Method NextRandom

BeefRT/gperftools/src/sampler.h:155–162

Returns the next prng value. pRNG is: aX+b mod c with a = 0x5DEECE66D, b = 0xB, c = 1<<48 This is the lrand64 generator.

// pRNG is: aX+b mod c with a = 0x5DEECE66D, b =  0xB, c = 1<<48
// This is the lrand64 generator.
inline uint64_t Sampler::NextRandom(uint64_t rnd) {
  const uint64_t prng_mult = 0x5DEECE66DLL;
  const uint64_t prng_add = 0xB;
  const uint64_t prng_mod_power = 48;
  const uint64_t prng_mod_mask =
                ~((~static_cast<uint64_t>(0)) << prng_mod_power);
  return (prng_mult * rnd + prng_add) & prng_mod_mask;
}

// Adapted from //util/math/fastmath.[h|cc] by Noam Shazeer
// This mimics the VeryFastLog2 code in those files