76 lines
2.3 KiB
C
76 lines
2.3 KiB
C
|
/***************************************************************************
|
||
|
|
* __________ __ ___.
|
||
|
|
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
|
||
|
|
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
|
||
|
|
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
|
||
|
|
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
|
||
|
|
* \/ \/ \/ \/ \/
|
||
|
|
* $Id$
|
||
|
|
*
|
||
|
|
* Copyright (C) 2021 James Buren (adaptations from tinf/zlib)
|
||
|
|
*
|
||
|
|
* This program is free software; you can redistribute it and/or
|
||
|
|
* modify it under the terms of the GNU General Public License
|
||
|
|
* as published by the Free Software Foundation; either version 2
|
||
|
|
* of the License, or (at your option) any later version.
|
||
|
|
*
|
||
|
|
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
||
|
|
* KIND, either express or implied.
|
||
|
|
*
|
||
|
|
****************************************************************************/
|
||
|
|
|
||
|
|
#include "adler32.h"
|
||
|
|
#include "system.h"
|
||
|
|
|
||
|
|
/* adler_32 (derived from tinf adler32 which was taken from zlib)
|
||
|
|
* Adler-32 algorithm taken from the zlib source, which is
|
||
|
|
* Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
|
||
|
|
*/
|
||
|
|
uint32_t adler_32(const void *src, uint32_t len, uint32_t adler32)
|
||
|
|
{
|
||
|
|
const unsigned char *buf = (const unsigned char *)src;
|
||
|
|
uint32_t s1 = (adler32 & 0xffff);
|
||
|
|
uint32_t s2 = (adler32 >> 16);
|
||
|
|
|
||
|
|
enum {
|
||
|
|
A32_BASE = 65521,
|
||
|
|
A32_NMAX = 5552,
|
||
|
|
};
|
||
|
|
|
||
|
|
while (len > 0) {
|
||
|
|
uint32_t k = MIN(len, A32_NMAX);
|
||
|
|
uint32_t i;
|
||
|
|
|
||
|
|
for (i = k / 16; i; --i, buf += 16) {
|
||
|
|
s2 += s1 += buf[0];
|
||
|
|
s2 += s1 += buf[1];
|
||
|
|
s2 += s1 += buf[2];
|
||
|
|
s2 += s1 += buf[3];
|
||
|
|
s2 += s1 += buf[4];
|
||
|
|
s2 += s1 += buf[5];
|
||
|
|
s2 += s1 += buf[6];
|
||
|
|
s2 += s1 += buf[7];
|
||
|
|
s2 += s1 += buf[8];
|
||
|
|
s2 += s1 += buf[9];
|
||
|
|
s2 += s1 += buf[10];
|
||
|
|
s2 += s1 += buf[11];
|
||
|
|
s2 += s1 += buf[12];
|
||
|
|
s2 += s1 += buf[13];
|
||
|
|
s2 += s1 += buf[14];
|
||
|
|
s2 += s1 += buf[15];
|
||
|
|
}
|
||
|
|
|
||
|
|
for (i = k % 16; i; --i) {
|
||
|
|
s1 += *buf++;
|
||
|
|
s2 += s1;
|
||
|
|
}
|
||
|
|
|
||
|
|
s1 %= A32_BASE;
|
||
|
|
s2 %= A32_BASE;
|
||
|
|
|
||
|
|
len -= k;
|
||
|
|
}
|
||
|
|
|
||
|
|
return (s1 | (s2 << 16));
|
||
|
|
}
|