org.spearce.jgit/src/org/spearce/jgit/lib/ByteBufferWindow.java

   1 /*
   2  * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
   3  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
   4  *
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or
   8  * without modification, are permitted provided that the following
   9  * conditions are met:
  10  *
  11  * - Redistributions of source code must retain the above copyright
  12  *   notice, this list of conditions and the following disclaimer.
  13  *
  14  * - Redistributions in binary form must reproduce the above
  15  *   copyright notice, this list of conditions and the following
  16  *   disclaimer in the documentation and/or other materials provided
  17  *   with the distribution.
  18  *
  19  * - Neither the name of the Git Development Community nor the
  20  *   names of its contributors may be used to endorse or promote
  21  *   products derived from this software without specific prior
  22  *   written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  25  * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  26  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  27  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  29  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  31  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  32  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  33  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  34  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  36  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 package org.spearce.jgit.lib;
  40
  41 import java.nio.ByteBuffer;
  42 import java.util.zip.DataFormatException;
  43 import java.util.zip.Inflater;
  44
  45 /**
  46  * A window for accessing git packs using a {@link ByteBuffer} for storage.
  47  *
  48  * @see ByteWindow
  49  */
  50 final class ByteBufferWindow extends ByteWindow<ByteBuffer> {
  51         /**
  52          * Constructor.
  53          *
  54          * @See ByteWindow
  55          *
  56          * @param o The WindowedFile
  57          * @param p the file offset.
  58          * @param d Window id
  59          * @param b ByteBuffer storage
  60          */
  61         ByteBufferWindow(final WindowedFile o, final long p, final int d,
  62                         final ByteBuffer b) {
  63                 super(o, p, d, b, b.capacity());
  64         }
  65
  66         final int copy(final ByteBuffer buffer, final int p, final byte[] b,
  67                         final int o, int n) {
  68                 final ByteBuffer s = buffer.slice();
  69                 s.position(p);
  70                 n = Math.min(s.remaining(), n);
  71                 s.get(b, o, n);
  72                 return n;
  73         }
  74
  75         int inflate(final ByteBuffer buffer, final int pos, final byte[] b, int o,
  76                         final Inflater inf)
  77                         throws DataFormatException {
  78                 final byte[] tmp = new byte[512];
  79                 final ByteBuffer s = buffer.slice();
  80                 s.position(pos);
  81                 while (s.remaining() > 0 && !inf.finished()) {
  82                         if (inf.needsInput()) {
  83                                 final int n = Math.min(s.remaining(), tmp.length);
  84                                 s.get(tmp, 0, n);
  85                                 inf.setInput(tmp, 0, n);
  86                         }
  87                         o += inf.inflate(b, o, b.length - o);
  88                 }
  89                 while (!inf.finished() && !inf.needsInput())
  90                         o += inf.inflate(b, o, b.length - o);
  91                 return o;
  92         }
  93 }