add ranges

src/server/torr/storage/torrstor/ranges.go

@@ -0,0 +1,49 @@
+package torrstor
+
+import (
+	"sort"
+)
+
+type Range struct {
+	Start, End int
+}
+
+func inRanges(ranges []Range, ind int) bool {
+	for _, r := range ranges {
+		if ind >= r.Start && ind <= r.End {
+			return true
+		}
+	}
+	return false
+}
+
+func mergeRange(ranges []Range) []Range {
+	if len(ranges) <= 1 {
+		return ranges
+	}
+	// copy ranges
+	merged := append([]Range(nil), ranges...)
+
+	sort.Slice(merged, func(i, j int) bool {
+		if merged[i].Start < merged[j].Start {
+			return true
+		}
+		if merged[i].Start == merged[j].Start && merged[i].End < merged[j].End {
+			return true
+		}
+		return false
+	})
+
+	j := 0
+	for i := 1; i < len(merged); i++ {
+		if merged[j].End >= merged[i].Start {
+			if merged[j].End < merged[i].End {
+				merged[j].End = merged[i].End
+			}
+		} else {
+			j++
+			merged[j] = merged[i]
+		}
+	}
+	return merged[:j+1]
+}