/*************************************************************************
 *
 *  $RCSfile: stgcache.hxx,v $
 *
 *  $Revision: 1.2 $
 *
 *  last change: $Author: vg $ $Date: 2001/02/13 14:15:19 $
 *
 *  The Contents of this file are made available subject to the terms of
 *  either of the following licenses
 *
 *         - GNU Lesser General Public License Version 2.1
 *         - Sun Industry Standards Source License Version 1.1
 *
 *  Sun Microsystems Inc., October, 2000
 *
 *  GNU Lesser General Public License Version 2.1
 *  =============================================
 *  Copyright 2000 by Sun Microsystems, Inc.
 *  901 San Antonio Road, Palo Alto, CA 94303, USA
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License version 2.1, as published by the Free Software Foundation.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA  02111-1307  USA
 *
 *
 *  Sun Industry Standards Source License Version 1.1
 *  =================================================
 *  The contents of this file are subject to the Sun Industry Standards
 *  Source License Version 1.1 (the "License"); You may not use this file
 *  except in compliance with the License. You may obtain a copy of the
 *  License at http://www.openoffice.org/license.html.
 *
 *  Software provided under this License is provided on an "AS IS" basis,
 *  WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
 *  WITHOUT LIMITATION, WARRANTIES THAT THE SOFTWARE IS FREE OF DEFECTS,
 *  MERCHANTABLE, FIT FOR A PARTICULAR PURPOSE, OR NON-INFRINGING.
 *  See the License for the specific provisions governing your rights and
 *  obligations concerning the Software.
 *
 *  The Initial Developer of the Original Code is: Sun Microsystems, Inc.
 *
 *  Copyright: 2000 by Sun Microsystems, Inc.
 *
 *  All Rights Reserved.
 *
 *  Contributor(s): _______________________________________
 *
 *
 ************************************************************************/

#ifndef _STGCACHE_HXX
#define _STGCACHE_HXX

#ifndef _TOOLS_SOLAR_H
#include <tools/solar.h>
#endif
#ifndef _TOOLS_STREAM_HXX
#include <tools/stream.hxx>
#endif

#ifndef _STGELEM_HXX
#include <sot/stgelem.hxx>
#endif

class StgIo;
class StgPage;
class StgDirEntry;
class StorageBase;

class StgCache {
	StgPage* pCur;							// top of LRU list
	StgPage* pElem1;						// top of ordered list
	ULONG nError;							// error code
	INT32 nPages;							// size of data area in pages
	USHORT nRef;							// reference count
	void * pLRUCache;						// hash table of cached objects
	short nPageSize;						// page size of the file
	void Erase( StgPage* );					// delete a cache element
	void InsertToLRU( StgPage* );			// insert into LRU list
	void InsertToOrdered( StgPage* );		// insert into ordered list
	StgPage* Create( INT32 );				// create a cached page
protected:
	SvStream* pStrm;						// physical stream
	BOOL  bMyStream;						// TRUE: delete stream in dtor
	BOOL  bFile;							// TRUE: file stream
	INT32 Page2Pos( INT32 );				// page address --> file position
	INT32 Pos2Page( INT32 );				// file position --> page address
public:
	StgCache();
	~StgCache();
	void  IncRef()						{ nRef++;			}
	USHORT DecRef()						{ return --nRef;	}
	void  SetPhysPageSize( short );
	INT32 GetPhysPages()				{ return nPages;	}
	short GetPhysPageSize()				{ return nPageSize; }
	SvStream* GetStrm()	  				{ return pStrm;  	}
	void  SetStrm( SvStream*, BOOL );
	BOOL  IsWritable()					{ return pStrm->IsWritable(); }
	BOOL  Good()						{ return BOOL( nError == SVSTREAM_OK ); }
	BOOL  Bad()                         { return BOOL( nError != SVSTREAM_OK ); }
	ULONG GetError()					{ return nError; 	}
	void  MoveError( StorageBase& );
	void  SetError( ULONG );
	void  ResetError();
	BOOL  Open( const String& rName, StreamMode );
	void  Close();
	BOOL  Read( INT32 nPage, void* pBuf, INT32 nPages );
	BOOL  Write( INT32 nPage, void* pBuf, INT32 nPages );
	BOOL  SetSize( INT32 nPages );
	StgPage* Find( INT32 );					// find a cached page
	StgPage* Get( INT32, BOOL );			// get a cached page
	StgPage* Copy( INT32, INT32=STG_FREE );	// copy a page
	BOOL Commit( StgDirEntry* = NULL );		// flush all pages
	void Revert( StgDirEntry* = NULL );		// revert dirty pages
	void Clear();							// clear the cache
};

class StgPage {
	friend class StgCache;
	StgCache* pCache;						// the cache
	StgPage *pNext1, *pLast1;				// LRU chain
	StgPage *pNext2, *pLast2;				// ordered chain
	StgDirEntry* pOwner;					// owner
	INT32	nPage;							// page #
	void*	pData;							// nPageSize characters
	short	nData;							// size of this page
	BOOL	bDirty;							// dirty flag
	StgPage( StgCache*, short );
	~StgPage();
public:
	void  SetDirty()					{ bDirty = TRUE; 	 		}
	INT32 GetPage()						{ return nPage;				}
	void* GetData()						{ return pData; 	 		}
	short GetSize()						{ return nData; 	 		}
	void  SetOwner( StgDirEntry* p )	{ pOwner = p;				}
	// routines for accessing FAT pages
	// Assume that the data is a FAT page and get/put FAT data.
	INT32 GetPage( short nOff )
	{
		if( ( nOff >= (short) ( nData / sizeof( INT32 ) ) ) || nOff < 0 )
			return -1;
		INT32 n = ((INT32*) pData )[ nOff ];
#ifdef __BIGENDIAN
		return SWAPLONG(n);
#else
		return n;
#endif
	}
	void  SetPage( short, INT32 );		// put an element
};

#endif
