ut0byte.ic

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/******************************************************************
Utilities for byte operations

(c) 1994, 1995 Innobase Oy

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

/***********************************************************
Creates a 64-bit dulint out of two ulints. */
UNIV_INLINE
dulint
ut_dulint_create(
/*=============*/
			/* out: created dulint */
	ulint	high,	/* in: high-order 32 bits */
	ulint	low)	/* in: low-order 32 bits */
{
	dulint	res;

	ut_ad(high <= 0xFFFFFFFF);
	ut_ad(low <= 0xFFFFFFFF);

	res.high = high;
	res.low  = low;

	return(res);
}

/***********************************************************
Gets the high-order 32 bits of a dulint. */
UNIV_INLINE
ulint
ut_dulint_get_high(
/*===============*/
			/* out: 32 bits in ulint */
	dulint	d)	/* in: dulint */
{
	return(d.high);
}

/***********************************************************
Gets the low-order 32 bits of a dulint. */
UNIV_INLINE
ulint
ut_dulint_get_low(
/*==============*/
			/* out: 32 bits in ulint */
	dulint	d)	/* in: dulint */
{
	return(d.low);
}

/***********************************************************
Converts a dulint (a struct of 2 ulints) to ib_longlong, which is a 64-bit
integer type. */
UNIV_INLINE
ib_longlong
ut_conv_dulint_to_longlong(
/*=======================*/
			/* out: value in ib_longlong type */
	dulint	d)	/* in: dulint */
{
	return((ib_longlong)d.low
		+ (((ib_longlong)d.high) << 32));
}

/***********************************************************
Tests if a dulint is zero. */
UNIV_INLINE
ibool
ut_dulint_is_zero(
/*==============*/
			/* out: TRUE if zero */
	dulint	a)	/* in: dulint */
{
	if ((a.low == 0) && (a.high == 0)) {

		return(TRUE);
	}

	return(FALSE);
}

/***********************************************************
Compares two dulints. */
UNIV_INLINE
int
ut_dulint_cmp(
/*==========*/
			/* out: -1 if a < b, 0 if a == b,
			1 if a > b */ 
	dulint	a,	/* in: dulint */
	dulint	b)	/* in: dulint */
{
	if (a.high > b.high) {
		return(1);
	} else if (a.high < b.high) {
		return(-1);
	} else if (a.low > b.low) {
		return(1);
	} else if (a.low < b.low) {
		return(-1);
	} else {
		return(0);
	}
}

/***********************************************************
Calculates the max of two dulints. */
UNIV_INLINE
dulint
ut_dulint_get_max(
/*==============*/
			/* out: max(a, b) */
	dulint	a,	/* in: dulint */
	dulint	b)	/* in: dulint */
{
	if (ut_dulint_cmp(a, b) > 0) {

		return(a);
	}

	return(b);
}

/***********************************************************
Calculates the min of two dulints. */
UNIV_INLINE
dulint
ut_dulint_get_min(
/*==============*/
			/* out: min(a, b) */
	dulint	a,	/* in: dulint */
	dulint	b)	/* in: dulint */
{
	if (ut_dulint_cmp(a, b) > 0) {

		return(b);
	}

	return(a);
}

/***********************************************************
Adds a ulint to a dulint. */
UNIV_INLINE
dulint
ut_dulint_add(
/*==========*/
			/* out: sum a + b */
	dulint	a,	/* in: dulint */
	ulint	b)	/* in: ulint */
{
	if (0xFFFFFFFFUL - b >= a.low) {
		a.low += b;

		return(a);
	}

	a.low = a.low - (0xFFFFFFFFUL - b) - 1;

	a.high++;

	return(a);
}

/***********************************************************
Subtracts a ulint from a dulint. */
UNIV_INLINE
dulint
ut_dulint_subtract(
/*===============*/
			/* out: a - b */
	dulint	a,	/* in: dulint */
	ulint	b)	/* in: ulint, b <= a */
{
	if (a.low >= b) {
		a.low -= b;

		return(a);
	}

	b -= a.low + 1;

	a.low = 0xFFFFFFFFUL - b;

	ut_ad(a.high > 0);
	
	a.high--;

	return(a);
}

/***********************************************************
Subtracts a dulint from another. NOTE that the difference must be positive
and smaller that 4G. */
UNIV_INLINE
ulint
ut_dulint_minus(
/*============*/
			/* out: a - b */
	dulint	a,	/* in: dulint; NOTE a must be >= b and at most
			2 to power 32 - 1 greater */
	dulint	b)	/* in: dulint */
{
	ulint	diff;

	if (a.high == b.high) {
		ut_ad(a.low >= b.low);

		return(a.low - b.low);
	}

	ut_ad(a.high == b.high + 1);

	diff = (ulint)(0xFFFFFFFFUL - b.low);
	diff += 1 + a.low;

