mru.h

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