windows-nt-4.0/private/windows/win4help/hcrtf/cjtable.cpp

#include "stdafx.h"

#pragma hdrstop
#include "ctable.h"

// acLeadingZeroes gives the low order zeroes before the first
// one bit in a byte value.

extern char bCharTypes[];

BYTE acLeadingZeroes[256] =
{
    8, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0,
    4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0
};


// Count of one leading one bits in lower half byte, going right to left.
BYTE acOneBits[16] =
{
    0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4
};

CCompressTable *CCompressTable::NewCompressTable(HGLOBAL hImage, LONG cbImage, HGLOBAL hIndex, LONG cbIndex)
{
    CCompressTable *pct = new CCompressTable();

    JBITHDR   jIHdr;
    int         iWeightCount;
    int         base;
    LPSTR       lpIndex = (LPSTR) GlobalLock(hIndex);
    int         ii;
    char  *hlpImage;
    LPSTR      lpImage;
    BOOL       bSkip = (cbImage > (64L * 1024L)) ? TRUE : FALSE;
    int         cb;

    ASSERT(pct);

    pct->m_hImage = hImage;

    hlpImage = (char *) GlobalLock(hImage);
    lpImage  = (LPSTR) hlpImage;


    jIHdr = *((JBITHDR *) lpIndex);
    ASSERT(jIHdr.Magic == 'J');

    base            = (int) jIHdr.cBits;
    iWeightCount    = (int) jIHdr.cCount;
    lpIndex        += sizeof(jIHdr);


    //
    // This must be less than 64K.
    //
    pct->m_hWeight = GlobalAlloc(GMEM_FIXED, sizeof(WEIGHT) * iWeightCount);

    PWEIGHTS pWeights = (PWEIGHTS) GlobalLock(pct->m_hWeight);

    CJCode JCode(base, iWeightCount, (LPSTR) lpIndex);

    for (ii = 0; ii < iWeightCount; ii++)
        {
        cb = JCode.GetNextDelta();
        pWeights[ii].cb = cb;
        pWeights[ii].pb = (LPSTR) lpImage;
        if (bCharTypes[*(pWeights[ii].pb)] & SYMBOL_CHAR)
            pWeights[ii].bSymbol = TRUE;
        else
            pWeights[ii].bSymbol = FALSE;

        lpImage += cb;
        if ((lpImage - ((LPSTR) hlpImage)) > (63L * 1024L))
            {
            if (bSkip)
                {
                cb        = ((LPSTR) hlpImage) - (LPSTR) (63L * 1024L);
                hlpImage += (63L * 1024L);
                lpImage   = (LPSTR) hlpImage + cb;
                }
            }
        }

    pct->m_pWeights = pWeights;

    return(pct);
}

INT  CCompressTable::DeCompressString(LPSTR pbComp, LPSTR pbDecomp, int cbComp)
{
    LPSTR pbLimit = pbComp + cbComp;
    LPSTR pbStartDecomp = pbDecomp;
    BYTE  bCode;
    BOOL bPrevTokenSymbol = FALSE;
    BOOL bNextTokenSymbol = FALSE;

    int   iIndex;
    int    cb;


    while(pbComp < pbLimit)
        {
        bCode = *pbComp++;
        switch( acOneBits[0x0f & bCode])
            {
            case NDX_LOW_CLASS:
                bCode >>= 1;
                iIndex = ((int) bCode) & 0x00ff;

                ASSERT(iIndex > -1);
                bNextTokenSymbol =  m_pWeights[iIndex].bSymbol;
                if (bNextTokenSymbol && bPrevTokenSymbol)
                    {
                    *pbDecomp++ = ' ';
                    }
                memcpy( pbDecomp, m_pWeights[iIndex].pb, m_pWeights[iIndex].cb);
                pbDecomp += m_pWeights[iIndex].cb;

                break;

            case NDX_MEDIUM_CLASS:
                bCode >>= 2;
                iIndex = ((int) bCode) & 0x00ff;
                iIndex <<= 8;
                bCode    = *pbComp++;
                iIndex  |= bCode;
				iIndex  += 128;

