NumberUtils.java revision cb83d271e5485aa85ec7b8b3dc7b6e01417e1e43 
1/*
2 * [The "BSD licence"]
3 * Copyright (c) 2009 Ben Gruver
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29package org.jf.dexlib.Util;
30
31public class NumberUtils {
32
33    public static byte decodeHighSignedNibble(byte b) {
34        return (byte)(b >> 4);
35    }
36
37    public static byte decodeHighUnsignedNibble(byte b) {
38        return (byte)((b & 0xFF) >>> 4);
39    }
40
41    public static byte decodeLowUnsignedNibble(byte b) {
42        return (byte)(b & 0x0F);
43    }
44
45    public static short decodeUnsignedByte(byte b) {
46        return (short)(b & 0xFF);
47    }
48
49    public static short decodeShort(byte lsb, byte msb) {
50        return (short)
51               (    (lsb & 0xFF) |
52                    (msb << 8)
53               );
54    }
55
56    public static int decodeUnsignedShort(byte lsb, byte msb) {
57        return  ((msb & 0xFF) << 8) |
58                 (lsb & 0xFF);
59    }
60
61    public static int decodeInt(byte lsb, byte mlsb, byte mmsb, byte msb) {
62        return (lsb & 0xFF) |
63               ((mlsb & 0xFF) << 8) |
64               ((mmsb & 0xFF) << 16) |
65               (msb << 24);
66    }
67
68    public static long decodeLong(byte[] array, int startIndex) {
69        return  array[startIndex++] |
70                (array[startIndex++] >> 8) |
71                (array[startIndex++] >> 16) |
72                (array[startIndex++] >> 24) |
73                ((long)array[startIndex++] >> 32) |
74                ((long)array[startIndex++] >> 40) |
75                ((long)array[startIndex++] >> 48) |
76                ((long)array[startIndex++] >> 56);
77    }
78}
79