gifcodec.cpp

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/* ***** BEGIN LICENSE BLOCK *****
 * Source last modified: $Id: gifcodec.cpp,v 1.2.24.1 2004/07/09 01:54:29 hubbe Exp $
 * 
 * Portions Copyright (c) 1995-2004 RealNetworks, Inc. All Rights Reserved.
 * 
 * The contents of this file, and the files included with this file,
 * are subject to the current version of the RealNetworks Public
 * Source License (the "RPSL") available at
 * http://www.helixcommunity.org/content/rpsl unless you have licensed
 * the file under the current version of the RealNetworks Community
 * Source License (the "RCSL") available at
 * http://www.helixcommunity.org/content/rcsl, in which case the RCSL
 * will apply. You may also obtain the license terms directly from
 * RealNetworks.  You may not use this file except in compliance with
 * the RPSL or, if you have a valid RCSL with RealNetworks applicable
 * to this file, the RCSL.  Please see the applicable RPSL or RCSL for
 * the rights, obligations and limitations governing use of the
 * contents of the file.
 * 
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL") in which case the provisions of the GPL are applicable
 * instead of those above. If you wish to allow use of your version of
 * this file only under the terms of the GPL, and not to allow others
 * to use your version of this file under the terms of either the RPSL
 * or RCSL, indicate your decision by deleting the provisions above
 * and replace them with the notice and other provisions required by
 * the GPL. If you do not delete the provisions above, a recipient may
 * use your version of this file under the terms of any one of the
 * RPSL, the RCSL or the GPL.
 * 
 * This file is part of the Helix DNA Technology. RealNetworks is the
 * developer of the Original Code and owns the copyrights in the
 * portions it created.
 * 
 * This file, and the files included with this file, is distributed
 * and made available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY
 * KIND, EITHER EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS
 * ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET
 * ENJOYMENT OR NON-INFRINGEMENT.
 * 
 * Technology Compatibility Kit Test Suite(s) Location:
 *    http://www.helixcommunity.org/content/tck
 * 
 * Contributor(s):
 * 
 * ***** END LICENSE BLOCK ***** */

// system
#include <hlxclib/memory.h>
#include <string.h>

// include
#include "hxtypes.h"
#include "hxcom.h"

// pnmisc
#include "baseobj.h"
#include "unkimp.h"

// pxcomlib
#include "glist.h"

// pxgiflib
#include "gifimage.h"
#include "gifcodec.h"

// pndebug
#include "hxheap.h"
#ifdef _DEBUG
#undef HX_THIS_FILE		
static char HX_THIS_FILE[] = __FILE__;
#endif

BEGIN_INTERFACE_LIST(CGIFCodec)
END_INTERFACE_LIST

CGIFCodec::CGIFCodec()
{
    ResetParse();
    ResetDecompress();
};

CGIFCodec::~CGIFCodec()
{
    TermParse();
    TermDecompress();
};

void CGIFCodec::ResetParse()
{
    m_ulParseState           = kStateConstructed;
    m_pParseBuffer           = NULL;
    m_ulParseBufferLength    = 0;
    m_pSegment               = NULL;
    m_ulDelayTimeSum         = 0;
    m_ulNumSegmentsAllocated = 0;
    m_ulNumSegments          = 0;
    m_ulNumImages            = 0;
    m_ulCurSegIndex          = 0;
    m_ulCurSegOffset         = 0;
    m_ulLoopCount            = 1;
}

void CGIFCodec::ResetDecompress()
{
    m_cLSD.m_ulLogicalScreenWidth     = 0;
    m_cLSD.m_ulLogicalScreenHeight    = 0;
    m_cLSD.m_bGlobalColorTablePresent = FALSE;
    m_cLSD.m_ulOriginalColorBits      = 0;
    m_cLSD.m_bColorsSorted            = FALSE;
    m_cLSD.m_ulColorTableBits         = 0;
    m_cLSD.m_ulColorTableNumEntries   = 0;
    m_cLSD.m_ulBackgroundColorIndex   = 0;
    m_cLSD.m_ulPixelAspectRatio       = 0;
    m_cLSD.m_fPixelAspectRatio        = 0.0F;
    m_bIsGIF89a                       = FALSE;
    m_pucGlobalColorMap               = NULL;
    m_ulNumImages                     = 0;
    m_pImageHeaderSize                = NULL;
    m_pCompressedBufferSize           = NULL;
    m_pImage                          = NULL;
    m_ulCurrentImageIndex             = 0;
    m_bNeedPacket                     = TRUE;
    m_ulState                         = kStateConstructed;
    m_bValid                          = TRUE;
    m_ulLoopCount                     = 1;
}

void CGIFCodec::TermParse()
{
    if (m_pSegment)
    {
        delete [] m_pSegment;
        m_pSegment = NULL;
    }
    ResetParse();
}

void CGIFCodec::TermDecompress()
{
    if (m_pucGlobalColorMap)
    {
        delete [] m_pucGlobalColorMap;
        m_pucGlobalColorMap = NULL;
    }
    if (m_pImageHeaderSize)
    {
        delete [] m_pImageHeaderSize;
        m_pImageHeaderSize = NULL;
    }
    if (m_pCompressedBufferSize)
    {
        delete [] m_pCompressedBufferSize;
        m_pCompressedBufferSize = NULL;
    }
    if (m_pImage)
    {
        delete [] m_pImage;
        m_pImage = NULL;
    }
    ResetDecompress();
}

