blob: aaebb40b5a1b0d92f7aee8c19945ade6d5f399c2 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
/*
Copyright (c) 1990-2005 Info-ZIP. All rights reserved.
See the accompanying file LICENSE, version 2004-May-22 or later
(the contents of which are also included in zip.h) for terms of use.
If, for some reason, both of these files are missing, the Info-ZIP license
also may be found at: ftp://ftp.info-zip.org/pub/infozip/license.html
*/
/* crc32.c -- compute the CRC-32 of a data stream
* Copyright (C) 1995 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* $Id: crc32.c,v 1.5 1996/01/13 14:55:12 spc Exp $ */
#define __CRC32_C /* identifies this source module */
#include "zip.h"
#ifndef USE_ZLIB
#ifndef ASM_CRC
#ifndef ZCONST
# define ZCONST const
#endif
#ifdef CRC32
# undef CRC32
#endif
#define CRC32(c, b) (crc_table[((int)(c) ^ (b)) & 0xff] ^ ((c) >> 8))
#define DO1(buf) crc = CRC32(crc, *buf++)
#define DO2(buf) DO1(buf); DO1(buf)
#define DO4(buf) DO2(buf); DO2(buf)
#define DO8(buf) DO4(buf); DO4(buf)
/* ========================================================================= */
ulg crc32(crc, buf, len)
register ulg crc; /* crc shift register */
register ZCONST uch *buf; /* pointer to bytes to pump through */
extent len; /* number of bytes in buf[] */
/* Run a set of bytes through the crc shift register. If buf is a NULL
pointer, then initialize the crc shift register contents instead.
Return the current crc in either case. */
{
register ZCONST ulg near *crc_table;
if (buf == NULL) return 0L;
crc_table = get_crc_table();
crc = crc ^ 0xffffffffL;
#ifndef NO_UNROLLED_LOOPS
while (len >= 8) {
DO8(buf);
len -= 8;
}
#endif
if (len) do {
DO1(buf);
} while (--len);
return crc ^ 0xffffffffL; /* (instead of ~c for 64-bit machines) */
}
#endif /* !ASM_CRC */
#endif /* !USE_ZLIB */
|
