/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"

#include "primes.h"

static const unsigned int primes[] = {

#define PRIME_SKIP_COUNT 3

  17,

  37,

  67,

  131,

  257, /* next from 2^8 */

  521,

  1031,

  2053,

  4099,

  8209,

  16411,

  32771,

  65537, /* next from 2^16 */

  131101,

  262147,

  524309,

  1048583,

  2097169,

  4194319,

  8388617,

  16777259, /* next from 2^24 */

  33554467,

  67108879,

  134217757,

  268435459,

  536870923,

  1073741827,

  2147483659U,

  4294967291U /* previous from 2^32 */

};

unsigned int primes_closest(unsigned int num)

{

  unsigned int i;

  for (i = 31; i > PRIME_SKIP_COUNT; i--) {

    if ((num & (1U << i)) != 0)

      return primes[i - PRIME_SKIP_COUNT];

  }

  return primes[0];

}