random.cpp

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#include <ion.h>
#include <stdlib.h>

uint32_t Ion::random() {
  /* rand() returns a pseudo-random integral number in the range between 0 and
   * RAND_MAX. We assert that RAND_MAX is at least 8 bit, this way we can merge
   * four rand() calls to create a single 32 bit value. Merging is done using
   * XOR, whose output is as likely to be a 1 as a 0. */
  static_assert(RAND_MAX >= (1<<8), "RAND_MAX is too small");
  return (rand() << 24) ^ (rand() << 16) ^ (rand() << 8) ^ rand();
}