added -pushIfNotPresent:

Author: rfm

Headers/GNUstepBase/GSMinHeap.h

@@ -102,12 +102,20 @@ GS_EXPORT_CLASS
 - (id) pop;
 
 /** Adds obj to the heap and returns YES on success.  May return NO on failure
- * (of obj was nil or if there is insufficient memory for the heap to grow).
+ * (if obj was nil or if there is insufficient memory for the heap to grow).
  * The heap takes ownership of (retains) obj on success, but not on failure.
  * It is possible to push the same object ot the heap more than once.
  */
 - (BOOL) push: (id)obj;
 
+/** Adds obj to the heap if (and only if) it is not already present.
+ * Returns YES on success (the object was present or was added).
+ * May return NO on failure (if obj was nil or if there is insufficient
+ * memory for the heap to grow).
+ * The heap takes ownership of (retains) obj on success if it was added.
+ */
+- (BOOL) pushIfNotPresent: (id)obj;
+
 /** Removes all objects matching obj using the -isEqual: method.
  */
 - (void) removeObject: (id)obj;

Source/Additions/GSMinHeap.m

@@ -362,11 +362,36 @@ - (id) pop
 
 - (BOOL) push: (id)obj
 {
-  if (obj != nil && heap_push(internal, RETAIN(obj)))
+  if (obj != nil)
     {
-      return YES;
+      if (heap_push(internal, obj))
+	{
+	  RETAIN(obj);
+	  return YES;
+	}
+    }
+  return NO;
+}
+
+- (BOOL) pushIfNotPresent: (id)obj
+{
+  if (obj != nil)
+    {
+      size_t	index = internal->size;
+
+      while (index-- > 0)
+	{
+	  if (obj == internal->data[index])
+	    {
+	      return YES;
+	    }
+	}
+      if (heap_push(internal, obj))
+	{
+	  RETAIN(obj);
+	  return YES;
+	}
     }
-  RELEASE(obj);
   return NO;
 }
 

Tests/base/GSMinHeap/test00.m

@@ -61,6 +61,14 @@
   PASS_EQUAL([heap next], @"b", "heap -next of a,b returns b")
   PASS([heap count] == 1, "heap count 1 after push push next")
 
+  PASS([heap pushIfNotPresent: @"a"] == YES, "-pushIfNotPresent: reports a added to heap")
+  PASS([heap count] == 2, "heap count 2 after -pushIfNotPresent: added a")
+  PASS([heap pushIfNotPresent: @"a"] == YES, "-pushIfNotPresent: reports a already in heap")
+  PASS([heap count] == 2, "heap count 2 after -pushIfNotPresent: added a again")
+
+  PASS([heap pushIfNotPresent: nil] == NO, "-pushIfNotPresent: refuses to add nil")
+  PASS([heap count] == 2, "heap count 2 after -pushIfNotPresent: refused to add nil")
+
   DESTROY(heap);
 
   END_SET("GSMinHeap")