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#ifndef HASHMAP_H
#define HASHMAP_H
 
/*
 * Generic implementation of hash-based key-value mappings.
 * See Documentation/technical/api-hashmap.txt.
 */
 
/* FNV-1 functions */
 
extern unsigned int strhash(const char *buf);
extern unsigned int strihash(const char *buf);
extern unsigned int memhash(const void *buf, size_t len);
extern unsigned int memihash(const void *buf, size_t len);
 
static inline unsigned int sha1hash(const unsigned char *sha1)
{
	/*
	 * Equivalent to 'return *(unsigned int *)sha1;', but safe on
	 * platforms that don't support unaligned reads.
	 */
	unsigned int hash;
	memcpy(&hash, sha1, sizeof(hash));
	return hash;
}
 
/* data structures */
 
struct hashmap_entry {
	struct hashmap_entry *next;
	unsigned int hash;
};
 
typedef int (*hashmap_cmp_fn)(const void *entry, const void *entry_or_key,
		const void *keydata);
 
struct hashmap {
	struct hashmap_entry **table;
	hashmap_cmp_fn cmpfn;
	unsigned int size, tablesize, grow_at, shrink_at;
};
 
struct hashmap_iter {
	struct hashmap *map;
	struct hashmap_entry *next;
	unsigned int tablepos;
};
 
/* hashmap functions */
 
extern void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function,
		size_t initial_size);
extern void hashmap_free(struct hashmap *map, int free_entries);
 
/* hashmap_entry functions */
 
static inline void hashmap_entry_init(void *entry, unsigned int hash)
{
	struct hashmap_entry *e = entry;
	e->hash = hash;
	e->next = NULL;
}
extern void *hashmap_get(const struct hashmap *map, const void *key,
		const void *keydata);
extern void *hashmap_get_next(const struct hashmap *map, const void *entry);
extern void hashmap_add(struct hashmap *map, void *entry);
extern void *hashmap_put(struct hashmap *map, void *entry);
extern void *hashmap_remove(struct hashmap *map, const void *key,
		const void *keydata);
 
/* hashmap_iter functions */
 
extern void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter);
extern void *hashmap_iter_next(struct hashmap_iter *iter);
static inline void *hashmap_iter_first(struct hashmap *map,
		struct hashmap_iter *iter)
{
	hashmap_iter_init(map, iter);
	return hashmap_iter_next(iter);
}
 
#endif