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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.
*/
#include "bu/nids.h"
#include "bu/stream.h"
#include "bu/nidsstream.h"
#include <stdio.h>
#define NIDS_MAGIC_CODE ((unsigned char *)"\xFF\xC3\x99\xBD")
namespace Bu
{
subExceptionDef( NidsException )
}
Bu::Nids::Nids( Bu::Stream &sStore ) :
sStore( sStore ),
iBlockSize( 0 ),
iBlocks( 0 ),
iBlockStart( -1 )
{
}
Bu::Nids::~Nids()
{
}
void Bu::Nids::initialize()
{
unsigned char buf[4];
int iUsed;
if( sStore.read( buf, 4 ) < 4 )
throw NidsException("Input stream appears to be empty.");
if( memcmp( buf, NIDS_MAGIC_CODE, 4 ) )
{
throw NidsException(
"Stream does not appear to be a valid NIDS format.");
}
sStore.read( buf, 2 );
if( buf[0] != 0 )
throw NidsException(
"We can only handle version 0 for now.");
if( buf[1] != 4 )
throw NidsException(
"We can only handle 4-byte words at the moment.");
sStore.read( &iBlockSize, 4 );
sStore.read( &iBlocks, 4 );
sStore.read( &iUsed, 4 ); // number of used blocks...
sStore.seek( 7 ); // skip reserved space.
iBlockStart = sStore.tell();
//printf("%d blocks, %db each, %db block offset\n",
// iBlocks, iBlockSize, iBlockStart );
bsBlockUsed.setSize( iBlocks, true );
Block bTmp;
for( int j = 0; j < iBlocks; j++ )
{
sStore.seek( iBlockStart+iBlockSize*j );
sStore.read( &bTmp, sizeof(bTmp) );
if( bTmp.uFirstBlock != blockUnused )
bsBlockUsed.setBit( j );
}
}
void Bu::Nids::initialize( int iBlockSize, int iPreAllocate )
{
char cBuf = 0;
int iBuf = 0;
// Magic number
sStore.write( NIDS_MAGIC_CODE, 4 );
// Version (0)
sStore.write( &cBuf, 1 );
// Bytes per int
cBuf = 4;
sStore.write( &cBuf, 1 );
// The size of each block and the number of blocks we're pre-allocating
sStore.write( &iBlockSize, 4 );
sStore.write( &iPreAllocate, 4 );
// The number of used blocks
sStore.write( &iBuf, 4 );
// Reserved space
sStore.write( "\x00\x00\x00\x00\x00\x00\x00", 7 );
this->iBlockSize = iBlockSize;
this->iBlocks = iPreAllocate;
this->iBlockStart = sStore.tell();
//printf("iBlockStart = %d\n", this->iBlockStart );
bsBlockUsed.setSize( iPreAllocate, true );
//printf("%d blocks, %db each, %db block offset\n",
// iBlocks, iBlockSize, iBlockStart );
Block *block = (Block *)new char[iBlockSize];
memset( block, 0, iBlockSize );
block->uFirstBlock = block->uNextBlock = block->uPrevBlock = blockUnused;
for( int j = 0; j < iPreAllocate; j++ )
{
sStore.write( block, iBlockSize );
}
delete[] (char *)block;
}
void Bu::Nids::initBlock( uint32_t uPos, uint32_t uFirstBlock,
uint32_t uPrevBlock, bool bNew )
{
Block b = { uPos, blockUnused, uPrevBlock, 0, 0, { } };
if( uFirstBlock != blockUnused )
b.uFirstBlock = uFirstBlock;
bsBlockUsed.setBit( uPos );
sStore.setPos( iBlockStart+(iBlockSize*uPos) );
sStore.write( &b, sizeof(Block) );
if( bNew )
{
// It's a new one, at the end, write some zeros.
int iSize = iBlockSize-sizeof(Block);
char *buf = new char[iSize];
memset( buf, 0, iSize );
sStore.write( buf, iSize );
delete[] buf;
}
}
uint32_t Bu::Nids::createBlock( uint32_t uFirstBlock, uint32_t uPrevBlock,
int /*iPreAllocate*/ )
{
for( int j = 0; j < iBlocks; j++ )
{
if( !bsBlockUsed.getBit( j ) )
{
initBlock( j, uFirstBlock, uPrevBlock );
return j;
}
}
// Oh, we don't have any blocks left...allocate a new one.
iBlocks++;
bsBlockUsed.setSize( iBlocks, false );
initBlock( iBlocks-1, uFirstBlock, uPrevBlock, true );
return iBlocks-1;
}
int Bu::Nids::createStream( int iPreAllocate )
{
return createBlock( blockUnused, blockUnused, iPreAllocate );
}
void Bu::Nids::deleteStream( int /*iID*/ )
{
}
Bu::NidsStream Bu::Nids::openStream( int iID )
{
if( iBlockStart < 0 )
{
initialize();
}
return NidsStream( *this, iID );
}
int Bu::Nids::getBlockSize()
{
return iBlockSize;
}
/*
void Bu::Nids::extendStream( int iID, int iBlockCount )
{
}*/
void Bu::Nids::getBlock( uint32_t uIndex, Bu::Nids::Block *pBlock )
{
sStore.setPos( iBlockStart + (iBlockSize*uIndex) );
sStore.read( pBlock, iBlockSize );
}
void Bu::Nids::setBlock( uint32_t uIndex, Bu::Nids::Block *pBlock )
{
sStore.setPos( iBlockStart + (iBlockSize*uIndex) );
sStore.write( pBlock, iBlockSize );
}
void Bu::Nids::updateStreamSize( uint32_t uIndex, uint32_t uSize )
{
sStore.setPos( iBlockStart + (iBlockSize*uIndex)+4*3 );
sStore.write( &uSize, 4 );
}
uint32_t Bu::Nids::getNextBlock( uint32_t uIndex,
struct Bu::Nids::Block *pBlock, bool bCreate )
{
uint32_t uNew;
if( pBlock->uNextBlock == blockUnused )
{
if( bCreate )
{
uNew = createBlock( pBlock->uFirstBlock, uIndex );
sStore.setPos( iBlockStart + (iBlockSize*uIndex)+1*4 );
sStore.write( &uNew, 4 );
getBlock( uNew, pBlock );
}
else
{
throw Bu::NidsException("Reached end of stream.");
}
}
else
{
uNew = pBlock->uNextBlock;
getBlock( pBlock->uNextBlock, pBlock );
}
return uNew;
}
Bu::Nids::Block *Bu::Nids::newBlock()
{
return (Block *)new char[iBlockSize];
}
void Bu::Nids::deleteBlock( Block *pBlock )
{
delete[] (char *)pBlock;
}
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