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.IOException;
  43: import java.io.InputStream;
  44: 
  45: /**
  46:  * @author Michael Koch (konqueror@gmx.de)
  47:  */
  48: public class MemoryCacheImageInputStream extends ImageInputStreamImpl
  49: {
  50:   private InputStream stream;
  51:   private BufferedInputStream buffer;
  52: 
  53:   private int READLIMIT = 2048;
  54: 
  55:   public MemoryCacheImageInputStream(InputStream stream)
  56:   {
  57:     this.stream = stream;
  58:     buffer = new BufferedInputStream(stream);
  59:     buffer.mark(READLIMIT);
  60:   }
  61: 
  62:   public void close()
  63:     throws IOException
  64:   {
  65:     super.close();
  66:     stream.close();
  67:   }
  68: 
  69:   public void flushBefore(long position)
  70:     throws IOException
  71:   {
  72:     long prevFlushedPosition = getFlushedPosition();
  73:     super.flushBefore(position);
  74:     buffer.reset();
  75:     buffer.skip(getFlushedPosition() - prevFlushedPosition);
  76:     buffer.mark(READLIMIT);
  77:   }
  78: 
  79:   public boolean isCached()
  80:   {
  81:     return true;
  82:   }
  83: 
  84:   public boolean isCachedFile()
  85:   {
  86:     return false;
  87:   }
  88: 
  89:   public boolean isCachedMemory()
  90:   {
  91:     return true;
  92:   }
  93: 
  94:   public int read()
  95:     throws IOException
  96:   {
  97:     setBitOffset(0);
  98:     int retval = buffer.read();
  99: 
 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: }