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/* MIT License - Copyright (c) 2025 wallstop
* Original C# implementation from: https://github.com/wallstop/unity-helpers
* Converted to C for librandom project
*/
#ifndef PCG_RANDOM_H
#define PCG_RANDOM_H
#include <stdint.h>
#include <stdbool.h>
/* PCG (Permuted Congruential Generator): High-quality, small-state PRNG.
*
* PCG offers excellent statistical quality with very small state and extremely
* fast generation. This implementation uses a 64-bit state with 32-bit outputs
* and an increment (stream selector).
*
* Pros:
* - Fast and allocation-free; suitable for gameplay hot paths
* - Great statistical quality; passes TestU01 BigCrush and PractRand
* - Deterministic and reproducible across platforms
* - Small state footprint
*
* Cons:
* - Not cryptographically secure
* - 32-bit outputs (use multiple calls for 64-bit)
*/
typedef struct {
uint64_t state;
uint64_t increment;
} pcg_random_t;
/* Initialize the generator with a seed */
void pcg_init(pcg_random_t *rng, uint64_t seed);
/* Initialize with explicit state and increment */
void pcg_init_full(pcg_random_t *rng, uint64_t state, uint64_t increment);
/* Generate next random 32-bit unsigned integer */
uint32_t pcg_next_uint(pcg_random_t *rng);
/* Generate next random 64-bit unsigned integer */
uint64_t pcg_next_ulong(pcg_random_t *rng);
/* Generate next random float in [0, 1) */
float pcg_next_float(pcg_random_t *rng);
/* Generate next random double in [0, 1) */
double pcg_next_double(pcg_random_t *rng);
#endif /* PCG_RANDOM_H */
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