1 /*
2 * Copyright (C) 2008-2011, Google Inc.
3 * Copyright (C) 2007, Robin Rosenberg <robin.rosenberg@dewire.com>
4 * Copyright (C) 2006-2008, Shawn O. Pearce <spearce@spearce.org>
5 * and other copyright owners as documented in the project's IP log.
6 *
7 * This program and the accompanying materials are made available
8 * under the terms of the Eclipse Distribution License v1.0 which
9 * accompanies this distribution, is reproduced below, and is
10 * available at http://www.eclipse.org/org/documents/edl-v10.php
11 *
12 * All rights reserved.
13 *
14 * Redistribution and use in source and binary forms, with or
15 * without modification, are permitted provided that the following
16 * conditions are met:
17 *
18 * - Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 *
21 * - Redistributions in binary form must reproduce the above
22 * copyright notice, this list of conditions and the following
23 * disclaimer in the documentation and/or other materials provided
24 * with the distribution.
25 *
26 * - Neither the name of the Eclipse Foundation, Inc. nor the
27 * names of its contributors may be used to endorse or promote
28 * products derived from this software without specific prior
29 * written permission.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
32 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
33 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
35 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
36 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
37 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
38 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
39 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
40 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
43 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
44 */
45
46 package org.eclipse.jgit.internal.storage.dfs;
47
48 import java.io.IOException;
49 import java.nio.ByteBuffer;
50 import java.util.zip.CRC32;
51 import java.util.zip.DataFormatException;
52 import java.util.zip.Inflater;
53
54 import org.eclipse.jgit.internal.storage.pack.PackOutputStream;
55
56 /** A cached slice of a {@link BlockBasedFile}. */
57 final class DfsBlock {
58 final DfsStreamKey stream;
59 final long start;
60 final long end;
61 private final byte[] block;
62
63 DfsBlock(DfsStreamKey p, long pos, byte[] buf) {
64 stream = p;
65 start = pos;
66 end = pos + buf.length;
67 block = buf;
68 }
69
70 int size() {
71 return block.length;
72 }
73
74 ByteBuffer zeroCopyByteBuffer(int n) {
75 ByteBuffer b = ByteBuffer.wrap(block);
76 b.position(n);
77 return b;
78 }
79
80 boolean contains(DfsStreamKey want, long pos) {
81 return stream.equals(want) && start <= pos && pos < end;
82 }
83
84 int copy(long pos, byte[] dstbuf, int dstoff, int cnt) {
85 int ptr = (int) (pos - start);
86 return copy(ptr, dstbuf, dstoff, cnt);
87 }
88
89 int copy(int p, byte[] b, int o, int n) {
90 n = Math.min(block.length - p, n);
91 System.arraycopy(block, p, b, o, n);
92 return n;
93 }
94
95 int setInput(long pos, Inflater inf) throws DataFormatException {
96 int ptr = (int) (pos - start);
97 int cnt = block.length - ptr;
98 if (cnt <= 0) {
99 throw new DataFormatException(cnt + " bytes to inflate:" //$NON-NLS-1$
100 + " at pos=" + pos //$NON-NLS-1$
101 + "; block.start=" + start //$NON-NLS-1$
102 + "; ptr=" + ptr //$NON-NLS-1$
103 + "; block.length=" + block.length); //$NON-NLS-1$
104 }
105 inf.setInput(block, ptr, cnt);
106 return cnt;
107 }
108
109 void crc32(CRC32 out, long pos, int cnt) {
110 int ptr = (int) (pos - start);
111 out.update(block, ptr, cnt);
112 }
113
114 void write(PackOutputStream out, long pos, int cnt)
115 throws IOException {
116 out.write(block, (int) (pos - start), cnt);
117 }
118
119 void check(Inflater inf, byte[] tmp, long pos, int cnt)
120 throws DataFormatException {
121 // Unlike inflate() above the exact byte count is known by the caller.
122 // Push all of it in a single invocation to avoid unnecessary loops.
123 //
124 inf.setInput(block, (int) (pos - start), cnt);
125 while (inf.inflate(tmp, 0, tmp.length) > 0)
126 continue;
127 }
128 }