.

wcfs/δbtail.go

@@ -505,22 +505,21 @@ type nodeInRange struct {
 	node     Node
 }
 
-// rangeCover represents set of nodes covering a range.
-// nodes come with key↑ and not intersection [lo,hi)
-// XXX -> nodeSet? nodeSetInRange?
-type rangeCover []*nodeInRange // key↑
+// rangeSplit represents set of nodes covering a range.
+// nodes come with key↑ and no intersection in between their [lo,hi)
+type rangeSplit []*nodeInRange // key↑
 
 // Get returns node covering key k.
 // Get panics if k is outside covered range.
-func (rc rangeCover) Get(k Key) *nodeInRange { // XXX -> Get_ -> rn, ok
-	i := sort.Search(len(rc), func(i int) bool {
-		return k <= rc[i].hi_
+func (rs rangeSplit) Get(k Key) *nodeInRange { // XXX -> Get_ -> rn, ok
+	i := sort.Search(len(rs), func(i int) bool {
+		return k <= rs[i].hi_
 	})
-	if i == len(rc) {
+	if i == len(rs) {
 		panicf("key %v not covered", k) // XXX + coverage: ...
 	}
 
-	rn := rc[i]
+	rn := rs[i]
 	if !(rn.lo <= k && k <= rn.hi_) {
 		panicf("BUG: get(%v) -> [%v, %v]", k, rn.lo, rn.hi_)
 	}
@@ -530,15 +529,15 @@ func (rc rangeCover) Get(k Key) *nodeInRange { // XXX -> Get_ -> rn, ok
 
 // Expand replaces rnode with its children.
 //
-// rnode must be initially in rc.
+// rnode must be initially in *prs.
 // rnode.node must be tree.
 // rnode.node must be aleady activated.
-func (prc *rangeCover) Expand(rnode *nodeInRange) []*nodeInRange {
-	rc := *prc
-	i := sort.Search(len(rc), func(i int) bool {
-		return rnode.hi_ <= rc[i].hi_
+func (prs *rangeCover) Expand(rnode *nodeInRange) []*nodeInRange {
+	rs := *prs
+	i := sort.Search(len(rs), func(i int) bool {
+		return rnode.hi_ <= rs[i].hi_
 	})
-	if i == len(rc) || rc[i] != rnode {
+	if i == len(rs) || rs[i] != rnode {
 		panicf("%s not in rangeCover", rnode)
 	}
 
@@ -563,7 +562,7 @@ func (prc *rangeCover) Expand(rnode *nodeInRange) []*nodeInRange {
 	}
 
 	// del[i]; insert(@i, children)
-	*prc = append(rc[:i], append(children, rc[i+1:]...)...)
+	*prs = append(rs[:i], append(children, rs[i+1:]...)...)
 	return children
 }
 
@@ -573,7 +572,7 @@ func (rc rangeCover) String() string {
 		if s != "" {
 			s += " "
 		}
-		s += fmt.Sprintf("[%v,%v]%s", rn.lo, rn.hi_, vnode(rn.node))
+		s += fmt.Sprintf("%s", rn)
 	}
 	return s
 }
@@ -1335,7 +1334,9 @@ func vnode(node Node) string {
 }
 
 func (rn nodeInRange) String() string {
-	return fmt.Sprintf("[%v,%v]%s", rn.lo, rn.hi_, vnode(rn.node))
+	slo := "-∞";  if rn.lo  > KeyMin { slo = fmt.Sprintf("%v", rn.lo) }
+	shi := "∞";   if rn.hi_ < KeyMax { shi = fmt.Sprintf("%v", rn.hi_+1) }
+	return fmt.Sprintf("[%s,%s)%s", slo, shi, vnode(rn.node))
 }
 
 func (track nodeTrack) String() string {