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/* rand-isaac.h - header for ISAAC
Copyright (C) 1999-2005 Free Software Foundation, Inc.
Copyright (C) 1997, 1998, 1999 Colin Plumb.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
Written by Colin Plumb. */
/* Size of the state tables to use. */
/* (You may change ISAAC_LOG but it should be >= 3, and smaller values
* give less security) */
#ifndef ISAAC_LOG
# define ISAAC_LOG 8
#endif
#define ISAAC_MAX_WORDS (1 << ISAAC_LOG)
#define ISAAC_MAX_BYTES (ISAAC_MAX_WORDS * sizeof (uint32_t))
/* RNG state variables */
struct isaac_state
{
uint32_t iv[8]; /* Seeding initial vector */
uint32_t a, b, c; /* Extra index variables */
uint32_t words; /* Words in main state array */
uint32_t log; /* Log of words */
uint32_t mm[ISAAC_MAX_WORDS]; /* Main state array */
};
/* This index operation is more efficient on many processors */
#define ind(words, mm, x) \
(* (uint32_t *) ((char *) (mm) \
+ ((x) & (words - 1) * sizeof (uint32_t))))
/*
* The central step. This uses two temporaries, x and y. s is the
* state, while m is a pointer to the current word. off is the offset
* from m to the word s->words/2 words away in the mm array, i.e.
* +/- s->words/2.
*/
#define isaac_step(s, mix, a, b, m, off, r) \
( \
a = ((a) ^ (mix)) + (m)[off], \
x = *(m), \
*(m) = y = ind (s->words, s->mm, x) + (a) + (b), \
*(r) = b = ind (s->words, s->mm, (y) >> s->log) + x \
)
struct isaac_state *
isaac_new (struct isaac_state *s, int words);
void
isaac_copy (struct isaac_state *dst, struct isaac_state *src);
void
isaac_refill (struct isaac_state *s, uint32_t r[/* s->words */]);
void
isaac_mix (struct isaac_state *s, uint32_t const seed[/* s->words */]);
void
isaac_init (struct isaac_state *s, uint32_t const *seed, size_t seedsize);
void
isaac_seed_start (struct isaac_state *s);
void
isaac_seed_data (struct isaac_state *s, void const *buffer, size_t size);
void
isaac_seed_finish (struct isaac_state *s);
#define ISAAC_SEED(s,x) isaac_seed_data (s, &(x), sizeof (x))
void
isaac_seed (struct isaac_state *s);
/* Single-word RNG built on top of ISAAC */
struct irand_state
{
uint32_t r[ISAAC_MAX_WORDS];
unsigned int numleft;
struct isaac_state *s;
};
void
irand_init (struct irand_state *r, struct isaac_state *s);
uint32_t
irand32 (struct irand_state *r);
uint32_t
irand_mod (struct irand_state *r, uint32_t n);
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