diff options
Diffstat (limited to 'usr.sbin/xntpd/lib/ranny.c')
| -rw-r--r-- | usr.sbin/xntpd/lib/ranny.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/usr.sbin/xntpd/lib/ranny.c b/usr.sbin/xntpd/lib/ranny.c new file mode 100644 index 000000000000..2a47e03f59ac --- /dev/null +++ b/usr.sbin/xntpd/lib/ranny.c @@ -0,0 +1,97 @@ +/* ranny.c,v 3.1 1993/07/06 01:08:43 jbj Exp + * Random number generator is: + * + * Copyright 1988 by Rayan S. Zachariassen, all rights reserved. + * This will be free software, but only when it is finished. + * + * Used in xntp by permission of the author. If copyright is + * annoying to you, read no further. Instead, look up the reference, + * write me an equivalent to this and send it back to me. + */ + +/* + * Random number generator; see Knuth Vol 2. 2nd ed. p.27 (section 3.2.2) + */ +#include "ntp_stdlib.h" + +extern time_t time P((time_t *loc)); + +/* + * 55 random numbers, not all even. Note we don't initialize ran_y + * directly since I have had thoughts of putting this in an EPROM + */ +static U_LONG ran_y[55]; + +static U_LONG init_ran_y[55] = { + 1860909544, 231033423, 437666411, 1349655137, 2014584962, + 504613712, 656256107, 1246027206, 573713775, 643466871, + 540235388, 1630565153, 443649364, 729302839, 1933991552, + 944681982, 949111118, 406212522, 1065063137, 1712954727, + 73280612, 787623973, 1874130997, 801658492, 73395958, + 739165367, 596047144, 490055249, 1131094323, 662727104, + 483614097, 844520219, 893760527, 921280508, 46691708, + 760861842, 1425894220, 702947816, 2006889048, 1999607995, + 1346414687, 399640789, 1482689501, 1790064052, 1128943628, + 1269197405, 587262386, 2078054746, 1675409928, 1652325524, + 1643525825, 1748690540, 292465849, 1370173174, 402865384 +}; + +static int ran_j; +static int ran_k; + + +/* + * ranp2 - return a random integer in the range 0 .. (1<<m)-1 + */ +U_LONG +ranp2(m) + int m; +{ + U_LONG r; + + ran_y[ran_k] += ran_y[ran_j]; /* overflow does a mod */ + r = ran_y[ran_k]; + if (ran_k-- == 0) ran_k = 54; + if (ran_j-- == 0) ran_j = 54; + return (r & ((1<<m)-1)); +} + +#ifdef notdef +/* + * ranny - return a random integer in the range 0 .. m-1 + */ +U_LONG +ranny(m) + u_int m; +{ + unsigned LONG r; + + ran_y[ran_k] += ran_y[ran_j]; /* overflow does a mod */ + r = ran_y[ran_k]; + if (ran_k-- == 0) ran_k = 54; + if (ran_j-- == 0) ran_j = 54; + return (r % m); +} +#endif /* notdef */ + +/* + * init_random - do initialization of random number routine + */ +void +init_random() +{ + register int i; + register time_t now; + + ran_j = 23; + ran_k = 54; + + /* + * Randomize the seed array some more. The time of day + * should be initialized by now. + */ + now = (time_t)(time((time_t *)0))|01; + + for (i = 0; i < 55; ++i) + ran_y[i] = now * init_ran_y[i]; /* overflow does a mod */ +} |