.

wcfs/internal/xbtree/rangeset.go

@@ -102,7 +102,7 @@ func (S *RangeSet) AddRange(r Range) {
 			S.rangev[:ilo],		append([]Range{
 			Range{lo, hi_}},
 			S.rangev[jhi:]...)...)
-		debugfRSet("\tmerge [%d:%d]\t-> %s\n", ilo, jhi, S)
+		debugfRSet("\tmerge S[%d:%d]\t-> %s\n", ilo, jhi, S)
 	}
 	jhi = -1 // no longer valid
 
@@ -162,7 +162,63 @@ func (S *RangeSet) DelRange(r Range) {
 	S.verify()
 	defer S.verify()
 
-	panic("TODO")	// XXX
+	// find first ilo: r.lo < [ilo].hi
+	l := len(S.rangev)
+	ilo := sort.Search(l, func(i int) bool {
+		 return r.lo <= S.rangev[i].hi_
+	})
+	debugfRSet("\tilo: %d\n", ilo)
+
+	if ilo == l { // not found
+		debugfRSet("\tnon-overlap right")
+		return
+	}
+
+	// find last jhi: [jhi].lo < r.hi
+	jhi := ilo
+	for ;; jhi++ {
+		if jhi == l {
+			break
+		}
+		if S.rangev[jhi].lo <= r.hi_ {
+			continue
+		}
+		break
+	}
+	debugfRSet("\tjhi: %d\n", jhi)
+
+	if jhi == 0 {
+		debugfRSet("\tnon-overlap left")
+		return
+	}
+
+	// [ilo+1:jhi-1] should be deleted
+	// [ilo] and [jhi-1] overlap with [r.lo,r.hi) - they shuold be deleted or shrinked.
+	if S.rangev[ilo].lo < r.lo { // shrink left
+		S.rangev = append(
+			S.rangev[:ilo],		append([]Range{
+			Range{S.rangev[ilo].lo, r.lo-1}},
+			S.rangev[ilo+1:]...)...)
+		ilo++
+		debugfRSet("\tshrink left\t-> %s\n", S)
+	}
+	if r.hi_ < S.rangev[jhi-1].hi_ { // shrink right
+		S.rangev = append(
+			S.rangev[:jhi-1],	append([]Range{
+			Range{r.hi_+1, S.rangev[jhi-1].hi_}},
+			S.rangev[jhi:]...)...)
+		jhi--
+		debugfRSet("\tshrink right\t-> %s\n", S)
+	}
+
+	if (jhi - ilo) > 1 {
+		S.rangev = append(
+			S.rangev[:ilo],
+			S.rangev[jhi:]...)
+		debugfRSet("\tdelete S[%d:%d]\t-> %s\n", ilo, jhi, S)
+	}
+
+	// done
 }