Added libpqueue

will be part of the scheduler

1 files changed, 107 insertions, 0 deletions

diff --git a/inc/lib/pqueue.h b/inc/lib/pqueue.h
new file mode 100644
index 0000000..860a366
--- /dev/null
+++ b/inc/lib/pqueue.h
@@ -0,0 +1,107 @@
+/*
+ * Copyright (c) 2014, Volkan Yazıcı <volkan.yazici@gmail.com>
+ * Copyright (c) 2014, Marvin Borner <dev@marvinborner.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * @file  pqueue.h
+ * @brief Priority Queue function declarations
+ *
+ * @{
+ */
+
+#ifndef CALM_PQUEUE_H
+#define CALM_PQUEUE_H
+
+#include <stddef.h>
+#include <stdio.h>
+
+/** priority data type */
+typedef unsigned long long pqueue_pri_t;
+
+/** callback functions to get/set/compare the priority of an element */
+typedef pqueue_pri_t (*pqueue_get_pri_f)(void *a);
+typedef int (*pqueue_cmp_pri_f)(pqueue_pri_t next, pqueue_pri_t curr);
+
+/** callback functions to get/set the position of an element */
+typedef size_t (*pqueue_get_pos_f)(void *a);
+typedef void (*pqueue_set_pos_f)(void *a, size_t pos);
+
+/** debug callback function to print a entry */
+typedef void (*pqueue_print_entry_f)(FILE *out, void *a);
+
+/** the priority queue handle */
+struct pqueue {
+	size_t size; /**< number of elements in this queue */
+	size_t avail; /**< slots available in this queue */
+	size_t step; /**< growth stepping setting */
+	pqueue_cmp_pri_f cmppri; /**< callback to compare nodes */
+	pqueue_get_pri_f getpri; /**< callback to get priority of a node */
+	pqueue_set_pos_f setpos; /**< callback to set position of a node */
+	void **d; /**< The actualy queue in binary heap form */
+};
+
+/**
+ * initialize the queue
+ *
+ * @param n the initial estimate of the number of queue items for which memory
+ *     should be preallocated
+ * @param cmppri The callback function to run to compare two elements
+ *     This callback should return 0 for 'lower' and non-zero
+ *     for 'higher', or vice versa if reverse priority is desired
+ * @param getpri the callback function to run to set a score to an element
+ *
+ * @return the handle or NULL for insufficent memory
+ */
+struct pqueue *pqueue_init(size_t n, pqueue_cmp_pri_f cmppri,
+			   pqueue_get_pri_f getpri, pqueue_set_pos_f set_pos);
+
+/**
+ * free all memory used by the queue
+ * @param q the queue
+ */
+void pqueue_free(struct pqueue *q);
+
+/**
+ * return the size of the queue.
+ * @param q the queue
+ */
+size_t pqueue_size(struct pqueue *q);
+
+/**
+ * insert an item into the queue.
+ * @param q the queue
+ * @param d the item
+ * @return 0 on success
+ */
+int pqueue_insert(struct pqueue *q, void *d);
+
+/**
+ * pop the highest-ranking item from the queue.
+ * @param q the queue
+ * @return NULL on error, otherwise the entry
+ */
+void *pqueue_pop(struct pqueue *q);
+
+#endif