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.util.zip.CRC32;
50 import java.util.zip.DataFormatException;
51 import java.util.zip.Inflater;
52
53 import org.eclipse.jgit.internal.storage.pack.PackOutputStream;
54
55 /** A cached slice of a {@link DfsPackFile}. */
56 final class DfsBlock {
57 final DfsPackKey pack;
58
59 final long start;
60
61 final long end;
62
63 private final byte[] block;
64
65 DfsBlock(DfsPackKey p, long pos, byte[] buf) {
66 pack = p;
67 start = pos;
68 end = pos + buf.length;
69 block = buf;
70 }
71
72 int size() {
73 return block.length;
74 }
75
76 boolean contains(DfsPackKey want, long pos) {
77 return pack == want && start <= pos && pos < end;
78 }
79
80 int copy(long pos, byte[] dstbuf, int dstoff, int cnt) {
81 int ptr = (int) (pos - start);
82 return copy(ptr, dstbuf, dstoff, cnt);
83 }
84
85 int copy(int p, byte[] b, int o, int n) {
86 n = Math.min(block.length - p, n);
87 System.arraycopy(block, p, b, o, n);
88 return n;
89 }
90
91 int setInput(long pos, Inflater inf) throws DataFormatException {
92 int ptr = (int) (pos - start);
93 int cnt = block.length - ptr;
94 if (cnt <= 0) {
95 throw new DataFormatException(cnt + " bytes to inflate:" //$NON-NLS-1$
96 + " at pos=" + pos //$NON-NLS-1$
97 + "; block.start=" + start //$NON-NLS-1$
98 + "; ptr=" + ptr //$NON-NLS-1$
99 + "; block.length=" + block.length); //$NON-NLS-1$
100 }
101 inf.setInput(block, ptr, cnt);
102 return cnt;
103 }
104
105 void crc32(CRC32 out, long pos, int cnt) {
106 int ptr = (int) (pos - start);
107 out.update(block, ptr, cnt);
108 }
109
110 void write(PackOutputStream out, long pos, int cnt)
111 throws IOException {
112 out.write(block, (int) (pos - start), cnt);
113 }
114
115 void check(Inflater inf, byte[] tmp, long pos, int cnt)
116 throws DataFormatException {
117 // Unlike inflate() above the exact byte count is known by the caller.
118 // Push all of it in a single invocation to avoid unnecessary loops.
119 //
120 inf.setInput(block, (int) (pos - start), cnt);
121 while (inf.inflate(tmp, 0, tmp.length) > 0)
122 continue;
123 }
124 }