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 #include <xen/bitmap.h>
18
19 #define EBITMAP_UNIT_NUMS ((32 - sizeof(void *) - sizeof(u32)) \
20 / sizeof(unsigned long))
21 #define EBITMAP_UNIT_SIZE BITS_PER_LONG
22 #define EBITMAP_SIZE (EBITMAP_UNIT_NUMS * EBITMAP_UNIT_SIZE)
23 #define EBITMAP_BIT 1ULL
24 #define EBITMAP_SHIFT_UNIT_SIZE(x) \
25 (((x) >> EBITMAP_UNIT_SIZE / 2) >> EBITMAP_UNIT_SIZE / 2)
26
27 struct ebitmap_node {
28 struct ebitmap_node *next;
29 unsigned long maps[EBITMAP_UNIT_NUMS];
30 u32 startbit;
31 };
32
33 struct ebitmap {
34 struct ebitmap_node *node; /* first node in the bitmap */
35 u32 highbit; /* highest position in the total bitmap */
36 };
37
38 #define ebitmap_length(e) ((e)->highbit)
39 #define ebitmap_startbit(e) ((e)->node ? (e)->node->startbit : 0)
40
ebitmap_start_positive(struct ebitmap * e,struct ebitmap_node ** n)41 static inline unsigned int ebitmap_start_positive(struct ebitmap *e,
42 struct ebitmap_node **n)
43 {
44 unsigned int ofs;
45
46 for ( *n = e->node; *n; *n = (*n)->next )
47 {
48 ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
49 if ( ofs < EBITMAP_SIZE )
50 return (*n)->startbit + ofs;
51 }
52 return ebitmap_length(e);
53 }
54
ebitmap_init(struct ebitmap * e)55 static inline void ebitmap_init(struct ebitmap *e)
56 {
57 memset(e, 0, sizeof(*e));
58 }
59
ebitmap_next_positive(struct ebitmap * e,struct ebitmap_node ** n,unsigned int bit)60 static inline unsigned int ebitmap_next_positive(struct ebitmap *e,
61 struct ebitmap_node **n,
62 unsigned int bit)
63 {
64 unsigned int ofs;
65
66 ofs = find_next_bit((*n)->maps, EBITMAP_SIZE, bit - (*n)->startbit + 1);
67 if ( ofs < EBITMAP_SIZE )
68 return ofs + (*n)->startbit;
69
70 for ( *n = (*n)->next; *n; *n = (*n)->next )
71 {
72 ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
73 if ( ofs < EBITMAP_SIZE )
74 return ofs + (*n)->startbit;
75 }
76 return ebitmap_length(e);
77 }
78
79 #define EBITMAP_NODE_INDEX(node, bit) \
80 (((bit) - (node)->startbit) / EBITMAP_UNIT_SIZE)
81 #define EBITMAP_NODE_OFFSET(node, bit) \
82 (((bit) - (node)->startbit) % EBITMAP_UNIT_SIZE)
83
ebitmap_node_get_bit(struct ebitmap_node * n,unsigned int bit)84 static inline int ebitmap_node_get_bit(struct ebitmap_node *n,
85 unsigned int bit)
86 {
87 unsigned int index = EBITMAP_NODE_INDEX(n, bit);
88 unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
89
90 BUG_ON( index >= EBITMAP_UNIT_NUMS );
91 if ( (n->maps[index] & (EBITMAP_BIT << ofs)) )
92 return 1;
93 return 0;
94 }
95
ebitmap_node_set_bit(struct ebitmap_node * n,unsigned int bit)96 static inline void ebitmap_node_set_bit(struct ebitmap_node *n,
97 unsigned int bit)
98 {
99 unsigned int index = EBITMAP_NODE_INDEX(n, bit);
100 unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
101
102 BUG_ON(index >= EBITMAP_UNIT_NUMS);
103 n->maps[index] |= (EBITMAP_BIT << ofs);
104 }
105
ebitmap_node_clr_bit(struct ebitmap_node * n,unsigned int bit)106 static inline void ebitmap_node_clr_bit(struct ebitmap_node *n,
107 unsigned int bit)
108 {
109 unsigned int index = EBITMAP_NODE_INDEX(n, bit);
110 unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
111
112 BUG_ON( index >= EBITMAP_UNIT_NUMS );
113 n->maps[index] &= ~(EBITMAP_BIT << ofs);
114 }
115
116 #define ebitmap_for_each_positive_bit(e, n, bit) \
117 for ( bit = ebitmap_start_positive(e, &n); \
118 bit < ebitmap_length(e); \
119 bit = ebitmap_next_positive(e, &n, bit) ) \
120
121 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
122 int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
123 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);
124 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
125 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
126 void ebitmap_destroy(struct ebitmap *e);
127 int ebitmap_read(struct ebitmap *e, void *fp);
128
129 #endif /* _SS_EBITMAP_H_ */
130