X fixes for empty set/range

wcfs/internal/xbtree/blib/rangemap.go.in

@@ -116,7 +116,7 @@ func (M *RangedMap) SetRange(r KeyRange, v VALUE) {
 	defer M.verify()
 
 	if r.Empty() {
-		return // XXX or panic?
+		return
 	}
 
 	// clear range for r and insert new entry
@@ -235,11 +235,17 @@ func (M *RangedMap) DelRange(r KeyRange) {
 	M.verify()
 	defer M.verify()
 
+	if r.Empty() {
+		return
+	}
+
 	M.delRange(r)
 }
 
 // delRange deletes range r from the map and returns .entryv index where r
 // should be inserted/appended if needed.
+//
+// r must be !empty.
 func (M *RangedMap) delRange(r KeyRange) (i int) {
 	// find first ilo: r.Lo < [ilo].hi
 	l := len(M.entryv)
@@ -315,6 +321,10 @@ func (M *RangedMap) HasRange(r KeyRange) (yes bool) {
 
 	M.verify()
 
+	if r.Empty() {
+		return true
+	}
+
 	// find first ilo: r.lo < [ilo].hi
 	l := len(M.entryv)
 	ilo := sort.Search(l, func(i int) bool {

wcfs/internal/xbtree/blib/rangemap_test.go

@@ -101,7 +101,7 @@ func TestRangedMap(t *testing.T) {
 			X(0,0,x),		// X
 				M(),			// Set
 				M(),			// Del
-				n),			// Has
+				y),			// Has
 
 		// empty vs !empty
 		E(
@@ -117,7 +117,7 @@ func TestRangedMap(t *testing.T) {
 			X(0,0,x),		// X
 				M(1,2,a),		// Set
 				M(1,2,a),		// Del
-				y),			// Has XXX ok
+				y),			// Has
 
 		// basic change
 		E(
@@ -226,7 +226,11 @@ func TestRangedMap(t *testing.T) {
 		}
 
 		assertMapHasRange(t, Mset, r, true)
-		assertMapHasRange(t, Mdel, r, false)
+		rInMdel := false
+		if r.Empty() {
+			rInMdel = true
+		}
+		assertMapHasRange(t, Mdel, r, rInMdel)
 
 		verifyGet(t, M)
 		verifyGet(t, Mset)

wcfs/internal/xbtree/blib/zrangemap_str.go

@@ -118,7 +118,7 @@ func (M *_RangedMap_str) SetRange(r KeyRange, v string) {
 	defer M.verify()
 
 	if r.Empty() {
-		return // XXX or panic?
+		return
 	}
 
 	// clear range for r and insert new entry
@@ -237,11 +237,17 @@ func (M *_RangedMap_str) DelRange(r KeyRange) {
 	M.verify()
 	defer M.verify()
 
+	if r.Empty() {
+		return
+	}
+
 	M.delRange(r)
 }
 
 // delRange deletes range r from the map and returns .entryv index where r
 // should be inserted/appended if needed.
+//
+// r must be !empty.
 func (M *_RangedMap_str) delRange(r KeyRange) (i int) {
 	// find first ilo: r.Lo < [ilo].hi
 	l := len(M.entryv)
@@ -317,6 +323,10 @@ func (M *_RangedMap_str) HasRange(r KeyRange) (yes bool) {
 
 	M.verify()
 
+	if r.Empty() {
+		return true
+	}
+
 	// find first ilo: r.lo < [ilo].hi
 	l := len(M.entryv)
 	ilo := sort.Search(l, func(i int) bool {

wcfs/internal/xbtree/blib/zrangemap_void.go

@@ -118,7 +118,7 @@ func (M *_RangedMap_void) SetRange(r KeyRange, v void) {
 	defer M.verify()
 
 	if r.Empty() {
-		return // XXX or panic?
+		return
 	}
 
 	// clear range for r and insert new entry
@@ -237,11 +237,17 @@ func (M *_RangedMap_void) DelRange(r KeyRange) {
 	M.verify()
 	defer M.verify()
 
+	if r.Empty() {
+		return
+	}
+
 	M.delRange(r)
 }
 
 // delRange deletes range r from the map and returns .entryv index where r
 // should be inserted/appended if needed.
+//
+// r must be !empty.
 func (M *_RangedMap_void) delRange(r KeyRange) (i int) {
 	// find first ilo: r.Lo < [ilo].hi
 	l := len(M.entryv)
@@ -317,6 +323,10 @@ func (M *_RangedMap_void) HasRange(r KeyRange) (yes bool) {
 
 	M.verify()
 
+	if r.Empty() {
+		return true
+	}
+
 	// find first ilo: r.lo < [ilo].hi
 	l := len(M.entryv)
 	ilo := sort.Search(l, func(i int) bool {