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1
2 /*
3 * M_APM - mapm_rnd.c
4 *
5 * Copyright (C) 1999 - 2007 Michael C. Ring
6 *
7 * Permission to use, copy, and distribute this software and its
8 * documentation for any purpose with or without fee is hereby granted,
9 * provided that the above copyright notice appear in all copies and
10 * that both that copyright notice and this permission notice appear
11 * in supporting documentation.
12 *
13 * Permission to modify the software is granted. Permission to distribute
14 * the modified code is granted. Modifications are to be distributed by
15 * using the file 'license.txt' as a template to modify the file header.
16 * 'license.txt' is available in the official MAPM distribution.
17 *
18 * This software is provided "as is" without express or implied warranty.
19 */
20
21 /*
22 * $Id: mapm_rnd.c,v 1.12 2007/12/03 01:47:17 mike Exp $
23 *
24 * This file contains the Random Number Generator function.
25 *
26 * $Log: mapm_rnd.c,v $
27 * Revision 1.12 2007/12/03 01:47:17 mike
28 * Update license
29 *
30 * Revision 1.11 2003/10/25 22:55:43 mike
31 * add support for National Instruments LabWindows CVI
32 *
33 * Revision 1.10 2002/11/03 22:41:03 mike
34 * Updated function parameters to use the modern style
35 *
36 * Revision 1.9 2002/02/14 21:50:45 mike
37 * add _set_random_seed
38 *
39 * Revision 1.8 2001/07/16 19:30:32 mike
40 * add function M_free_all_rnd
41 *
42 * Revision 1.7 2001/03/20 17:19:45 mike
43 * use a new multiplier
44 *
45 * Revision 1.6 2000/08/20 23:46:07 mike
46 * add more possible multupliers (no code changes)
47 *
48 * Revision 1.5 1999/09/19 23:32:14 mike
49 * added comments
50 *
51 * Revision 1.4 1999/09/18 03:49:25 mike
52 * *** empty log message ***
53 *
54 * Revision 1.3 1999/09/18 03:35:36 mike
55 * only prototype get_microsec for non-DOS
56 *
57 * Revision 1.2 1999/09/18 02:35:36 mike
58 * delete debug printf's
59 *
60 * Revision 1.1 1999/09/18 02:26:52 mike
61 * Initial revision
62 */
63
64 #include "m_apm_lc.h"
65
66 #ifndef _HAVE_NI_LABWIN_CVI_
67 #ifdef MSDOS
68 #include <time.h>
69 #include <sys/timeb.h>
70 #else
71 #include <sys/time.h>
72 extern void M_get_microsec(unsigned long *, long *);
73 #endif
74 #endif
75
76 #ifdef _HAVE_NI_LABWIN_CVI_
77 #include <time.h>
78 #include <utility.h>
79 #include <ansi/math.h>
80 #endif
81
82 extern void M_reverse_string(char *);
83 extern void M_get_rnd_seed(M_APM);
84
85 static M_APM M_rnd_aa;
86 static M_APM M_rnd_mm;
87 static M_APM M_rnd_XX;
88 static M_APM M_rtmp0;
89 static M_APM M_rtmp1;
90
91 static int M_firsttime2 = TRUE;
92
93 /*
94 Used Knuth's The Art of Computer Programming, Volume 2 as
95 the basis. Assuming the random number is X, compute
96 (where all the math is performed on integers) :
97
98 X = (a * X + c) MOD m
99
100 From Knuth:
101
102 'm' should be large, at least 2^30 : we use 1.0E+15
103
104 'a' should be between .01m and .99m and not have a simple
105 pattern. 'a' should not have any large factors in common
106 with 'm' and (since 'm' is a power of 10) if 'a' MOD 200
107 = 21 then all 'm' different possible values will be
108 generated before 'X' starts to repeat.
109
110 We use 'a' = 716805947629621.
111
112 This is a prime number and also meets 'a' MOD 200 = 21.
113 Commented out below are many potential multipliers that
114 are all prime and meet 'a' MOD 200 = 21.
115
116 There are few restrictions on 'c' except 'c' can have no
117 factor in common with 'm', hence we set 'c' = 'a'.
118
119 On the first call, the system time is used to initialize X.
120 */
121
122 /*
123 * the following constants are all potential multipliers. they are
124 * all prime numbers that also meet the criteria of NUM mod 200 = 21.
