goodies/source/filter.vcl/egif/giflzwc.cxx

   1 /*************************************************************************
   2  *
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * Copyright 2008 by Sun Microsystems, Inc.
   6  *
   7  * OpenOffice.org - a multi-platform office productivity suite
   8  *
   9  * $RCSfile: giflzwc.cxx,v $
  10  * $Revision: 1.5 $
  11  *
  12  * This file is part of OpenOffice.org.
  13  *
  14  * OpenOffice.org is free software: you can redistribute it and/or modify
  15  * it under the terms of the GNU Lesser General Public License version 3
  16  * only, as published by the Free Software Foundation.
  17  *
  18  * OpenOffice.org is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU Lesser General Public License version 3 for more details
  22  * (a copy is included in the LICENSE file that accompanied this code).
  23  *
  24  * You should have received a copy of the GNU Lesser General Public License
  25  * version 3 along with OpenOffice.org.  If not, see
  26  * <http://www.openoffice.org/license.html>
  27  * for a copy of the LGPLv3 License.
  28  *
  29  ************************************************************************/
  30
  31 // MARKER(update_precomp.py): autogen include statement, do not remove
  32 #include "precompiled_goodies.hxx"
  33
  34 #include <tools/stream.hxx>
  35 #include "giflzwc.hxx"
  36
  37 // ----------------------------
  38 // - GIFImageDataOutputStream -
  39 // ----------------------------
  40
  41 class GIFImageDataOutputStream
  42 {
  43 private:
  44
  45     void                FlushBlockBuf();
  46     inline void FlushBitsBufsFullBytes();
  47
  48     SvStream&   rStream;
  49     BYTE*               pBlockBuf;
  50     BYTE                nBlockBufSize;
  51     ULONG               nBitsBuf;
  52     USHORT              nBitsBufSize;
  53
  54 public:
  55
  56                 GIFImageDataOutputStream( SvStream & rGIF, BYTE nLZWDataSize );
  57                 ~GIFImageDataOutputStream();
  58
  59     inline void WriteBits( USHORT nCode, USHORT nCodeLen );
  60 };
  61
  62 // ------------------------------------------------------------------------
  63
  64 inline void GIFImageDataOutputStream::FlushBitsBufsFullBytes()
  65 {
  66     while (nBitsBufSize>=8)
  67     {
  68         if( nBlockBufSize==255 )
  69             FlushBlockBuf();
  70
  71         pBlockBuf[nBlockBufSize++] = (BYTE) nBitsBuf;
  72         nBitsBuf >>= 8;
  73         nBitsBufSize -= 8;
  74     }
  75 }
  76
  77 // ------------------------------------------------------------------------
  78
  79 inline void GIFImageDataOutputStream::WriteBits( USHORT nCode, USHORT nCodeLen )
  80 {
  81     if( nBitsBufSize+nCodeLen>32 )
  82         FlushBitsBufsFullBytes();
  83
  84     nBitsBuf |= (ULONG) nCode << nBitsBufSize;
  85     nBitsBufSize = nBitsBufSize + nCodeLen;
  86 }
  87
  88 // ------------------------------------------------------------------------
  89
  90 GIFImageDataOutputStream::GIFImageDataOutputStream( SvStream & rGIF, BYTE nLZWDataSize ) :
  91         rStream(rGIF)
  92 {
  93     pBlockBuf = new BYTE[ 255 ];
  94     nBlockBufSize = 0;
  95     nBitsBufSize = 0;
  96     nBitsBuf = 0;
  97     rStream << nLZWDataSize;
  98 }
  99
 100 // ------------------------------------------------------------------------
 101
 102
 103 GIFImageDataOutputStream::~GIFImageDataOutputStream()
 104 {
 105     WriteBits(0,7);
 106     FlushBitsBufsFullBytes();
 107     FlushBlockBuf();
 108     rStream << (BYTE)0;
 109     delete[] pBlockBuf;
 110 }
 111
 112 // ------------------------------------------------------------------------
 113
 114 void GIFImageDataOutputStream::FlushBlockBuf()
 115 {
 116     if( nBlockBufSize )
 117     {
 118         rStream << (BYTE) nBlockBufSize;
 119         rStream.Write( pBlockBuf,nBlockBufSize );
 120         nBlockBufSize = 0;
 121     }
 122 }
 123
 124 // -------------------
 125 // - GIFLZWCTreeNode -
