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/*
* Copyright (C) 2007-2008 Xagasoft, All rights reserved.
*
* This file is part of the libbu++ library and is released under the
* terms of the license contained in the file LICENSE.
*/
#ifndef BU_NIDS_H
#define BU_NIDS_H
#include <stdint.h>
#include "bu/bitstring.h"
#include "bu/exceptionbase.h"
namespace Bu
{
class Stream;
class NidsStream;
subExceptionDecl( NidsException )
/**
* Numerically Indexed Data Streams. This is a working name so I can
* actually get some code written instead of agonizing over the name.
*
* This is a system for creating streams that contain other streams in
* a flexible block-allocated system.
*/
class Nids
{
friend class NidsStream;
public:
Nids( Bu::Stream &sStore );
virtual ~Nids();
/**
* Initialize this object based on the data already in the assosiated
* stream. This will be called automatically for you if you forget,
* but if you want to pre-initialize for some reason, just call this
* once before you actually start doing anything with your Nids.
*/
void initialize();
/**
* Create a new Nids system in the assosiated stream. This should be
* used carefully, it will destroy all data already within the stream.
* More options will probably be added soon.
*/
void initialize( int iBlockSize, int iPreAllocate=1 );
/**
* Create a new stream within the Nids system. The ID of the new stream
* is returned.
*/
int createStream( int iPreAllocate=1 );
/**
* Delete a stream that's already within the Nids.
*/
void deleteStream( int iID );
/**
* Return a new Stream object assosiated with the given stream ID.
*/
NidsStream openStream( int iID );
int getBlockSize();
int getNumBlocks();
int getNumUsedBlocks();
int getBlockStart();
int getBlockOverhead();
/**
* Syncronize the header data, etc. with the storage stream. It's not
* a bad idea to call this periodically.
*/
void sync();
private:
typedef struct Block
{
uint32_t uFirstBlock;
uint32_t uNextBlock;
// uint32_t uPrevBlock;
uint32_t uBytesUsed;
// uint32_t uReserved;
unsigned char pData[0];
} Block;
enum
{
blockUnused = 0xFFFFFFFFUL
};
void initBlock( uint32_t uPos, uint32_t uFirstBlock,
/*uint32_t uPrevBlock,*/ bool bNew=false );
uint32_t createBlock( uint32_t uFirstBlock, /*uint32_t uPrevBlock,*/
int iPreAllocate=1 );
void getBlock( uint32_t uIndex, struct Nids::Block *pBlock );
void setBlock( uint32_t uIndex, struct Nids::Block *pBlock );
void updateStreamSize( uint32_t uIndex, uint32_t uSize );
uint32_t getNextBlock( uint32_t uIndex, struct Nids::Block *pBlock,
bool bCreate=true);
void updateHeader();
// Block allocation routines
Block *newBlock();
void deleteBlock( Block *pBlock );
private:
Bu::Stream &sStore;
int iBlockSize;
int iBlocks;
int iBlockStart;
int iUsed;
Bu::BitString bsBlockUsed;
};
};
#endif
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