os161/kern/include/bitmap.h
2015-12-23 00:50:04 +00:00

60 lines
2.6 KiB
C

/*
* Copyright (c) 2000, 2001
* The President and Fellows of Harvard College.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _BITMAP_H_
#define _BITMAP_H_
/*
* Fixed-size array of bits. (Intended for storage management.)
*
* Functions:
* bitmap_create - allocate a new bitmap object.
* Returns NULL on error.
* bitmap_getdata - return pointer to raw bit data (for I/O).
* bitmap_alloc - locate a cleared bit, set it, and return its index.
* bitmap_mark - set a clear bit by its index.
* bitmap_unmark - clear a set bit by its index.
* bitmap_isset - return whether a particular bit is set or not.
* bitmap_destroy - destroy bitmap.
*/
struct bitmap; /* Opaque. */
struct bitmap *bitmap_create(unsigned nbits);
void *bitmap_getdata(struct bitmap *);
int bitmap_alloc(struct bitmap *, unsigned *index);
void bitmap_mark(struct bitmap *, unsigned index);
void bitmap_unmark(struct bitmap *, unsigned index);
int bitmap_isset(struct bitmap *, unsigned index);
void bitmap_destroy(struct bitmap *);
#endif /* _BITMAP_H_ */