001    /* MemoryCacheImageInputStream.java --
002       Copyright (C) 2004  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.imageio.stream;
040    
041    import java.io.BufferedInputStream;
042    import java.io.IOException;
043    import java.io.InputStream;
044    
045    /**
046     * @author Michael Koch (konqueror@gmx.de)
047     */
048    public class MemoryCacheImageInputStream extends ImageInputStreamImpl
049    {
050      private InputStream stream;
051      private BufferedInputStream buffer;
052    
053      private int READLIMIT = 2048;
054      
055      public MemoryCacheImageInputStream(InputStream stream)
056      {
057        this.stream = stream;
058        buffer = new BufferedInputStream(stream);
059        buffer.mark(READLIMIT);
060      }
061    
062      public void close()
063        throws IOException
064      {
065        super.close();
066        stream.close();
067      }
068    
069      public void flushBefore(long position)
070        throws IOException
071      {
072        long prevFlushedPosition = getFlushedPosition();
073        super.flushBefore(position);
074        buffer.reset();
075        buffer.skip(getFlushedPosition() - prevFlushedPosition);
076        buffer.mark(READLIMIT);
077      }
078    
079      public boolean isCached()
080      {
081        return true;
082      }
083    
084      public boolean isCachedFile()
085      {
086        return false;
087      }
088      
089      public boolean isCachedMemory()
090      {
091        return true;
092      }
093    
094      public int read()
095        throws IOException
096      {
097        setBitOffset(0);
098        int retval = buffer.read();
099        
100        if (retval != -1)
101          streamPos++;
102    
103        return retval;
104      }
105    
106      public int read(byte[] data, int offset, int len)
107        throws IOException
108      {
109        setBitOffset(0);
110        int retval = buffer.read(data, offset, len);
111    
112        if (retval != -1)
113          {
114            streamPos += retval;
115          }
116    
117        return retval; 
118      }
119      
120      public void seek(long position)
121      throws IOException
122      {
123        super.seek(position);
124        buffer.reset();
125        buffer.skip(position - getFlushedPosition());
126      }
127    }