smart_ptr_policies.cpp

Go to the documentation of this file.

/** @file
 *  @author Bram de Greve (bramz@users.sourceforge.net)
 *  @author Tom De Muer (tomdemuer@users.sourceforge.net)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2007 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
 *  others to use your version of this file under the CPAL, indicate your decision by 
 *  deleting the provisions above and replace them with the notice and other 
 *  provisions required by the GPL License. If you do not delete the provisions above,
 *  a recipient may use your version of this file under either the CPAL or the GPL.
 *  
 *  *** END LICENSE INFORMATION ***
 */

#include "util_common.h"
#include "smart_ptr_policies.h"
#include "allocator.h"

namespace lass
{
namespace util
{
namespace impl
{

// We used to utilize util::Singleton to implement the heap counter allocator,
// but that can result in a static initilisation catastrophe.
// So, we'll deploy a custom "leaking singleton" here.  So, memory is allocated
// but never deallocated ...
// [Bramz]

typedef AllocatorThrow<
        AllocatorStaticFixed<
            AllocatorConcurrentFreeList<>, sizeof(int)
        >
    >
    THeapCounterAllocator;

THeapCounterAllocator* heapCounterAllocatorSingleton = 0;
int heapCounterAllocatorSemaphore = 1;

THeapCounterAllocator& heapCounterAllocator()
{
    if (!heapCounterAllocatorSingleton)
    {
        // enter semaphore
        //
        int oldSlots, newSlots;
        do
        {
            oldSlots = heapCounterAllocatorSemaphore;
            LASS_ASSERT(oldSlots >= 0);
            newSlots = oldSlots - 1;
        }
        while (oldSlots == 0 || !atomicCompareAndSwap(heapCounterAllocatorSemaphore, oldSlots, newSlots));

        // double check on create
        //
        if (heapCounterAllocatorSingleton == 0)
        {
            heapCounterAllocatorSingleton = new THeapCounterAllocator;
        }

        // leave semaphore
        //
        atomicIncrement(heapCounterAllocatorSemaphore);
    }

    return *heapCounterAllocatorSingleton;
}

void initHeapCounter(int*& ioCounter, int iInitialValue)
{
    ioCounter = static_cast<int*>(heapCounterAllocator().allocate());
    *ioCounter = iInitialValue;
}

void disposeHeapCounter(int*& ioCounter)
{
    heapCounterAllocator().deallocate(ioCounter);
    ioCounter = 0;
}

}

}

}

// EOF