1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
|
#ifndef HASH_H
#define HASH_H
/*
* These are some simple generic hash table helper functions.
* Not necessarily suitable for all users, but good for things
* where you want to just keep track of a list of things, and
* have a good hash to use on them.
*
* It keeps the hash table at roughly 50-75% free, so the memory
* cost of the hash table itself is roughly
*
* 3 * 2*sizeof(void *) * nr_of_objects
*
* bytes.
*
* FIXME: on 64-bit architectures, we waste memory. It would be
* good to have just 32-bit pointers, requiring a special allocator
* for hashed entries or something.
*/
struct hash_table_entry {
unsigned int hash;
void *ptr;
};
struct hash_table {
unsigned int size, nr;
struct hash_table_entry *array;
};
extern void *lookup_hash(unsigned int hash, const struct hash_table *table);
extern void **insert_hash(unsigned int hash, void *ptr, struct hash_table *table);
extern int for_each_hash(const struct hash_table *table, int (*fn)(void *, void *), void *data);
extern void free_hash(struct hash_table *table);
static inline void init_hash(struct hash_table *table)
{
table->size = 0;
table->nr = 0;
table->array = NULL;
}
#endif
|
