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 }