git.squeep.com Git - fb-resolver/blob - lru_cache.h

   1 #ifndef LRU_CACHE_H
   2 #define LRU_CACHE_H
   3
   4 #include <stddef.h>
   5
   6 struct lru_cache_entry {
   7         struct lru_cache_entry *next;
   8         struct lru_cache_entry *prev;
   9         struct lru_cache_entry *hash_next;
  10         unsigned long hash_slot;
  11 };
  12 typedef struct lru_cache_entry lru_entry_t;
  13
  14
  15 /*
  16         A function which, given an entry, returns a pointer to a buffer
  17         and a number of bytes to use to generate a hash of the entry.
  18 */
  19 typedef void (lru_hash_feed_fn)(lru_entry_t *, char **, size_t *);
  20
  21 /*
  22         A function which compares two entries for equality.
  23 */
  24 typedef int (lru_entry_cmp_fn)(lru_entry_t *, lru_entry_t *);
  25
  26 struct lru_cache_hashslot_ {
  27         size_t tally;
  28         struct lru_cache_entry *entry;
  29 };
  30
  31 struct lru_cache {
  32         const size_t hash_sz;
  33         const size_t capacity;
  34
  35         lru_hash_feed_fn *feed_fn;
  36         lru_entry_cmp_fn *cmp_fn;
  37
  38         size_t num_entries;
  39         struct lru_cache_entry *newest;
  40         struct lru_cache_entry *oldest;
  41         struct lru_cache_hashslot_ hash[1];
  42 };
  43
  44 struct lru_cache *lru_cache_new(size_t, size_t, lru_hash_feed_fn *, lru_entry_cmp_fn *);
  45 void lru_cache_insert(struct lru_cache *, lru_entry_t *, lru_entry_t **);
  46 void lru_cache_extract(struct lru_cache *, lru_entry_t *);
  47 lru_entry_t *lru_cache_locate(struct lru_cache *, lru_entry_t *);
  48 void lru_cache_foreach(struct lru_cache *, void (*)(lru_entry_t *, size_t, void *), void *);
  49
  50 #endif /* LRU_CACHE_H */