ebitmap.h

来自「鼎力推荐！本程序是基于嵌入式LUNUX系统开发的源程序代码」· C头文件 代码 · 共 50 行

/*
 * An extensible bitmap is a bitmap that supports an
 * arbitrary number of bits.  Extensible bitmaps are
 * used to represent sets of values, such as types,
 * roles, categories, and classes.
 *
 * Each extensible bitmap is implemented as a linked
 * list of bitmap nodes, where each bitmap node has
 * an explicitly specified starting bit position within
 * the total bitmap.
 *
 * Author : Stephen Smalley, <[e-mail]>
 */
#ifndef _SS_EBITMAP_H_
#define _SS_EBITMAP_H_

#define MAPTYPE u64			/* portion of bitmap in each node */
#define MAPSIZE (sizeof(MAPTYPE) * 8)	/* number of bits in node bitmap */
#define MAPBIT  1ULL			/* a bit in the node bitmap */

struct ebitmap_node {
	u32 startbit;		/* starting position in the total bitmap */
	MAPTYPE map;		/* this node's portion of the bitmap */
	struct ebitmap_node *next;
};

struct ebitmap {
	struct ebitmap_node *node;	/* first node in the bitmap */
	u32 highbit;	/* highest position in the total bitmap */
};

#define ebitmap_length(e) ((e)->highbit)
#define ebitmap_startbit(e) ((e)->node ? (e)->node->startbit : 0)

static inline void ebitmap_init(struct ebitmap *e)
{
	memset(e, 0, sizeof(*e));
}

int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
int ebitmap_or(struct ebitmap *dst, struct ebitmap *e1, struct ebitmap *e2);
int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);
int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
void ebitmap_destroy(struct ebitmap *e);
int ebitmap_read(struct ebitmap *e, void *fp);

#endif	/* _SS_EBITMAP_H_ */