Andrew's git / gitweb.git /
a8b9e3dc8c9a49869191e33cfa9e974b6f11e3d1
   1#ifndef HASHMAP_H
   2#define HASHMAP_H
   3
   4/*
   5 * Generic implementation of hash-based key-value mappings.
   6 * See Documentation/technical/api-hashmap.txt.
   7 */
   8
   9/* FNV-1 functions */
  10
  11extern unsigned int strhash(const char *buf);
  12extern unsigned int strihash(const char *buf);
  13extern unsigned int memhash(const void *buf, size_t len);
  14extern unsigned int memihash(const void *buf, size_t len);
  15
  16static inline unsigned int sha1hash(const unsigned char *sha1)
  17{
  18        /*
  19         * Equivalent to 'return *(unsigned int *)sha1;', but safe on
  20         * platforms that don't support unaligned reads.
  21         */
  22        unsigned int hash;
  23        memcpy(&hash, sha1, sizeof(hash));
  24        return hash;
  25}
  26
  27/* data structures */
  28
  29struct hashmap_entry {
  30        struct hashmap_entry *next;
  31        unsigned int hash;
  32};
  33
  34typedef int (*hashmap_cmp_fn)(const void *entry, const void *entry_or_key,
  35                const void *keydata);
  36
  37struct hashmap {
  38        struct hashmap_entry **table;
  39        hashmap_cmp_fn cmpfn;
  40        unsigned int size, tablesize, grow_at, shrink_at;
  41};
  42
  43struct hashmap_iter {
  44        struct hashmap *map;
  45        struct hashmap_entry *next;
  46        unsigned int tablepos;
  47};
  48
  49/* hashmap functions */
  50
  51extern void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function,
  52                size_t initial_size);
  53extern void hashmap_free(struct hashmap *map, int free_entries);
  54
  55/* hashmap_entry functions */
  56
  57static inline void hashmap_entry_init(void *entry, unsigned int hash)
  58{
  59        struct hashmap_entry *e = entry;
  60        e->hash = hash;
  61        e->next = NULL;
  62}
  63extern void *hashmap_get(const struct hashmap *map, const void *key,
  64                const void *keydata);
  65extern void *hashmap_get_next(const struct hashmap *map, const void *entry);
  66extern void hashmap_add(struct hashmap *map, void *entry);
  67extern void *hashmap_put(struct hashmap *map, void *entry);
  68extern void *hashmap_remove(struct hashmap *map, const void *key,
  69                const void *keydata);
  70
  71static inline void *hashmap_get_from_hash(const struct hashmap *map,
  72                unsigned int hash, const void *keydata)
  73{
  74        struct hashmap_entry key;
  75        hashmap_entry_init(&key, hash);
  76        return hashmap_get(map, &key, keydata);
  77}
  78
  79/* hashmap_iter functions */
  80
  81extern void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter);
  82extern void *hashmap_iter_next(struct hashmap_iter *iter);
  83static inline void *hashmap_iter_first(struct hashmap *map,
  84                struct hashmap_iter *iter)
  85{
  86        hashmap_iter_init(map, iter);
  87        return hashmap_iter_next(iter);
  88}
  89
  90#endif