//
// 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