From 6c467f5fbc333d45519184d6ea99842032044c76 Mon Sep 17 00:00:00 2001
From: suzaku <satorulogic@gmail.com>
Date: Sat, 18 Sep 2021 14:07:07 +0800
Subject: [PATCH] Reuse function

---
 set/subtract.go |  8 +++-----
 set/union.go    | 17 -----------------
 set/utils.go    | 16 ++++++++++++++++
 3 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/set/subtract.go b/set/subtract.go
index 0ae3ad2..e501489 100644
--- a/set/subtract.go
+++ b/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
diff --git a/set/union.go b/set/union.go
index 2be8d85..51b9d40 100644
--- a/set/union.go
+++ b/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
-}
diff --git a/set/utils.go b/set/utils.go
index 6d6459d..c526b8d 100644
--- a/set/utils.go
+++ b/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
+}