zenilib  0.5.3.0
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1 /* adler32.c -- compute the Adler-32 checksum of a data stream
3  * For conditions of distribution and use, see copyright notice in zlib.h
4  */
5
6 /* @(#) \$Id\$ */
7
8 #include "zlib.h"
9
10 #define BASE 65521L /* largest prime smaller than 65536 */
11 #define NMAX 5552
12 /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
13
14 #define DO1(buf,i) {s1 += buf[i]; s2 += s1;}
15 #define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);
16 #define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);
17 #define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);
18 #define DO16(buf) DO8(buf,0); DO8(buf,8);
19
20 /* ========================================================================= */
23  const Bytef *buf,
24  uInt len )
25 {
26  unsigned long s1 = adler & 0xffff;
27  unsigned long s2 = (adler >> 16) & 0xffff;
28  int k;
29
30  if (buf == Z_NULL) return 1L;
31
32  while (len > 0) {
33  k = len < NMAX ? len : NMAX;
34  len -= k;
35  while (k >= 16) {
36  DO16(buf);
37  buf += 16;
38  k -= 16;
39  }
40  if (k != 0) do {
41  s1 += *buf++;
42  s2 += s1;
43  } while (--k);
44  s1 %= BASE;
45  s2 %= BASE;
46  }
47  return (s2 << 16) | s1;
48 }
#define BASE
unsigned long uLong
Definition: zconf.h:222
Byte FAR Bytef
Definition: zconf.h:228
int32_t k
Definition: e_log.c:102
#define ZEXPORT(x)
Definition: zconf.h:202
GLenum GLsizei len
Definition: glew.h:7035
unsigned int uInt
Definition: zconf.h:221
#define Z_NULL
Definition: zlib.h:164
GLuint GLfloat GLfloat GLfloat GLfloat GLfloat GLfloat GLfloat GLfloat s1
Definition: glew.h:11582
#define const
Definition: zconf.h:91
GLenum GLuint GLsizei const GLchar * buf
Definition: glew.h:2539
#define NMAX