 126 // -------------------
 127
 128 struct GIFLZWCTreeNode
 129 {
 130
 131     GIFLZWCTreeNode*    pBrother;               // naechster Knoten, der den selben Vater hat
 132     GIFLZWCTreeNode*    pFirstChild;    // erster Sohn
 133     USHORT                              nCode;                  // Der Code fuer den String von Pixelwerten, der sich ergibt, wenn
 134     USHORT                              nValue;                 // Der Pixelwert
 135 };
 136
 137 // --------------------
 138 // - GIFLZWCompressor -
 139 // --------------------
 140
 141 GIFLZWCompressor::GIFLZWCompressor()
 142 {
 143     pIDOS=NULL;
 144 }
 145
 146 // ------------------------------------------------------------------------
 147
 148 GIFLZWCompressor::~GIFLZWCompressor()
 149 {
 150     if (pIDOS!=NULL) EndCompression();
 151 }
 152
 153 // ------------------------------------------------------------------------
 154
 155 void GIFLZWCompressor::StartCompression( SvStream& rGIF, USHORT nPixelSize )
 156 {
 157     if( !pIDOS )
 158     {
 159         USHORT i;
 160
 161         nDataSize = nPixelSize;
 162
 163         if( nDataSize < 2 )
 164             nDataSize=2;
 165
 166         nClearCode=1<<nDataSize;
 167         nEOICode=nClearCode+1;
 168         nTableSize=nEOICode+1;
 169         nCodeSize=nDataSize+1;
 170
 171         pIDOS=new GIFImageDataOutputStream(rGIF,(BYTE)nDataSize);
 172         pTable=new GIFLZWCTreeNode[4096];
 173
 174         for (i=0; i<4096; i++)
 175         {
 176             pTable[i].pBrother = pTable[i].pFirstChild = NULL;
 177             pTable[i].nValue = (BYTE) ( pTable[i].nCode = i );
 178         }
 179
 180         pPrefix = NULL;
 181         pIDOS->WriteBits( nClearCode,nCodeSize );
 182     }
 183 }
 184
 185 // ------------------------------------------------------------------------
 186
 187 void GIFLZWCompressor::Compress( HPBYTE pSrc, ULONG nSize )
 188 {
 189     if( pIDOS )
 190     {
 191         GIFLZWCTreeNode*        p;
 192         USHORT                          i;
 193         BYTE                            nV;
 194
 195         if( !pPrefix && nSize )
 196         {
 197             pPrefix=pTable+(*pSrc++);
 198             nSize--;
 199         }
 200
 201         while( nSize )
 202         {
 203             nSize--;
 204             nV=*pSrc++;
 205             for( p=pPrefix->pFirstChild; p!=NULL; p=p->pBrother )
 206             {
 207                 if (p->nValue==nV)
 208                     break;
 209             }
 210
 211             if( p)
 212                 pPrefix=p;
 213             else
 214             {
 215                 pIDOS->WriteBits(pPrefix->nCode,nCodeSize);
 216
 217                 if (nTableSize==4096)
 218                 {
 219                     pIDOS->WriteBits(nClearCode,nCodeSize);
 220
 221                     for (i=0; i<nClearCode; i++)
 222                         pTable[i].pFirstChild=NULL;
 223
 224                     nCodeSize=nDataSize+1;
 225                     nTableSize=nEOICode+1;
 226                 }
 227                 else
 228                 {
 229                     if(nTableSize==(USHORT)(1<<nCodeSize))
 230                         nCodeSize++;
 231
 232                     p=pTable+(nTableSize++);
 233                     p->pBrother=pPrefix->pFirstChild;
 234                     pPrefix->pFirstChild=p;
 235                     p->nValue=nV;
 236                     p->pFirstChild=NULL;
 237                 }
 238
 239                 pPrefix=pTable+nV;
 240             }
 241         }
 242     }
 243 }
 244
 245 // ------------------------------------------------------------------------
 246
 247 void GIFLZWCompressor::EndCompression()
 248 {
 249     if( pIDOS )
 250     {
 251         if( pPrefix )
 252             pIDOS->WriteBits(pPrefix->nCode,nCodeSize);
 253
 254         pIDOS->WriteBits( nEOICode,nCodeSize );
 255         delete[] pTable;
 256         delete pIDOS;
 257         pIDOS=NULL;
 258     }
 259 }