125 */
126
127 /*
128 439682071525421 439682071528421 439682071529221 439682071529821
129 439682071530421 439682071532021 439682071538821 439682071539421
130 439682071540021 439682071547021 439682071551221 439682071553821
131 439682071555421 439682071557221 439682071558021 439682071558621
132 439682071559821 439652381461621 439652381465221 439652381465621
133 439652381466421 439652381467421 439652381468621 439652381470021
134 439652381471221 439652381477021 439652381484221 439652381488421
135 439652381491021 439652381492021 439652381494021 439652381496821
136 617294387035621 617294387038621 617294387039221 617294387044421
137 617294387045221 617294387048621 617294387051621 617294387051821
138 617294387053621 617294387058421 617294387064221 617294387065621
139 617294387068621 617294387069221 617294387069821 617294387070421
140 617294387072021 617294387072621 617294387073821 617294387076821
141 649378126517621 649378126517821 649378126518221 649378126520821
142 649378126523821 649378126525621 649378126526621 649378126528421
143 649378126529621 649378126530821 649378126532221 649378126533221
144 649378126535221 649378126539421 649378126543621 649378126546021
145 649378126546421 649378126549421 649378126550821 649378126555021
146 649378126557421 649378126560221 649378126561621 649378126562021
147 649378126564621 649378126565821 672091582360421 672091582364221
148 672091582364621 672091582367021 672091582368421 672091582369021
149 672091582370821 672091582371421 672091582376821 672091582380821
150 716805243983221 716805243984821 716805947623621 716805947624621
151 716805947629021 716805947629621 716805947630621 716805947633621
152 716805947634221 716805947635021 716805947635621 716805947642221
153 */
154
155 /****************************************************************************/
156 void M_free_all_rnd()
157 {
158 if (M_firsttime2 == FALSE)
159 {
160 m_apm_free(M_rnd_aa);
161 m_apm_free(M_rnd_mm);
162 m_apm_free(M_rnd_XX);
163 m_apm_free(M_rtmp0);
164 m_apm_free(M_rtmp1);
165
166 M_firsttime2 = TRUE;
167 }
168 }
169 /****************************************************************************/
170 void m_apm_set_random_seed(char *ss)
171 {
172 M_APM btmp;
173
174 if (M_firsttime2)
175 {
176 btmp = M_get_stack_var();
177 m_apm_get_random(btmp);
178 M_restore_stack(1);
179 }
180
181 m_apm_set_string(M_rnd_XX, ss);
182 }
183 /****************************************************************************/
184 /*
185 * compute X = (a * X + c) MOD m where c = a
186 */
187 void m_apm_get_random(M_APM mrnd)
188 {
189
190 if (M_firsttime2) /* use the system time as the initial seed value */
191 {
192 M_firsttime2 = FALSE;
193
194 M_rnd_aa = m_apm_init();
195 M_rnd_XX = m_apm_init();
196 M_rnd_mm = m_apm_init();
197 M_rtmp0 = m_apm_init();
198 M_rtmp1 = m_apm_init();
199
200 /* set the multiplier M_rnd_aa and M_rnd_mm */
201
202 m_apm_set_string(M_rnd_aa, "716805947629621");
203 m_apm_set_string(M_rnd_mm, "1.0E15");
204
205 M_get_rnd_seed(M_rnd_XX);
206 }
207
208 m_apm_multiply(M_rtmp0, M_rnd_XX, M_rnd_aa);
209 m_apm_add(M_rtmp1, M_rtmp0, M_rnd_aa);
210 m_apm_integer_div_rem(M_rtmp0, M_rnd_XX, M_rtmp1, M_rnd_mm);
211 m_apm_copy(mrnd, M_rnd_XX);
212 mrnd->m_apm_exponent -= 15;
213 }
214 /****************************************************************************/
215 void M_reverse_string(char *s)
216 {
217 int ct;
218 char ch, *p1, *p2;
219
220 if ((ct = strlen(s)) <= 1)
221 return;
222
223 p1 = s;
224 p2 = s + ct - 1;
225 ct /= 2;
226
227 while (TRUE)
228 {
229 ch = *p1;
230 *p1++ = *p2;
231 *p2-- = ch;
232
233 if (--ct == 0)
234 break;
235 }
236 }
237 /****************************************************************************/
238
239 #ifndef _HAVE_NI_LABWIN_CVI_
240
241 #ifdef MSDOS
242
