cachrand.cpp

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// $Id: cachrand.cpp 751 2006-03-31 15:43:49Z alex $
/* @@tag:xara-cn@@ DO NOT MODIFY THIS LINE
================================XARAHEADERSTART===========================
 
               Xara LX, a vector drawing and manipulation program.
                    Copyright (C) 1993-2006 Xara Group Ltd.
       Copyright on certain contributions may be held in joint with their
              respective authors. See AUTHORS file for details.

LICENSE TO USE AND MODIFY SOFTWARE
----------------------------------

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Franklin St, Fifth Floor, Boston, MA  02110-1301 USA


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=================================XARAHEADEREND============================
 */

/*
*/

#include "camtypes.h"
#include "cachrand.h"
#include "objcache.h"
#include "cache.h"
#include <time.h>
#include <stdlib.h>


DECLARE_SOURCE( "$Revision: 751 $" );


CC_IMPLEMENT_DYNCREATE(ObjectCacheRandom, ObjectCache)

#define new CAM_DEBUG_NEW


/*********************************************************************************************

>   ObjectCacheRandom::ObjectCacheRandom()

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    20/01/97
    Purpose:    default constructor for ObjectCache
    Note:       
    SeeAlso:    
**********************************************************************************************/
ObjectCacheRandom::ObjectCacheRandom()
{
    m_Ceiling = 0;
}

/*********************************************************************************************

>   ObjectCacheRandom::ObjectCacheRandom(UINT32 ceiling)

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    20/01/97
    Inputs:     ceiling: max size of the cache.
    Purpose:    constructor for ObjectCacheRandom. Set the size of the cache.
    Note:       
    SeeAlso:    
**********************************************************************************************/
ObjectCacheRandom::ObjectCacheRandom(UINT32 ceiling)
{
    m_Ceiling = ceiling;
}

/*********************************************************************************************

>   ObjectCacheRandom::~ObjectCacheRandom()

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    20/01/97
    Purpose:    destructor for ObjectCache
    Note:       
    SeeAlso:    
**********************************************************************************************/
ObjectCacheRandom::~ObjectCacheRandom()
{
}


/*********************************************************************************************

>   BOOL ObjectCacheRandom::Delete()

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    21/01/97
    Returns:    TRUE is success, FALSE otherwise.
    Purpose:    delete an object in the cache according a radom algorithm.
    Note:       
    SeeAlso:    
**********************************************************************************************/

BOOL ObjectCacheRandom::DeleteObject()
{
    if (m_NumObjects == 0)
        return FALSE;

    srand((unsigned)time(NULL));
    BOOL ok = FALSE;
    WORD Factory = 0;
    CachedObject* pObj = NULL;

    do
    {
        WORD hObj = rand() % m_HandleFactory + 1;       // generate a handle 
        Factory++;                                  // count the number of generated numbers

        pObj = LookUp(hObj);                        // look up in the hash table
        ok = (pObj != NULL);

        if(ok)
        {
            Remove(hObj);                           // remove from the hash table
            m_NumObjects--;                         // decrease the number of objects
            m_CurrentSize -= pObj->GetSize();           // decrease the used space of cache
        }
    }
    while (!ok && Factory<=m_HandleFactory);

    //if(ok && Factory<=HandleFactory)
    if(ok)
    {
        delete pObj;
        pObj = NULL;
        return TRUE;
    }

    return FALSE;
}

---