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2a0c02c27d
Cheung <fred at 82ask.com>. [ruby-talk:216047] git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@11014 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
491 lines
14 KiB
C
491 lines
14 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) 1993-2003 Yukihiro Matsumoto
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**********************************************************************/
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/*
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This is based on trimmed version of MT19937. To get the original version,
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contact <http://www.math.keio.ac.jp/~matumoto/emt.html>.
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The original copyright notice follows.
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A C-program for MT19937, with initialization improved 2002/2/10.
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Coded by Takuji Nishimura and Makoto Matsumoto.
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This is a faster version by taking Shawn Cokus's optimization,
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Matthe Bellew's simplification, Isaku Wada's real version.
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Before using, initialize the state by using init_genrand(seed)
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or init_by_array(init_key, key_length).
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Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. The names of its contributors may not be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Any feedback is very welcome.
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http://www.math.keio.ac.jp/matumoto/emt.html
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email: matumoto@math.keio.ac.jp
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*/
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/* Period parameters */
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#define N 624
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#define M 397
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#define MATRIX_A 0x9908b0dfUL /* constant vector a */
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#define UMASK 0x80000000UL /* most significant w-r bits */
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#define LMASK 0x7fffffffUL /* least significant r bits */
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#define MIXBITS(u,v) ( ((u) & UMASK) | ((v) & LMASK) )
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#define TWIST(u,v) ((MIXBITS(u,v) >> 1) ^ ((v)&1UL ? MATRIX_A : 0UL))
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static unsigned long state[N]; /* the array for the state vector */
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static int left = 1;
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static int initf = 0;
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static unsigned long *next;
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/* initializes state[N] with a seed */
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static void
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init_genrand(unsigned long s)
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{
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int j;
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state[0]= s & 0xffffffffUL;
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for (j=1; j<N; j++) {
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state[j] = (1812433253UL * (state[j-1] ^ (state[j-1] >> 30)) + j);
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/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
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/* In the previous versions, MSBs of the seed affect */
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/* only MSBs of the array state[]. */
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/* 2002/01/09 modified by Makoto Matsumoto */
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state[j] &= 0xffffffffUL; /* for >32 bit machines */
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}
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left = 1; initf = 1;
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}
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/* initialize by an array with array-length */
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/* init_key is the array for initializing keys */
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/* key_length is its length */
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/* slight change for C++, 2004/2/26 */
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static void
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init_by_array(unsigned long init_key[], int key_length)
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{
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int i, j, k;
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init_genrand(19650218UL);
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i=1; j=0;
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k = (N>key_length ? N : key_length);
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for (; k; k--) {
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state[i] = (state[i] ^ ((state[i-1] ^ (state[i-1] >> 30)) * 1664525UL))
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+ init_key[j] + j; /* non linear */
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state[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
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i++; j++;
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if (i>=N) { state[0] = state[N-1]; i=1; }
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if (j>=key_length) j=0;
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}
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for (k=N-1; k; k--) {
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state[i] = (state[i] ^ ((state[i-1] ^ (state[i-1] >> 30)) * 1566083941UL))
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- i; /* non linear */
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state[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
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i++;
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if (i>=N) { state[0] = state[N-1]; i=1; }
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}
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state[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
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left = 1; initf = 1;
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}
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static void
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next_state(void)
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{
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unsigned long *p=state;
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int j;
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/* if init_genrand() has not been called, */
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/* a default initial seed is used */
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if (initf==0) init_genrand(5489UL);
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left = N;
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next = state;
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for (j=N-M+1; --j; p++)
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*p = p[M] ^ TWIST(p[0], p[1]);
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for (j=M; --j; p++)
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*p = p[M-N] ^ TWIST(p[0], p[1]);
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*p = p[M-N] ^ TWIST(p[0], state[0]);
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}
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/* generates a random number on [0,0xffffffff]-interval */
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unsigned long
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genrand_int32(void)
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{
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unsigned long y;
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if (--left == 0) next_state();
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y = *next++;
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/* Tempering */
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y ^= (y >> 11);
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y ^= (y << 7) & 0x9d2c5680UL;
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y ^= (y << 15) & 0xefc60000UL;
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y ^= (y >> 18);
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return y;
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}
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/* generates a random number on [0,1) with 53-bit resolution*/
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double
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genrand_real(void)
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{
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unsigned long a=genrand_int32()>>5, b=genrand_int32()>>6;
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return(a*67108864.0+b)*(1.0/9007199254740992.0);
