Andrew's git - gitweb.git/blob

   1#ifndef MRU_H
   2#define MRU_H
   3
   4/**
   5 * A simple most-recently-used cache, backed by a doubly-linked list.
   6 *
   7 * Usage is roughly:
   8 *
   9 *   // Create a list.  Zero-initialization is required.
  10 *   static struct mru cache;
  11 *   mru_append(&cache, item);
  12 *   ...
  13 *
  14 *   // Iterate in MRU order.
  15 *   struct mru_entry *p;
  16 *   for (p = cache.head; p; p = p->next) {
  17 *      if (matches(p->item))
  18 *              break;
  19 *   }
  20 *
  21 *   // Mark an item as used, moving it to the front of the list.
  22 *   mru_mark(&cache, p);
  23 *
  24 *   // Reset the list to empty, cleaning up all resources.
  25 *   mru_clear(&cache);
  26 *
  27 * Note that you SHOULD NOT call mru_mark() and then continue traversing the
  28 * list; it reorders the marked item to the front of the list, and therefore
  29 * you will begin traversing the whole list again.
  30 */
  31
  32struct mru_entry {
  33        void *item;
  34        struct mru_entry *prev, *next;
  35};
  36
  37struct mru {
  38        struct mru_entry *head, *tail;
  39};
  40
  41void mru_append(struct mru *mru, void *item);
  42void mru_mark(struct mru *mru, struct mru_entry *entry);
  43void mru_clear(struct mru *mru);
  44
  45#endif /* MRU_H */