deadbeef_rand.c

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#include "deadbeef_rand.h"

static uint32_t deadbeef_seed;
static uint32_t deadbeef_beef = 0xdeadbeef;

/** Generate a 32-bit random number.
 *
 * Before using this function, you should seed the generator by
 * calling deadbeef_srand().
 */
uint32_t deadbeef_rand() {
  deadbeef_seed = (deadbeef_seed << 7) ^ ((deadbeef_seed >> 25) + deadbeef_beef);
  deadbeef_beef = (deadbeef_beef << 7) ^ ((deadbeef_beef >> 25) + 0xdeadbeef);
  return deadbeef_seed;
}

/** Seed the deadbeef random number generator.
 *
 * Starting from the same seed, multiple runs of the deadbeef random
 * number generator will generate identical sequences of pseudo-random
 * numbers. This is sometime useful. In cases where it is desirable to
 * have different runs of the generator generate different sequences,
 * you should seed them with different seeds.
 *
 * @param seed The value to seed the deadbeef generator with
 */
void deadbeef_srand(uint32_t seed) {
  deadbeef_seed = seed;
  deadbeef_beef = 0xdeadbeef;
}

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