blob: c4eb44c133bb836e4b6d30ba497639444f49610b (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
|
/* vi: set sw=4 ts=4: */
/*
* $RANDOM support.
*
* Copyright (C) 2009 Denys Vlasenko
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
#ifndef SHELL_RANDOM_H
#define SHELL_RANDOM_H 1
PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
typedef struct random_t {
/* State of random number generators: */
/* Galois LFSR (fast but weak) */
int32_t galois_LFSR; /* must be signed! */
/* LCG (fast but weak) */
uint32_t LCG;
/* 64-bit xorshift (fast, moderate strength) */
uint32_t xs64_x;
uint32_t xs64_y;
} random_t;
#define UNINITED_RANDOM_T(rnd) \
((rnd)->galois_LFSR == 0)
#define INIT_RANDOM_T(rnd, nonzero, v) \
((rnd)->galois_LFSR = (rnd)->xs64_x = (nonzero), (rnd)->LCG = (rnd)->xs64_y = (v))
#define CLEAR_RANDOM_T(rnd) \
((rnd)->galois_LFSR = 0)
uint32_t next_random(random_t *rnd) FAST_FUNC;
POP_SAVED_FUNCTION_VISIBILITY
#endif
|