UINT32 CGIFCodec::GetMaxNumPackets(BYTE* pBuf, UINT32 ulLen)
{
    UINT32 ulNumPackets = 0;

    if (pBuf && ulLen)
    {
        BYTE* pBufLimit = pBuf + ulLen;
        if (pBuf[0] == 'G' && pBuf[1] == 'I' && pBuf[2] == 'F' &&
            pBuf[3] == '8' && pBuf[5] == 'a')
        {
            // Advance past the signature
            pBuf += 6;
            // Parse the logical screen descriptor
            LogicalScreenDescriptor cLSD;
            ParseLogicalScreenDescriptor(pBuf, cLSD);
            pBuf += 7;
            // Skip the color table
            if (cLSD.m_bGlobalColorTablePresent == TRUE)
            {
                // Advance that number of bytes
                pBuf += (UINT32) (cLSD.m_ulColorTableNumEntries * 3);
            }
            // We count this as the first packet
            ulNumPackets++;
            // Loop through the GIF blocks - we know that the max number
            // of packets would be if each GIF block were its own packet,
            // so we simply need to count the GIF blocks
            while (pBuf < pBufLimit)
            {
                if (pBuf[0] == kImageDescriptor)
                {
                    // Skip the Image Descriptor marker
                    pBuf++;
                    // Parse the image descriptor struct
                    CGIFImage::ImageDescriptor cID;
                    CGIFImage::ParseImageDescriptor(pBuf, cID);
                    pBuf += 9;
                    // If a local color table IS present, then skip it
                    if (cID.m_bLocalColorTablePresent == TRUE)
                    {
                        pBuf += cID.m_ulLocalColorTableNumEntries * 3;
                    }
                    // Skip the minimum LZW code size
                    pBuf++;
                    // We count the image descriptor as a packet
                    ulNumPackets++;
                    // Now skip the LZW blocks
                    UINT32 ulBlockSize = 0;
                    do
                    {
                        // Get the block size
                        ulBlockSize = *pBuf++;
                        // Skip that amount of bytes
                        pBuf += ulBlockSize;
                        // Count this as a packet
                        ulNumPackets++;
                    }
                    while (ulBlockSize);
                }
                else if (pBuf[0] == kExtension)
                {
                    // Skip the extension marker and type
                    pBuf += 2;
                    // Count the blocks in this extension
                    UINT32 ulBlockSize = 0;
                    do
                    {
                        // Get the block size
                        ulBlockSize = *pBuf++;
                        // Skip that amount of bytes
                        pBuf += ulBlockSize;
                        // Count this as a packet
                        ulNumPackets++;
                    }
                    while (ulBlockSize);
                }
                else if (pBuf[0] == kTrailer)
                {
                    // We found a GIF trailer - we should be at the end of the file
                    pBuf++;
                    // Go ahead and count it as a packet
                    ulNumPackets++;
                }
                else
                {
                    // Sometimes extra 0 blocks get stuck in GIFs. Check for them
                    // here - if the current byte is 0, then it's OK. If it's not,
                    // then we've gotten lost somewhere.
                    if (pBuf[0] == 0x00)
                    {
                        pBuf++;
                    }
                    else
                    {
                        // Something is wrong with the GIF file.
                        break;
                    }
                }
            }
        }
    }

    return ulNumPackets;
}

HX_RESULT CGIFCodec::InitParseWireFormat(BYTE *pBuffer, UINT32 ulLen)
{
    /* Check for input error conditions */
    if (pBuffer == NULL || ulLen == 0)
    {
        return HXR_INVALID_PARAMETER;
    }

    /* Check state */
    if (m_ulParseState != kStateConstructed)
    {
        return HXR_UNEXPECTED;
    }

    /* Save copy of the buffer pointer and length */
    m_pParseBuffer        = pBuffer;
    m_ulParseBufferLength = ulLen;

    /*
     * We have to make a pass through the image to determine the mark points.
     * Will store these mark points (BYTE pointers) in cMarkList. The first
     * mark point is, of course, the beginning of the file.
     */
    GList cMarkList;
    cMarkList.PushBack((void *) m_pParseBuffer);

    /* Get local copy of buffer */
    BYTE  *pBuf      = m_pParseBuffer;
    BYTE  *pBufLimit = pBuf + m_ulParseBufferLength;

    /* Check the signature */
    if (pBuf[0] != 'G' || pBuf[1] != 'I' || pBuf[2] != 'F')
    {
        return HXR_INVALID_OPERATION;
    }
    pBuf += 3;

