Andrew's git - gitweb.git/blob

   1#ifndef PRIO_QUEUE_H
   2#define PRIO_QUEUE_H
   3
   4/*
   5 * A priority queue implementation, primarily for keeping track of
   6 * commits in the 'date-order' so that we process them from new to old
   7 * as they are discovered, but can be used to hold any pointer to
   8 * struct.  The caller is responsible for supplying a function to
   9 * compare two "things".
  10 *
  11 * Alternatively, this data structure can also be used as a LIFO stack
  12 * by specifying NULL as the comparison function.
  13 */
  14
  15/*
  16 * Compare two "things", one and two; the third parameter is cb_data
  17 * in the prio_queue structure.  The result is returned as a sign of
  18 * the return value, being the same as the sign of the result of
  19 * subtracting "two" from "one" (i.e. negative if "one" sorts earlier
  20 * than "two").
  21 */
  22typedef int (*prio_queue_compare_fn)(const void *one, const void *two, void *cb_data);
  23
  24struct prio_queue {
  25        prio_queue_compare_fn compare;
  26        void *cb_data;
  27        int alloc, nr;
  28        void **array;
  29};
  30
  31/*
  32 * Add the "thing" to the queue.
  33 */
  34extern void prio_queue_put(struct prio_queue *, void *thing);
  35
  36/*
  37 * Extract the "thing" that compares the smallest out of the queue,
  38 * or NULL.  If compare function is NULL, the queue acts as a LIFO
  39 * stack.
  40 */
  41extern void *prio_queue_get(struct prio_queue *);
  42
  43extern void clear_prio_queue(struct prio_queue *);
  44
  45/* Reverse the LIFO elements */
  46extern void prio_queue_reverse(struct prio_queue *);
  47
  48#endif /* PRIO_QUEUE_H */