cachfifo.cpp

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00001 // $Id: cachfifo.cpp 751 2006-03-31 15:43:49Z alex $
00002 /* @@tag:xara-cn@@ DO NOT MODIFY THIS LINE
00003 ================================XARAHEADERSTART===========================
00004  
00005                Xara LX, a vector drawing and manipulation program.
00006                     Copyright (C) 1993-2006 Xara Group Ltd.
00007        Copyright on certain contributions may be held in joint with their
00008               respective authors. See AUTHORS file for details.
00009 
00010 LICENSE TO USE AND MODIFY SOFTWARE
00011 ----------------------------------
00012 
00013 This file is part of Xara LX.
00014 
00015 Xara LX is free software; you can redistribute it and/or modify it
00016 under the terms of the GNU General Public License version 2 as published
00017 by the Free Software Foundation.
00018 
00019 Xara LX and its component source files are distributed in the hope
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00022 See the GNU General Public License for more details.
00023 
00024 You should have received a copy of the GNU General Public License along
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00027 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
00028 
00029 
00030 ADDITIONAL RIGHTS
00031 -----------------
00032 
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00036 
00037 The additional rights are to use, modify, and distribute the software
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00046 Nothing in this section restricts any of the rights you have under
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00048 
00049 
00050 SCOPE OF LICENSE
00051 ----------------
00052 
00053 This license applies to this program (XaraLX) and its constituent source
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00057 
00058 This license does not apply to files in the wxXtra directory, which
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00062 This license does not apply to the binary libraries (if any) within
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00065 
00066 
00067 ARRANGEMENTS FOR CONTRIBUTION OF MODIFICATIONS
00068 ----------------------------------------------
00069 
00070 Subject to the terms of the GNU Public License (see above), you are
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00080 Please note that Xara will not accept modifications which modify any of
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00084 
00085 MARKS
00086 -----
00087 
00088 Xara, Xara LX, Xara X, Xara X/Xtreme, Xara Xtreme, the Xtreme and Xara
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00092 
00093       Xara Group Ltd, Gaddesden Place, Hemel Hempstead, HP2 6EX, UK.
00094                         http://www.xara.com/
00095 
00096 =================================XARAHEADEREND============================
00097  */
00098 
00099 /*
00100 */
00101 
00102 #include "camtypes.h"
00103 #include "cachfifo.h"
00104 #include "objcache.h"
00105 #include "cache.h"
00106 
00107 
00108 DECLARE_SOURCE( "$Revision: 751 $" );
00109 
00110 
00111 CC_IMPLEMENT_DYNCREATE(ObjectCacheFIFO, ObjectCache)
00112 
00113 // Declare smart memory handling in Debug builds
00114 #define new CAM_DEBUG_NEW
00115 
00116 
00117 /*********************************************************************************************
00118 
00119 >   ObjectCacheFIFO::ObjectCacheFIFO()
00120 
00121     Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
00122     Created:    28/01/97
00123     Purpose:    default constructor for ObjectCacheFIFO. First contains the handle of the first
00124                 object in the hash table.
00125     Note:       
00126     SeeAlso:    
00127 **********************************************************************************************/
00128 ObjectCacheFIFO::ObjectCacheFIFO()
00129 {
00130     m_Ceiling = 0;
00131     m_first = 1;
00132 }
00133 
00134 /*********************************************************************************************
00135 
00136 >   ObjectCacheFIFO::ObjectCacheFIFO(UINT32 ceiling)
00137 
00138     Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
00139     Created:    28/01/97
00140     Inputs:     ceiling: max size of available memory for the cache
00141     Purpose:    constructor for ObjectCacheFIFO
00142     Note:       
00143     SeeAlso:    
00144 **********************************************************************************************/
00145 ObjectCacheFIFO::ObjectCacheFIFO(UINT32 ceiling)
00146 {
00147     m_first = 1;
00148     m_Ceiling = ceiling;
00149 }
00150 
00151 /*********************************************************************************************
00152 
00153 >   ObjectCacheFIFO::~ObjectCacheFIFO()
00154 
00155     Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
00156     Created:    28/01/97
00157     Purpose:    destructor for ObjectCache
00158     Note:       
00159     SeeAlso:    
00160 **********************************************************************************************/
00161 ObjectCacheFIFO::~ObjectCacheFIFO()
00162 {
00163 }
00164 
00165 
00166 /*********************************************************************************************
00167 
00168 >   BOOL ObjectCacheFIFO::Delete()
00169 
00170     Author:     Olivier_Gascoin (Xara Group Ltd) <camelotdev@xara.com>
00171     Created:    28/01/97
00172     Return:     TRUE if success (an object is deleted), FALSE otherwise.
00173     Purpose:    FIFO Cache replacement policy. 
00174     Note:       
00175     SeeAlso:    
00176 **********************************************************************************************/
00177 
00178 BOOL ObjectCacheFIFO::DeleteObject()
00179 {
00180     CachedObject* pObj = NULL;
00181 
00182     if (m_NumObjects == 0)
00183         return FALSE;
00184 
00185     WORD hObj = m_first;                    // First element in the hash table, 
00186                                             // corresponds to the first generated handle.
00187     pObj = LookUp(hObj);
00188     BOOL ok = (pObj != NULL);
00189 
00190     if (ok)
00191     {
00192         Remove(hObj);                       // remove from the hash table
00193         m_NumObjects--;                     // decrease the number of objects
00194         m_CurrentSize -= pObj->GetSize();   // decrease the used space of cache
00195 
00196         delete pObj;
00197         pObj = NULL;
00198 
00199         if (m_NumObjects >= 1)
00200             m_first++;
00201 
00202         return TRUE;
00203     }
00204 
00205     return FALSE;
00206 }

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