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comparison dcrypt/misc/checksums/Adler32.d @ 14:5ce3012f1def

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Removed some redundancy in code. Added NotSupportedError, a base PRNG class and a class which creates a PRNG from a hash function. Changed the MAC class' finalization methods to digest and hexDigest instead of finish and hexFinish respectively. Also added a base Checksum class, crc32 and adler32 in dcrypt.misc as per request.
author Thomas Dixon <reikon@reikon.us>
date Tue, 18 Nov 2008 18:03:40 -0500
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children 176c933827a8
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13:7ea528b61802 14:5ce3012f1def
1 /**
2 * This file is part of the dcrypt project.
3 *
4 * Copyright: Copyright (C) dcrypt contributors 2008. All rights reserved.
5 * License: MIT
6 * Authors: Thomas Dixon
7 */
8
9 module dcrypt.misc.checksums.Adler32;
10
11 import dcrypt.misc.Checksum;
12
13 /**
14 * Implementation of Mark Adler's Adler32 checksum.
15 *
16 * Conforms: RFC 1950
17 * References: http://tools.ietf.org/html/rfc1950#page-10
18 */
19 class Adler32 : Checksum {
20 private static const uint BASE = 65521;
21
22 uint compute(void[] input_, uint start=1) {
23 ubyte[] input = cast(ubyte[])input_;
24 uint adler = start,
25 s1 = adler & 0xffff,
26 s2 = (adler >> 16) & 0xffff;
27
28 foreach (ubyte i; input) {
29 s1 = (s1 + i) % BASE;
30 s2 = (s2 + s1) % BASE;
31 }
32
33 return (s2 << 16) + s1;
34 }
35
36 char[] name() {
37 return "Adler32";
38 }
39
40 version (UnitTest) {
41 unittest {
42 static char[][] test_inputs = [
43 "",
44 "a",
45 "checksum",
46 "chexksum"
47 ];
48
49 static const uint[] test_results = [
50 0x1u,
51 0x620062u,
52 0xea10354u,
53 0xf0a0369u
54 ];
55
56 Adler32 adler32 = new Adler32;
57 foreach (uint i, char[] j; test_inputs)
58 assert(adler32.compute(j) == test_results[i], adler32.name);
59 }
60 }
61 }