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 #include <xen/bug.h>
19
20 #define EBITMAP_UNIT_NUMS ((32 - sizeof(void *) - sizeof(u32)) \
21 / sizeof(unsigned long))
22 #define EBITMAP_UNIT_SIZE BITS_PER_LONG
23 #define EBITMAP_SIZE (EBITMAP_UNIT_NUMS * EBITMAP_UNIT_SIZE)
24 #define EBITMAP_BIT 1ULL
25 #define EBITMAP_SHIFT_UNIT_SIZE(x) \
26 (((x) >> EBITMAP_UNIT_SIZE / 2) >> EBITMAP_UNIT_SIZE / 2)
27
28 struct ebitmap_node {
29 struct ebitmap_node *next;
30 unsigned long maps[EBITMAP_UNIT_NUMS];
31 u32 startbit;
32 };
33
34 struct ebitmap {
35 struct ebitmap_node *node; /* first node in the bitmap */
36 u32 highbit; /* highest position in the total bitmap */
37 };
38
39 #define ebitmap_length(e) ((e)->highbit)
40 #define ebitmap_startbit(e) ((e)->node ? (e)->node->startbit : 0)
41
ebitmap_start_positive(struct ebitmap * e,struct ebitmap_node ** n)42 static inline unsigned int ebitmap_start_positive(struct ebitmap *e,
43 struct ebitmap_node **n)
44 {
45 unsigned int ofs;
46
47 for ( *n = e->node; *n; *n = (*n)->next )
48 {
49 ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
50 if ( ofs < EBITMAP_SIZE )
51 return (*n)->startbit + ofs;
52 }
53 return ebitmap_length(e);
54 }
55
ebitmap_init(struct ebitmap * e)56 static inline void ebitmap_init(struct ebitmap *e)
57 {
58 memset(e, 0, sizeof(*e));
59 }
60
ebitmap_next_positive(struct ebitmap * e,struct ebitmap_node ** n,unsigned int bit)61 static inline unsigned int ebitmap_next_positive(struct ebitmap *e,
62 struct ebitmap_node **n,
63 unsigned int bit)
64 {
65 unsigned int ofs;
66
67 ofs = find_next_bit((*n)->maps, EBITMAP_SIZE, bit - (*n)->startbit + 1);
68 if ( ofs < EBITMAP_SIZE )
69 return ofs + (*n)->startbit;
70
71 for ( *n = (*n)->next; *n; *n = (*n)->next )
72 {
73 ofs = find_first_bit((*n)->maps, EBITMAP_SIZE);
74 if ( ofs < EBITMAP_SIZE )
75 return ofs + (*n)->startbit;
76 }
77 return ebitmap_length(e);
78 }
79
80 #define EBITMAP_NODE_INDEX(node, bit) \
81 (((bit) - (node)->startbit) / EBITMAP_UNIT_SIZE)
82 #define EBITMAP_NODE_OFFSET(node, bit) \
83 (((bit) - (node)->startbit) % EBITMAP_UNIT_SIZE)
84
ebitmap_node_get_bit(struct ebitmap_node * n,unsigned int bit)85 static inline int ebitmap_node_get_bit(struct ebitmap_node *n,
86 unsigned int bit)
87 {
88 unsigned int index = EBITMAP_NODE_INDEX(n, bit);
89 unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
90
91 BUG_ON( index >= EBITMAP_UNIT_NUMS );
92 if ( (n->maps[index] & (EBITMAP_BIT << ofs)) )
93 return 1;
94 return 0;
95 }
96
ebitmap_node_set_bit(struct ebitmap_node * n,unsigned int bit)97 static inline void ebitmap_node_set_bit(struct ebitmap_node *n,
98 unsigned int bit)
99 {
100 unsigned int index = EBITMAP_NODE_INDEX(n, bit);
101 unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
102
103 BUG_ON(index >= EBITMAP_UNIT_NUMS);
104 n->maps[index] |= (EBITMAP_BIT << ofs);
105 }
106
ebitmap_node_clr_bit(struct ebitmap_node * n,unsigned int bit)107 static inline void ebitmap_node_clr_bit(struct ebitmap_node *n,
108 unsigned int bit)
109 {
110 unsigned int index = EBITMAP_NODE_INDEX(n, bit);
111 unsigned int ofs = EBITMAP_NODE_OFFSET(n, bit);
112
113 BUG_ON( index >= EBITMAP_UNIT_NUMS );
114 n->maps[index] &= ~(EBITMAP_BIT << ofs);
115 }
116
117 #define ebitmap_for_each_positive_bit(e, n, bit) \
118 for ( bit = ebitmap_start_positive(e, &n); \
119 bit < ebitmap_length(e); \
120 bit = ebitmap_next_positive(e, &n, bit) ) \
121
122 int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
123 int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
124 int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);
125 int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
126 int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
127 void ebitmap_destroy(struct ebitmap *e);
128 int ebitmap_read(struct ebitmap *e, void *fp);
129
130 #endif /* _SS_EBITMAP_H_ */
131