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 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 42 static inline void ebitmap_init(struct ebitmap *e) 43 { 44 memset(e, 0, sizeof(*e)); 45 } 46 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 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_ */ 79