1 /* Licensed under LGPLv2+ - see LICENSE file for details */
10 * struct htable - private definition of a htable.
12 * It's exposed here so you can put it in your structures and so we can
13 * supply inline functions.
16 size_t (*rehash)(const void *elem, void *priv);
19 size_t elems, deleted, max, max_with_deleted;
20 /* These are the bits which are the same in all pointers. */
21 uintptr_t common_mask, common_bits;
22 uintptr_t perfect_bit;
27 * HTABLE_INITIALIZER - static initialization for a hash table.
28 * @name: name of this htable.
29 * @rehash: hash function to use for rehashing.
30 * @priv: private argument to @rehash function.
32 * This is useful for setting up static and global hash tables.
35 * // For simplicity's sake, say hash value is contents of elem.
36 * static size_t rehash(const void *elem, void *unused)
38 * return *(size_t *)elem;
40 * static struct htable ht = HTABLE_INITIALIZER(ht, rehash, NULL);
42 #define HTABLE_INITIALIZER(name, rehash, priv) \
43 { rehash, priv, 0, 0, 0, 0, 0, -1, 0, 0, &name.perfect_bit }
46 * htable_init - initialize an empty hash table.
47 * @ht: the hash table to initialize
48 * @rehash: hash function to use for rehashing.
49 * @priv: private argument to @rehash function.
51 void htable_init(struct htable *ht,
52 size_t (*rehash)(const void *elem, void *priv), void *priv);
55 * htable_clear - empty a hash table.
56 * @ht: the hash table to clear
58 * This doesn't do anything to any pointers left in it.
60 void htable_clear(struct htable *ht);
63 * htable_rehash - use a hashtree's rehash function
64 * @elem: the argument to rehash()
67 size_t htable_rehash(const void *elem);
70 * htable_add - add a pointer into a hash table.
72 * @hash: the hash value of the object
73 * @p: the non-NULL pointer
75 * Also note that this can only fail due to allocation failure. Otherwise, it
78 bool htable_add(struct htable *ht, size_t hash, const void *p);
81 * htable_del - remove a pointer from a hash table
83 * @hash: the hash value of the object
86 * Returns true if the pointer was found (and deleted).
88 bool htable_del(struct htable *ht, size_t hash, const void *p);
91 * struct htable_iter - iterator or htable_first or htable_firstval etc.
93 * This refers to a location inside the hashtable.
100 * htable_firstval - find a candidate for a given hash value
101 * @htable: the hashtable
102 * @i: the struct htable_iter to initialize
103 * @hash: the hash value
105 * You'll need to check the value is what you want; returns NULL if none.
109 void *htable_firstval(const struct htable *htable,
110 struct htable_iter *i, size_t hash);
113 * htable_nextval - find another candidate for a given hash value
114 * @htable: the hashtable
115 * @i: the struct htable_iter to initialize
116 * @hash: the hash value
118 * You'll need to check the value is what you want; returns NULL if no more.
120 void *htable_nextval(const struct htable *htable,
121 struct htable_iter *i, size_t hash);
124 * htable_get - find an entry in the hash table
126 * @h: the hash value of the entry
127 * @cmp: the comparison function
128 * @ptr: the pointer to hand to the comparison function.
130 * Convenient inline wrapper for htable_firstval/htable_nextval loop.
132 static inline void *htable_get(const struct htable *ht,
134 bool (*cmp)(const void *candidate, void *ptr),
137 struct htable_iter i;
140 for (c = htable_firstval(ht,&i,h); c; c = htable_nextval(ht,&i,h)) {
141 if (cmp(c, (void *)ptr))
148 * htable_first - find an entry in the hash table
150 * @i: the struct htable_iter to initialize
152 * Get an entry in the hashtable; NULL if empty.
154 void *htable_first(const struct htable *htable, struct htable_iter *i);
157 * htable_next - find another entry in the hash table
159 * @i: the struct htable_iter to use
161 * Get another entry in the hashtable; NULL if all done.
162 * This is usually used after htable_first or prior non-NULL htable_next.
164 void *htable_next(const struct htable *htable, struct htable_iter *i);
167 * htable_delval - remove an iterated pointer from a hash table
169 * @i: the htable_iter
171 * Usually used to delete a hash entry after it has been found with
172 * htable_firstval etc.
174 void htable_delval(struct htable *ht, struct htable_iter *i);
176 #endif /* CCAN_HTABLE_H */