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45eda693bdbc7efc53f6b0ce29a172bcb574cfdf
   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);
  15extern unsigned int memihash_cont(unsigned int hash_seed, const void *buf, size_t len);
  16
  17static inline unsigned int sha1hash(const unsigned char *sha1)
  18{
  19        /*
  20         * Equivalent to 'return *(unsigned int *)sha1;', but safe on
  21         * platforms that don't support unaligned reads.
  22         */
  23        unsigned int hash;
  24        memcpy(&hash, sha1, sizeof(hash));
  25        return hash;
  26}
  27
  28/* data structures */
  29
  30struct hashmap_entry {
  31        struct hashmap_entry *next;
  32        unsigned int hash;
  33};
  34
  35typedef int (*hashmap_cmp_fn)(const void *entry, const void *entry_or_key,
  36                const void *keydata);
  37
  38struct hashmap {
  39        struct hashmap_entry **table;
  40        hashmap_cmp_fn cmpfn;
  41        unsigned int size, tablesize, grow_at, shrink_at;
  42};
  43
  44struct hashmap_iter {
  45        struct hashmap *map;
  46        struct hashmap_entry *next;
  47        unsigned int tablepos;
  48};
  49
  50/* hashmap functions */
  51
  52extern void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function,
  53                size_t initial_size);
  54extern void hashmap_free(struct hashmap *map, int free_entries);
  55
  56/* hashmap_entry functions */
  57
  58static inline void hashmap_entry_init(void *entry, unsigned int hash)
  59{
  60        struct hashmap_entry *e = entry;
  61        e->hash = hash;
  62        e->next = NULL;
  63}
  64extern void *hashmap_get(const struct hashmap *map, const void *key,
  65                const void *keydata);
  66extern void *hashmap_get_next(const struct hashmap *map, const void *entry);
  67extern void hashmap_add(struct hashmap *map, void *entry);
  68extern void *hashmap_put(struct hashmap *map, void *entry);
  69extern void *hashmap_remove(struct hashmap *map, const void *key,
  70                const void *keydata);
  71
  72static inline void *hashmap_get_from_hash(const struct hashmap *map,
  73                unsigned int hash, const void *keydata)
  74{
  75        struct hashmap_entry key;
  76        hashmap_entry_init(&key, hash);
  77        return hashmap_get(map, &key, keydata);
  78}
  79
  80/* hashmap_iter functions */
  81
  82extern void hashmap_iter_init(struct hashmap *map, struct hashmap_iter *iter);
  83extern void *hashmap_iter_next(struct hashmap_iter *iter);
  84static inline void *hashmap_iter_first(struct hashmap *map,
  85                struct hashmap_iter *iter)
  86{
  87        hashmap_iter_init(map, iter);
  88        return hashmap_iter_next(iter);
  89}
  90
  91/* string interning */
  92
  93extern const void *memintern(const void *data, size_t len);
  94static inline const char *strintern(const char *string)
  95{
  96        return memintern(string, strlen(string));
  97}
  98
  99#endif