objcache.cpp

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// $Id: objcache.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.
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              respective authors. See AUTHORS file for details.

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----------------------------------

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

/*
*/

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


DECLARE_SOURCE( "$Revision: 751 $" );


CC_IMPLEMENT_DYNCREATE(ObjectCache, CCObject)

// Declare smart memory handling in Debug builds
#define new CAM_DEBUG_NEW


#define MYTRACE if(IsUserName("Olivier")) TRACE

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

>   ObjectCache::ObjectCache()

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    20/01/97
    Purpose:    default constructor for ObjectCache
    Note:       
    SeeAlso:    
**********************************************************************************************/
ObjectCache::ObjectCache()
{
    // Compute the available amount of memory
    /*TunedMemory* pTuneMem = GetTunedMemManager();
    if (pTuneMem != NULL)
        Ceiling = pTuneMem->GetAvailableTunedMem();*/

    m_NumObjects    = 0;
    m_HandleFactory = 1;
    m_CurrentSize   = 0;
}

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

>   ObjectCache::ObjectCache(UINT32 ceiling)

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    20/01/97
    Purpose:    constructor for ObjectCache, set the cache size.
    Inputs:     ceiling: the amount of memory available for the cache
    Note:       
    SeeAlso:    
**********************************************************************************************/
ObjectCache::ObjectCache(UINT32 ceiling)
{
    m_Ceiling       = ceiling;
    m_NumObjects    = 0;
    m_HandleFactory = 1;    // we don't start from 0 
    m_CurrentSize   = 0;
}

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

>   ObjectCache::~ObjectCache()

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


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

>   void ObjectCache::SetMaxCacheSize(UINT32 NewCeiling)

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    20/01/97
    Inputs:     NewCeiling: The size of the new ceiling
    Purpose:    dynamically change the size (in bytes) of the Cache.
    Note:       
    SeeAlso:    
**********************************************************************************************/

BOOL ObjectCache::SetMaxCacheSize(UINT32 NewCeiling)
{
//  MYTRACE( _T("ObjectCache::SetMaxCacheSize()\n"));
    while (m_CurrentSize > NewCeiling)
    {
        if(!DeleteObject())
            break;
    }
    m_Ceiling = NewCeiling;
    return TRUE;
}


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

>   CACHE_HANDLE ObjectCache::Add(CachedObject *pObj)

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    21/01/97
    Inputs:     pObj: the Object to cache
    Purpose:    Add an object in the Hash table of the cache
    Note:       
    SeeAlso:    
**********************************************************************************************/

CACHE_HANDLE ObjectCache::Add(CachedObject *pObj)
{
    ERROR3IF(pObj==NULL, "Error: the object to cache can't be NULL");

    if (pObj == NULL)
        return 0;

//  MYTRACE( _T("ObjectCache::Add()\n"));

    // if we can make room for the object then assign the object a unique handle and cache it
    if (MakeRoomFor(pObj))
    {
        CACHE_HANDLE hObj = m_HandleFactory++;

        pObj->StoreHandle(hObj);        // store the CachedObject Handle
        m_NumObjects++;                 // Increase the number of objects
        m_CurrentSize += pObj->GetSize();   // Increase the space used
        m_ObjectMap[hObj] = pObj;   // set the object in the hash table
        return hObj;
    }

    return 0;
}


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

>   BOOL ObjectCache::MakeRoomFor(CachedObject* pObj)

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    21/01/97
    Inputs:     pObj: The object to add in the cache
    Returns:    TRUE if succesful, FALSE otherwise
    Purpose:    make room for another object by deleting old objects if the cache is full
    Note:       
    SeeAlso:    
**********************************************************************************************/

BOOL ObjectCache::MakeRoomFor(CachedObject* pObj)
{
    ERROR3IF(pObj==NULL, "Error: the object to cache can't be NULL");

    if (pObj == NULL)
        return FALSE;

    // is there room in the cache or do we have to free some memory ?
    if (pObj->GetSize() + m_CurrentSize <= m_Ceiling)
        return TRUE;    // enough room

    // is the cache big enough ? 
    if (pObj->GetSize() > m_Ceiling)
        return FALSE;   // the object is bigger than the cache size

    // Scan the cache deleting objects until there is room
    BOOL EnoughRoom = (pObj->GetSize() + m_CurrentSize <= m_Ceiling);
    do
    {
        BOOL ObjectDeleted = DeleteObject();

        EnoughRoom = (pObj->GetSize() + m_CurrentSize <= m_Ceiling);

        if(!ObjectDeleted && !EnoughRoom)
            return FALSE;       // no room and no deleted objects 
    }
    while (!EnoughRoom);

    return TRUE;
}


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

>   CachedObject *ObjectCache::LookUp(CACHE_HANDLE hObj)

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    21/01/97
    Purpose:    LookUp in the hash table
    Returns:    return a pointer to the object found, NULL otherwise
    Note:       
    SeeAlso:    
**********************************************************************************************/

CachedObject *ObjectCache::LookUp(CACHE_HANDLE hObj)
{
//  void* pObjMap = NULL;

    std::map<WORD, PVOID>::iterator iter = m_ObjectMap.find( hObj );
    if( m_ObjectMap.end() != iter  )
        return (CachedObject *)iter->second;

    return NULL;
}


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

>   BOOL ObjectCache::Remove(CACHE_HANDLE hObj)

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    21/01/97
    Inputs:     hObj: the object handle
    Returns:    TRUE if success, FALSE otherwise
    Purpose:    Remove a key from the hash table
    Note:       
    SeeAlso:    
**********************************************************************************************/

BOOL ObjectCache::Remove(CACHE_HANDLE hObj)
{
    if( m_ObjectMap.erase( hObj ) )
        return TRUE;

    return FALSE;
}


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

>   BOOL ObjectCache::DeleteObject()

    Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
    Created:    21/01/97
    Purpose:    virtual function. This is the base class delete function. All algorithms
                are implemented in the derived classes such as ObjectCacheRandom...etc.
    Note:       
    SeeAlso:    
**********************************************************************************************/

BOOL ObjectCache::DeleteObject()
{
    return TRUE;
}

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