lzw.cpp
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- /* ***** BEGIN LICENSE BLOCK *****
- * Source last modified: $Id: lzw.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 ***** */
- #include <hlxclib/memory.h>
- #include <string.h>
- #include "lzw.h"
- #include "hxheap.h"
- #ifdef _DEBUG
- #undef HX_THIS_FILE
- static char HX_THIS_FILE[] = __FILE__;
- #endif
- LZWCodec::LZWCodec()
- {
- /* Initialize all member variables */
- m_bFresh = TRUE;
- m_bPostClearCode = FALSE;
- m_lCodeSize = 0;
- m_lSetCodeSize = 0;
- m_lMaxCode = 0;
- m_lMaxCodeSize = 0;
- m_lFirstCode = 0;
- m_lOldCode = 0;
- m_lClearCode = 0;
- m_lEndCode = 0;
- m_pCurByte = NULL;
- m_lCurBit = 0;
- m_lBytesInBuffer = -1;
- m_bFinished = FALSE;
- m_bSuspended = TRUE;
- m_bAllCompressedDataCopied = FALSE;
- m_pCompressedBuffer = NULL;
- m_lCompressedBufferSize = 0;
- m_lCompressedBytesCopied = 0;
- /* Clear the tables */
- ClearTables();
- /* Reset the stack */
- m_plStackPtr = m_lStack;
- };
- LZWCodec::~LZWCodec()
- {
- if (m_pCompressedBuffer)
- {
- delete [] m_pCompressedBuffer;
- m_pCompressedBuffer = NULL;
- }
- };
- HX_RESULT LZWCodec::SetCompressedBufferSize(INT32 lSize)
- {
- /* Check for input error conditions */
- if (lSize < 1)
- {
- return HXR_INVALID_PARAMETER;
- }
- /* Allocate space for the compressed buffer */
- if (m_pCompressedBuffer)
- {
- delete [] m_pCompressedBuffer;
- m_pCompressedBuffer = NULL;
- }
- m_pCompressedBuffer = new BYTE [lSize];
- if (!m_pCompressedBuffer)
- {
- return HXR_OUTOFMEMORY;
- }
- /* Set the size */
- m_lCompressedBufferSize = lSize;
- m_lCompressedBytesCopied = 0;
- /* Initialize the state variables */
- m_pCurByte = m_pCompressedBuffer;
- m_lBytesInBuffer = -1;
- m_bAllCompressedDataCopied = FALSE;
- m_bSuspended = TRUE;
- return HXR_OK;
- }
- HX_RESULT LZWCodec::InitDecompress(INT32 lMinCodeBits)
- {
- /* Check for input error conditions */
- if (lMinCodeBits < 1 || lMinCodeBits > kMaxLZWBits)
- {
- return HXR_INVALID_PARAMETER;
- }
- /* Set up code size parameters */
- m_lSetCodeSize = lMinCodeBits;
- m_lCodeSize = m_lSetCodeSize + 1;
- m_lClearCode = 1 << m_lSetCodeSize;
- m_lEndCode = m_lClearCode + 1;
- m_lMaxCodeSize = m_lClearCode << 1;
- m_lMaxCode = m_lClearCode + 2;
- /* This says to look for clear codes */
- m_bFresh = TRUE;
- /* Clear out all table entries */
- ClearTables();
- /* Reset the stack pointer */
- m_plStackPtr = m_lStack;
- return HXR_OK;
- }
- HX_RESULT LZWCodec::AppendCompressedBuffer(BYTE *pBuffer, INT32 lBufLen)
- {
- /* Check for input error conditions */
- if (pBuffer == NULL || lBufLen < 1)
- {
- return HXR_INVALID_PARAMETER;
- }
- /* Make sure we're not called after we should be */
- if (m_bAllCompressedDataCopied == TRUE)
- {
- return HXR_OK;
- }
- /* Make sure we don't copy off the end of the buffer */
- INT32 lBytesToCopy;
- if (m_lCompressedBytesCopied + lBufLen <= m_lCompressedBufferSize)
- {
- lBytesToCopy = lBufLen;
- }
- else
- {
- lBytesToCopy = m_lCompressedBufferSize - m_lCompressedBytesCopied;
- }
- /* Do the copy */
