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 "common.h"
  11
  12 #include "vector.h"
  13
  14 typedef git_vector git_pqueue;
  15
  16 enum {
  17         /* flag meaning: don't grow heap, keep highest values only */
  18         GIT_PQUEUE_FIXED_SIZE = (GIT_VECTOR_FLAG_MAX << 1)
  19 };
  20
  21 /**
  22  * Initialize priority queue
  23  *
  24  * @param pq The priority queue struct to initialize
  25  * @param flags Flags (see above) to control queue behavior
  26  * @param init_size The initial queue size
  27  * @param cmp The entry priority comparison function
  28  * @return 0 on success, <0 on error
  29  */
  30 extern int git_pqueue_init(
  31         git_pqueue *pq,
  32         uint32_t flags,
  33         size_t init_size,
  34         git_vector_cmp cmp);
  35
  36 #define git_pqueue_free  git_vector_free
  37 #define git_pqueue_clear git_vector_clear
  38 #define git_pqueue_size  git_vector_length
  39 #define git_pqueue_get   git_vector_get
  40 #define git_pqueue_reverse git_vector_reverse
  41
  42 /**
  43  * Insert a new item into the queue
  44  *
  45  * @param pq The priority queue
  46  * @param item Pointer to the item data
  47  * @return 0 on success, <0 on failure
  48  */
  49 extern int git_pqueue_insert(git_pqueue *pq, void *item);
  50
  51 /**
  52  * Remove the top item in the priority queue
  53  *
  54  * @param pq The priority queue
  55  * @return item from heap on success, NULL if queue is empty
  56  */
  57 extern void *git_pqueue_pop(git_pqueue *pq);
  58
  59 #endif