[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / xfs / xfs_bit.c

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * 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.
 *
 * This program is distributed in the hope that it would 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 the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_buf_item.h"

/*
 * XFS bit manipulation routines, used in non-realtime code.
 */

/*
 * Return whether bitmap is empty.
 * Size is number of words in the bitmap, which is padded to word boundary
 * Returns 1 for empty, 0 for non-empty.
 */
int
xfs_bitmap_empty(uint *map, uint size)
{
	uint i;
	uint ret = 0;

	for (i = 0; i < size; i++) {
		ret |= map[i];
	}

	return (ret == 0);
}

/*
 * Count the number of contiguous bits set in the bitmap starting with bit
 * start_bit.  Size is the size of the bitmap in words.
 */
int
xfs_contig_bits(uint *map, uint	size, uint start_bit)
{
	uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
	uint result = 0;
	uint tmp;

	size <<= BIT_TO_WORD_SHIFT;

	ASSERT(start_bit < size);
	size -= start_bit & ~(NBWORD - 1);
	start_bit &= (NBWORD - 1);
	if (start_bit) {
		tmp = *p++;
		/* set to one first offset bits prior to start */
		tmp |= (~0U >> (NBWORD-start_bit));
		if (tmp != ~0U)
			goto found;
		result += NBWORD;
		size -= NBWORD;
	}
	while (size) {
		if ((tmp = *p++) != ~0U)
			goto found;
		result += NBWORD;
		size -= NBWORD;
	}
	return result - start_bit;
found:
	return result + ffz(tmp) - start_bit;
}

/*
 * This takes the bit number to start looking from and
 * returns the next set bit from there.  It returns -1
 * if there are no more bits set or the start bit is
 * beyond the end of the bitmap.
 *
 * Size is the number of words, not bytes, in the bitmap.
 */
int xfs_next_bit(uint *map, uint size, uint start_bit)
{
	uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
	uint result = start_bit & ~(NBWORD - 1);
	uint tmp;

	size <<= BIT_TO_WORD_SHIFT;

	if (start_bit >= size)
		return -1;
	size -= result;
	start_bit &= (NBWORD - 1);
	if (start_bit) {
		tmp = *p++;
		/* set to zero first offset bits prior to start */
		tmp &= (~0U << start_bit);
		if (tmp != 0U)
			goto found;
		result += NBWORD;
		size -= NBWORD;
	}
	while (size) {
		if ((tmp = *p++) != 0U)
			goto found;
		result += NBWORD;
		size -= NBWORD;
	}
	return -1;
found:
	return result + ffs(tmp) - 1;
}
Commit	Line	Data
1da177e4	1	/*
7b718769 NS	2	* Copyright (c) 2000-2005 Silicon Graphics, Inc.
7b718769 NS	3	* All Rights Reserved.
1da177e4	4	*
7b718769 NS	5	* This program is free software; you can redistribute it and/or
7b718769 NS	6	* modify it under the terms of the GNU General Public License as
1da177e4 LT	7	* published by the Free Software Foundation.
1da177e4 LT	8	*
7b718769 NS	9	* This program is distributed in the hope that it would be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
1da177e4	13	*
7b718769 NS	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write the Free Software Foundation,
	16	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
1da177e4	17	*/
1da177e4 LT	18	#include "xfs.h"
	19	#include "xfs_bit.h"
	20	#include "xfs_log.h"
	21	#include "xfs_trans.h"
	22	#include "xfs_buf_item.h"
	23
7b718769 NS	24	/*
	25	* XFS bit manipulation routines, used in non-realtime code.
	26	*/
1da177e4	27
1da177e4	28	/*
24ad33ff ES	29	* Return whether bitmap is empty.
	30	* Size is number of words in the bitmap, which is padded to word boundary
	31	* Returns 1 for empty, 0 for non-empty.
1da177e4 LT	32	*/
1da177e4 LT	33	int
24ad33ff	34	xfs_bitmap_empty(uint *map, uint size)
1da177e4	35	{
24ad33ff ES	36	uint i;
24ad33ff ES	37	uint ret = 0;
1da177e4	38
24ad33ff ES	39	for (i = 0; i < size; i++) {
24ad33ff ES	40	ret \|= map[i];
1da177e4 LT	41	}
1da177e4 LT	42
24ad33ff	43	return (ret == 0);
1da177e4 LT	44	}
	45
	46	/*
	47	* Count the number of contiguous bits set in the bitmap starting with bit
	48	* start_bit. Size is the size of the bitmap in words.
	49	*/
	50	int
	51	xfs_contig_bits(uint *map, uint size, uint start_bit)
	52	{
	53	uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
	54	uint result = 0;
	55	uint tmp;
	56
	57	size <<= BIT_TO_WORD_SHIFT;
	58
	59	ASSERT(start_bit < size);
	60	size -= start_bit & ~(NBWORD - 1);
	61	start_bit &= (NBWORD - 1);
	62	if (start_bit) {
	63	tmp = *p++;
	64	/* set to one first offset bits prior to start */
	65	tmp \|= (~0U >> (NBWORD-start_bit));
	66	if (tmp != ~0U)
	67	goto found;
	68	result += NBWORD;
	69	size -= NBWORD;
	70	}
	71	while (size) {
	72	if ((tmp = *p++) != ~0U)
	73	goto found;
	74	result += NBWORD;
	75	size -= NBWORD;
	76	}
	77	return result - start_bit;
	78	found:
	79	return result + ffz(tmp) - start_bit;
	80	}
	81
	82	/*
	83	* This takes the bit number to start looking from and
	84	* returns the next set bit from there. It returns -1
	85	* if there are no more bits set or the start bit is
	86	* beyond the end of the bitmap.
	87	*
	88	* Size is the number of words, not bytes, in the bitmap.
	89	*/
	90	int xfs_next_bit(uint *map, uint size, uint start_bit)
	91	{
	92	uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT);
	93	uint result = start_bit & ~(NBWORD - 1);
	94	uint tmp;
	95
	96	size <<= BIT_TO_WORD_SHIFT;
	97
	98	if (start_bit >= size)
	99	return -1;
	100	size -= result;
	101	start_bit &= (NBWORD - 1);
	102	if (start_bit) {
	103	tmp = *p++;
	104	/* set to zero first offset bits prior to start */
	105	tmp &= (~0U << start_bit);
	106	if (tmp != 0U)
	107	goto found;
108	result += NBWORD;
109	size -= NBWORD;
110	}
111	while (size) {
112	if ((tmp = *p++) != 0U)
113	goto found;
114	result += NBWORD;
115	size -= NBWORD;
116	}
117	return -1;
118	found:
119	return result + ffs(tmp) - 1;
120	}