xref: /openbsd-src/lib/libc/stdlib/seed48.c (revision cb39b41371628601fbe4c618205356d538b9d08a)
1 /*	$OpenBSD: seed48.c,v 1.4 2014/12/08 21:45:20 deraadt Exp $ */
2 /*
3  * Copyright (c) 1993 Martin Birgmeier
4  * All rights reserved.
5  *
6  * You may redistribute unmodified or modified versions of this source
7  * code provided that the above copyright notice and this and the
8  * following conditions are retained.
9  *
10  * This software is provided ``as is'', and comes with no warranties
11  * of any kind. I shall in no event be liable for anything that happens
12  * to anyone/anything when using this software.
13  */
14 
15 #include "rand48.h"
16 
17 extern unsigned short __rand48_seed[3];
18 extern unsigned short __rand48_mult[3];
19 extern unsigned short __rand48_add;
20 
21 unsigned short *
22 seed48(unsigned short xseed[3])
23 {
24 	unsigned short *res;
25 
26 	res = seed48_deterministic(xseed);
27 	__rand48_deterministic = 0;
28 	return res;
29 }
30 
31 unsigned short *
32 seed48_deterministic(unsigned short xseed[3])
33 {
34 	static unsigned short sseed[3];
35 
36 	__rand48_deterministic = 1;
37 	sseed[0] = __rand48_seed[0];
38 	sseed[1] = __rand48_seed[1];
39 	sseed[2] = __rand48_seed[2];
40 	__rand48_seed[0] = xseed[0];
41 	__rand48_seed[1] = xseed[1];
42 	__rand48_seed[2] = xseed[2];
43 	__rand48_mult[0] = RAND48_MULT_0;
44 	__rand48_mult[1] = RAND48_MULT_1;
45 	__rand48_mult[2] = RAND48_MULT_2;
46 	__rand48_add = RAND48_ADD;
47 	return sseed;
48 }
49