add: GetIndex func

Author: 54m

chunk.go

@@ -0,0 +1,25 @@
+package chunk
+
+// Index - index
+type Index struct {
+	From, To int
+}
+
+// GetIndex - returns index of specified size length
+func GetIndex(length int, chunkSize int) <-chan Index {
+	ch := make(chan Index)
+
+	go func() {
+		defer close(ch)
+
+		for i := 0; i < length; i += chunkSize {
+			idx := Index{i, i + chunkSize}
+			if length < idx.To {
+				idx.To = length
+			}
+			ch <- idx
+		}
+	}()
+
+	return ch
+}