Source for gnu.javax.imageio.gif.GIFImageReaderSpi

   1: /* GIFImageReaderSpi.java --
   2:    Copyright (C)  2006  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.javax.imageio.gif;
  39: 
  40: import gnu.javax.imageio.IIOInputStream;
  41: 
  42: import java.io.InputStream;
  43: import java.io.IOException;
  44: import java.util.Locale;
  45: import javax.imageio.ImageReader;
  46: import javax.imageio.spi.ImageReaderSpi;
  47: import javax.imageio.stream.ImageInputStream;
  48: 
  49: public class GIFImageReaderSpi extends ImageReaderSpi
  50: {
  51:   static final String vendorName = "GNU";
  52:   static final String version = "0.1";
  53:   static final String readerClassName =
  54:     "gnu.javax.imageio.gif.GIFImageReader";
  55:   static final String[] names = { "Compuserve GIF" };
  56:   static final String[] suffixes = { ".gif" };
  57:   static final String[] MIMETypes = {
  58:     "image/gif",
  59:     "image/x-gif"}; // Not sure this is legal, but it seems to be used a bit
  60:   static final String[] writerSpiNames = null;
  61:   static final boolean supportsStandardStreamMetadataFormat = false;
  62:   static final String nativeStreamMetadataFormatName = null;
  63:   static final String nativeStreamMetadataFormatClassName = null;
  64:   static final String[] extraStreamMetadataFormatNames = null;
  65:   static final String[] extraStreamMetadataFormatClassNames = null;
  66:   static final boolean supportsStandardImageMetadataFormat = false;
  67:   static final String nativeImageMetadataFormatName = null;
  68:   static final String nativeImageMetadataFormatClassName = null;
  69:   static final String[] extraImageMetadataFormatNames = null;
  70:   static final String[] extraImageMetadataFormatClassNames = null;
  71: 
  72:   public GIFImageReaderSpi()
  73:   {
  74:     super(vendorName, version,
  75:           names, suffixes, MIMETypes,
  76:           readerClassName,
  77:           new Class[]{ ImageInputStream.class, InputStream.class },
  78:           writerSpiNames,
  79:           supportsStandardStreamMetadataFormat,
  80:           nativeStreamMetadataFormatName,
  81:           nativeStreamMetadataFormatClassName,
  82:           extraStreamMetadataFormatNames,
  83:           extraStreamMetadataFormatClassNames,
  84:           supportsStandardImageMetadataFormat,
  85:           nativeImageMetadataFormatName,
  86:           nativeImageMetadataFormatClassName,
  87:           extraImageMetadataFormatNames,
  88:           extraImageMetadataFormatClassNames);
  89:   }
  90: 
  91:   public String getDescription(Locale locale)
  92:   {
  93:     return "Compuserve GIF";
  94:   }
  95: 
  96:   public boolean canDecodeInput(Object input)
  97:     throws IOException
  98:   {
  99:     if( input == null )
 100:       throw new IllegalArgumentException("Input object cannot be null.");
 101: 
 102:     if( !(input instanceof ImageInputStream) &&
 103:         !(input instanceof InputStream))
 104:       return false;
 105: 
 106:     boolean retval;
 107:     InputStream in;
 108:     if( input instanceof ImageInputStream )
 109:       in = new IIOInputStream( (ImageInputStream)input );
 110:     else
 111:       in = (InputStream)input;
 112: 
 113:     in.mark(10); // we read 6 bytes
 114:     retval = GIFFile.readSignature( in );
 115:     in.reset();
 116: 
 117:     return retval;
 118:   }
 119: 
 120:   public ImageReader createReaderInstance(Object extension)
 121:   {
 122:     return new GIFImageReader(this);
 123:   }
 124: }