mariadb/innobase/include/ut0ut.ic

/******************************************************************
Various utilities

(c) 1994, 1995 Innobase Oy

Created 5/30/1994 Heikki Tuuri
*******************************************************************/

/**********************************************************
Calculates the minimum of two ulints. */
UNIV_INLINE
ulint
ut_min(
/*===*/
			/* out: minimum */
	ulint    n1,	/* in: first number */
	ulint    n2)	/* in: second number */
{
	return((n1 <= n2) ? n1 : n2);
}

/**********************************************************
Calculates the maximum of two ulints. */
UNIV_INLINE
ulint
ut_max(
/*===*/
			/* out: maximum */
	ulint    n1,	/* in: first number */
	ulint    n2)	/* in: second number */
{
	return((n1 <= n2) ? n2 : n1);
}

/********************************************************************
Calculates minimum of two ulint-pairs. */
UNIV_INLINE
void
ut_pair_min(
/*========*/
	ulint*	a,	/* out: more significant part of minimum */
	ulint*	b,	/* out: less significant part of minimum */
	ulint	a1,	/* in: more significant part of first pair */
	ulint	b1,	/* in: less significant part of first pair */
	ulint	a2,	/* in: more significant part of second pair */
	ulint	b2)	/* in: less significant part of second pair */
{	
	if (a1 == a2) {
		*a = a1;
		*b = ut_min(b1, b2);
	} else if (a1 < a2) {
		*a = a1;
		*b = b1;
	} else {
		*a = a2;
		*b = b2;
	}
}

/**********************************************************
Compares two ulints. */
UNIV_INLINE
int
ut_ulint_cmp(
/*=========*/
			/* out: 1 if a > b, 0 if a == b, -1 if a < b */
	ulint	a,	/* in: ulint */
	ulint	b)	/* in: ulint */
{
	if (a < b) {
		return(-1);
	} else if (a == b) {
		return(0);
	} else {
		return(1);
	}
}

/***********************************************************
Compares two pairs of ulints. */
UNIV_INLINE
int
ut_pair_cmp(
/*========*/
			/* out: -1 if a < b, 0 if a == b, 1 if a > b */ 
	ulint	a1,	/* in: more significant part of first pair */
	ulint	a2,	/* in: less significant part of first pair */
	ulint	b1,	/* in: more significant part of second pair */
	ulint	b2)	/* in: less significant part of second pair */
{
	if (a1 > b1) {
		return(1);
	} else if (a1 < b1) {
		return(-1);
	} else if (a2 > b2) {
		return(1);
	} else if (a2 < b2) {
		return(-1);
	} else {
		return(0);
	}
}

/*****************************************************************
Calculates fast the remainder when divided by a power of two. */
UNIV_INLINE
ulint
ut_2pow_remainder(
/*==============*/	/* out: remainder */
	ulint	n,	/* in: number to be divided */
	ulint	m)	/* in: divisor; power of 2 */
{
	ut_ad(0x80000000 % m == 0);

	return(n & (m - 1));
}

/*****************************************************************
Calculates fast a value rounded to a multiple of a power of 2. */
UNIV_INLINE
ulint
ut_2pow_round(
/*==========*/		/* out: value of n rounded down to nearest
			multiple of m */
	ulint	n,	/* in: number to be rounded */
	ulint	m)	/* in: divisor; power of 2 */
{
	ut_ad(0x80000000 % m == 0);

	return(n & ~(m - 1));
}

/*****************************************************************
Calculates fast the 2-logarithm of a number, rounded upward to an
integer. */
UNIV_INLINE
ulint
ut_2_log(
/*=====*/
			/* out: logarithm in the base 2, rounded upward */
	ulint	n)	/* in: number != 0 */
{
	ulint	res;

	res = 0;

	ut_ad(n > 0);

	n = n - 1;

	for (;;) {
		n = n / 2;

		if (n == 0) {
			break;
		}

		res++;
	}

	return(res + 1);
}

/*****************************************************************
Calculates 2 to power n. */
UNIV_INLINE
ulint
ut_2_exp(
/*=====*/
			/* out: 2 to power n */
	ulint	n)	/* in: number */
{
	return(1 << n);
}

/*****************************************************************
Calculates fast the number rounded up to the nearest power of 2. */
UNIV_INLINE
ulint
ut_2_power_up(
/*==========*/
			/* out: first power of 2 which is >= n */
	ulint	n)	/* in: number != 0 */
{
	ulint	res;

	res = 1;

	ut_ad(n > 0);

	while (res < n) {
		res = res * 2;
	}

	return(res);
}