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}
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/* These real versions are due to Isaku Wada, 2002/01/09 added */
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#undef N
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#undef M
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/* These real versions are due to Isaku Wada, 2002/01/09 added */
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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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#include <sys/types.h>
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#include <sys/stat.h>
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#ifdef HAVE_FCNTL_H
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#include <fcntl.h>
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#endif
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static VALUE saved_seed = INT2FIX(0);
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static VALUE
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rand_init(VALUE vseed)
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{
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volatile VALUE seed;
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VALUE old;
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long len;
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unsigned long *buf;
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seed = rb_to_int(vseed);
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switch (TYPE(seed)) {
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case T_FIXNUM:
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len = sizeof(VALUE);
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break;
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case T_BIGNUM:
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len = RBIGNUM(seed)->len * SIZEOF_BDIGITS;
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if (len == 0)
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len = 4;
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break;
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default:
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rb_raise(rb_eTypeError, "failed to convert %s into Integer",
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rb_obj_classname(vseed));
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}
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len = (len + 3) / 4; /* number of 32bit words */
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buf = ALLOC_N(unsigned long, len); /* allocate longs for init_by_array */
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memset(buf, 0, len * sizeof(long));
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if (FIXNUM_P(seed)) {
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buf[0] = FIX2ULONG(seed) & 0xffffffff;
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#if SIZEOF_LONG > 4
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buf[1] = FIX2ULONG(seed) >> 32;
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#endif
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}
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else {
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int i, j;
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for (i = RBIGNUM(seed)->len-1; 0 <= i; i--) {
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j = i * SIZEOF_BDIGITS / 4;
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#if SIZEOF_BDIGITS < 4
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buf[j] <<= SIZEOF_BDIGITS * 8;
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#endif
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buf[j] |= ((BDIGIT *)RBIGNUM(seed)->digits)[i];
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}
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}
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while (1 < len && buf[len-1] == 0) {
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len--;
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}
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if (len <= 1) {
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init_genrand(buf[0]);
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}
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else {
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if (buf[len-1] == 1) /* remove leading-zero-guard */
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len--;
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init_by_array(buf, len);
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}
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old = saved_seed;
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saved_seed = seed;
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free(buf);
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return old;
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}
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static VALUE
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random_seed(void)
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{
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static int n = 0;
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struct timeval tv;
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int fd;
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struct stat statbuf;
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int seed_len;
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BDIGIT *digits;
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unsigned long *seed;
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NEWOBJ(big, struct RBignum);
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OBJSETUP(big, rb_cBignum, T_BIGNUM);
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seed_len = 4 * sizeof(long);
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big->sign = 1;
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big->len = seed_len / SIZEOF_BDIGITS + 1;
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digits = big->digits = ALLOC_N(BDIGIT, big->len);
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seed = (unsigned long *)big->digits;
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memset(digits, 0, big->len * SIZEOF_BDIGITS);
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#ifdef S_ISCHR
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if ((fd = open("/dev/urandom", O_RDONLY
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#ifdef O_NONBLOCK
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|O_NONBLOCK
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#endif
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#ifdef O_NOCTTY
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|O_NOCTTY
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#endif
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#ifdef O_NOFOLLOW
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|O_NOFOLLOW
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#endif
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)) >= 0) {
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if (fstat(fd, &statbuf) == 0 && S_ISCHR(statbuf.st_mode)) {
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read(fd, seed, seed_len);
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}
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close(fd);
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}
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#endif
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gettimeofday(&tv, 0);
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seed[0] ^= tv.tv_usec;
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seed[1] ^= tv.tv_sec;
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seed[2] ^= getpid() ^ (n++ << 16);
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seed[3] ^= (unsigned long)&seed;
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/* set leading-zero-guard if need. */
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digits[big->len-1] = digits[big->len-2] <= 1 ? 1 : 0;
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return rb_big_norm((VALUE)big);
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}
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/*
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* call-seq:
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* srand(number=0) => old_seed
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*
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* Seeds the pseudorandom number generator to the value of
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* <i>number</i>.<code>to_i.abs</code>. If <i>number</i> is omitted
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* or zero, seeds the generator using a combination of the time, the
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* process id, and a sequence number. (This is also the behavior if
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* <code>Kernel::rand</code> is called without previously calling
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* <code>srand</code>, but without the sequence.) By setting the seed
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* to a known value, scripts can be made deterministic during testing.
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* The previous seed value is returned. Also see <code>Kernel::rand</code>.
