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de71615260
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@598 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
152 lines
2.7 KiB
C
152 lines
2.7 KiB
C
/************************************************
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random.c -
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$Author$
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$Date$
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created at: Fri Dec 24 16:39:21 JST 1993
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Copyright (C) 1993-2000 Yukihiro Matsumoto
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************************************************/
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#include "ruby.h"
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <time.h>
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#ifndef NT
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#ifdef HAVE_SYS_TIME_H
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# include <sys/time.h>
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#else
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struct timeval {
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long tv_sec; /* seconds */
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long tv_usec; /* and microseconds */
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};
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#endif
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#endif /* NT */
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#ifdef HAVE_STDLIB_H
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# include <stdlib.h>
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#endif
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/*
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* Prefer to use drand48, otherwise use random, or rand as a last resort.
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*/
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#ifdef HAVE_DRAND48
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#ifndef HAVE_DRAND48_DECL
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double drand48 _((void));
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void srand48 _((long));
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#endif
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#define SRANDOM(s) srand48((long)(s))
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#define RANDOM_NUMBER drand48()
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#else /* not HAVE_DRAND48 */
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/*
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* The largest number returned by the random number generator is
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* RANDOM_MAX. If we're using `rand' it's RAND_MAX, but if we're
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* using `random' it's 2^31-1.
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*/
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#ifndef RANDOM_MAX
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# ifndef HAVE_RANDOM
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# define RANDOM_MAX RAND_MAX
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# else
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# define RANDOM_MAX 2147483647.0
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# endif
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#endif
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#ifdef HAVE_RANDOM
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#define RANDOM random
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#define SRANDOM srandom
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#else /* HAVE_RANDOM */
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#define RANDOM rand
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#define SRANDOM srand
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#endif /* HAVE_RANDOM */
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/* 0 <= RANDOM_NUMBER <= 1 */
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#define RANDOM_NUMBER (((double)RANDOM())/((double)RANDOM_MAX+1))
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#endif /* not HAVE_DRAND48 */
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#ifdef HAVE_RANDOM
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static int first = 1;
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static char state[256];
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#endif
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static VALUE
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rb_f_srand(argc, argv, obj)
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int argc;
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VALUE *argv;
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VALUE obj;
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{
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VALUE a;
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unsigned int seed, old;
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static unsigned int saved_seed;
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if (rb_scan_args(argc, argv, "01", &a) == 0) {
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static int n = 0;
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struct timeval tv;
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gettimeofday(&tv, 0);
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seed = tv.tv_sec ^ tv.tv_usec ^ getpid() ^ n++;
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}
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else {
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seed = NUM2UINT(a);
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}
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#ifdef HAVE_RANDOM
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if (first == 1) {
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initstate(1, state, sizeof state);
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first = 0;
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}
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else {
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setstate(state);
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}
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#endif
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SRANDOM(seed);
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old = saved_seed;
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saved_seed = seed;
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return rb_uint2inum(old);
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}
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static VALUE
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rb_f_rand(obj, vmax)
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VALUE obj, vmax;
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{
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long val, max;
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switch (TYPE(vmax)) {
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case T_FLOAT:
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if (RFLOAT(vmax)->value <= LONG_MAX && RFLOAT(vmax)->value >= LONG_MIN)
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break;
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/* fall through */
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case T_BIGNUM:
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return rb_big_rand(vmax, RANDOM_NUMBER);
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}
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max = NUM2LONG(vmax);
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if (max == 0) {
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return rb_float_new(RANDOM_NUMBER);
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}
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val = max*RANDOM_NUMBER;
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if (val < 0) val = -val;
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return rb_int2inum(val);
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}
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void
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Init_Random()
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{
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rb_define_global_function("srand", rb_f_srand, -1);
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rb_define_global_function("rand", rb_f_rand, 1);
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}
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