    /* Check the version */
    if (pBuf[0] == '8' && pBuf[1] == '9' && pBuf[2] == 'a')
    {
        m_bIsGIF89a = TRUE;
    }
    else if (pBuf[0] == '8' && pBuf[1] == '7' && pBuf[2] == 'a')
    {
        m_bIsGIF89a = FALSE;
    }
    else
    {
        return HXR_INVALID_OPERATION;
    }
    pBuf += 3;

    /* Get the logical screen descriptor */
    ParseLogicalScreenDescriptor(pBuf, m_cLSD);
    pBuf += 7;

    /* Skip the color table */
    if (m_cLSD.m_bGlobalColorTablePresent == TRUE)
    {
        /* Calculate the number of bytes for the global color table */
        UINT32 ulNumBytes = m_cLSD.m_ulColorTableNumEntries * 3;

        /* Advance that number of bytes */
        pBuf += ulNumBytes;
    }

    /*
     * Parse the file and enter marks in the mark list. We're looking for:
     *    a) Beginnings of GCEs and IDs (although if a ID immediately follows
     *       a GCE, we only mark the beginning of the GCE;
     *    b) Beginnings of LZW data for each image.
     */
    BOOL bMarkImageDescriptor = TRUE;
    m_ulDelayTimeSum          = 0;
    m_ulNumImages             = 0;
    while (pBuf < pBufLimit)
    {
        if (pBuf[0] == kImageDescriptor)
        {
            /*
             * We've found an Image Descriptor (ID). If m_bMarkImageDescriptor is
             * FALSE, then this ID is one that immediately followed a GCE, so we
             * DON'T mark it. If m_bMarkImageDescriptor is TRUE, this is an 
             * ID that was NOT preceded by a GCE - these usually happen in GIF87a's.
             */
            if (bMarkImageDescriptor == TRUE)
            {
                cMarkList.PushBack((void *) pBuf);
            }
            else
            {
                bMarkImageDescriptor = TRUE;
            }

            /* Skip the Image Descriptor marker */
            pBuf++;

            /*
             * Whether we mark it or not, we still have to parse it to find out
             * whether or not a local color table is present.
             */
            CGIFImage::ImageDescriptor cID;
            CGIFImage::ParseImageDescriptor(pBuf, cID);
            pBuf += 9;

            // We make sure this frame's dimensions are within the dimensions
            // of the logical screen. If they are not, then we are probably
            // dealing with a corrupt GIF. That's really really bad, cause we probably
            // can't trust any of the data. Therefore, we will simply fail out of
            // parsing and rely on the app above us to do the right thing.
            if (cID.m_ulImageLeft + cID.m_ulImageWidth  > m_cLSD.m_ulLogicalScreenWidth ||
                cID.m_ulImageTop  + cID.m_ulImageHeight > m_cLSD.m_ulLogicalScreenHeight)
            {
                return HXR_FAIL;
            }

            /* If a local color table IS present, then skip it */
            if (cID.m_bLocalColorTablePresent == TRUE)
            {
                pBuf += cID.m_ulLocalColorTableNumEntries * 3;
            }

            /* Now we should be at the beginning of LZW data, so mark this pointer */
            cMarkList.PushBack((void *) pBuf);

            /* Skip the minimum LZW code size */
            UINT32 ulInitialCodeSize = *pBuf++;
            if (ulInitialCodeSize > 12)
            {
                // Code size can't be any bigger than 12. If we
                // do get one bigger than that, then we're dealing
                // with a corrupt file here.
                return HXR_FAIL;
            }

            /* Now skip the LZW blocks */
            SkipBlocks(pBuf, pBufLimit);

            // Check to see if we went past the end of the buffer
            if (pBuf >= pBufLimit)
            {
                // This is really really bad if we get here. That almost certainly
                // means the GIF is corrupt, cause we were happily parsing LZW blocks
                // and went off the end of the file. In reality it probably means that
                // the GIF was corrupt earlier. We will simply fail here. We cannot
                // reliably parse any of this image.
                return HXR_FAIL;
            }

            /* We've just seen an image */
            m_ulNumImages++;
        }
        else if (pBuf[0] == kExtension)
        {
            /* This is an extension, but what type? */
            switch(pBuf[1])
            {
                case kGraphicControlExtension:
                    /* We've found a GCE - mark it but don't mark the ID */
                    cMarkList.PushBack((void *) pBuf);
                    bMarkImageDescriptor = FALSE;
                    pBuf                += 2;
                    UINT32 ulBlockSize;
                    do
                    {
                        /* Get the block size */
                        ulBlockSize = *pBuf++;

                        /* Initialize the GCE */
                        CGIFImage::GraphicControlExtension cGCE;
                        if (ulBlockSize >= 4)
                        {
                            CGIFImage::ParseGraphicControlExtension(pBuf, cGCE);

                            /* Add the delay time */
                            m_ulDelayTimeSum += cGCE.m_ulDelayTime * 10;
                        }

                        /* Advance by the block size */
                        pBuf += ulBlockSize;