79 lines
2.2 KiB
C
79 lines
2.2 KiB
C
/*
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* An extensible bitmap is a bitmap that supports an
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* arbitrary number of bits. Extensible bitmaps are
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* used to represent sets of values, such as types,
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* roles, categories, and classes.
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*
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* Each extensible bitmap is implemented as a linked
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* list of bitmap nodes, where each bitmap node has
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* an explicitly specified starting bit position within
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* the total bitmap.
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*
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* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
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*/
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#ifndef _SS_EBITMAP_H_
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#define _SS_EBITMAP_H_
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#define MAPTYPE u64 /* portion of bitmap in each node */
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#define MAPSIZE (sizeof(MAPTYPE) * 8) /* number of bits in node bitmap */
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#define MAPBIT 1ULL /* a bit in the node bitmap */
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struct ebitmap_node {
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u32 startbit; /* starting position in the total bitmap */
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MAPTYPE map; /* this node's portion of the bitmap */
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struct ebitmap_node *next;
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};
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struct ebitmap {
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struct ebitmap_node *node; /* first node in the bitmap */
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u32 highbit; /* highest position in the total bitmap */
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};
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#define ebitmap_length(e) ((e)->highbit)
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#define ebitmap_startbit(e) ((e)->node ? (e)->node->startbit : 0)
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static inline unsigned int ebitmap_start(struct ebitmap *e,
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struct ebitmap_node **n)
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{
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*n = e->node;
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return ebitmap_startbit(e);
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}
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static inline void ebitmap_init(struct ebitmap *e)
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{
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memset(e, 0, sizeof(*e));
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}
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static inline unsigned int ebitmap_next(struct ebitmap_node **n,
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unsigned int bit)
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{
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if ((bit == ((*n)->startbit + MAPSIZE - 1)) &&
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(*n)->next) {
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*n = (*n)->next;
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return (*n)->startbit;
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}
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return (bit+1);
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}
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static inline int ebitmap_node_get_bit(struct ebitmap_node * n,
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unsigned int bit)
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{
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if (n->map & (MAPBIT << (bit - n->startbit)))
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return 1;
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return 0;
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}
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#define ebitmap_for_each_bit(e, n, bit) \
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for (bit = ebitmap_start(e, &n); bit < ebitmap_length(e); bit = ebitmap_next(&n, bit)) \
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int ebitmap_cmp(struct ebitmap *e1, struct ebitmap *e2);
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int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src);
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int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2);
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int ebitmap_get_bit(struct ebitmap *e, unsigned long bit);
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int ebitmap_set_bit(struct ebitmap *e, unsigned long bit, int value);
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void ebitmap_destroy(struct ebitmap *e);
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int ebitmap_read(struct ebitmap *e, void *fp);
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#endif /* _SS_EBITMAP_H_ */
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