4coder/custom/lexer_generator/pcg_basic.h

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2019-09-27 03:52:29 +00:00
/*
* PCG Random Number Generation for C.
*
* Copyright 2014 Melissa O'Neill <oneill@pcg-random.org>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* For additional information about the PCG random number generation scheme,
* including its license and other licensing options, visit
*
* http://www.pcg-random.org
*/
/*
* This code is derived from the full C implementation, which is in turn
* derived from the canonical C++ PCG implementation. The C++ version
* has many additional features and is preferable if you can use C++ in
* your project.
*/
#ifndef PCG_BASIC_H_INCLUDED
#define PCG_BASIC_H_INCLUDED 1
#include <inttypes.h>
#if __cplusplus
extern "C" {
#endif
struct pcg_state_setseq_64 { // Internals are *Private*.
uint64_t state; // RNG state. All values are possible.
uint64_t inc; // Controls which RNG sequence (stream) is
// selected. Must *always* be odd.
};
typedef struct pcg_state_setseq_64 pcg32_random_t;
// If you *must* statically initialize it, here's one.
#define PCG32_INITIALIZER { 0x853c49e6748fea9bULL, 0xda3e39cb94b95bdbULL }
// pcg32_srandom(initstate, initseq)
// pcg32_srandom_r(rng, initstate, initseq):
// Seed the rng. Specified in two parts, state initializer and a
// sequence selection constant (a.k.a. stream id)
void pcg32_srandom(uint64_t initstate, uint64_t initseq);
void pcg32_srandom_r(pcg32_random_t* rng, uint64_t initstate,
uint64_t initseq);
// pcg32_random()
// pcg32_random_r(rng)
// Generate a uniformly distributed 32-bit random number
uint32_t pcg32_random(void);
uint32_t pcg32_random_r(pcg32_random_t* rng);
// pcg32_boundedrand(bound):
// pcg32_boundedrand_r(rng, bound):
// Generate a uniformly distributed number, r, where 0 <= r < bound
uint32_t pcg32_boundedrand(uint32_t bound);
uint32_t pcg32_boundedrand_r(pcg32_random_t* rng, uint32_t bound);
#if __cplusplus
}
#endif
#endif // PCG_BASIC_H_INCLUDED