- memcpy(&m_pCompressedBuffer[m_lCompressedBytesCopied], pBuffer, lBytesToCopy); /* Flawfinder: ignore */
- /* Update the member variables */
- m_lCompressedBytesCopied += lBufLen;
- m_lBytesInBuffer += lBufLen;
- m_bSuspended = FALSE;
- /* Check if we've received all data */
- if (m_lCompressedBytesCopied >= m_lCompressedBufferSize)
- {
- m_bAllCompressedDataCopied = TRUE;
- }
- return HXR_OK;
- }
- HX_RESULT LZWCodec::LZWReadByte(INT32 &rlSymbol)
- {
- /* Are we still suspended? */
- if (m_bSuspended == TRUE)
- {
- rlSymbol = -1;
- return HXR_OK;
- }
- INT32 lCode;
- /* If this flag is set, it means skip all clear codes at the current point */
- if (m_bFresh == TRUE)
- {
- do
- {
- lCode = GetCode();
- if (lCode < 0)
- {
- rlSymbol = -1;
- m_bSuspended = TRUE;
- return HXR_OK;
- }
- m_lFirstCode = m_lOldCode = lCode;
- }
- while (m_lFirstCode == m_lClearCode);
- m_bFresh = FALSE;
- rlSymbol = m_lFirstCode;
- return HXR_OK;
- }
- /* If we're currently copying off the stack, then return the stack values */
- if (m_plStackPtr > m_lStack)
- {
- rlSymbol = *--m_plStackPtr;
- return HXR_OK;
- }
- /* Read values until we're done or we suspend */
- while (1)
- {
- /* Get a code */
- lCode = GetCode();
- if (lCode < 0)
- {
- rlSymbol = -1;
- m_bSuspended = TRUE;
- return HXR_OK;
- }
- /* Is this a code just after a clear code? */
- if (m_bPostClearCode == TRUE)
- {
- m_bPostClearCode = FALSE;
- m_lFirstCode = m_lOldCode = rlSymbol = lCode;
- return HXR_OK;
- }
- /* We got a valid code, so now take action based on that code */
- if (lCode == m_lClearCode)
- {
- /* We got a clear code, so we clear the tables and reset everything */
- ClearTables();
- m_lCodeSize = m_lSetCodeSize + 1;
- m_lMaxCodeSize = m_lClearCode << 1;
- m_lMaxCode = m_lClearCode + 2;
- m_plStackPtr = m_lStack;
- /* Set the flag which says we just got a clear code */
- m_bPostClearCode = TRUE;
- }
- else if (lCode == m_lEndCode)
- {
- rlSymbol = lCode;
- m_bFinished = TRUE;
- m_bSuspended = FALSE;
- return HXR_OK;
- }
- else
- {
- INT32 lInCode = lCode;
- if (lCode >= m_lMaxCode)
- {
- *m_plStackPtr++ = m_lFirstCode;
- lCode = m_lOldCode;
- }
- INT32* pStackLimit = &m_lStack[0] + (kMaxLZWVal << 1);
- while (lCode >= m_lClearCode)
- {
- if (m_plStackPtr >= pStackLimit)
- {
- // We've blown our code stack, so we have a corrupt
- // GIF image. In this case, we need to error out.
- return HXR_FAIL;
- }
- *m_plStackPtr++ = m_lTable[1][lCode];
- if (lCode == m_lTable[0][lCode])
- {
- /* Tables have a circular reference in them - corrupt file */
- return HXR_FAILED;
- }
- lCode = m_lTable[0][lCode];
- }
- *m_plStackPtr++ = m_lFirstCode = m_lTable[1][lCode];
- lCode = m_lMaxCode;
- if (lCode < kMaxLZWVal)
- {
- m_lTable[0][lCode] = m_lOldCode;
- m_lTable[1][lCode] = m_lFirstCode;
- m_lMaxCode++;
- if (m_lMaxCode >= m_lMaxCodeSize &&
- m_lMaxCodeSize < kMaxLZWVal)
- {
- m_lMaxCodeSize <<= 1;
- m_lCodeSize++;
- }
- }
- m_lOldCode = lInCode;
- if (m_plStackPtr > m_lStack)
- {
- rlSymbol = *--m_plStackPtr;
- return HXR_OK;
- }
- }
- }
- rlSymbol = 0;
- return HXR_OK;
- }