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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 PHOTON_SPIN_RANDOM_H
#define PHOTON_SPIN_RANDOM_H
#include <stdint.h>
#include <stdbool.h>
/* PhotonSpin32: a 20-word ring-buffer generator inspired by SHISHUA,
* tuned for high throughput and large period.
*
* Reference: Will Stafford Parsons (wileylooper/photonspin, repository offline).
* This generator produces batches of 20 new 32-bit values per round,
* offering a huge period (~2^512) and robust statistical performance.
*
* Pros:
* - Large state with excellent distribution; great for heavy simulation workloads
* - Deterministic snapshots through state capture
*
* Cons:
* - Higher per-instance memory (~20×4 bytes)
* - Not cryptographically secure
*/
#define PHOTON_SPIN_BLOCK_SIZE 20
#define PHOTON_SPIN_INCREMENT 111111U
typedef struct {
uint32_t elements[PHOTON_SPIN_BLOCK_SIZE];
uint32_t a;
uint32_t b;
uint32_t c;
int index;
bool has_primed;
} photon_spin_random_t;
/* Initialize the generator with a single seed */
void photon_spin_init(photon_spin_random_t *rng, uint32_t seed);
/* Initialize the generator with three seeds */
void photon_spin_init_scalars(photon_spin_random_t *rng, uint32_t seed_a, uint32_t seed_b, uint32_t seed_c);
/* Initialize the generator with two 64-bit seeds */
void photon_spin_init_ulongs(photon_spin_random_t *rng, uint64_t seed0, uint64_t seed1);
/* Generate next random 32-bit unsigned integer */
uint32_t photon_spin_next_uint(photon_spin_random_t *rng);
/* Generate next random float in [0, 1) */
float photon_spin_next_float(photon_spin_random_t *rng);
/* Generate next random double in [0, 1) */
double photon_spin_next_double(photon_spin_random_t *rng);
/* Generate next random int in range [min, max) */
int32_t photon_spin_next_int_range(photon_spin_random_t *rng, int32_t min, int32_t max);
#endif /* PHOTON_SPIN_RANDOM_H */
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