Source for gnu.javax.imageio.png.PNGData

   1: /* PNGData.java -- PNG IDAT chunk.
   2:    Copyright (C) 2006 Free Software Foundation
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: package gnu.javax.imageio.png;
  39: 
  40: import java.util.zip.Inflater;
  41: import java.util.zip.Deflater;
  42: 
  43: /**
  44:  * A PNG IDAT (data) chunk.
  45:  */
  46: public class PNGData extends PNGChunk
  47: {
  48:   private int offset;
  49: 
  50:   protected PNGData( int type, byte[] data, int crc )
  51:   {
  52:     super( type, data, crc );
  53:   }
  54: 
  55:   protected PNGData( int chunkSize )
  56:   {
  57:     super( PNGChunk.TYPE_DATA );
  58:     data = new byte[ chunkSize ];
  59:     offset = 0;
  60:   }
  61: 
  62:   /**
  63:    * Deflates the available data in def to the chunk.
  64:    *
  65:    * @return true if the chunk is filled and no more data can be written,
  66:    * false otherwise.
  67:    */
  68:   public void deflateToChunk( Deflater def )
  69:   {
  70:     offset += def.deflate( data, offset, data.length - offset );
  71:   }
  72: 
  73:   /**
  74:    * Returns true if the chunk is filled.
  75:    */
  76:   public boolean chunkFull()
  77:   {
  78:     return (offset >= data.length);
  79:   }
  80: 
  81:   /**
  82:    * Shrink the chunk to offset size, used for the last chunk in a stream
  83:    * (no trailing data!)
  84:    */
  85:   public void shrink()
  86:   {
  87:     byte[] newData = new byte[ offset ];
  88:     System.arraycopy( data, 0, newData, 0, offset );
  89:     data = newData;
  90:   }
  91: 
  92:   /**
  93:    * Feeds the data in the chunk to a ZIP inflater object.
  94:    */
  95:   public void feedToInflater( Inflater inf )
  96:   {
  97:     inf.setInput( data );
  98:   }
  99: 
 100:   public String toString()
 101:   {
 102:     return "PNG Data chunk. Length = "+data.length;
 103:   }
 104: }