+++ /dev/null
-/*-
- * Copyright (c) 1990, 1993
- * The Regents of the University of California. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * Posix rand_r function added May 1999 by Wes Peters <wes@softweyr.com>.
- */
-
-#if defined(LIBC_SCCS) && !defined(lint)
-static char sccsid[] = "@(#)rand.c 8.1 (Berkeley) 6/14/93";
-#endif /* LIBC_SCCS and not lint */
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/lib/libc/stdlib/rand.c,v 1.15 2003/02/17 03:52:35 ache Exp $");
-
-#include "namespace.h"
-#include <sys/time.h> /* for sranddev() */
-#include <sys/types.h>
-#include <fcntl.h> /* for sranddev() */
-#include <stdlib.h>
-#include <unistd.h> /* for sranddev() */
-#include "un-namespace.h"
-
-#ifdef TEST
-#include <stdio.h>
-#endif /* TEST */
-
-static int
-do_rand(unsigned long *ctx)
-{
-#ifdef USE_WEAK_SEEDING
-/*
- * Historic implementation compatibility.
- * The random sequences do not vary much with the seed,
- * even with overflowing.
- */
- return ((*ctx = *ctx * 1103515245 + 12345) % ((u_long)RAND_MAX + 1));
-#else /* !USE_WEAK_SEEDING */
-/*
- * Compute x = (7^5 * x) mod (2^31 - 1)
- * wihout overflowing 31 bits:
- * (2^31 - 1) = 127773 * (7^5) + 2836
- * From "Random number generators: good ones are hard to find",
- * Park and Miller, Communications of the ACM, vol. 31, no. 10,
- * October 1988, p. 1195.
- */
- long hi, lo, x;
-
- /* Can't be initialized with 0, so use another value. */
- if (*ctx == 0)
- *ctx = 123459876;
- hi = *ctx / 127773;
- lo = *ctx % 127773;
- x = 16807 * lo - 2836 * hi;
- if (x < 0)
- x += 0x7fffffff;
- return ((*ctx = x) % ((u_long)RAND_MAX + 1));
-#endif /* !USE_WEAK_SEEDING */
-}
-
-
-int
-rand_r(unsigned int *ctx)
-{
- u_long val = (u_long) *ctx;
- int r = do_rand(&val);
-
- *ctx = (unsigned int) val;
- return (r);
-}
-
-
-static u_long next = 1;
-
-int
-rand()
-{
- return (do_rand(&next));
-}
-
-void
-srand(seed)
-u_int seed;
-{
- next = seed;
-}
-
-
-/*
- * sranddev:
- *
- * Many programs choose the seed value in a totally predictable manner.
- * This often causes problems. We seed the generator using the much more
- * secure random(4) interface.
- */
-void
-sranddev()
-{
- int fd, done;
-
- done = 0;
- fd = _open("/dev/random", O_RDONLY, 0);
- if (fd >= 0) {
- if (_read(fd, (void *) &next, sizeof(next)) == sizeof(next))
- done = 1;
- _close(fd);
- }
-
- if (!done) {
- struct timeval tv;
- unsigned long junk;
-
- gettimeofday(&tv, NULL);
- srand((getpid() << 16) ^ tv.tv_sec ^ tv.tv_usec ^ junk);
- }
-}
-
-
-#ifdef TEST
-
-main()
-{
- int i;
- unsigned myseed;
-
- printf("seeding rand with 0x19610910: \n");
- srand(0x19610910);
-
- printf("generating three pseudo-random numbers:\n");
- for (i = 0; i < 3; i++)
- {
- printf("next random number = %d\n", rand());
- }
-
- printf("generating the same sequence with rand_r:\n");
- myseed = 0x19610910;
- for (i = 0; i < 3; i++)
- {
- printf("next random number = %d\n", rand_r(&myseed));
- }
-
- return 0;
-}
-
-#endif /* TEST */
-
projects / apple / libc.git / blobdiff