243 /****************************************************************************/
244 /*
245 * for DOS / Win 9x/NT systems : use 'ftime'
246 */
247 void M_get_rnd_seed(M_APM mm)
248 {
249 int millisec;
250 time_t timestamp;
251 unsigned long ul;
252 char ss[32], buf1[48], buf2[32];
253 struct timeb timebuffer;
254 M_APM atmp;
255
256 atmp = M_get_stack_var();
257
258 ftime(&timebuffer);
259
260 millisec = (int)timebuffer.millitm;
261 timestamp = timebuffer.time;
262 ul = (unsigned long)(timestamp / 7);
263 ul += timestamp + 537;
264 strcpy(ss,ctime(×tamp)); /* convert to string and copy to ss */
265
266 sprintf(buf1,"%d",(millisec / 10));
267 sprintf(buf2,"%lu",ul);
268
269 ss[0] = ss[18];
270 ss[1] = ss[17];
271 ss[2] = ss[15];
272 ss[3] = ss[14];
273 ss[4] = ss[12];
274 ss[5] = ss[11];
275 ss[6] = ss[9];
276 ss[7] = ss[23];
277 ss[8] = ss[20];
278 ss[9] = '\0';
279
280 M_reverse_string(buf2);
281 strcat(buf1,buf2);
282 strcat(buf1,ss);
283
284 m_apm_set_string(atmp, buf1);
285 atmp->m_apm_exponent = 15;
286 m_apm_integer_divide(mm, atmp, MM_One);
287
288 M_restore_stack(1);
289 }
290 /****************************************************************************/
291
292 #else
293
294 /****************************************************************************/
295 /*
296 * for unix systems : use 'gettimeofday'
297 */
298 void M_get_rnd_seed(M_APM mm)
299 {
300 unsigned long sec3;
301 long usec3;
302 char buf1[32], buf2[32];
303 M_APM atmp;
304
305 atmp = M_get_stack_var();
306 M_get_microsec(&sec3,&usec3);
307
308 sprintf(buf1,"%ld",usec3);
309 sprintf(buf2,"%lu",sec3);
310 M_reverse_string(buf2);
311 strcat(buf1,buf2);
312
313 m_apm_set_string(atmp, buf1);
314 atmp->m_apm_exponent = 15;
315 m_apm_integer_divide(mm, atmp, MM_One);
316
317 M_restore_stack(1);
318 }
319 /****************************************************************************/
320 void M_get_microsec(unsigned long *sec, long *usec)
321 {
322 struct timeval time_now; /* current time for elapsed time check */
323 struct timezone time_zone; /* time zone for gettimeofday call */
324
325 gettimeofday(&time_now, &time_zone); /* get current time */
326
327 *sec = time_now.tv_sec;
328 *usec = time_now.tv_usec;
329 }
330 /****************************************************************************/
331
332 #endif
333 #endif
334
335 #ifdef _HAVE_NI_LABWIN_CVI_
336
337 /****************************************************************************/
338 /*
339 * for National Instruments LabWindows CVI
340 */
341
342 void M_get_rnd_seed(M_APM mm)
343 {
344 double timer0;
345 int millisec;
346 char *cvi_time, *cvi_date, buf1[64], buf2[32];
347 M_APM atmp;
348
349 atmp = M_get_stack_var();
350
351 cvi_date = DateStr();
352 cvi_time = TimeStr();
353 timer0 = Timer();
354
355 /*
356 * note that Timer() is not syncronized to TimeStr(),
357 * but we don't care here since we are just looking
358 * for a random source of digits.
359 */
360
361 millisec = (int)(0.01 + 1000.0 * (timer0 - floor(timer0)));
362
363 sprintf(buf1, "%d", millisec);
364
365 buf2[0] = cvi_time[6]; /* time format: "HH:MM:SS" */
366 buf2[1] = cvi_time[7];
367 buf2[2] = cvi_time[3];
368 buf2[3] = cvi_time[4];
369 buf2[4] = cvi_time[0];
370 buf2[5] = cvi_time[1];
371
372 buf2[6] = cvi_date[3]; /* date format: "MM-DD-YYYY" */
373 buf2[7] = cvi_date[4];
374 buf2[8] = cvi_date[0];
375 buf2[9] = cvi_date[1];
376 buf2[10] = cvi_date[8];
377 buf2[11] = cvi_date[9];
378 buf2[12] = cvi_date[7];
379
380 buf2[13] = '4';
381 buf2[14] = '7';
382 buf2[15] = '\0';
383
384 strcat(buf1, buf2);
385
386 m_apm_set_string(atmp, buf1);
387 atmp->m_apm_exponent = 15;
388 m_apm_integer_divide(mm, atmp, MM_One);
389
390 M_restore_stack(1);
391 }
392
393 #endif
394
395 /****************************************************************************/
396