X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fadt%2Fpqueue.c;h=0a7702ca3928931affedf9543c734fdb68483d14;hb=d6a6c024a4742e89a95deffaa5e95ca93c9d8c08;hp=e8495b0fee7dd8d25e44c123d885efa59ca994b1;hpb=db40734d1c57aa6898d9ea3a1156ad0a78cd6610;p=libfirm

diff --git a/ir/adt/pqueue.c b/ir/adt/pqueue.c
index e8495b0fe..0a7702ca3 100644
--- a/ir/adt/pqueue.c
+++ b/ir/adt/pqueue.c
@@ -1,7 +1,35 @@
+/*
+ * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
+ */
+
+/**
+ * @file
+ * @author  Christian Wuerdig, Matthias Braun
+ * @brief   Priority Queue implementation based on the heap datastructure
+ * @version $Id$
+ */
+#include "config.h"
+
 #include "array.h"
 #include "pqueue.h"
+#include "error.h"
 
-/**
+/*
  * Implements a heap.
  *
  * Implementation note: It might seem strange that we start indexing at 0
@@ -15,13 +43,12 @@
  * implementations or the ugly (i+1)*2 - 1 and (i+1)*2 for calculating the
  * left and right child. (At the expense that stuff easily breaks when you make
  * changes and don't think that the left child of 0 is 0 :-/)
- * @author matze
  *
  */
 
 typedef struct _pqueue_el_t {
 	void *data;
-	int  key;
+	int  priority;
 } pqueue_el_t;
 
 struct _pqueue_t {
@@ -32,18 +59,20 @@ struct _pqueue_t {
  * Enforces the heap characteristics if the queue
  * starting from element at position @p pos.
  */
-static void pqueue_heapify(pqueue *q, int pos) {
-	int len = ARR_LEN(q->elems);
+static void pqueue_heapify(pqueue_t *q, unsigned pos)
+{
+	unsigned len = ARR_LEN(q->elems);
 
 	while (pos * 2 < len) {
 		pqueue_el_t tmp;
-		int         exchange = pos;
+		unsigned    exchange = pos;
 
-		if (q->elems[exchange].key < q->elems[pos * 2].key) {
+		if (q->elems[exchange].priority < q->elems[pos * 2].priority) {
 			exchange = pos * 2;
 		}
 
-		if ((pos * 2 + 1) < len && q->elems[exchange].key < q->elems[pos * 2 + 1].key) {
+		if ((pos * 2 + 1) < len
+				&& q->elems[exchange].priority < q->elems[pos * 2 + 1].priority) {
 			exchange = pos * 2 + 1;
 		}
 
@@ -61,8 +90,9 @@ static void pqueue_heapify(pqueue *q, int pos) {
 /**
  * Sifts up a newly inserted element at position @p pos.
  */
-static void pqueue_sift_up(pqueue *q, int pos) {
-	while(q->elems[pos].key > q->elems[pos / 2].key) {
+static void pqueue_sift_up(pqueue_t *q, unsigned pos)
+{
+	while (q->elems[pos].priority > q->elems[pos / 2].priority) {
 		pqueue_el_t tmp;
 
 		tmp               = q->elems[pos];
@@ -73,57 +103,39 @@ static void pqueue_sift_up(pqueue *q, int pos) {
 	}
 }
 
-/**
- * Creates a new priority queue.
- * @return A priority queue of initial length 0.
- */
-pqueue *new_pqueue() {
-	pqueue *res = xmalloc(sizeof(*res));
+pqueue_t *new_pqueue(void)
+{
+	pqueue_t *res = XMALLOC(pqueue_t);
 	res->elems = NEW_ARR_F(pqueue_el_t, 0);
 	return res;
 }
 
-/**
- * Frees all memory allocated by the priority queue.
- * @param q   The priority queue to destroy.
- */
-void del_pqueue(pqueue *q) {
+void del_pqueue(pqueue_t *q)
+{
 	DEL_ARR_F(q->elems);
 	free(q);
 }
 
-/**
- * Inserts a new element into a priority queue.
- * @param q      The priority queue the element should be inserted to.
- * @param data   The actual data which should be stored in the queue.
- * @param key    The priority for the data.
- */
-void pqueue_put(pqueue *q, void *data, int key) {
+void pqueue_put(pqueue_t *q, void *data, int priority)
+{
 	pqueue_el_t el;
 
-	el.data = data;
-	el.key  = key;
+	el.data     = data;
+	el.priority = priority;
 
 	ARR_APP1(pqueue_el_t, q->elems, el);
 
-	pqueue_sift_up(q, ARR_LEN(q->elems));
+	pqueue_sift_up(q, ARR_LEN(q->elems) - 1);
 }
 
-/**
- * Returns and removes the first element, ie. that one with the highest priority, from the queue.
- * @param q   The priority queue.
- * @return The first element of the queue. Asserts if queue is empty.
- */
-void *pqueue_get(pqueue *q) {
-	switch(ARR_LEN(q->elems)) {
+void *pqueue_pop_front(pqueue_t *q)
+{
+	switch (ARR_LEN(q->elems)) {
 		case 0:
-			assert(0 && "Attempt to retrieve element from empty priority queue.");
-			return NULL;
-			break;
+			panic("Attempt to retrieve element from empty priority queue.");
 		case 1:
 			ARR_SHRINKLEN(q->elems, 0);
 			return q->elems[0].data;
-			break;
 		default: {
 			void *data = q->elems[0].data;
 			int  len   = ARR_LEN(q->elems) - 1;
@@ -137,20 +149,12 @@ void *pqueue_get(pqueue *q) {
 	}
 }
 
-/**
- * Get the length of the priority queue.
- * @param q   The priority queue.
- * @return The length of the queue.
- */
-int pqueue_length(pqueue *q) {
+int pqueue_length(const pqueue_t *q)
+{
 	return ARR_LEN(q->elems);
 }
 
-/**
- * Returns true if queue is empty.
- * @param q   The priority queue.
- * @return 1 if the queue is empty, 0 otherwise.
- */
-int pqueue_empty(pqueue *q) {
+int pqueue_empty(const pqueue_t *q)
+{
 	return ARR_LEN(q->elems) == 0;
 }