.

wcfs/internal/xbtree/pptreesubset.go

@@ -160,7 +160,15 @@ func (A PPTreeSubSet) UnionInplace(B PPTreeSubSet) {
 	A.xUnionInplace(B)
 }
 
-// XXX Difference
+// Difference returns D = PP(A.leafs \ B.leafs)
+//
+// In other words ... XXX
+func (A PPTreeSubSet) Difference(B PPTreeSubSet) PPTreeSubSet {
+	D := A.Clone()
+	D.DifferenceInplace(B)
+	return D
+}
+
 
 // DifferenceInplace sets A = PP(A.leafs \ B.leafs)
 //

wcfs/internal/xbtree/rangeset.go

@@ -128,8 +128,6 @@ func (S *RangeSet) verify() {
 	}
 }
 
-// XXX Equal
-
 // Clone returns copy of the set.
 func (orig *RangeSet) Clone() *RangeSet {
 	klon := &RangeSet{}
@@ -137,6 +135,20 @@ func (orig *RangeSet) Clone() *RangeSet {
 	return klon
 }
 
+// Equal returns whether A == B.
+func (A *RangeSet) Equal(B *RangeSet) bool {
+	if len(A.rangev) != len(B.rangev) {
+		return false
+	}
+	for i, ra := range A.rangev {
+		rb := B.rangev[i]
+		if ra != rb {
+			return false
+		}
+	}
+	return true
+}
+
 func (S RangeSet) String() string {
 	s := "{"
 	for i, r := range S.rangev {