McRogueFace/deps_windows/libtcod-1.23.1-x86_64-msvc/include/libtcod/random.h

62 lines
2.5 KiB
C

/* BSD 3-Clause License
*
* Copyright © 2008-2022, Jice and the libtcod contributors.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef LIBTCOD_RANDOM_H_
#define LIBTCOD_RANDOM_H_
#include <stdint.h>
#include "config.h"
#ifdef __cplusplus
extern "C" {
#endif // __cplusplus
/**
Return the next random uint64_t from a SplitMix64 generator.
`state[1]` is a non-NULL pointer to the internal state of the generator.
There is no initializer function because the first value of `state[1]` is
itself the seed which can start at any value.
`state[1]` will be updated by this call.
This function is provisional and may change.
*/
static inline uint64_t TCOD_rng_splitmix64_next(uint64_t* state) {
// Based on http://xoshiro.di.unimi.it/splitmix64.c
uint64_t z = (*state += 0x9e3779b97f4a7c15);
z = (z ^ (z >> 30)) * 0xbf58476d1ce4e5b9;
z = (z ^ (z >> 27)) * 0x94d049bb133111eb;
return z ^ (z >> 31);
}
#ifdef __cplusplus
} // extern "C"
#endif // __cplusplus
#endif // LIBTCOD_RANDOM_H_