tripwire-open-source/src/db/block.h

202 lines
6.8 KiB
C++

//
// 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.
//
///////////////////////////////////////////////////////////////////////////////
// block.h
//
#ifndef __BLOCK_H
#define __BLOCK_H
#ifndef __ARCHIVE_H
#include "core/archive.h"
#endif
#ifndef __DEBUG_H
#include "core/debug.h"
#endif
//-----------------------------------------------------------------------------
// cBlock
//-----------------------------------------------------------------------------
template <int SIZE>
class cBlock
{
public:
enum { INVALID_NUM = -1 };
cBlock();
void SetDirty () { mbDirty = true; }
bool IsDirty () const { return mbDirty; }
int GetBlockNum () const { return mBlockNum; }
int8* GetData() { return mpData; }
bool AssertValid() const;
// this asserts and returns false if the guard bytes have been corrupted
bool IsValidAddr(int8* pAddr) const;
// returns true if pAddr falls within mpData
protected:
enum { NUM_GUARD_BLOCKS = 8, // associated with BYTE_ALIGN: see ctor for info
GUARD_BLOCK_VAL = 0xAB }; // odd, non-zero value for debugging
// guardMin and guardMax are used to detect bad writes
uint8 mGuardMin[NUM_GUARD_BLOCKS];
int8 mpData[SIZE];
uint8 mGuardMax[NUM_GUARD_BLOCKS];
bool mbDirty;
int mBlockNum;
};
///////////////////////////////////////////////////////////////////////////////
// ctor
///////////////////////////////////////////////////////////////////////////////
template <int SIZE>
inline cBlock<SIZE>::cBlock()
: mbDirty (false),
mBlockNum (cBlock::INVALID_NUM)
{
// To prevent misaligned memory access, the size of the data and the
// number of guard blocks must be a multiple of the byte alignment
// and they both must be at least as large as the byte alignment
ASSERT( 0 == ( SIZE % BYTE_ALIGN ) );
ASSERT( 0 == ( NUM_GUARD_BLOCKS % BYTE_ALIGN ) );
ASSERT( SIZE >= BYTE_ALIGN );
ASSERT( NUM_GUARD_BLOCKS >= BYTE_ALIGN );
// init guard blocks to dummy value
for( int i = 0; i < NUM_GUARD_BLOCKS; i++ )
{
mGuardMin[i] = (uint8)GUARD_BLOCK_VAL;
mGuardMax[i] = (uint8)GUARD_BLOCK_VAL;
}
// zero out memory
memset( mpData, 0, SIZE );
}
///////////////////////////////////////////////////////////////////////////////
// ctor
///////////////////////////////////////////////////////////////////////////////
template <int SIZE>
inline bool cBlock<SIZE>::AssertValid() const
{
// determine if guard bites have been accidentally overwritten
for( int i = 0; i < NUM_GUARD_BLOCKS; i++ )
{
if(
( mGuardMin[i] != (uint8) GUARD_BLOCK_VAL )
||
( mGuardMax[i] != (uint8) GUARD_BLOCK_VAL )
)
{
ASSERT( false );
return false;
}
}
return true;
}
template <int SIZE>
inline bool cBlock<SIZE>::IsValidAddr(int8* pAddr) const
{
return ( (pAddr >= &mpData[0]) && (pAddr <= &mpData[SIZE-1]) );
}
//-----------------------------------------------------------------------------
// cBlockImpl
//-----------------------------------------------------------------------------
template <int SIZE>
class cBlockImpl : public cBlock<SIZE>
{
public:
enum { INVALID_NUM = -1 };
cBlockImpl();
void SetBlockNum ( int blockNum ) { cBlock<SIZE>::mBlockNum = blockNum; }
void SetTimestamp( uint32 timestamp ) { mTimestamp = timestamp; }
uint32 GetTimestamp() const { return mTimestamp; }
void Write ( cBidirArchive& arch ); //throw( eArchive )
void Read ( cBidirArchive& arch, int blockNum = INVALID_NUM ); //throw( eArchive )
// if blockNum is INVALID_NUM, then it reads in the current block number
protected:
uint32 mTimestamp;
};
///////////////////////////////////////////////////////////////////////////////
// ctor
///////////////////////////////////////////////////////////////////////////////
template <int SIZE>
inline cBlockImpl<SIZE>::cBlockImpl()
: cBlock<SIZE> ( ),
mTimestamp (0)
{
}
///////////////////////////////////////////////////////////////////////////////
// Write
///////////////////////////////////////////////////////////////////////////////
template <int SIZE>
inline void cBlockImpl<SIZE>::Write( cBidirArchive& arch ) //throw( eArchive )
{
ASSERT( mbDirty );
ASSERT( (mBlockNum >= 0) && (((mBlockNum + 1) * SIZE) <= arch.Length()) );
arch.Seek ( (cBlock<SIZE>::mBlockNum * SIZE), cBidirArchive::BEGINNING );
arch.WriteBlob ( cBlock<SIZE>::mpData, SIZE );
cBlock<SIZE>::mbDirty = false;
}
///////////////////////////////////////////////////////////////////////////////
// Read
///////////////////////////////////////////////////////////////////////////////
template <int SIZE>
inline void cBlockImpl<SIZE>::Read( cBidirArchive& arch, int blockNum ) //throw( eArchive )
{
if( blockNum != INVALID_NUM )
cBlock<SIZE>::mBlockNum = blockNum;
ASSERT( (mBlockNum >= 0) && (((mBlockNum + 1) * SIZE) <= arch.Length()) );
// std::cout << "cBlockImpl<SIZE>::Read() mBlockNum = " << mBlockNum << " arch.Length() = " << arch.Length() << std::endl;
arch.Seek ( (cBlock<SIZE>::mBlockNum * SIZE), cBidirArchive::BEGINNING );
arch.ReadBlob ( cBlock<SIZE>::mpData, SIZE );
cBlock<SIZE>::mbDirty = false;
}
#endif