author  Ryan C. Gordon <icculus@icculus.org> 
Fri, 19 Dec 2003 01:49:12 +0000  
changeset 612  03b07cbd1bc7 
parent 602  691c1eadb8b7 
permissions  rwrr 
602
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

1 
/* adler32.c  compute the Adler32 checksum of a data stream 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

2 
* Copyright (C) 19952003 Mark Adler 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

3 
* For conditions of distribution and use, see copyright notice in zlib.h 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

4 
*/ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

5 

691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

6 
/* @(#) $Id: adler32.c,v 1.1 2003/12/07 05:29:20 icculus Exp $ */ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

7 

691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

8 
#define ZLIB_INTERNAL 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

9 
#include "zlib.h" 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

10 

691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

11 
#define BASE 65521UL /* largest prime smaller than 65536 */ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

12 
#define NMAX 5552 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

13 
/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE1) <= 2^321 */ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

14 

691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

15 
#define DO1(buf,i) {s1 += buf[i]; s2 += s1;} 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

16 
#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1); 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

17 
#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2); 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

18 
#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4); 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

19 
#define DO16(buf) DO8(buf,0); DO8(buf,8); 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

20 

691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

21 
#ifdef NO_DIVIDE 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

22 
# define MOD(a) \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

23 
do { \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

24 
if (a >= (BASE << 16)) a = (BASE << 16); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

25 
if (a >= (BASE << 15)) a = (BASE << 15); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

26 
if (a >= (BASE << 14)) a = (BASE << 14); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

27 
if (a >= (BASE << 13)) a = (BASE << 13); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

28 
if (a >= (BASE << 12)) a = (BASE << 12); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

29 
if (a >= (BASE << 11)) a = (BASE << 11); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

30 
if (a >= (BASE << 10)) a = (BASE << 10); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

31 
if (a >= (BASE << 9)) a = (BASE << 9); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

32 
if (a >= (BASE << 8)) a = (BASE << 8); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

33 
if (a >= (BASE << 7)) a = (BASE << 7); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

34 
if (a >= (BASE << 6)) a = (BASE << 6); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

35 
if (a >= (BASE << 5)) a = (BASE << 5); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

36 
if (a >= (BASE << 4)) a = (BASE << 4); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

37 
if (a >= (BASE << 3)) a = (BASE << 3); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

38 
if (a >= (BASE << 2)) a = (BASE << 2); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

39 
if (a >= (BASE << 1)) a = (BASE << 1); \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

40 
if (a >= BASE) a = BASE; \ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

41 
} while (0) 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

42 
#else 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

43 
# define MOD(a) a %= BASE 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

44 
#endif 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

45 

691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

46 
/* ========================================================================= */ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

47 
uLong ZEXPORT adler32(adler, buf, len) 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

48 
uLong adler; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

49 
const Bytef *buf; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

50 
uInt len; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

51 
{ 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

52 
unsigned long s1 = adler & 0xffff; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

53 
unsigned long s2 = (adler >> 16) & 0xffff; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

54 
int k; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

55 

691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

56 
if (buf == Z_NULL) return 1L; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

57 

691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

58 
while (len > 0) { 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

59 
k = len < NMAX ? (int)len : NMAX; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

60 
len = k; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

61 
while (k >= 16) { 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

62 
DO16(buf); 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

63 
buf += 16; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

64 
k = 16; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

65 
} 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

66 
if (k != 0) do { 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

67 
s1 += *buf++; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

68 
s2 += s1; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

69 
} while (k); 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

70 
MOD(s1); 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

71 
MOD(s2); 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

72 
} 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

73 
return (s2 << 16)  s1; 
691c1eadb8b7
Upgraded internal zlib to 1.2.1 (thanks, Adam!)
Ryan C. Gordon <icculus@icculus.org>
parents:
diff
changeset

74 
} 