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/*
* 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 canonical C++ PCG implementation, which
* has many additional features and is preferable if you can use C++ in
* your project.
*
* The contents of this file were mechanically derived from pcg_variants.h
* (every inline function defined there gets an exern declaration here).
*/
#include "pcg_variants.h"
/* Functions to advance the underlying LCG, one version for each size and
* each style. These functions are considered semi-private. There is rarely
* a good reason to call them directly.
*/
extern inline void pcg_oneseq_8_step_r(struct pcg_state_8* rng);
extern inline void pcg_oneseq_8_advance_r(struct pcg_state_8* rng,
uint8_t delta);
extern inline void pcg_mcg_8_step_r(struct pcg_state_8* rng);
extern inline void pcg_mcg_8_advance_r(struct pcg_state_8* rng, uint8_t delta);
extern inline void pcg_unique_8_step_r(struct pcg_state_8* rng);
extern inline void pcg_unique_8_advance_r(struct pcg_state_8* rng,
uint8_t delta);
extern inline void pcg_setseq_8_step_r(struct pcg_state_setseq_8* rng);
extern inline void pcg_setseq_8_advance_r(struct pcg_state_setseq_8* rng,
uint8_t delta);
/* Functions to seed the RNG state, one version for each size and each
* style. Unlike the step functions, regular users can and should call
* these functions.
*/
extern inline void pcg_oneseq_8_srandom_r(struct pcg_state_8* rng,
uint8_t initstate);
extern inline void pcg_mcg_8_srandom_r(struct pcg_state_8* rng,
uint8_t initstate);
extern inline void pcg_unique_8_srandom_r(struct pcg_state_8* rng,
uint8_t initstate);
extern inline void pcg_setseq_8_srandom_r(struct pcg_state_setseq_8* rng,
uint8_t initstate, uint8_t initseq);
/* Now, finally we create each of the individual generators. We provide
* a random_r function that provides a random number of the appropriate
* type (using the full range of the type) and a boundedrand_r version
* that provides
*
* Implementation notes for boundedrand_r:
*
* To avoid bias, we need to make the range of the RNG a multiple of
* bound, which we do by dropping output less than a threshold.
* Let's consider a 32-bit case... A naive scheme to calculate the
* threshold would be to do
*
* uint32_t threshold = 0x100000000ull % bound;
*
* but 64-bit div/mod is slower than 32-bit div/mod (especially on
* 32-bit platforms). In essence, we do
*
* uint32_t threshold = (0x100000000ull-bound) % bound;
*
* because this version will calculate the same modulus, but the LHS
* value is less than 2^32.
*
* (Note that using modulo is only wise for good RNGs, poorer RNGs
* such as raw LCGs do better using a technique based on division.)
* Empricical tests show that division is preferable to modulus for
* reducting the range of an RNG. It's faster, and sometimes it can
* even be statistically prefereable.
*/
/* Generation functions for XSH RS */
/* Generation functions for XSH RR */
/* Generation functions for RXS M XS (no MCG versions because they
* don't make sense when you want to use the entire state)
*/
extern inline uint8_t pcg_oneseq_8_rxs_m_xs_8_random_r(struct pcg_state_8* rng);
extern inline uint8_t
pcg_oneseq_8_rxs_m_xs_8_boundedrand_r(struct pcg_state_8* rng, uint8_t bound);
extern inline uint8_t
pcg_setseq_8_rxs_m_xs_8_random_r(struct pcg_state_setseq_8* rng);
extern inline uint8_t
pcg_setseq_8_rxs_m_xs_8_boundedrand_r(struct pcg_state_setseq_8* rng,
uint8_t bound);
/* Generation functions for XSL RR (only defined for "large" types) */
/* Generation functions for XSL RR RR (only defined for "large" types) */
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