//
// The developer of the original code and/or files is Tripwire, Inc.
// Portions created by Tripwire, Inc. are copyright (C) 2000 Tripwire,
// Inc. Tripwire is a registered trademark of Tripwire, Inc.  All rights
// reserved.
// 
// This program is free software.  The contents of this file are subject
// to the terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2 of the License, or (at your
// option) any later version.  You may redistribute it and/or modify it
// only in compliance with the GNU General Public License.
// 
// This program is distributed in the hope that it will be useful.
// However, this program is distributed AS-IS WITHOUT ANY
// WARRANTY; INCLUDING THE IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS
// FOR A PARTICULAR PURPOSE.  Please see the GNU General Public License
// for more details.
// 
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.
// 
// Nothing in the GNU General Public License or any other license to use
// the code or files shall permit you to use Tripwire's trademarks,
// service marks, or other intellectual property without Tripwire's
// prior written consent.
// 
// If you have any questions, please contact Tripwire, Inc. at either
// info@tripwire.org or www.tripwire.org.
//
///////////////////////////////////////////////////////////////////////////////
// blockfile.h
//
// cBlockFile -- 
#ifndef __BLOCKFILE_H
#define __BLOCKFILE_H

#ifndef __TYPES_H
#include "types.h"
#endif
#ifndef __TCHAR_H
#include "core/tchar.h"
#endif
#ifndef __BLOCK_H
#include "block.h"
#endif

#ifdef _DEBUG
#undef _BLOCKFILE_DEBUG // If we dont do this, test does not compile on unix
#define _BLOCKFILE_DEBUG // If we dont do this, test does not compile on unix
#endif

class cBlockFile_i;
class eArchive;
class cBidirArchive;
//-----------------------------------------------------------------------------
// cBlockFile
//-----------------------------------------------------------------------------
class cBlockFile
{
public:
	enum {						BLOCK_SIZE = 4096 };
	typedef cBlock<BLOCK_SIZE>	Block;

	cBlockFile();
	~cBlockFile();

	void	Open( const TSTRING& fileName, int numPages, bool bTruncate = false ); //throw (eArchive)	
		// opens the given file name as a block file, and uses numPages to signify the 
		// number of pages to cache blocks in as they are accessed from disk.
		// if bTruncate is true, then the file is created with zero length.
	void	Open( cBidirArchive* pArch, int numPages ); //throw (eArchive)
		// the same as the previous Open(), except the passed in archive is used. This class will destroy
		// the archive when it is done (when Close() is called). If the archive length is zero, then
		// we create a new database. Otherwise, we assume we are opening an existing file.
	void	Close(); //throw (eArchive)
		// writes all unsaved data to disk and disassociates the block file from its archive
	void	Flush(); //throw (eArchive)
		// flushes all dirty data to disk

	Block*	GetBlock( int blockNum ); //throw (eArchive)
		// returns the specified block. This asserts that the block number is below GetNumBlocks()
		// this method takes care of paging the block into memory and returns a pointer to the block.

	Block* CreateBlock(); //throw (eArchive)
		// this creates a new block, sets its number to GetNumBlocks(), pages it into memory, and 
		// returns a pointer to it

	void DestroyLastBlock(  );
		// this method removes the last block from the file

	int		GetNumBlocks() const { return mNumBlocks; }
	int		GetBlockSize() const { return BLOCK_SIZE; }

	cBidirArchive*	GetArchive() { return mpArchive; }
		// NOTE -- be _very_ careful with this archive. It should probably not be written to
private:
	typedef cBlockImpl<BLOCK_SIZE>		BlockImpl;
	typedef std::vector< BlockImpl >	BlockVector;
	
	int				mNumPages;
	int				mNumBlocks;		// the total number of blocks in the archive.
	uint32			mTimer;			// keeps track of the current "time"
	cBidirArchive*	mpArchive;		// note: I always own the deletion of the archive
	BlockVector		mvPagedBlocks;

	void FlushBlock( BlockImpl* pBlock ); //throw (eArchive)
		// helper function that writes a block to disk if it is dirty

	///////////////////////////////////////////////////////////////////////////
	// Profiling / Debugging interface
	///////////////////////////////////////////////////////////////////////////
#ifdef _BLOCKFILE_DEBUG
public:
	void TraceContents(int dl = -1) const;
		// traces out all the info we can on the current state of this class
		// dl is the debug level to trace it at; -1 means to use D_DEBUG
	void AssertValid() const;
		// ASSERTs as much as we can about the consistancy of our internal state.
	int mNumBlockWrite;
		// counts how many writes we have done
	int mNumBlockRead;
		// counts how many reads we have done
	int mNumPageFault;
		// number of times a page fault occured
	int mNumPageRequests;
		// number of page requests (useful to compare with mNumPageFault)

#endif //_BLOCKFILE_DEBUG

};


//#############################################################################
// inline implementation
//#############################################################################
inline void cBlockFile::FlushBlock( cBlockFile::BlockImpl* pBlock ) //throw (eArchive)
{

	if( (pBlock->GetBlockNum() != Block::INVALID_NUM) && pBlock->IsDirty() )
	{
		// mNumBlockWrite keeps track of how many block writes we do
		//
#ifdef _BLOCKFILE_DEBUG
		mNumBlockWrite++;
#endif

		pBlock->Write( *mpArchive );
	}
}


#endif //__BLOCKFILE_H