                ASSERT(iIndex > -1);
                bNextTokenSymbol =  m_pWeights[iIndex].bSymbol;
                if (bNextTokenSymbol && bPrevTokenSymbol)
                    {
                    *pbDecomp++ = ' ';
                    }
                memcpy( pbDecomp, m_pWeights[iIndex].pb, m_pWeights[iIndex].cb);
                pbDecomp += m_pWeights[iIndex].cb;

                break;

            case LITERAL_CLASS:
                bNextTokenSymbol = FALSE;
                bCode >>= 3;
                cb      = (((int) bCode) & 0x00ff) + 1;
                memcpy( pbDecomp, pbComp, cb);
                pbDecomp += cb;
                pbComp   += cb;

                break;

            case SPACES_CLASS:
                bNextTokenSymbol = FALSE;
                bCode >>= 4;
                cb      = (((int) bCode) & 0x00ff) + 1;
                ASSERT(cb > 0);



                while (cb--)
                    {
                    *pbDecomp++ = ' ';
                    }

                break;

            case NULL_CLASS:
                bNextTokenSymbol = FALSE;
                bCode >>= 4;
                cb      = (((int) bCode) & 0x00ff) + 1;
                ASSERT(cb > 0);

                while (cb--)
                    {
                    *pbDecomp++ = 0x00;
                    }
                break;
            }
        bPrevTokenSymbol = bNextTokenSymbol;
        }
    return( pbDecomp - pbStartDecomp);
}
CCompressTable::~CCompressTable()
{
    GlobalUnlock(m_hWeight);
    GlobalFree(m_hWeight);
    GlobalUnlock(m_hImage);
    GlobalFree(m_hImage);
}


CJCode::CJCode( int base, int cCount, LPSTR pv)
{
    m_base          = base;
    m_cCount        = cCount;
    m_pData         = (DWORD FAR *) pv;
    m_cCurrent      = 0;
    m_pDataCurrent  = m_pData;
    m_iLeft         = BITS_AVAIL;
    m_fBasisMask    = ((DWORD)(~0)) >> (32 - m_base);
}

int CJCode::GetBits()
{
    BYTE byte;
    int   iBits;

    byte = (BYTE) (~(0x000000ff & *m_pDataCurrent));
    iBits = acLeadingZeroes[byte];

    if (iBits == 8)
        {
        *m_pDataCurrent >>= iBits;
        m_iLeft        -= 8;
        return(iBits + GetBits());
        }

    if (iBits < m_iLeft)
        {
        *m_pDataCurrent >>= iBits + 1;
        m_iLeft        -= iBits + 1;
        return(iBits);
        }

    ASSERT(!(iBits > m_iLeft));

    m_iLeft = BITS_AVAIL;
    m_pDataCurrent++;
    return(iBits + GetBits());

    
}
int CJCode::GetNextDelta()
{
    DWORD dwCode = 0;
    int   iBits;
    int   iDelta;
    DWORD dwTmp;

    iDelta = 0;

    iBits = GetBits();

    dwCode = *m_pDataCurrent & m_fBasisMask;

    if (m_iLeft >= m_base)
        {
        *m_pDataCurrent >>= m_base;
        m_iLeft        -= m_base;
        }
    else
        {
        m_pDataCurrent++;
        dwTmp           = *m_pDataCurrent & (((DWORD) ~0) >> (32 - m_base + m_iLeft));
        dwTmp         <<= m_iLeft;
        dwCode         |= dwTmp;
        *m_pDataCurrent >>= m_base - m_iLeft;

        m_iLeft     = BITS_AVAIL - m_base + m_iLeft;
        }

    iDelta   = iBits << m_base;
    iDelta  |= dwCode;
    return(iDelta + 1);

}