1#ifndef FIO_RAND_H
2#define FIO_RAND_H
3
4#include <inttypes.h>
5#include <assert.h>
6#include "types.h"
7#include "../arch/arch.h"
8
9#define FRAND32_MAX	(-1U)
10#define FRAND64_MAX	(-1ULL)
11
12struct taus88_state {
13	unsigned int s1, s2, s3;
14};
15
16struct taus258_state {
17	uint64_t s1, s2, s3, s4, s5;
18};
19
20struct frand_state {
21	unsigned int use64;
22	union {
23		struct taus88_state state32;
24		struct taus258_state state64;
25	};
26};
27
28static inline uint64_t rand_max(struct frand_state *state)
29{
30	if (state->use64)
31		return FRAND64_MAX;
32	else
33		return FRAND32_MAX;
34}
35
36static inline void __frand32_copy(struct taus88_state *dst,
37				  struct taus88_state *src)
38{
39	dst->s1 = src->s1;
40	dst->s2 = src->s2;
41	dst->s3 = src->s3;
42}
43
44static inline void __frand64_copy(struct taus258_state *dst,
45				  struct taus258_state *src)
46{
47	dst->s1 = src->s1;
48	dst->s2 = src->s2;
49	dst->s3 = src->s3;
50	dst->s4 = src->s4;
51	dst->s5 = src->s5;
52}
53
54static inline void frand_copy(struct frand_state *dst, struct frand_state *src)
55{
56	if (src->use64)
57		__frand64_copy(&dst->state64, &src->state64);
58	else
59		__frand32_copy(&dst->state32, &src->state32);
60
61	dst->use64 = src->use64;
62}
63
64static inline unsigned int __rand32(struct taus88_state *state)
65{
66#define TAUSWORTHE(s,a,b,c,d) ((s&c)<<d) ^ (((s <<a) ^ s)>>b)
67
68	state->s1 = TAUSWORTHE(state->s1, 13, 19, 4294967294UL, 12);
69	state->s2 = TAUSWORTHE(state->s2, 2, 25, 4294967288UL, 4);
70	state->s3 = TAUSWORTHE(state->s3, 3, 11, 4294967280UL, 17);
71
72	return (state->s1 ^ state->s2 ^ state->s3);
73}
74
75static inline uint64_t __rand64(struct taus258_state *state)
76{
77	uint64_t xval;
78
79	xval = ((state->s1 <<  1) ^ state->s1) >> 53;
80	state->s1 = ((state->s1 & 18446744073709551614ULL) << 10) ^ xval;
81
82	xval = ((state->s2 << 24) ^ state->s2) >> 50;
83	state->s2 = ((state->s2 & 18446744073709551104ULL) <<  5) ^ xval;
84
85	xval = ((state->s3 <<  3) ^ state->s3) >> 23;
86	state->s3 = ((state->s3 & 18446744073709547520ULL) << 29) ^ xval;
87
88	xval = ((state->s4 <<  5) ^ state->s4) >> 24;
89	state->s4 = ((state->s4 & 18446744073709420544ULL) << 23) ^ xval;
90
91	xval = ((state->s5 <<  3) ^ state->s5) >> 33;
92	state->s5 = ((state->s5 & 18446744073701163008ULL) <<  8) ^ xval;
93
94	return (state->s1 ^ state->s2 ^ state->s3 ^ state->s4 ^ state->s5);
95}
96
97static inline uint64_t __rand(struct frand_state *state)
98{
99	if (state->use64)
100		return __rand64(&state->state64);
101	else
102		return __rand32(&state->state32);
103}
104
105static inline double __rand_0_1(struct frand_state *state)
106{
107	if (state->use64) {
108		uint64_t val = __rand64(&state->state64);
109
110		return (val + 1.0) / (FRAND64_MAX + 1.0);
111	} else {
112		uint32_t val = __rand32(&state->state32);
113
114		return (val + 1.0) / (FRAND32_MAX + 1.0);
115	}
116}
117
118/*
119 * Generate a random value between 'start' and 'end', both inclusive
120 */
121static inline int rand32_between(struct frand_state *state, int start, int end)
122{
123	uint32_t r;
124
125	assert(!state->use64);
126
127	r = __rand32(&state->state32);
128	return start + (int) ((double)end * (r / (FRAND32_MAX + 1.0)));
129}
130
131extern void init_rand(struct frand_state *, bool);
132extern void init_rand_seed(struct frand_state *, unsigned int seed, bool);
133extern void __fill_random_buf(void *buf, unsigned int len, unsigned long seed);
134extern unsigned long fill_random_buf(struct frand_state *, void *buf, unsigned int len);
135extern void __fill_random_buf_percentage(unsigned long, void *, unsigned int, unsigned int, unsigned int, char *, unsigned int);
136extern unsigned long fill_random_buf_percentage(struct frand_state *, void *, unsigned int, unsigned int, unsigned int, char *, unsigned int);
137
138#endif
139