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Diffstat (limited to '')
-rw-r--r-- | libraries/irrlicht-1.8/source/Irrlicht/zlib/adler32.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/libraries/irrlicht-1.8/source/Irrlicht/zlib/adler32.c b/libraries/irrlicht-1.8/source/Irrlicht/zlib/adler32.c new file mode 100644 index 0000000..003d373 --- /dev/null +++ b/libraries/irrlicht-1.8/source/Irrlicht/zlib/adler32.c | |||
@@ -0,0 +1,179 @@ | |||
1 | /* adler32.c -- compute the Adler-32 checksum of a data stream | ||
2 | * Copyright (C) 1995-2011 Mark Adler | ||
3 | * For conditions of distribution and use, see copyright notice in zlib.h | ||
4 | */ | ||
5 | |||
6 | /* @(#) $Id$ */ | ||
7 | |||
8 | #include "zutil.h" | ||
9 | |||
10 | #define local static | ||
11 | |||
12 | local uLong adler32_combine_ OF((uLong adler1, uLong adler2, z_off64_t len2)); | ||
13 | |||
14 | #define BASE 65521 /* largest prime smaller than 65536 */ | ||
15 | #define NMAX 5552 | ||
16 | /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */ | ||
17 | |||
18 | #define DO1(buf,i) {adler += (buf)[i]; sum2 += adler;} | ||
19 | #define DO2(buf,i) DO1(buf,i); DO1(buf,i+1); | ||
20 | #define DO4(buf,i) DO2(buf,i); DO2(buf,i+2); | ||
21 | #define DO8(buf,i) DO4(buf,i); DO4(buf,i+4); | ||
22 | #define DO16(buf) DO8(buf,0); DO8(buf,8); | ||
23 | |||
24 | /* use NO_DIVIDE if your processor does not do division in hardware -- | ||
25 | try it both ways to see which is faster */ | ||
26 | #ifdef NO_DIVIDE | ||
27 | /* note that this assumes BASE is 65521, where 65536 % 65521 == 15 | ||
28 | (thank you to John Reiser for pointing this out) */ | ||
29 | # define CHOP(a) \ | ||
30 | do { \ | ||
31 | unsigned long tmp = a >> 16; \ | ||
32 | a &= 0xffffUL; \ | ||
33 | a += (tmp << 4) - tmp; \ | ||
34 | } while (0) | ||
35 | # define MOD28(a) \ | ||
36 | do { \ | ||
37 | CHOP(a); \ | ||
38 | if (a >= BASE) a -= BASE; \ | ||
39 | } while (0) | ||
40 | # define MOD(a) \ | ||
41 | do { \ | ||
42 | CHOP(a); \ | ||
43 | MOD28(a); \ | ||
44 | } while (0) | ||
45 | # define MOD63(a) \ | ||
46 | do { /* this assumes a is not negative */ \ | ||
47 | z_off64_t tmp = a >> 32; \ | ||
48 | a &= 0xffffffffL; \ | ||
49 | a += (tmp << 8) - (tmp << 5) + tmp; \ | ||
50 | tmp = a >> 16; \ | ||
51 | a &= 0xffffL; \ | ||
52 | a += (tmp << 4) - tmp; \ | ||
53 | tmp = a >> 16; \ | ||
54 | a &= 0xffffL; \ | ||
55 | a += (tmp << 4) - tmp; \ | ||
56 | if (a >= BASE) a -= BASE; \ | ||
57 | } while (0) | ||
58 | #else | ||
59 | # define MOD(a) a %= BASE | ||
60 | # define MOD28(a) a %= BASE | ||
61 | # define MOD63(a) a %= BASE | ||
62 | #endif | ||
63 | |||
64 | /* ========================================================================= */ | ||
65 | uLong ZEXPORT adler32(adler, buf, len) | ||
66 | uLong adler; | ||
67 | const Bytef *buf; | ||
68 | uInt len; | ||
69 | { | ||
70 | unsigned long sum2; | ||
71 | unsigned n; | ||
72 | |||
73 | /* split Adler-32 into component sums */ | ||
74 | sum2 = (adler >> 16) & 0xffff; | ||
75 | adler &= 0xffff; | ||
76 | |||
77 | /* in case user likes doing a byte at a time, keep it fast */ | ||
78 | if (len == 1) { | ||
79 | adler += buf[0]; | ||
80 | if (adler >= BASE) | ||
