Merge branch 'jk/mailsplit-maildir-muttsort' into maint
[git/jnareb-git.git] / hash.h
blobb875ce67c49eb39a8ca8ad6a688a334985db0534
1 #ifndef HASH_H
2 #define HASH_H
4 /*
5 * These are some simple generic hash table helper functions.
6 * Not necessarily suitable for all users, but good for things
7 * where you want to just keep track of a list of things, and
8 * have a good hash to use on them.
10 * It keeps the hash table at roughly 50-75% free, so the memory
11 * cost of the hash table itself is roughly
13 * 3 * 2*sizeof(void *) * nr_of_objects
15 * bytes.
17 * FIXME: on 64-bit architectures, we waste memory. It would be
18 * good to have just 32-bit pointers, requiring a special allocator
19 * for hashed entries or something.
21 struct hash_table_entry {
22 unsigned int hash;
23 void *ptr;
26 struct hash_table {
27 unsigned int size, nr;
28 struct hash_table_entry *array;
31 extern void *lookup_hash(unsigned int hash, const struct hash_table *table);
32 extern void **insert_hash(unsigned int hash, void *ptr, struct hash_table *table);
33 extern int for_each_hash(const struct hash_table *table, int (*fn)(void *, void *), void *data);
34 extern void free_hash(struct hash_table *table);
36 static inline void init_hash(struct hash_table *table)
38 table->size = 0;
39 table->nr = 0;
40 table->array = NULL;
43 #endif