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.BufferedReader;
043    import java.io.IOException;
044    import java.io.InputStream;
045    import java.io.InputStreamReader;
046    
047    /**
048     * @author Michael Koch (konqueror@gmx.de)
049     */
050    public class MemoryCacheImageInputStream extends ImageInputStreamImpl
051    {
052      private InputStream stream;
053      private BufferedInputStream buffer;
054    
055      private int READLIMIT = 2048;
056      
057      public MemoryCacheImageInputStream(InputStream stream)
058      {
059        this.stream = stream;
060        buffer = new BufferedInputStream(stream);
061        buffer.mark(READLIMIT);
062      }
063    
064      public void close()
065        throws IOException
066      {
067        super.close();
068        stream.close();
069      }
070    
071      public void flushBefore(long position)
072        throws IOException
073      {
074        long prevFlushedPosition = getFlushedPosition();
075        super.flushBefore(position);
076        buffer.reset();
077        buffer.skip(getFlushedPosition() - prevFlushedPosition);
078        buffer.mark(READLIMIT);
079      }
080    
081      public boolean isCached()
082      {
083        return true;
084      }
085    
086      public boolean isCachedFile()
087      {
088        return false;
089      }
090      
091      public boolean isCachedMemory()
092      {
093        return true;
094      }
095    
096      public int read()
097        throws IOException
098      {
099        setBitOffset(0);
100        int retval = buffer.read();
101        
102        if (retval != -1)
103          streamPos++;
104    
105        return retval;
106      }
107    
108      public int read(byte[] data, int offset, int len)
109        throws IOException
110      {
111        setBitOffset(0);
112        int retval = buffer.read(data, offset, len);
113    
114        if (retval != -1)
115          {
116            streamPos += retval;
117          }
118    
119        return retval; 
120      }
121      
122      public void seek(long position)
123      throws IOException
124      {
125        super.seek(position);
126        buffer.reset();
127        buffer.skip(position - getFlushedPosition());
128      }
129    }