change interface to take a range pointer for the result and return a

1999-12-22  JP Rosevear  <jpr@arcavia.com>

	* src/ranges.c (range_intersection): change interface to take a
 	range pointer for the  result and return a boolean dictating
	whether or not the ranges actually intersect

	* src/ranges.h : update for new range_intersection interface

ChangeLog-2000-02-23

+1999-12-22  JP Rosevear  <jpr@arcavia.com>
+
+	* src/ranges.c (range_intersection): change interface to take a range
+	pointer for the  result and return a boolean dictating whether or not 
+	the ranges actually intersect
+
+	* src/ranges.h : update for new range_intersection interface
+
 1999-12-22  JP Rosevear  <jpr@arcavia.com>
 
 	* src/ranges.c (range_intersection): Clean to meet coding specs.

OChangeLog-2000-02-23

+1999-12-22  JP Rosevear  <jpr@arcavia.com>
+
+	* src/ranges.c (range_intersection): change interface to take a range
+	pointer for the  result and return a boolean dictating whether or not 
+	the ranges actually intersect
+
+	* src/ranges.h : update for new range_intersection interface
+
 1999-12-22  JP Rosevear  <jpr@arcavia.com>
 
 	* src/ranges.c (range_intersection): Clean to meet coding specs.

src/ranges.c

@@ -717,30 +717,31 @@ range_fragment_free (GList *fragments)
 
 /**
  * range_intersection:
+ * @r: intersection range
  * @a: range a
  * @b: range b
  * 
- * This computes the intersection; on a Venn
- * diagram this would be A (upside down U) B
- * NB. totally commutative.
- * 
- * Return value: the intersection
+ * This computes the intersection of two ranges; on a Venn
+ * diagram this would be A (upside down U) B.
+ * If the ranges do not intersect, false is returned an the
+ * values of r are unpredictable. 
+ *
+ * NB. totally commutative
+ *
+ * Return value: True if the ranges intersect, false otherwise
  **/
-Range
-range_intersection (Range const *a, Range const *b)
+gboolean
+range_intersection (Range *r, Range const *a, Range const *b)
 {
-	Range ans;
-
-	g_return_if_fail (range_overlap (a, b));
+	g_return_val_if_fail (range_overlap (a, b), FALSE);
 	
-	ans.start.col = MAX (a->start.col, b->start.col);
-	ans.start.row = MAX (a->start.row, b->start.row);
+	r->start.col = MAX (a->start.col, b->start.col);
+	r->start.row = MAX (a->start.row, b->start.row);
 	
-	ans.end.col = MIN (a->end.col, b->end.col);
-	ans.end.row = MIN (a->end.row, b->end.row);
+	r->end.col = MIN (a->end.col, b->end.col);
+	r->end.row = MIN (a->end.row, b->end.row);
 
-	/* Make sure this is an actual intersection */
-	return ans;
+	return TRUE;
 }
 
 /**

src/ranges.h

@@ -55,7 +55,9 @@ gboolean    range_overlap       (Range const *a, Range const *b);
 gboolean    range_contained     (Range const *a, Range const *b);
 gboolean    range_adjacent      (Range const *a, Range const *b);
 Range       range_merge         (Range const *a, Range const *b);
-Range       range_intersection  (Range const *a, Range const *b);
+gboolean    range_intersection  (Range *r,
+				 Range const *a,
+				 Range const *b);
 Range       range_union         (Range const *a, Range const *b);
 gboolean    range_translate     (Range *range, int col_offset, int row_offset);
 gboolean    range_expand        (Range *range, int d_tlx, int d_tly, int d_brx, int d_bry);