org.spearce.jgit/src/org/spearce/jgit/lib/ByteArrayWindow.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.io.IOException;
  42 import java.nio.ByteBuffer;
  43 import java.util.zip.DataFormatException;
  44 import java.util.zip.Inflater;
  45
  46 /**
  47  * A {@link ByteWindow} with an underlying byte array for storage.
  48  */
  49 final class ByteArrayWindow extends ByteWindow<byte[]> {
  50         boolean loaded;
  51
  52         /**
  53          * Constructor for ByteWindow.
  54          *
  55          * @param o
  56          *            the PackFile providing data access
  57          * @param p
  58          *            the file offset.
  59          * @param d
  60          *            an id provided by the PackFile. See
  61          *            {@link WindowCache#get(WindowCursor, PackFile, long)}.
  62          * @param b
  63          *            byte array for storage
  64          */
  65         ByteArrayWindow(final PackFile o, final long p, final int d, final byte[] b) {
  66                 super(o, p, d, b, b.length);
  67         }
  68
  69         int copy(final byte[] array, final int p, final byte[] b, final int o, int n) {
  70                 n = Math.min(array.length - p, n);
  71                 System.arraycopy(array, p, b, o, n);
  72                 return n;
  73         }
  74
  75         int inflate(final byte[] array, final int pos, final byte[] b, int o,
  76                         final Inflater inf) throws DataFormatException {
  77                 while (!inf.finished()) {
  78                         if (inf.needsInput()) {
  79                                 inf.setInput(array, pos, array.length - pos);
  80                                 break;
  81                         }
  82                         o += inf.inflate(b, o, b.length - o);
  83                 }
  84                 while (!inf.finished() && !inf.needsInput())
  85                         o += inf.inflate(b, o, b.length - o);
  86                 return o;
  87         }
  88
  89         void inflateVerify(final byte[] array, final int pos, final Inflater inf)
  90                         throws DataFormatException {
  91                 while (!inf.finished()) {
  92                         if (inf.needsInput()) {
  93                                 inf.setInput(array, pos, array.length - pos);
  94                                 break;
  95                         }
  96                         inf.inflate(verifyGarbageBuffer, 0, verifyGarbageBuffer.length);
  97                 }
  98                 while (!inf.finished() && !inf.needsInput())
  99                         inf.inflate(verifyGarbageBuffer, 0, verifyGarbageBuffer.length);
 100         }
 101
 102         void ensureLoaded(final byte[] array) {
 103                 boolean release = false;
 104                 try {
 105                         synchronized (this) {
 106                                 if (!loaded) {
 107                                         release = true;
 108                                         try {
 109                                                 provider.fd.getChannel().read(ByteBuffer.wrap(array),
 110                                                                 start);
 111                                         } catch (IOException e) {
 112                                                 throw new RuntimeException("Cannot fault in window", e);
 113                                         }
 114                                         loaded = true;
 115                                 }
 116                         }
 117                 } finally {
 118                         if (release) {
 119                                 WindowCache.markLoaded(this);
 120                         }
 121                 }
 122         }
 123 }