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temple.c
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temple.c
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/*
* Derived from the TempleOS system (code released into the public domain).
*
* A simple LCG with the added fun of inserting the current time stamp.
*
* Obviously this is no better than a normal RNG.
*/
#include <stdint.h>
#include <time.h>
#include <unistd.h>
#include <talloc.h>
#include "temple.h"
#include "rngod.h"
#include "rng-private.h"
struct rng_temple_lcg {
struct rngod rng;
uint64_t seed;
uint64_t a, c;
};
static uint64_t
holyrand(struct rngod *rng) {
struct rng_temple_lcg *trng = talloc_get_type(rng, struct rng_temple_lcg);
if (!trng) {
// FIXME: Should have a better eror process
return 0;
}
uint64_t s = trng->seed;
s = trng->a * s ^ ((s & 0xFFFFFFFF0000) >> 16) + trng->c;
#if 0
s ^= __rdtsc();
#endif
return (trng->seed = s);
}
struct rngod *
rngod_temple_lcg_add(uint64_t seed, uint64_t a, uint64_t c) {
struct rng_temple_lcg *trng;
trng = talloc(NULL, struct rng_temple_lcg);
// A zero seed we set to a random time.
if (seed == 0) {
seed = time(NULL);
}
trng->seed = seed;
trng->a = a;
trng->c = c;
trng->rng.rand = holyrand;
default_init(&trng->rng);
return (struct rngod *)trng;
}
struct rngod *
rngod_temple_lcg_seed(uint64_t seed) {
return rngod_temple_lcg_add(seed, RNGOD_TEMPLE_LIN_CONGRUE_A, RNDO_TEMPLE_LIN_CONGRUE_C);
}
struct rngod *
rngod_temple_lcg_default(void) {
return rngod_temple_lcg_add(0, RNGOD_TEMPLE_LIN_CONGRUE_A, RNDO_TEMPLE_LIN_CONGRUE_C);
}