src/pqueue.h

   1 /*
   2  * Copyright (C) the libgit2 contributors.  All rights reserved.
   3  *
   4  * This file is part of libgit2, distributed under the GNU GPL v2 with
   5  * a Linking Exception. For full terms see the included COPYING file.
   6  */
   7 #ifndef INCLUDE_pqueue_h__
   8 #define INCLUDE_pqueue_h__
   9
  10 #include "vector.h"
  11
  12 typedef git_vector git_pqueue;
  13
  14 enum {
  15         /* flag meaning: don't grow heap, keep highest values only */
  16         GIT_PQUEUE_FIXED_SIZE = (GIT_VECTOR_FLAG_MAX << 1),
  17 };
  18
  19 /**
  20  * Initialize priority queue
  21  *
  22  * @param pq The priority queue struct to initialize
  23  * @param flags Flags (see above) to control queue behavior
  24  * @param init_size The initial queue size
  25  * @param cmp The entry priority comparison function
  26  * @return 0 on success, <0 on error
  27  */
  28 extern int git_pqueue_init(
  29         git_pqueue *pq,
  30         uint32_t flags,
  31         size_t init_size,
  32         git_vector_cmp cmp);
  33
  34 #define git_pqueue_free  git_vector_free
  35 #define git_pqueue_clear git_vector_clear
  36 #define git_pqueue_size  git_vector_length
  37 #define git_pqueue_get   git_vector_get
  38
  39 /**
  40  * Insert a new item into the queue
  41  *
  42  * @param pq The priority queue
  43  * @param item Pointer to the item data
  44  * @return 0 on success, <0 on failure
  45  */
  46 extern int git_pqueue_insert(git_pqueue *pq, void *item);
  47
  48 /**
  49  * Remove the top item in the priority queue
  50  *
  51  * @param pq The priority queue
  52  * @return item from heap on success, NULL if queue is empty
  53  */
  54 extern void *git_pqueue_pop(git_pqueue *pq);
  55
  56 #endif