git/hash.h
Linus Torvalds 11f944dd6b for_each_hash: allow passing a 'void *data' pointer to callback
For the find_exact_renames() function, this allows us to pass the
diff_options structure pointer to the low-level routines.  We will use
that to distinguish between the "rename" and "copy" cases.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-02-18 22:25:51 -08:00

44 lines
1.1 KiB
C

#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