81 | adler -= BASE; | ||
82 | sum2 += adler; | ||
83 | if (sum2 >= BASE) | ||
84 | sum2 -= BASE; | ||
85 | return adler | (sum2 << 16); | ||
86 | } | ||
87 | |||
88 | /* initial Adler-32 value (deferred check for len == 1 speed) */ | ||
89 | if (buf == Z_NULL) | ||
90 | return 1L; | ||
91 | |||
92 | /* in case short lengths are provided, keep it somewhat fast */ | ||
93 | if (len < 16) { | ||
94 | while (len--) { | ||
95 | adler += *buf++; | ||
96 | sum2 += adler; | ||
97 | } | ||
98 | if (adler >= BASE) | ||
99 | adler -= BASE; | ||
100 | MOD28(sum2); /* only added so many BASE's */ | ||
101 | return adler | (sum2 << 16); | ||
102 | } | ||
103 | |||
104 | /* do length NMAX blocks -- requires just one modulo operation */ | ||
105 | while (len >= NMAX) { | ||
106 | len -= NMAX; | ||
107 | n = NMAX / 16; /* NMAX is divisible by 16 */ | ||
108 | do { | ||
109 | DO16(buf); /* 16 sums unrolled */ | ||
110 | buf += 16; | ||
111 | } while (--n); | ||
112 | MOD(adler); | ||
113 | MOD(sum2); | ||
114 | } | ||
115 | |||
116 | /* do remaining bytes (less than NMAX, still just one modulo) */ | ||
117 | if (len) { /* avoid modulos if none remaining */ | ||
118 | while (len >= 16) { | ||
119 | len -= 16; | ||
120 | DO16(buf); | ||
121 | buf += 16; | ||
122 | } | ||
123 | while (len--) { | ||
124 | adler += *buf++; | ||
125 | sum2 += adler; | ||
126 | } | ||
127 | MOD(adler); | ||
128 | MOD(sum2); | ||
129 | } | ||
130 | |||
131 | /* return recombined sums */ | ||
132 | return adler | (sum2 << 16); | ||
133 | } | ||
134 | |||
135 | /* ========================================================================= */ | ||
136 | local uLong adler32_combine_(adler1, adler2, len2) | ||
137 | uLong adler1; | ||
138 | uLong adler2; | ||
139 | z_off64_t len2; | ||
140 | { | ||
141 | unsigned long sum1; | ||
142 | unsigned long sum2; | ||
143 | unsigned rem; | ||
144 | |||
145 | /* for negative len, return invalid adler32 as a clue for debugging */ | ||
146 | if (len2 < 0) | ||
147 | return 0xffffffffUL; | ||
148 | |||
149 | /* the derivation of this formula is left as an exercise for the reader */ | ||
150 | MOD63(len2); /* assumes len2 >= 0 */ | ||
151 | rem = (unsigned)len2; | ||
152 | sum1 = adler1 & 0xffff; | ||
153 | sum2 = rem * sum1; | ||
154 | MOD(sum2); | ||
155 | sum1 += (adler2 & 0xffff) + BASE - 1; | ||
156 | sum2 += ((adler1 >> 16) & 0xffff) + ((adler2 >> 16) & 0xffff) + BASE - rem; | ||
157 | if (sum1 >= BASE) sum1 -= BASE; | ||
158 | if (sum1 >= BASE) sum1 -= BASE; | ||
159 | if (sum2 >= (BASE << 1)) sum2 -= (BASE << 1); | ||
160 | if (sum2 >= BASE) sum2 -= BASE; | ||
161 | return sum1 | (sum2 << 16); | ||
162 | } | ||
163 | |||
164 | /* ========================================================================= */ | ||
165 | uLong ZEXPORT adler32_combine(adler1, adler2, len2) | ||
166 | uLong adler1; | ||
167 | uLong adler2; | ||
168 | z_off_t len2; | ||
169 | { | ||
170 | return adler32_combine_(adler1, adler2, len2); | ||
171 | } | ||
172 | |||
173 | uLong ZEXPORT adler32_combine64(adler1, adler2, len2) | ||
174 | uLong adler1; | ||
175 | uLong adler2; | ||
176 | z_off64_t len2; | ||
177 | { | ||
178 | return adler32_combine_(adler1, adler2, len2); | ||
179 | } | ||