c_cpp/etc/calc/sample_many.c

   1 /*
   2  * sample_many - generate many random values via random number generator
   3  *
   4  * Copyright (C) 1999-2007  Landon Curt Noll
   5  *
   6  * Calc is open software; you can redistribute it and/or modify it under
   7  * the terms of the version 2.1 of the GNU Lesser General Public License
   8  * as published by the Free Software Foundation.
   9  *
  10  * Calc is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
  13  * Public License for more details.
  14  *
  15  * A copy of version 2.1 of the GNU Lesser General Public License is
  16  * distributed with calc under the filename COPYING-LGPL.  You should have
  17  * received a copy with calc; if not, write to Free Software Foundation, Inc.
  18  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  19  *
  20  * @(#) $Revision: 30.1 $
  21  * @(#) $Id: sample_many.c,v 30.1 2007/03/16 11:09:46 chongo Exp $
  22  * @(#) $Source: /usr/local/src/bin/calc/RCS/sample_many.c,v $
  23  *
  24  * Under source code control:   1997/04/19 22:46:49
  25  * File existed as early as:    1997
  26  *
  27  * chongo <was here> /\oo/\     http://www.isthe.com/chongo/
  28  * Share and enjoy!  :-)        http://www.isthe.com/chongo/tech/comp/calc/
  29  */
  30
  31 /*
  32  * usage:
  33  *      many_random [[bits] seed_string]
  34  *
  35  *      seed_string     something for which we can seed (def: default seed)
  36  *      bits            number of bits to generate
  37  */
  38
  39
  40 #include <sys/types.h>
  41 #include <stdio.h>
  42 #include "calc.h"
  43 #include "zrandom.h"
  44 #include "have_const.h"
  45 #include "lib_util.h"
  46
  47 #define DEF_CNT 128     /* default number of bits to generate */
  48 #define RESEED 1000     /* number of random numbers to generate */
  49 #define MANY 100        /* number of random numbers to generate */
  50
  51 extern char *program;   /* our name */
  52
  53
  54 int
  55 main(int argc, char **argv)
  56 {
  57         RANDOM *prev_state;     /* previous random number state */
  58         ZVALUE seed;            /* seed for Blum-Blum-Shub */
  59         ZVALUE tmp;             /* temp value */
  60         ZVALUE tmp2;            /* temp value */
  61         ZVALUE random_val;      /* random number produced */
  62         long cnt;               /* number of bits to generate */
  63         char *hexstr;           /* random number as hex string */
  64         int i;
  65         int j;
  66
  67         /*
  68          * parse args
  69          */
  70         program = argv[0];
  71         switch (argc) {
  72         case 3:
  73                 seed = convstr2z(argv[2]);
  74                 cnt = strtol(argv[1], NULL, 0);
  75                 break;
  76         case 2:
  77                 seed = _zero_;  /* use the default seed */
  78                 cnt = strtol(argv[1], NULL, 0);
  79                 break;
  80         case 1:
  81                 seed = _zero_;  /* use the default seed */
  82                 cnt = DEF_CNT;
  83                 break;
  84         default:
  85                 fprintf(stderr, "usage: %s [[bits] seed_string]\n", program);
  86                 exit(1);
  87         }
  88         if (cnt <= 0) {
  89                 fprintf(stderr, "%s: cnt:%d must be > 0\n", program, (int)cnt);
  90                 exit(2);
  91         }
  92
  93         /*
  94          * libcalc setup
  95          */
  96         libcalc_call_me_first();
  97
  98         /*
  99          * reseed every so often
 100          */
 101         for (j=0; j < RESEED; ++j) {
 102
 103                 /*
 104                  * seed the generator
 105                  */
 106                 prev_state = zsrandom2(seed, zconst[1]);
 107                 if (prev_state == NULL) {
 108                         math_error("previous random state is NULL");
 109                         /*NOTREACHED*/
 110                 }
 111                 randomfree(prev_state);
 112
 113                 /*
 114                  * generate random values forever
 115                  */
 116                 for (i=0; i < MANY; ++i) {
 117
 118                         /*
 119                          * generate random bits
 120                          */
 121                         zrandom(cnt, &random_val);
 122
 123                         /*
 124                          * convert into hex string
 125                          */
 126                         hexstr = convz2hex(random_val);
 127                         printf("%s\n", hexstr);
 128
 129                         /*
 130                          * free
 131                          */
 132                         if (i < MANY-1) {
 133                                 zfree(random_val);
 134                         }
 135                         free(hexstr);
 136                 }
 137
 138                 /*
 139                  * increment the seed to better test different seeds
 140                  *
 141                  * NOTE: It is generally a bad idea to use the
 142                  *       same random number generator to modify
 143                  *       the seed.  We only do this below to
 144                  *       try different seeds for debugging.
 145                  *
 146                  *       Don't do this in real life applications!
 147                  *
 148                  * We want to add at least 2^32 to the seed, so
 149                  * we do the effect of:
 150                  *
 151                  *      seed += ((last_val<<32) + last_val);
 152                  */
 153                 zshift(random_val, 32, &tmp);
 154                 zadd(tmp, random_val, &tmp2);
 155                 zfree(random_val);
 156                 zfree(tmp);
 157                 zadd(seed, tmp2, &tmp);
 158                 zfree(tmp2);
 159                 zfree(seed);
 160                 seed = tmp;
 161         }
 162
 163         /*
 164          * libcalc shutdown
 165          */
 166         libcalc_call_me_last();
 167
 168         /*
 169          * all done
 170          */
 171         /* exit(0); */
 172         return 0;
 173 }