summaryrefslogtreecommitdiff
path: root/knuth-lfib.h
blob: 85dce637bcaeddd5b6061afdb7e52c07b1f2e1a3 (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
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
/* knuth-lfib.h
 *
 * A "lagged fibonacci" pseudorandomness generator.
 *
 * Described in Knuth, TAOCP, 3.6
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2002 Niels Möller
 *  
 * The nettle library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 * 
 * The nettle library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with the nettle library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02111-1301, USA.
 */

/* NOTE: This generator is totally inappropriate for cryptographic
 * applications. It is useful for generating deterministic but
 * random-looking test data, and is used by the Nettle testsuite. */
#ifndef NETTLE_KNUTH_LFIB_H_INCLUDED
#define NETTLE_KNUTH_LFIB_H_INCLUDED

#include "nettle-types.h"

#ifdef __cplusplus
extern "C" {
#endif

/* Namespace mangling */
#define knuth_lfib_init nettle_knuth_lfib_init
#define knuth_lfib_get nettle_knuth_lfib_get
#define knuth_lfib_get_array nettle_knuth_lfib_get_array
#define knuth_lfib_random nettle_knuth_lfib_random

#define _KNUTH_LFIB_KK 100

struct knuth_lfib_ctx
{
  uint32_t x[_KNUTH_LFIB_KK];
  unsigned index;
};

void
knuth_lfib_init(struct knuth_lfib_ctx *ctx, uint32_t seed);

/* Get's a single number in the range 0 ... 2^30-1 */
uint32_t
knuth_lfib_get(struct knuth_lfib_ctx *ctx);

/* Get an array of numbers */
void
knuth_lfib_get_array(struct knuth_lfib_ctx *ctx,
		     unsigned n, uint32_t *a);

/* Get an array of octets. */
void
knuth_lfib_random(struct knuth_lfib_ctx *ctx,
		  unsigned n, uint8_t *dst);

#ifdef __cplusplus
}
#endif

#endif /* NETTLE_KNUTH_LFIB_H_INCLUDED */