path: root/storage/innobase/include/ut0byte.ic

/*****************************************************************************

Copyright (c) 1994, 2009, Innobase Oy. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA

*****************************************************************************/

/**************************************************************//**
@file include/ut0byte.ic
Utilities for byte operations

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

/*******************************************************//**
Creates a 64-bit dulint out of two ulints.
@return	created dulint */
UNIV_INLINE
dulint
ut_dulint_create(
/*=============*/
	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.
@return	32 bits in ulint */
UNIV_INLINE
ulint
ut_dulint_get_high(
/*===============*/
	dulint	d)	/*!< in: dulint */
{
	return(d.high);
}

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

/*******************************************************//**
Converts a dulint (a struct of 2 ulints) to ib_int64_t, which is a 64-bit
integer type.
@return	value in ib_int64_t type */
UNIV_INLINE
ib_int64_t
ut_conv_dulint_to_longlong(
/*=======================*/
	dulint	d)	/*!< in: dulint */
{
	return((ib_int64_t)d.low
	       + (((ib_int64_t)d.high) << 32));
}

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

		return(TRUE);
	}

	return(FALSE);
}

/*******************************************************//**
Compares two dulints.
@return	-1 if a < b, 0 if a == b, 1 if a > b */
UNIV_INLINE
int
ut_dulint_cmp(
/*==========*/
	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.
@return	max(a, b) */
UNIV_INLINE
dulint
ut_dulint_get_max(
/*==============*/
	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.
@return	min(a, b) */
UNIV_INLINE
dulint
ut_dulint_get_min(
/*==============*/
	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.
@return	sum a + b */
UNIV_INLINE
dulint
ut_dulint_add(
/*==========*/
	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.
@return	a - b */
UNIV_INLINE
dulint
ut_dulint_subtract(
/*===============*/
	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.
@return	a - b */
UNIV_INLINE
ulint
ut_dulint_minus(
/*============*/
	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.
@return	rounded value */
UNIV_INLINE
dulint
ut_dulint_align_down(
/*=================*/
	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.
@return	rounded value */
UNIV_INLINE
dulint
ut_dulint_align_up(
/*===============*/
	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));
}

/********************************************************//**
Rounds ib_uint64_t downward to a multiple of a power of 2.
@return	rounded value */
UNIV_INLINE
ib_uint64_t
ut_uint64_align_down(
/*=================*/
	ib_uint64_t	 n,		/*!< in: number to be rounded */
	ulint		 align_no)	/*!< in: align by this number
					which must be a power of 2 */
{
	ut_ad(align_no > 0);
	ut_ad(ut_is_2pow(align_no));

	return(n & ~((ib_uint64_t) align_no - 1));
}

/********************************************************//**
Rounds ib_uint64_t upward to a multiple of a power of 2.
@return	rounded value */
UNIV_INLINE
ib_uint64_t
ut_uint64_align_up(
/*===============*/
	ib_uint64_t	 n,		/*!< in: number to be rounded */
	ulint		 align_no)	/*!< in: align by this number
					which must be a power of 2 */
{
	ib_uint64_t	align_1 = (ib_uint64_t) align_no - 1;

	ut_ad(align_no > 0);
	ut_ad(ut_is_2pow(align_no));

	return((n + align_1) & ~align_1);
}

/*********************************************************//**
The following function rounds up a pointer to the nearest aligned address.
@return	aligned pointer */
UNIV_INLINE
void*
ut_align(
/*=====*/
	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((void*)((((ulint)ptr) + align_no - 1) & ~(align_no - 1)));
}

/*********************************************************//**
The following function rounds down a pointer to the nearest
aligned address.
@return	aligned pointer */
UNIV_INLINE
void*
ut_align_down(
/*==========*/
	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((void*)((((ulint)ptr)) & ~(align_no - 1)));
}

/*********************************************************//**
The following function computes the offset of a pointer from the nearest
aligned address.
@return	distance from aligned pointer */
UNIV_INLINE
ulint
ut_align_offset(
/*============*/
	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.
@return	TRUE if nth bit is 1; 0th bit is defined to be the least significant */
UNIV_INLINE
ibool
ut_bit_get_nth(
/*===========*/
	ulint	a,	/*!< in: ulint */
	ulint	n)	/*!< in: nth bit requested */
{
	ut_ad(n < 8 * sizeof(ulint));
#if TRUE != 1
# error "TRUE != 1"
#endif
	return(1 & (a >> n));
}

/*****************************************************************//**
Sets the nth bit of a ulint.
@return	the ulint with the bit set as requested */
UNIV_INLINE
ulint
ut_bit_set_nth(
/*===========*/
	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));
#if TRUE != 1
# error "TRUE != 1"
#endif
	if (val) {
		return(((ulint) 1 << n) | a);
	} else {
		return(~((ulint) 1 << n) & a);
	}
}