include/ntfs-3g/bitmap.h

/*
 * bitmap.h - Exports for bitmap handling. Originated from the Linux-NTFS project.
 *
 * Copyright (c) 2000-2004 Anton Altaparmakov
 * Copyright (c) 2004-2005 Richard Russon
 *
 * This program/include file 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program/include file 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 (in the main directory of the NTFS-3G
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef _NTFS_BITMAP_H
#define _NTFS_BITMAP_H

#include "types.h"
#include "attrib.h"

/*
 * NOTES:
 *
 * - Operations are 8-bit only to ensure the functions work both on little
 *   and big endian machines! So don't make them 32-bit ops!
 * - bitmap starts at bit = 0 and ends at bit = bitmap size - 1.
 * - _Caller_ has to make sure that the bit to operate on is less than the
 *   size of the bitmap.
 */

extern void ntfs_bit_set(u8 *bitmap, const u64 bit, const u8 new_value);
extern char ntfs_bit_get(const u8 *bitmap, const u64 bit);
extern char ntfs_bit_get_and_set(u8 *bitmap, const u64 bit, const u8 new_value);
extern int  ntfs_bitmap_set_run(ntfs_attr *na, s64 start_bit, s64 count);
extern int  ntfs_bitmap_clear_run(ntfs_attr *na, s64 start_bit, s64 count);

/**
 * ntfs_bitmap_set_bit - set a bit in a bitmap
 * @na:		attribute containing the bitmap
 * @bit:	bit to set
 *
 * Set the @bit in the bitmap described by the attribute @na.
 *
 * On success return 0 and on error return -1 with errno set to the error code.
 */
static __inline__ int ntfs_bitmap_set_bit(ntfs_attr *na, s64 bit)
{
	return ntfs_bitmap_set_run(na, bit, 1);
}

/**
 * ntfs_bitmap_clear_bit - clear a bit in a bitmap
 * @na:		attribute containing the bitmap
 * @bit:	bit to clear
 *
 * Clear @bit in the bitmap described by the attribute @na.
 *
 * On success return 0 and on error return -1 with errno set to the error code.
 */
static __inline__ int ntfs_bitmap_clear_bit(ntfs_attr *na, s64 bit)
{
	return ntfs_bitmap_clear_run(na, bit, 1);
}

/*
 * rol32 - rotate a 32-bit value left
 *
 * @word: value to rotate
 * @shift: bits to roll
 */
static __inline__ u32 ntfs_rol32(u32 word, unsigned int shift)
{
        return (word << shift) | (word >> (32 - shift));
}

/*
 * ror32 - rotate a 32-bit value right
 *
 * @word: value to rotate
 * @shift: bits to roll
 */
static __inline__ u32 ntfs_ror32(u32 word, unsigned int shift)
{
        return (word >> shift) | (word << (32 - shift));
}

#endif /* defined _NTFS_BITMAP_H */