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*/
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static VALUE
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rb_f_srand(int argc, VALUE *argv, VALUE obj)
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{
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VALUE seed, old;
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rb_secure(4);
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if (rb_scan_args(argc, argv, "01", &seed) == 0) {
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seed = random_seed();
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}
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old = rand_init(seed);
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return old;
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}
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static unsigned long
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make_mask(unsigned long x)
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{
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x = x | x >> 1;
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x = x | x >> 2;
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x = x | x >> 4;
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x = x | x >> 8;
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x = x | x >> 16;
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#if 4 < SIZEOF_LONG
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x = x | x >> 32;
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#endif
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return x;
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}
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static unsigned long
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limited_rand(unsigned long limit)
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{
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unsigned long mask = make_mask(limit);
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int i;
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unsigned long val;
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retry:
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val = 0;
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for (i = SIZEOF_LONG/4-1; 0 <= i; i--) {
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if (mask >> (i * 32)) {
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val |= genrand_int32() << (i * 32);
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val &= mask;
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if (limit < val)
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goto retry;
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}
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}
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return val;
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}
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static VALUE
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limited_big_rand(struct RBignum *limit)
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{
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unsigned long mask, lim, rnd;
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struct RBignum *val;
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int i, len, boundary;
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len = (limit->len * SIZEOF_BDIGITS + 3) / 4;
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val = (struct RBignum *)rb_big_clone((VALUE)limit);
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val->sign = 1;
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#if SIZEOF_BDIGITS == 2
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# define BIG_GET32(big,i) (((BDIGIT *)(big)->digits)[(i)*2] | \
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((i)*2+1 < (big)->len ? (((BDIGIT *)(big)->digits)[(i)*2+1] << 16) \
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: 0))
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# define BIG_SET32(big,i,d) ((((BDIGIT *)(big)->digits)[(i)*2] = (d) & 0xffff), \
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((i)*2+1 < (big)->len ? (((BDIGIT *)(big)->digits)[(i)*2+1] = (d) >> 16) \
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: 0))
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#else
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/* SIZEOF_BDIGITS == 4 */
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# define BIG_GET32(big,i) (((BDIGIT *)(big)->digits)[i])
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# define BIG_SET32(big,i,d) (((BDIGIT *)(big)->digits)[i] = (d))
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#endif
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retry:
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mask = 0;
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boundary = 1;
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for (i = len-1; 0 <= i; i--) {
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lim = BIG_GET32(limit, i);
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mask = mask ? 0xffffffff : make_mask(lim);
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if (mask) {
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rnd = genrand_int32() & mask;
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if (boundary) {
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if (lim < rnd)
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goto retry;
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if (rnd < lim)
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boundary = 0;
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}
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}
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else {
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rnd = 0;
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}
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BIG_SET32(val, i, rnd);
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}
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return rb_big_norm((VALUE)val);
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}
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/*
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* call-seq:
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* rand(max=0) => number
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*
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* Converts <i>max</i> to an integer using max1 =
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* max<code>.to_i.abs</code>. If the result is zero, returns a
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* pseudorandom floating point number greater than or equal to 0.0 and
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* less than 1.0. Otherwise, returns a pseudorandom integer greater
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* than or equal to zero and less than max1. <code>Kernel::srand</code>
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* may be used to ensure repeatable sequences of random numbers between
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* different runs of the program. Ruby currently uses a modified
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* Mersenne Twister with a period of 2**19937-1.
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*
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* srand 1234 #=> 0
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* [ rand, rand ] #=> [0.191519450163469, 0.49766366626136]
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* [ rand(10), rand(1000) ] #=> [6, 817]
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* srand 1234 #=> 1234
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* [ rand, rand ] #=> [0.191519450163469, 0.49766366626136]
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*/
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static VALUE
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rb_f_rand(int argc, VALUE *argv, VALUE obj)
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{
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VALUE vmax;
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long val, max;
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rb_scan_args(argc, argv, "01", &vmax);
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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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max = (long)RFLOAT(vmax)->value;
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break;
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}
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if (RFLOAT(vmax)->value < 0)
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vmax = rb_dbl2big(-RFLOAT(vmax)->value);
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else
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vmax = rb_dbl2big(RFLOAT(vmax)->value);
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/* fall through */
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case T_BIGNUM:
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bignum:
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{
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struct RBignum *limit = (struct RBignum *)vmax;
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if (!limit->sign) {
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limit = (struct RBignum *)rb_big_clone(vmax);
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limit->sign = 1;
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}
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limit = (struct RBignum *)rb_big_minus((VALUE)limit, INT2FIX(1));
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if (FIXNUM_P((VALUE)limit)) {
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if (FIX2LONG((VALUE)limit) == -1)
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return rb_float_new(genrand_real());
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return LONG2NUM(limited_rand(FIX2LONG((VALUE)limit)));
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}
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return limited_big_rand(limit);
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}
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case T_NIL:
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max = 0;
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break;
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default:
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vmax = rb_Integer(vmax);
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if (TYPE(vmax) == T_BIGNUM) goto bignum;
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case T_FIXNUM:
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max = FIX2LONG(vmax);
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break;
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}
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if (max == 0) {
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return rb_float_new(genrand_real());
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}
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if (max < 0) max = -max;
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val = limited_rand(max-1);
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return LONG2NUM(val);
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}
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void
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Init_Random(void)
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{
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rand_init(random_seed());
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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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rb_global_variable(&saved_seed);
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}
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