| Dees_Troy | 83bd483 | 2013-05-04 12:39:56 +0000 | [diff] [blame] | 1 | /* |
| 2 | ------------------------------------------------------------------------------ |
| 3 | rand.h: definitions for a random number generator |
| 4 | By Bob Jenkins, 1996, Public Domain |
| 5 | MODIFIED: |
| 6 | 960327: Creation (addition of randinit, really) |
| 7 | 970719: use context, not global variables, for internal state |
| 8 | 980324: renamed seed to flag |
| 9 | 980605: recommend RANDSIZL=4 for noncryptography. |
| 10 | 010626: note this is public domain |
| 11 | ------------------------------------------------------------------------------ |
| 12 | */ |
| 13 | #ifndef STANDARD |
| 14 | #include "standard.h" |
| 15 | #endif |
| 16 | |
| 17 | #ifndef RAND |
| 18 | #define RAND |
| 19 | #define RANDSIZL (8) |
| 20 | #define RANDSIZ (1<<RANDSIZL) |
| 21 | |
| 22 | /* context of random number generator */ |
| 23 | struct randctx |
| 24 | { |
| 25 | ub4 randcnt; |
| 26 | ub4 randrsl[RANDSIZ]; |
| 27 | ub4 randmem[RANDSIZ]; |
| 28 | ub4 randa; |
| 29 | ub4 randb; |
| 30 | ub4 randc; |
| 31 | }; |
| 32 | typedef struct randctx randctx; |
| 33 | |
| 34 | /* |
| 35 | ------------------------------------------------------------------------------ |
| 36 | If (flag==TRUE), then use the contents of randrsl[0..RANDSIZ-1] as the seed. |
| 37 | ------------------------------------------------------------------------------ |
| 38 | */ |
| 39 | void randinit(/*_ randctx *r, word flag _*/); |
| 40 | |
| 41 | void isaac(/*_ randctx *r _*/); |
| 42 | |
| 43 | |
| 44 | /* |
| 45 | ------------------------------------------------------------------------------ |
| 46 | Call rand(/o_ randctx *r _o/) to retrieve a single 32-bit random value |
| 47 | ------------------------------------------------------------------------------ |
| 48 | */ |
| 49 | #define rand(r) \ |
| 50 | (!(r)->randcnt-- ? \ |
| 51 | (isaac(r), (r)->randcnt=RANDSIZ-1, (r)->randrsl[(r)->randcnt]) : \ |
| 52 | (r)->randrsl[(r)->randcnt]) |
| 53 | |
| 54 | #endif /* RAND */ |
| 55 | |
| 56 | |