1/*
2 * Copyright 2012, Google Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met:
8 *
9 *     * Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *     * Redistributions in binary form must reproduce the above
12 * copyright notice, this list of conditions and the following disclaimer
13 * in the documentation and/or other materials provided with the
14 * distribution.
15 *     * Neither the name of Google Inc. nor the names of its
16 * contributors may be used to endorse or promote products derived from
17 * this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32package org.jf.dexlib2.dexbacked;
33
34import org.jf.util.ExceptionWithContext;
35
36import javax.annotation.Nonnull;
37
38public class BaseDexBuffer {
39    @Nonnull /* package private */ final byte[] buf;
40
41    public BaseDexBuffer(@Nonnull byte[] buf) {
42        this.buf = buf;
43    }
44
45    public int readSmallUint(int offset) {
46        byte[] buf = this.buf;
47        int result = (buf[offset] & 0xff) |
48                ((buf[offset+1] & 0xff) << 8) |
49                ((buf[offset+2] & 0xff) << 16) |
50                ((buf[offset+3]) << 24);
51        if (result < 0) {
52            throw new ExceptionWithContext("Encountered small uint that is out of range at offset 0x%x", offset);
53        }
54        return result;
55    }
56
57    public int readOptionalUint(int offset) {
58        byte[] buf = this.buf;
59        int result = (buf[offset] & 0xff) |
60                ((buf[offset+1] & 0xff) << 8) |
61                ((buf[offset+2] & 0xff) << 16) |
62                ((buf[offset+3]) << 24);
63        if (result < -1) {
64            throw new ExceptionWithContext("Encountered optional uint that is out of range at offset 0x%x", offset);
65        }
66        return result;
67    }
68
69    public int readUshort(int offset) {
70        byte[] buf = this.buf;
71        return (buf[offset] & 0xff) |
72                ((buf[offset+1] & 0xff) << 8);
73    }
74
75    public int readUbyte(int offset) {
76        return buf[offset] & 0xff;
77    }
78
79    public long readLong(int offset) {
80        byte[] buf = this.buf;
81        return (buf[offset] & 0xff) |
82                ((buf[offset+1] & 0xff) << 8) |
83                ((buf[offset+2] & 0xff) << 16) |
84                ((buf[offset+3] & 0xffL) << 24) |
85                ((buf[offset+4] & 0xffL) << 32) |
86                ((buf[offset+5] & 0xffL) << 40) |
87                ((buf[offset+6] & 0xffL) << 48) |
88                (((long)buf[offset+7]) << 56);
89    }
90
91    public int readInt(int offset) {
92        byte[] buf = this.buf;
93        return (buf[offset] & 0xff) |
94                ((buf[offset+1] & 0xff) << 8) |
95                ((buf[offset+2] & 0xff) << 16) |
96                (buf[offset+3] << 24);
97    }
98
99    public int readShort(int offset) {
100        byte[] buf = this.buf;
101        return (buf[offset] & 0xff) |
102                (buf[offset+1] << 8);
103    }
104
105    public int readByte(int offset) {
106        return buf[offset];
107    }
108
109    @Nonnull
110    public BaseDexReader readerAt(int offset) {
111        return new BaseDexReader<BaseDexBuffer>(this, offset);
112    }
113
114    @Nonnull
115    protected byte[] getBuf() {
116        return buf;
117    }
118}
119