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5b2abdfb | 1 | /*- |
e9ce8d39 A |
2 | * Copyright (c) 1990, 1993 |
3 | * The Regents of the University of California. All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This product includes software developed by the University of | |
16 | * California, Berkeley and its contributors. | |
17 | * 4. Neither the name of the University nor the names of its contributors | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
5b2abdfb A |
32 | * |
33 | * Posix rand_r function added May 1999 by Wes Peters <wes@softweyr.com>. | |
34 | * | |
35 | * $FreeBSD: src/lib/libc/stdlib/rand.c,v 1.2.2.1 2001/03/05 11:33:57 obrien Exp $ | |
e9ce8d39 A |
36 | */ |
37 | ||
5b2abdfb A |
38 | #if defined(LIBC_SCCS) && !defined(lint) |
39 | static char sccsid[] = "@(#)rand.c 8.1 (Berkeley) 6/14/93"; | |
40 | #endif /* LIBC_SCCS and not lint */ | |
e9ce8d39 A |
41 | |
42 | #include <sys/types.h> | |
43 | #include <stdlib.h> | |
44 | ||
5b2abdfb A |
45 | #ifdef TEST |
46 | #include <stdio.h> | |
47 | #endif /* TEST */ | |
48 | ||
49 | static int | |
50 | do_rand(unsigned long *ctx) | |
51 | { | |
52 | return ((*ctx = *ctx * 1103515245 + 12345) % ((u_long)RAND_MAX + 1)); | |
53 | } | |
54 | ||
55 | ||
56 | int | |
57 | rand_r(unsigned int *ctx) | |
58 | { | |
59 | u_long val = (u_long) *ctx; | |
60 | *ctx = do_rand(&val); | |
61 | return (int) *ctx; | |
62 | } | |
63 | ||
64 | ||
e9ce8d39 A |
65 | static u_long next = 1; |
66 | ||
67 | int | |
68 | rand() | |
69 | { | |
5b2abdfb | 70 | return do_rand(&next); |
e9ce8d39 A |
71 | } |
72 | ||
73 | void | |
74 | srand(seed) | |
75 | u_int seed; | |
76 | { | |
77 | next = seed; | |
78 | } | |
5b2abdfb A |
79 | |
80 | #ifdef TEST | |
81 | ||
82 | main() | |
83 | { | |
84 | int i; | |
85 | unsigned myseed; | |
86 | ||
87 | printf("seeding rand with 0x19610910: \n"); | |
88 | srand(0x19610910); | |
89 | ||
90 | printf("generating three pseudo-random numbers:\n"); | |
91 | for (i = 0; i < 3; i++) | |
92 | { | |
93 | printf("next random number = %d\n", rand()); | |
94 | } | |
95 | ||
96 | printf("generating the same sequence with rand_r:\n"); | |
97 | myseed = 0x19610910; | |
98 | for (i = 0; i < 3; i++) | |
99 | { | |
100 | printf("next random number = %d\n", rand_r(&myseed)); | |
101 | } | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
106 | #endif /* TEST */ | |
107 |