001/* MemoryCacheImageInputStream.java --
002   Copyright (C) 2004  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.imageio.stream;
040
041import java.io.BufferedInputStream;
042import java.io.IOException;
043import java.io.InputStream;
044
045/**
046 * @author Michael Koch (konqueror@gmx.de)
047 */
048public 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}