randomkit.h

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/* Random kit 1.3 */
 
/*
 * Copyright (c) 2003-2005, Jean-Sebastien Roy (js@jeannot.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
/*
 * Typical use:
 *
 * {
 *  rk_state state;
 *  unsigned long seed = 1, random_value;
 *
 *  rk_seed(seed, &state); // Initialize the RNG
 *  ...
 *  random_value = rk_random(&state); // Generate random values in [0..RK_MAX]
 * }
 *
 * Instead of rk_seed, you can use rk_randomseed which will get a random seed
 * from /dev/urandom (or the clock, if /dev/urandom is unavailable):
 *
 * {
 *  rk_state state;
 *  unsigned long random_value;
 *
 *  rk_randomseed(&state); // Initialize the RNG with a random seed
 *  ...
 *  random_value = rk_random(&state); // Generate random values in [0..RK_MAX]
 * }
 */
 
/*
 * Useful macro:
 *  RK_DEV_RANDOM: the device used for random seeding.
 *                 defaults to "/dev/urandom"
 */
 
#pragma once
 
#include <stddef.h>
 
#if !defined(__CYGWIN__) && defined(__GNUC__) && !defined(__MINGW32__)
#define INTERNAL __attribute__((visibility("hidden")))
#else
#define INTERNAL /* nothing */
#endif
 
#define RK_STATE_LEN 624
 
typedef struct rk_state_
{
    unsigned long key[RK_STATE_LEN];
    int pos;
 
}
rk_state;
 
/* Maximum generated random value */
#define RK_MAX 0xFFFFFFFFUL
 
#ifdef __cplusplus
extern "C" {
#endif
 
/*
 * Initialize the RNG state using the given seed.
 */
INTERNAL void rk_seed(unsigned long seed, rk_state *state);
 
/*
 * Returns a random unsigned long between 0 and RK_MAX inclusive
 */
INTERNAL unsigned long rk_random(rk_state *state);
 
/*
 * Returns a random unsigned long between 0 and max inclusive.
 */
INTERNAL unsigned long rk_interval(unsigned long max, rk_state *state);
 
#ifdef __cplusplus
}
#endif
 
#undef INTERNAL