001    /* FileCacheImageOutputStream.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.File;
042    import java.io.IOException;
043    import java.io.OutputStream;
044    import java.io.RandomAccessFile;
045    
046    /**
047     * @author Michael Koch (konqueror@gmx.de)
048     */
049    public class FileCacheImageOutputStream extends ImageOutputStreamImpl
050    {
051      private OutputStream stream;
052      private File cacheFile;
053      private RandomAccessFile cache;
054      private long maxPos;
055    
056      public FileCacheImageOutputStream(OutputStream s, File cacheDir)
057        throws IOException
058      {
059        stream = s;
060        cacheFile = File.createTempFile("imageio", ".tmp", cacheDir);
061        cache = new RandomAccessFile(cacheFile, "rw");
062        maxPos = 0;
063      }
064    
065      public void close()
066        throws IOException
067      {
068        maxPos = cache.length();
069        seek(maxPos);
070        flushBefore(maxPos);
071        super.close();
072        cache.close();
073        cacheFile.delete();
074        stream.flush();
075        stream = null;
076      }
077    
078      public boolean isCached()
079      {
080        return true;
081      }
082    
083      public boolean isCachedFile()
084      {
085        return true;
086      }
087      
088      public boolean isCachedMemory()
089      {
090        return false;
091      }
092      
093      public int read()
094        throws IOException
095      {
096        bitOffset = 0;
097        int val = cache.read();
098        if (val != -1)
099          streamPos++;
100        return val;
101      }
102    
103      public int read(byte[] data, int offset, int len)
104        throws IOException
105      {
106        bitOffset = 0;
107        int num = cache.read(data, offset, len);
108        if (num != -1)
109          streamPos += num;
110        return num;
111      }
112    
113      public void write(byte[] data, int offset, int len)
114        throws IOException
115      {
116        flushBits();
117        cache.write(data, offset, len);
118        streamPos += len;
119        maxPos = Math.max(streamPos, maxPos);
120      }
121    
122      public void write(int value)
123        throws IOException
124      {
125        flushBits();
126        cache.write(value);
127        streamPos++;
128        maxPos = Math.max(streamPos, maxPos);
129      }
130    
131      public long length()
132      {
133        long l;
134        try
135          {
136            l = cache.length();
137          }
138        catch (IOException ex)
139          {
140            l = -1;
141          }
142        return l;
143      }
144    
145      public void seek(long pos)
146        throws IOException
147      {
148        checkClosed();
149        if (pos < flushedPos)
150          throw new IndexOutOfBoundsException();
151        cache.seek(pos);
152        streamPos = cache.getFilePointer();
153        maxPos = Math.max(streamPos, maxPos);
154        bitOffset = 0;
155      }
156    
157      public void flushBefore(long pos)
158        throws IOException
159      {
160        long oldPos = flushedPos;
161        super.flushBefore(pos);
162        long flushed = flushedPos - oldPos;
163        if (flushed > 0)
164          {
165            int len = 512;
166            byte[] buf = new byte[len];
167            cache.seek(oldPos);
168            while (flushed > 0)
169              {
170                int l = (int) Math.min(flushed, len);
171                cache.readFully(buf, 0, l);
172                stream.write(buf, 0, l);
173                flushed -= l;
174              }
175            stream.flush();
176          }
177      }
178    }