Source for gnu.java.awt.image.ImageDecoder

   1: /* ImageDecoder.java --
   2:    Copyright (C) 1999, 2000, 2004  Free Software Foundation, Inc.
   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.java.awt.image;
  39: 
  40: import java.awt.image.ImageConsumer;
  41: import java.awt.image.ImageProducer;
  42: import java.io.ByteArrayInputStream;
  43: import java.io.DataInput;
  44: import java.io.EOFException;
  45: import java.io.FileInputStream;
  46: import java.io.IOException;
  47: import java.io.InputStream;
  48: import java.net.URL;
  49: import java.util.Vector;
  50: 
  51: public abstract class ImageDecoder implements ImageProducer
  52: {
  53:   Vector consumers = new Vector ();
  54:   String filename;
  55:   URL url;
  56:   byte[] data;
  57:   int offset;
  58:   int length;
  59:   InputStream input;
  60:   DataInput datainput;
  61: 
  62:   static
  63:   {
  64:     // FIXME: there was some broken code here that looked like
  65:     // it wanted to rely on this property.  I don't have any idea
  66:     // what it was intended to do.
  67:     // String endian = System.getProperties ().getProperty ("gnu.cpu.endian");
  68:   }
  69: 
  70:   public ImageDecoder (String filename)
  71:   {
  72:     this.filename = filename;
  73:   }
  74: 
  75:   public ImageDecoder (URL url)
  76:   {
  77:     this.url = url;
  78:   }
  79: 
  80:   public ImageDecoder (InputStream is)
  81:   {
  82:     this.input = is;
  83:   }
  84: 
  85:   public ImageDecoder (DataInput datainput)
  86:   {
  87:     this.datainput = datainput;
  88:   }
  89: 
  90:   public ImageDecoder (byte[] imagedata, int imageoffset, int imagelength)
  91:   {
  92:     data = imagedata;
  93:     offset = imageoffset;
  94:     length = imagelength;
  95:   }
  96: 
  97:   public void addConsumer (ImageConsumer ic)
  98:   {
  99:     consumers.addElement (ic);
 100:   }
 101: 
 102:   public boolean isConsumer (ImageConsumer ic)
 103:   {
 104:     return consumers.contains (ic);
 105:   }
 106: 
 107:   public void removeConsumer (ImageConsumer ic)
 108:   {
 109:     consumers.removeElement (ic);
 110:   }
 111: 
 112:   public void startProduction (ImageConsumer ic)
 113:   {
 114:     if (!isConsumer(ic))
 115:       addConsumer(ic);
 116: 
 117:     Vector list = (Vector) consumers.clone ();
 118:     try
 119:       {
 120:         // Create the input stream here rather than in the
 121:         // ImageDecoder constructors so that exceptions cause
 122:         // imageComplete to be called with an appropriate error
 123:         // status.
 124:         if (input == null)
 125:           {
 126:             try
 127:               {
 128:                 if (url != null)
 129:                   input = url.openStream();
 130:                 else if (datainput != null)
 131:                   input = new DataInputStreamWrapper(datainput);
 132:                 else
 133:                   {
 134:                     if (filename != null)
 135:                       input = new FileInputStream (filename);
 136:                     else
 137:                       input = new ByteArrayInputStream (data, offset, length);
 138:                   }
 139:                 produce (list, input);
 140:               }
 141:             finally
 142:               {
 143:                 input = null;
 144:               }
 145:           }
 146:         else
 147:           {
 148:             produce (list, input);
 149:           }
 150:       }
 151:     catch (Exception e)
 152:       {
 153:         for (int i = 0; i < list.size (); i++)
 154:           {
 155:             ImageConsumer ic2 = (ImageConsumer) list.elementAt (i);
 156:             ic2.imageComplete (ImageConsumer.IMAGEERROR);
 157:           }
 158:       }
 159:   }
 160: 
 161:   public void requestTopDownLeftRightResend (ImageConsumer ic)
 162:   {
 163:   }
 164: 
 165:   public abstract void produce (Vector v, InputStream is) throws IOException;
 166: 
 167:   private static class DataInputStreamWrapper extends InputStream
 168:   {
 169:     private final DataInput datainput;
 170: 
 171:     DataInputStreamWrapper(DataInput datainput)
 172:     {
 173:       this.datainput = datainput;
 174:     }
 175: 
 176:     public int read() throws IOException
 177:     {
 178:       try
 179:         {
 180:           return datainput.readByte() & 0xFF;
 181:         }
 182:       catch (EOFException eofe)
 183:         {
 184:           return -1;
 185:         }
 186:     }
 187:   }
 188: }