rm_/lib/rand-isaac.h

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2020-09-02 16:47:03 +08:00
/* Bob Jenkins's cryptographic random number generators, ISAAC and ISAAC64.
Copyright (C) 1999-2020 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 3 of the License, 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, see <https://www.gnu.org/licenses/>.
Written by Colin Plumb and Paul Eggert. */
#ifndef _GL_RAND_ISAAC_H
#define _GL_RAND_ISAAC_H
#include <stddef.h>
#include <stdint.h>
/* Log base 2 of the number of useful bits in an ISAAC word. It must
be either 5 or 6. By default, this uses a value that should be
faster for this architecture. */
#ifndef ISAAC_BITS_LOG
#if SIZE_MAX >> 31 >> 31 < 3 /* SIZE_MAX < 2**64 - 1 */
#define ISAAC_BITS_LOG 5
#else
#define ISAAC_BITS_LOG 6
#endif
#endif
/* The number of bits in an ISAAC word. */
#define ISAAC_BITS (1 << ISAAC_BITS_LOG)
#if ISAAC_BITS == 32
typedef uint_least32_t isaac_word;
#else
typedef uint_least64_t isaac_word;
#endif
/* Size of the state tables to use. ISAAC_WORDS_LOG should be at least 3,
and smaller values give less security. */
#define ISAAC_WORDS_LOG 8
#define ISAAC_WORDS (1 << ISAAC_WORDS_LOG)
#define ISAAC_BYTES (ISAAC_WORDS * sizeof (isaac_word))
/* State variables for the random number generator. The M member
should be seeded with nonce data before calling isaac_seed. The
other members are private. */
struct isaac_state
{
isaac_word m[ISAAC_WORDS]; /* Main state array */
isaac_word a, b, c; /* Extra variables */
};
void isaac_seed (struct isaac_state *);
void isaac_refill (struct isaac_state *, isaac_word[ISAAC_WORDS]);
#endif