConstructs a new empty ObjectPool
(&t)->~ObjectPool()not usedDestructs the ObjectPool; ~ElementType() is called for each allocated ElementType that has not been deallocated. O(N).
u.is_from(p)boolReturns true if p was allocated from u or may be returned as the result of a future allocation from u. Returns false if p was allocated from some other pool or may be returned as the result of a future allocation from some other pool. Otherwise, the return value is meaningless; note that this function may not be used to reliably test random pointer values.

Allocation and Deallocation
ExpressionReturn TypePre-ConditionSemantic EquivalenceNotes
t.malloc()ElementType *Allocates memory that can hold an object of type ElementType. If out of memory, returns 0. Amortized O(1).
t.free(p)not usedp must have been previously allocated from tDeallocates a chunk of memory. Note that p may not be 0. Note that the destructor for p is not called. O(N).
t.construct(???)ElementType *ElementType must have a constructor matching ???; the number of parameters given must not exceed what is supported through pool_constructAllocates and initializes an object of type ElementType. If out of memory, returns 0. Amortized O(1).
t.destroy(p)not usedp must have been previously allocated from tp->~ElementType(); t.free(p);

Symbols

Implementation Details


Copyright © 2000, 2001 Stephen Cleary (scleary AT jerviswebb DOT com)

This file can be redistributed and/or modified under the terms found in copyright.html

This software and its documentation is provided "as is" without express or implied warranty, and with no claim as to its suitability for any purpose.