ReactOS 0.4.15-dev-8348-gc1b9bb5
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3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6/* @(#) \$Id\$ */
7
8#include "zutil.h"
9
11
12#define BASE 65521U /* largest prime smaller than 65536 */
13#define NMAX 5552
14/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
15
17#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);
18#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);
19#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);
20#define DO16(buf) DO8(buf,0); DO8(buf,8);
21
22/* use NO_DIVIDE if your processor does not do division in hardware --
23 try it both ways to see which is faster */
24#ifdef NO_DIVIDE
25/* note that this assumes BASE is 65521, where 65536 % 65521 == 15
26 (thank you to John Reiser for pointing this out) */
27# define CHOP(a) \
28 do { \
29 unsigned long tmp = a >> 16; \
30 a &= 0xffffUL; \
31 a += (tmp << 4) - tmp; \
32 } while (0)
33# define MOD28(a) \
34 do { \
35 CHOP(a); \
36 if (a >= BASE) a -= BASE; \
37 } while (0)
38# define MOD(a) \
39 do { \
40 CHOP(a); \
41 MOD28(a); \
42 } while (0)
43# define MOD63(a) \
44 do { /* this assumes a is not negative */ \
45 z_off64_t tmp = a >> 32; \
46 a &= 0xffffffffL; \
47 a += (tmp << 8) - (tmp << 5) + tmp; \
48 tmp = a >> 16; \
49 a &= 0xffffL; \
50 a += (tmp << 4) - tmp; \
51 tmp = a >> 16; \
52 a &= 0xffffL; \
53 a += (tmp << 4) - tmp; \
54 if (a >= BASE) a -= BASE; \
55 } while (0)
56#else
57# define MOD(a) a %= BASE
58# define MOD28(a) a %= BASE
59# define MOD63(a) a %= BASE
60#endif
61
62/* ========================================================================= */
65 const Bytef *buf;
67{
68 unsigned long sum2;
69 unsigned n;
70
71 /* split Adler-32 into component sums */
72 sum2 = (adler >> 16) & 0xffff;
74
75 /* in case user likes doing a byte at a time, keep it fast */
76 if (len == 1) {
81 if (sum2 >= BASE)
82 sum2 -= BASE;
83 return adler | (sum2 << 16);
84 }
85
86 /* initial Adler-32 value (deferred check for len == 1 speed) */
87 if (buf == Z_NULL)
88 return 1L;
89
90 /* in case short lengths are provided, keep it somewhat fast */
91 if (len < 16) {
92 while (len--) {
95 }
98 MOD28(sum2); /* only added so many BASE's */
99 return adler | (sum2 << 16);
100 }
101
102 /* do length NMAX blocks -- requires just one modulo operation */
103 while (len >= NMAX) {
104 len -= NMAX;
105 n = NMAX / 16; /* NMAX is divisible by 16 */
106 do {
107 DO16(buf); /* 16 sums unrolled */
108 buf += 16;
109 } while (--n);
111 MOD(sum2);
112 }
113
114 /* do remaining bytes (less than NMAX, still just one modulo) */
115 if (len) { /* avoid modulos if none remaining */
116 while (len >= 16) {
117 len -= 16;
118 DO16(buf);
119 buf += 16;
120 }
121 while (len--) {
124 }
126 MOD(sum2);
127 }
128
129 /* return recombined sums */
130 return adler | (sum2 << 16);
131}
132
133/* ========================================================================= */
136 const Bytef *buf;
137 uInt len;
138{
140}
141
142/* ========================================================================= */
146 z_off64_t len2;
147{
148 unsigned long sum1;
149 unsigned long sum2;
150 unsigned rem;
151
152 /* for negative len, return invalid adler32 as a clue for debugging */
153 if (len2 < 0)
154 return 0xffffffffUL;
155
156 /* the derivation of this formula is left as an exercise for the reader */
157 MOD63(len2); /* assumes len2 >= 0 */
158 rem = (unsigned)len2;
159 sum1 = adler1 & 0xffff;
160 sum2 = rem * sum1;
161 MOD(sum2);
162 sum1 += (adler2 & 0xffff) + BASE - 1;
163 sum2 += ((adler1 >> 16) & 0xffff) + ((adler2 >> 16) & 0xffff) + BASE - rem;
164 if (sum1 >= BASE) sum1 -= BASE;
165 if (sum1 >= BASE) sum1 -= BASE;
166 if (sum2 >= ((unsigned long)BASE << 1)) sum2 -= ((unsigned long)BASE << 1);
167 if (sum2 >= BASE) sum2 -= BASE;
168 return sum1 | (sum2 << 16);
169}
170
171/* ========================================================================= */
175 z_off_t len2;
176{
178}
179
183 z_off64_t len2;
184{
186}
Definition: inflate.c:72
unsigned long uLong
Definition: zlib.h:39
unsigned int uInt
Definition: zlib.h:38
#define Z_NULL
Definition: zlib.h:149
Byte FAR Bytef
Definition: zlib.h:41
#define NMAX
#define DO16(buf)
#define BASE
#define local
Definition: zutil.h:30
GLdouble n
Definition: glext.h:7729
GLenum GLuint GLenum GLsizei const GLchar * buf
Definition: glext.h:7751
GLenum GLsizei len
Definition: glext.h:6722
static unsigned(__cdecl *hash_bstr)(bstr_t s)
#define long
Definition: qsort.c:33
#define ZEXPORT
Definition: zconf.h:386
#define z_off_t
Definition: zconf.h:517
#define OF(args)
Definition: zconf.h:295
#define z_off64_t
Definition: zconf.h:526
unsigned long z_size_t
Definition: zconf.h:253