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root/svn/ircd-hybrid/branches/8.2.x/src/rng_mt.c
Revision: 3880
Committed: Fri Jun 6 16:40:19 2014 UTC (9 years, 9 months ago) by michael
Content type: text/x-csrc
File size: 4916 byte(s)
Log Message:
- rng_mt.c: removed trailing whitespaces

File Contents

# Content
1 /*
2 A C-program for MT19937, with initialization improved 2002/1/26.
3 Coded by Takuji Nishimura and Makoto Matsumoto.
4
5 Before using, initialize the state by using init_genrand(seed)
6 or init_by_array(init_key, key_length).
7
8 Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
9 All rights reserved.
10
11 Redistribution and use in source and binary forms, with or without
12 modification, are permitted provided that the following conditions
13 are met:
14
15 1. Redistributions of source code must retain the above copyright
16 notice, this list of conditions and the following disclaimer.
17
18 2. Redistributions in binary form must reproduce the above copyright
19 notice, this list of conditions and the following disclaimer in the
20 documentation and/or other materials provided with the distribution.
21
22 3. The names of its contributors may not be used to endorse or promote
23 products derived from this software without specific prior written
24 permission.
25
26 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
27 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
28 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
29 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
30 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
31 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
32 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37
38
39 Any feedback is very welcome.
40 http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
41 email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
42
43 $Id$
44 */
45
46 #include "stdinc.h"
47 #include "rng_mt.h"
48
49 /* Period parameters */
50 #define N 624
51 #define M 397
52 #define MATRIX_A 0x9908b0dfU /* constant vector a */
53 #define UPPER_MASK 0x80000000U /* most significant w-r bits */
54 #define LOWER_MASK 0x7fffffffU /* least significant r bits */
55
56 static uint32_t mt[N]; /* the array for the state vector */
57 static int mti = N + 1; /* mti==N+1 means mt[N] is not initialized */
58
59 /* initializes mt[N] with a seed */
60 void
61 init_genrand(uint32_t s)
62 {
63 mt[0] = s & 0xffffffffU;
64
65 for (mti = 1; mti < N; mti++)
66 {
67 mt[mti] = (1812433253U * (mt[mti - 1] ^ (mt[mti - 1] >> 30)) + mti);
68 /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
69 /* In the previous versions, MSBs of the seed affect */
70 /* only MSBs of the array mt[]. */
71 /* 2002/01/09 modified by Makoto Matsumoto */
72 mt[mti] &= 0xffffffffU;
73 /* for >32 bit machines */
74 }
75 }
76
77 /* initialize by an array with array-length */
78 /* init_key is the array for initializing keys */
79 /* key_length is its length */
80 /* slight change for C++, 2004/2/26 */
81 void
82 init_by_array(uint32_t init_key[], int key_length)
83 {
84 int i, j, k;
85
86 init_genrand(19650218U);
87
88 i = 1; j = 0;
89 k = (N > key_length ? N : key_length);
90
91 for (; k; k--)
92 {
93 mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1664525U))
94 + init_key[j] + j; /* non linear */
95 mt[i] &= 0xffffffffU; /* for WORDSIZE > 32 machines */
96 i++; j++;
97
98 if (i >= N)
99 {
100 mt[0] = mt[N - 1];
101 i = 1;
102 }
103
104 if (j >= key_length)
105 j = 0;
106 }
107
108 for (k = N - 1; k; k--)
109 {
110 mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >> 30)) * 1566083941U))
111 - i; /* non linear */
112 mt[i] &= 0xffffffffU; /* for WORDSIZE > 32 machines */
113 i++;
114
115 if (i >= N)
116 {
117 mt[0] = mt[N - 1];
118 i = 1;
119 }
120 }
121
122 mt[0] = 0x80000000U; /* MSB is 1; assuring non-zero initial array */
123 }
124
125 /* generates a random number on [0,0xffffffff]-interval */
126 uint32_t
127 genrand_int32(void)
128 {
129 uint32_t y;
130 static uint32_t mag01[2] = { 0x0U, MATRIX_A };
131 /* mag01[x] = x * MATRIX_A for x=0,1 */
132
133 if (mti >= N)
134 { /* generate N words at one time */
135 int kk;
136
137 if (mti == N + 1) /* if init_genrand() has not been called, */
138 init_genrand(5489U); /* a default initial seed is used */
139
140 for (kk = 0; kk < N - M; kk++)
141 {
142 y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
143 mt[kk] = mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x1U];
144 }
145
146 for (; kk < N - 1; kk++)
147 {
148 y = (mt[kk] & UPPER_MASK) | (mt[kk + 1] & LOWER_MASK);
149 mt[kk] = mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x1U];
150 }
151
152 y = (mt[N - 1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
153 mt[N - 1] = mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x1U];
154
155 mti = 0;
156 }
157
158 y = mt[mti++];
159
160 /* Tempering */
161 y ^= (y >> 11);
162 y ^= (y << 7) & 0x9d2c5680U;
163 y ^= (y << 15) & 0xefc60000U;
164 y ^= (y >> 18);
165
166 return y;
167 }

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svn:keywords Id Revision