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Diffstat (limited to 'firmware/common/adler32.c')
-rw-r--r-- | firmware/common/adler32.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/firmware/common/adler32.c b/firmware/common/adler32.c new file mode 100644 index 0000000000..8f5f85b453 --- /dev/null +++ b/firmware/common/adler32.c | |||
@@ -0,0 +1,75 @@ | |||
1 | /*************************************************************************** | ||
2 | * __________ __ ___. | ||
3 | * Open \______ \ ____ ____ | | _\_ |__ _______ ___ | ||
4 | * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / | ||
5 | * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < | ||
6 | * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ | ||
7 | * \/ \/ \/ \/ \/ | ||
8 | * $Id$ | ||
9 | * | ||
10 | * Copyright (C) 2021 James Buren (adaptations from tinf/zlib) | ||
11 | * | ||
12 | * This program is free software; you can redistribute it and/or | ||
13 | * modify it under the terms of the GNU General Public License | ||
14 | * as published by the Free Software Foundation; either version 2 | ||
15 | * of the License, or (at your option) any later version. | ||
16 | * | ||
17 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY | ||
18 | * KIND, either express or implied. | ||
19 | * | ||
20 | ****************************************************************************/ | ||
21 | |||
22 | #include "adler32.h" | ||
23 | #include "system.h" | ||
24 | |||
25 | /* adler_32 (derived from tinf adler32 which was taken from zlib) | ||
26 | * Adler-32 algorithm taken from the zlib source, which is | ||
27 | * Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler | ||
28 | */ | ||
29 | uint32_t adler_32(const void *src, uint32_t len, uint32_t adler32) | ||
30 | { | ||
31 | const unsigned char *buf = (const unsigned char *)src; | ||
32 | uint32_t s1 = (adler32 & 0xffff); | ||
33 | uint32_t s2 = (adler32 >> 16); | ||
34 | |||
35 | enum { | ||
36 | A32_BASE = 65521, | ||
37 | A32_NMAX = 5552, | ||
38 | }; | ||
39 | |||
40 | while (len > 0) { | ||
41 | uint32_t k = MIN(len, A32_NMAX); | ||
42 | uint32_t i; | ||
43 | |||
44 | for (i = k / 16; i; --i, buf += 16) { | ||
45 | s2 += s1 += buf[0]; | ||
46 | s2 += s1 += buf[1]; | ||
47 | s2 += s1 += buf[2]; | ||
48 | s2 += s1 += buf[3]; | ||
49 | s2 += s1 += buf[4]; | ||
50 | s2 += s1 += buf[5]; | ||
51 | s2 += s1 += buf[6]; | ||
52 | s2 += s1 += buf[7]; | ||
53 | s2 += s1 += buf[8]; | ||
54 | s2 += s1 += buf[9]; | ||
55 | s2 += s1 += buf[10]; | ||
56 | s2 += s1 += buf[11]; | ||
57 | s2 += s1 += buf[12]; | ||
58 | s2 += s1 += buf[13]; | ||
59 | s2 += s1 += buf[14]; | ||
60 | s2 += s1 += buf[15]; | ||
61 | } | ||
62 | |||
63 | for (i = k % 16; i; --i) { | ||
64 | s1 += *buf++; | ||
65 | s2 += s1; | ||
66 | } | ||
67 | |||
68 | s1 %= A32_BASE; | ||
69 | s2 %= A32_BASE; | ||
70 | |||
71 | len -= k; | ||
72 | } | ||
73 | |||
74 | return (s1 | (s2 << 16)); | ||
75 | } | ||