Source for javax.imageio.stream.MemoryCacheImageInputStream

   1: /* MemoryCacheImageInputStream.java --
   2:    Copyright (C) 2004  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10: 
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package javax.imageio.stream;
  40: 
  41: import java.io.BufferedInputStream;
  42: import java.io.BufferedReader;
  43: import java.io.IOException;
  44: import java.io.InputStream;
  45: import java.io.InputStreamReader;
  46: 
  47: /**
  48:  * @author Michael Koch (konqueror@gmx.de)
  49:  */
  50: public class MemoryCacheImageInputStream extends ImageInputStreamImpl
  51: {
  52:   private InputStream stream;
  53:   private BufferedInputStream buffer;
  54: 
  55:   private int READLIMIT = 2048;
  56:   
  57:   public MemoryCacheImageInputStream(InputStream stream)
  58:   {
  59:     this.stream = stream;
  60:     buffer = new BufferedInputStream(stream);
  61:     buffer.mark(READLIMIT);
  62:   }
  63: 
  64:   public void close()
  65:     throws IOException
  66:   {
  67:     super.close();
  68:     stream.close();
  69:   }
  70: 
  71:   public void flushBefore(long position)
  72:     throws IOException
  73:   {
  74:     long prevFlushedPosition = getFlushedPosition();
  75:     super.flushBefore(position);
  76:     buffer.reset();
  77:     buffer.skip(getFlushedPosition() - prevFlushedPosition);
  78:     buffer.mark(READLIMIT);
  79:   }
  80: 
  81:   public boolean isCached()
  82:   {
  83:     return true;
  84:   }
  85: 
  86:   public boolean isCachedFile()
  87:   {
  88:     return false;
  89:   }
  90:   
  91:   public boolean isCachedMemory()
  92:   {
  93:     return true;
  94:   }
  95: 
  96:   public int read()
  97:     throws IOException
  98:   {
  99:     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: }