X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=include%2Flibfirm%2Fadt%2Funionfind.h;h=b71d01651a3ed59f9f74bb3c5f934b2adc558104;hb=97bcf6f245eba55a1d3b25a7be543b367ab9c276;hp=5e1cb47d5cebc9e36ac35e0244ddd97edfcf42f3;hpb=972eca70744a2c9a0e0d472db4f62250cdeee01c;p=libfirm

diff --git a/include/libfirm/adt/unionfind.h b/include/libfirm/adt/unionfind.h
index 5e1cb47d5..b71d01651 100644
--- a/include/libfirm/adt/unionfind.h
+++ b/include/libfirm/adt/unionfind.h
@@ -21,29 +21,35 @@
  * @file
  * @brief      Union-Find datastructure
  * @author     Matthias Braun
- * @version    $Id$
- * @summary
- *  Union-Find datastructure
- *
- *  This implementation uses weighted sets and path compression which results
- *  in (nearly) O(n) complexity for n find and union operations
  */
 #ifndef FIRM_ADT_UNIONFIND_H
 #define FIRM_ADT_UNIONFIND_H
 
 #include <assert.h>
 
+#include "../begin.h"
+
+/**
+ * @ingroup adt
+ * @defgroup unionfind Union-Find
+ *  Union-Find datastructure
+ *
+ *  This implementation uses weighted sets and path compression which results
+ *  in (nearly) O(n) complexity for n find and union operations
+ * @{
+ */
+
 /**
  * Call this to initialize an array of @p count elements to be used by the
  * union find functions.
  *
- * @param data	The array (you have to allocate it yourself)
- * @param from	The first element that should be initialized
- * @param to	the index of the first element which is not initialized anymore
+ * @param data    The array (you have to allocate it yourself)
+ * @param n_elems number of elements handled by the datastructure
  */
-static inline void uf_init(int* data, int from, int to) {
-	int i;
-	for(i = from; i < to; ++i) {
+static inline void uf_init(int* data, size_t n_elems)
+{
+	size_t i;
+	for(i = 0; i < n_elems; ++i) {
 		data[i] = -1;
 	}
 }
@@ -52,32 +58,34 @@ static inline void uf_init(int* data, int from, int to) {
  * Merge 2 sets (union operation). Note that you have to pass the
  * representatives of the sets and not just random elements
  *
- * @param data	The union find data
- * @param set1	Representative of set1
- * @param set2	Representative of set2
- * @return		0 if the new union set is represented by set1, 1 if it is
- *              represented by set2
+ * @param data  The union find data
+ * @param set1  Representative of set1
+ * @param set2  Representative of set2
+ * @return      the new representative of the set (which is set1 or set2)
  */
-static inline int uf_union(int* data, int set1, int set2) {
-	int d1 = data[set1];
-	int d2 = data[set2];
+static inline int uf_union(int* data, int set1, int set2)
+{
+	int d1;
+	int d2;
 	int newcount;
 
 	if(set1 == set2)
-		return 0;
+		return set1;
 
 	/* need 2 set representatives */
+	d1 = data[set1];
+	d2 = data[set2];
 	assert(d1 < 0 && d2 < 0);
 
 	newcount = d1 + d2;
 	if(d1 > d2) {
 		data[set1] = set2;
 		data[set2] = newcount;
-		return 1;
+		return set2;
 	} else {
 		data[set2] = set1;
 		data[set1] = newcount;
-		return 0;
+		return set1;
 	}
 }
 
@@ -87,11 +95,12 @@ static inline int uf_union(int* data, int set1, int set2) {
  * the same/different representatives, then the elements are in the
  * the same/different sets.
  *
- * @param data	The union find data
- * @param e		The element
- * @return		The representative of the set that contains @p e
+ * @param data  The union find data
+ * @param e     The element
+ * @return      The representative of the set that contains @p e
  */
-static inline int uf_find(int* data, int e) {
+static inline int uf_find(int* data, int e)
+{
 	/* go through list to find representative */
 	int repr = e;
 	while(data[repr] >= 0) {
@@ -108,4 +117,8 @@ static inline int uf_find(int* data, int e) {
 	return repr;
 }
 
-#endif /* FIRM_ADT_UNIONFIND_H */
+/** @} */
+
+#include "../end.h"
+
+#endif