Reuse function

set/subtract.go

@@ -17,23 +17,21 @@ limitations under the License.
 package set
 
 import (
-	"bufio"
 	"io"
 )
 
 func Subtract(f1, f2 io.Reader) <-chan string {
 	ch := make(chan string, 16)
+	chLines1 := readNonEmptyLines(f1)
 	go func() {
 		defer close(ch)
-		scanner1 := bufio.NewScanner(f1)
 		searcher := &rowSearcher{
 			chRowsInBulk: readLinesInBulk(f2, 64),
 		}
 		var lastLine string
 		var f2Exhausted bool
-		for scanner1.Scan() {
-			line := scanner1.Text()
-			if len(line) == 0 || line == lastLine {
+		for line := range chLines1 {
+			if line == lastLine {
 				continue
 			}
 			lastLine = line

set/union.go

@@ -17,7 +17,6 @@ limitations under the License.
 package set
 
 import (
-	"bufio"
 	"io"
 )
 
@@ -88,19 +87,3 @@ func Union(f1, f2 io.Reader) <-chan string {
 	}()
 	return ch
 }
-
-func readNonEmptyLines(r io.Reader) <-chan string {
-	scanner := bufio.NewScanner(r)
-	chLine := make(chan string, 10)
-	go func() {
-		for scanner.Scan() {
-			line := scanner.Text()
-			if len(line) == 0 {
-				continue
-			}
-			chLine <- line
-		}
-		close(chLine)
-	}()
-	return chLine
-}

set/utils.go

@@ -69,3 +69,19 @@ func (rs *rowSearcher) Search(row string) (found bool, inRange bool, exhausted b
 	}
 	return
 }
+
+func readNonEmptyLines(r io.Reader) <-chan string {
+	scanner := bufio.NewScanner(r)
+	chLine := make(chan string, 10)
+	go func() {
+		for scanner.Scan() {
+			line := scanner.Text()
+			if len(line) == 0 {
+				continue
+			}
+			chLine <- line
+		}
+		close(chLine)
+	}()
+	return chLine
+}