add a generic priority queue implementation

src/pulsecore/prioq.h

@@ -0,0 +1,64 @@
+#ifndef foopulsecoreprioqhfoo
+#define foopulsecoreprioqhfoo
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2008 Lennart Poettering
+
+  PulseAudio is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+
+  PulseAudio is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#include <inttypes.h>
+
+#include <pulsecore/macro.h>
+#include <pulsecore/idxset.h>
+
+/* A heap-based priority queue. Removal and insertion is O(log
+ * n). Removal can happen a the top or at any position referenced by a
+ * pa_prioq_item.  */
+
+typedef struct pa_prioq pa_prioq;
+typedef struct pa_prioq_item pa_prioq_item;
+
+/* Instantiate a new prioq with the specified comparison functions */
+pa_prioq* pa_prioq_new(pa_compare_func_t compare_func);
+
+/* Free the prioq. When the prioq is not empty the specified function is called for every entry contained */
+void pa_prioq_free(pa_prioq *q, pa_free2_cb_t free_cb, void *userdata);
+
+/* Store a new item in the prioq. */
+pa_prioq_item* pa_prioq_put(pa_prioq *q, void* data);
+
+/* Get the item on the top of the queue, but don't remove it from the queue*/
+void* pa_prioq_peek(pa_prioq*q);
+
+/* Get the item on the top of the queue, and remove it from thq queue */
+void* pa_prioq_pop(pa_prioq*q);
+
+/* Remove an arbitrary from theq prioq, returning it's data */
+void* pa_prioq_remove(pa_prioq*q, pa_prioq_item *i);
+
+/* The priority of an item was modified. Adjustthe queue to that */
+void pa_prioq_reshuffle(pa_prioq *q, pa_prioq_item *i)
+
+/* Return the current number of items in the prioq */
+unsigned pa_prioq_size(pa_prioq*s);
+
+/* Return TRUE of the prioq is empty */
+pa_bool_t pa_prioq_isempty(pa_prioq *s);
+
+#endif