	ut_ad(diff > a.low);
	
	return(diff);
} 

/************************************************************
Rounds a dulint downward to a multiple of a power of 2. */
UNIV_INLINE
dulint
ut_dulint_align_down(
/*=================*/
				/* out: rounded value */
	dulint   n,        	/* in: number to be rounded */
	ulint    align_no)  	/* in: align by this number which must be a
				power of 2 */
{
	ulint	low, high;

	ut_ad(align_no > 0);
	ut_ad(((align_no - 1) & align_no) == 0);

	low = ut_dulint_get_low(n);
	high = ut_dulint_get_high(n);
	
	low = low & ~(align_no - 1);

	return(ut_dulint_create(high, low));
}

/************************************************************
Rounds a dulint upward to a multiple of a power of 2. */
UNIV_INLINE
dulint
ut_dulint_align_up(
/*===============*/
				/* out: rounded value */
	dulint   n,        	/* in: number to be rounded */
	ulint    align_no)  	/* in: align by this number which must be a
				power of 2 */
{
	return(ut_dulint_align_down(ut_dulint_add(n, align_no - 1), align_no));
}

/************************************************************
The following function calculates the value of an integer n rounded
to the least product of align_no which is >= n. align_no
has to be a power of 2. */
UNIV_INLINE
ulint
ut_calc_align(
/*==========*/
				/* out: rounded value */
	ulint    n,        	/* in: number to be rounded */
	ulint    align_no)  	/* in: align by this number */
{
	ut_ad(align_no > 0);
	ut_ad(((align_no - 1) & align_no) == 0);

	return((n + align_no - 1) & ~(align_no - 1));
}

/*************************************************************
The following function rounds up a pointer to the nearest aligned address. */
UNIV_INLINE
void*
ut_align(
/*=====*/
				/* out: aligned pointer */
	void*   ptr,            /* in: pointer */
	ulint   align_no)      	/* in: align by this number */
{
	ut_ad(align_no > 0);
	ut_ad(((align_no - 1) & align_no) == 0);
	ut_ad(ptr);

	ut_ad(sizeof(void*) == sizeof(ulint));

	return((void*)((((ulint)ptr) + align_no - 1) & ~(align_no - 1)));
}

/************************************************************
The following function calculates the value of an integer n rounded
to the biggest product of align_no which is <= n. align_no has to be a
power of 2. */
UNIV_INLINE
ulint
ut_calc_align_down(
/*===============*/
				/* out: rounded value */
	ulint    n,              /* in: number to be rounded */
	ulint    align_no)       /* in: align by this number */
{
	ut_ad(align_no > 0);
	ut_ad(((align_no - 1) & align_no) == 0);

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

/*************************************************************
The following function rounds down a pointer to the nearest
aligned address. */
UNIV_INLINE
void*
ut_align_down(
/*==========*/
				/* out: aligned pointer */
	void*   ptr,            /* in: pointer */
	ulint   align_no)      	/* in: align by this number */
{
	ut_ad(align_no > 0);
	ut_ad(((align_no - 1) & align_no) == 0);
	ut_ad(ptr);

	ut_ad(sizeof(void*) == sizeof(ulint));

	return((void*)((((ulint)ptr)) & ~(align_no - 1)));
}

/*************************************************************
The following function computes the offset of a pointer from the nearest
aligned address. */
UNIV_INLINE
ulint
ut_align_offset(
/*============*/
					/* out: distance from
					aligned pointer */
	const void*	ptr,            /* in: pointer */
	ulint		align_no)      	/* in: align by this number */
{
	ut_ad(align_no > 0);
	ut_ad(((align_no - 1) & align_no) == 0);
	ut_ad(ptr);

	ut_ad(sizeof(void*) == sizeof(ulint));

	return(((ulint)ptr) & (align_no - 1));
}

/*********************************************************************
Gets the nth bit of a ulint. */
UNIV_INLINE
ibool
ut_bit_get_nth(
/*===========*/
			/* out: TRUE if nth bit is 1; 0th bit is defined to
			be the least significant */
	ulint	a,	/* in: ulint */
	ulint	n)	/* in: nth bit requested */
{
	ut_ad(n < 8 * sizeof(ulint));
	ut_ad(TRUE == 1);

	return(1 & (a >> n));
}

/*********************************************************************
Sets the nth bit of a ulint. */
UNIV_INLINE
ulint
ut_bit_set_nth(
/*===========*/
			/* out: the ulint with the bit set as requested */
	ulint	a,	/* in: ulint */
	ulint	n,	/* in: nth bit requested */
	ibool	val)	/* in: value for the bit to set */
{
	ut_ad(n < 8 * sizeof(ulint));
	ut_ad(TRUE == 1);

	if (val) {
		return((1 << n) | a);
	} else {
		return(~(1 << n) & a);
	}
}