/**************************************************************
 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * 
 *************************************************************/



#ifndef _STGCACHE_HXX
#define _STGCACHE_HXX

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

class UCBStorageStream;

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

class StgCache {
	StgPage* pCur;							// top of LRU list
	StgPage* pElem1;						// top of ordered list
	sal_uLong nError;							// error code
	sal_Int32 nPages;							// size of data area in pages
	sal_uInt16 nRef;							// reference count
	void * pLRUCache;						// hash table of cached objects
	short nPageSize;						// page size of the file
	UCBStorageStream* pStorageStream;		// holds reference to UCB storage stream
	
	void Erase( StgPage* );					// delete a cache element
	void InsertToLRU( StgPage* );			// insert into LRU list
	void InsertToOrdered( StgPage* );		// insert into ordered list
	StgPage* Create( sal_Int32 );				// create a cached page
protected:
	SvStream* pStrm;						// physical stream
	sal_Bool  bMyStream;						// sal_True: delete stream in dtor
	sal_Bool  bFile;							// sal_True: file stream
	sal_Int32 Page2Pos( sal_Int32 );				// page address --> file position
	sal_Int32 Pos2Page( sal_Int32 );				// file position --> page address
public:
	StgCache();
	~StgCache();
	void  IncRef()						{ nRef++;			}
	sal_uInt16 DecRef()						{ return --nRef;	}
	void  SetPhysPageSize( short );
	sal_Int32 GetPhysPages()				{ return nPages;	}
	short GetPhysPageSize()				{ return nPageSize; }
	SvStream* GetStrm()	  				{ return pStrm;  	}
	void  SetStrm( SvStream*, sal_Bool );
	void  SetStrm( UCBStorageStream* );
	sal_Bool  IsWritable()					{ return ( pStrm && pStrm->IsWritable() ); }
	sal_Bool  Good()						{ return sal_Bool( nError == SVSTREAM_OK ); }
	sal_Bool  Bad()                         { return sal_Bool( nError != SVSTREAM_OK ); }
	sal_uLong GetError()					{ return nError; 	}
	void  MoveError( StorageBase& );
	void  SetError( sal_uLong );
	void  ResetError();
	sal_Bool  Open( const String& rName, StreamMode );
	void  Close();
	sal_Bool  Read( sal_Int32 nPage, void* pBuf, sal_Int32 nPages );
	sal_Bool  Write( sal_Int32 nPage, void* pBuf, sal_Int32 nPages );
	sal_Bool  SetSize( sal_Int32 nPages );
	StgPage* Find( sal_Int32 );					// find a cached page
	StgPage* Get( sal_Int32, sal_Bool );			// get a cached page
	StgPage* Copy( sal_Int32, sal_Int32=STG_FREE );	// copy a page
	sal_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
	sal_Int32	nPage;							// page #
	sal_uInt8*	pData;							// nPageSize characters
	short	nData;							// size of this page
	sal_Bool	bDirty;							// dirty flag
	StgPage( StgCache*, short );
	~StgPage();
public:
	void  SetDirty()					{ bDirty = sal_True; 	 		}
	sal_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.
	sal_Int32 GetPage( short nOff )
	{
		if( ( nOff >= (short) ( nData / sizeof( sal_Int32 ) ) ) || nOff < 0 )
			return -1;
		sal_Int32 n = ((sal_Int32*) pData )[ nOff ];
#ifdef OSL_BIGENDIAN
		return SWAPLONG(n);
#else
		return n;
#endif
	}
	void  SetPage( short, sal_Int32 );		// put an element
};

#endif