/* Copyright (c) 2001-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"

/*

 * We could use bits_required64() unconditionally, but that's unnecessary

 * and way more heavy weight on 32-bit systems.

 */

#if SIZEOF_SIZE_T > 4

#define BITS_REQUIRED(x)  bits_required64(x)

#else

#define BITS_REQUIRED(x)  bits_required32(x)

#endif

size_t nearest_power(size_t num)

{

  i_assert(num <= ((size_t)1 << (CHAR_BIT*sizeof(size_t) - 1)));

  if (num == 0)

    return 1;

  return 1UL << BITS_REQUIRED(num - 1);

}

#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)

/* Lucky you, it's all inline intrinsics */

#else

unsigned int bits_required8(uint8_t num)

{

  int ret = 0;

  if (num > 0xf) { ret += 4; num >>= 4; }

  if (num > 0x3) { ret += 2; num >>= 2; }

  num &= ~(num>>1); /* 3->2, else unchanged */

  return ret + num;

}

#endif