2 * bitmap.h - Exports for bitmap handling. Part of the Linux-NTFS project.
4 * Copyright (c) 2000-2003 Anton Altaparmakov
6 * This program/include file is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as published
8 * by the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program/include file is distributed in the hope that it will be
12 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program (in the main directory of the Linux-NTFS
18 * distribution in the file COPYING); if not, write to the Free Software
19 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #ifndef _NTFS_BITMAP_H
23 #define _NTFS_BITMAP_H
31 * - Operations are 8-bit only to ensure the functions work both on little
32 * and big endian machines! So don't make them 32-bit ops!
33 * - bitmap starts at bit = 0 and ends at bit = bitmap size - 1.
34 * - _Caller_ has to make sure that the bit to operate on is less than the
39 * ntfs_bit_set - set a bit in a field of bits
40 * @bitmap: field of bits
42 * @new_value: value to set bit to (0 or 1)
44 * Set the bit @bit in the @bitmap to @new_value. Ignore all errors.
46 static __inline__ void ntfs_bit_set(u8 *bitmap, const u64 bit,
49 // Dprintf("bitmap %p, bit 0x%Lx, new_value %i\n", bitmap, bit, new_value);
50 if (!bitmap || new_value > 1)
53 bitmap[bit >> 3] &= ~(1 << (bit & 7));
55 bitmap[bit >> 3] |= (1 << (bit & 7));
59 * ntfs_bit_get - get value of a bit in a field of bits
60 * @bitmap: field of bits
63 * Get and return the value of the bit @bit in @bitmap (0 or 1).
66 static __inline__ char ntfs_bit_get(const u8 *bitmap, const u64 bit)
70 return (bitmap[bit >> 3] >> (bit & 7)) & 1;
73 static __inline__ void ntfs_bit_change(u8 *bitmap, const u64 bit)
77 bitmap[bit >> 3] ^= 1 << (bit & 7);
81 * ntfs_bit_get_and_set - get value of a bit in a field of bits and set it
82 * @bitmap: field of bits
83 * @bit: bit to get/set
84 * @new_value: value to set bit to (0 or 1)
86 * Return the value of the bit @bit and set it to @new_value (0 or 1).
89 static __inline__ char ntfs_bit_get_and_set(u8 *bitmap, const u64 bit,
92 register u8 old_bit, shift;
94 if (!bitmap || new_value > 1)
97 old_bit = (bitmap[bit >> 3] >> shift) & 1;
98 if (new_value != old_bit)
99 bitmap[bit >> 3] ^= 1 << shift;
103 extern int ntfs_bitmap_set_run(ntfs_attr *na, s64 start_bit, s64 count);
104 extern int ntfs_bitmap_clear_run(ntfs_attr *na, s64 start_bit, s64 count);
106 #endif /* defined _NTFS_BITMAP_H */