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1da177e4 LT |
1 | /* |
2 | * An extensible bitmap is a bitmap that supports an | |
3 | * arbitrary number of bits. Extensible bitmaps are | |
4 | * used to represent sets of values, such as types, | |
5 | * roles, categories, and classes. | |
6 | * | |
7 | * Each extensible bitmap is implemented as a linked | |
8 | * list of bitmap nodes, where each bitmap node has | |
9 | * an explicitly specified starting bit position within | |
10 | * the total bitmap. | |
11 | * | |
12 | * Author : Stephen Smalley, <sds@epoch.ncsc.mil> | |
13 | */ | |
14 | #ifndef _SS_EBITMAP_H_ | |
15 | #define _SS_EBITMAP_H_ | |
16 | ||
17 | #define MAPTYPE u64 /* portion of bitmap in each node */ | |
18 | #define MAPSIZE (sizeof(MAPTYPE) * 8) /* number of bits in node bitmap */ | |
19 | #define MAPBIT 1ULL /* a bit in the node bitmap */ | |
20 | ||
21 | struct ebitmap_node { | |
22 | u32 startbit; /* starting position in the total bitmap */ | |
23 | MAPTYPE map; /* this node's portion of the bitmap */ | |
24 | struct ebitmap_node *next; | |
25 | }; | |
26 | ||
27 | struct ebitmap { | |
28 | struct ebitmap_node *node; /* first node in the bitmap */ | |
29 | u32 highbit; /* highest position in the total bitmap */ | |
30 | }; | |
31 | ||
32 | #define ebitmap_length(e) ((e)->highbit) | |
33 | #define ebitmap_startbit(e) ((e)->node ? (e)->node->startbit : 0) | |
34 | ||
782ebb99 SS |
35 | static inline unsigned int ebitmap_start(struct ebitmap *e, |
36 | struct ebitmap_node **n) | |
37 | { | |
38 | *n = e->node; | |
39 | return ebitmap_startbit(e); | |
40 | } | |
41 | ||
1da177e4 LT |
42 | static inline void ebitmap_init(struct ebitmap *e) |
43 | { | |
44 | memset(e, 0, sizeof(*e)); | |
45 | } | |
46 | ||
782ebb99 SS |
47 | static inline unsigned int ebitmap_next(struct ebitmap_node **n, |
48 | unsigned int bit) | |
49 | { | |
50 | if ((bit == ((*n)->startbit + MAPSIZE - 1)) && | |
51 | (*n)->next) { | |
52 | *n = (*n)->next; | |
53 | return (*n)->startbit; | |
54 | } | |
55 | ||
56 | return (bit+1); | |
57 | } | |
58 | ||
59 | static inline int ebitmap_node_get_bit(struct ebitmap_node * n, | |
60 | unsigned int bit) | |
61 | { | |
62 | if (n->map & (MAPBIT << (bit - n->startbit))) | |
63 | return 1; | |
64 | return 0; | |
65 | } | |
66 | ||
67 | #define ebitmap_for_each_bit(e, n, bit) \ | |
68 | for (bit = ebitmap_start(e, &n); bit < ebitmap_length(e); bit = ebitmap_next(&n, bit)) \ | |
69 | ||
1da177e4 LT |
70 | int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2); |
71 | int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src); | |
72 | int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2); | |
73 | int ebitmap_get_bit(struct ebitmap *e, unsigned long bit); | |
74 | int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value); | |
75 | void ebitmap_destroy(struct ebitmap *e); | |
76 | int ebitmap_read(struct ebitmap *e, void *fp); | |
77 | ||
78 | #endif /* _SS_EBITMAP_H_ */ |