refactored and optimized using buffer

Author: rsrini7

.gitignore

@@ -24,4 +24,5 @@ _testmain.go
 data/bigdata/
 debug.test
 .vscode
-debug
+debug
+.idea/

godiff.go

@@ -224,6 +224,7 @@ var (
 	flag_max_goroutines          = 1
 	flag_p_keys                  string
 	flag_html_output             string = "diff.html"
+	flag_txt_output              string = "diff.txt"
 	flag_csv_delta               string = "delta.csv"
 )
 
@@ -244,8 +245,10 @@ var regexp_exclude_files *regexp.Regexp
 
 // Buffered stdout
 var (
-	out      *bufio.Writer
-	out_lock sync.Mutex
+	out        *bufio.Writer
+	out_lock   sync.Mutex
+	outputFile *os.File
+	errF       error
 )
 
 // html entity strings
@@ -306,7 +309,8 @@ func main() {
 	flag.BoolVar(&flag_suppress_line_changes, "l", flag_suppress_line_changes, "Do not display changes within lines")
 	flag.BoolVar(&flag_suppress_missing_file, "m", flag_suppress_missing_file, "Do not show content if corresponding file is missing")
 	flag.BoolVar(&flag_unified_context, "u", flag_unified_context, "Unified context")
-	flag.BoolVar(&flag_output_as_text, "n", flag_output_as_text, "Output using 'diff' text format instead of HTML")
+	flag.BoolVar(&flag_output_as_text, "txt", flag_output_as_text, "Output using 'diff' text format instead of HTML")
+	flag.StringVar(&flag_txt_output, "n", flag_txt_output, "Generate given txt diff file")
 
 	flag.StringVar(&flag_p_keys, "key", "", "The Primary Key Columns")
 	flag.StringVar(&flag_html_output, "html", flag_html_output, "Generate HTML diff file")
@@ -316,12 +320,20 @@ func main() {
 
 	flag.Parse()
 
-	output_html_file, err := os.Create(flag_html_output)
-	if err != nil {
-		usage(err.Error())
+	if flag_txt_output != "diff.txt" {
+		flag_output_as_text = true
+	}
+
+	if flag_output_as_text {
+		outputFile, errF = os.Create(flag_txt_output)
+	} else {
+		outputFile, errF = os.Create(flag_html_output)
 	}
 
-	out = bufio.NewWriterSize(output_html_file, OUTPUT_BUF_SIZE)
+	if errF != nil {
+		usage(errF.Error())
+	}
+	out = bufio.NewWriterSize(outputFile, OUTPUT_BUF_SIZE)
 
 	if flag_version {
 		version()
@@ -349,7 +361,7 @@ func main() {
 	// flush output on termination
 	defer func() {
 		out.Flush()
-		output_html_file.Close()
+		outputFile.Close()
 	}()
 
 	// choose which compare and hash function to use
@@ -1250,9 +1262,7 @@ func sortCsv(fname string) (string, os.FileInfo) {
 	file, err := os.Open(fname)
 	defer file.Close()
 
-	if strings.HasSuffix(fname, ".colreordered") {
-		defer os.Remove(fname)
-	}
+	defer removeFile(fname, ".colreordered")
 
 	fnameSorted := fname + ".sorted"
 	wfile, err := os.Create(fnameSorted)
@@ -1363,9 +1373,7 @@ func open_file(fname string, finfo os.FileInfo) *Filedata {
 // Close file (and umap it)
 func (file *Filedata) close_file() {
 
-	if strings.HasSuffix(file.name, ".sorted") {
-		defer os.Remove(file.name)
-	}
+	defer removeFile(file.name, ".sorted")
 
 	if file.osfile != nil {
 		if file.is_mapped && file.data != nil {
@@ -1377,6 +1385,12 @@ func (file *Filedata) close_file() {
 	file.data = nil
 }
 
+func removeFile(fileName string, ext string) {
+	if strings.HasSuffix(fileName, ext) {
+		os.Remove(fileName)
+	}
+}
+
 // check if file is binary
 func (file *Filedata) check_binary() {
 	if file.data == nil {

htmlgen.go

@@ -237,7 +237,6 @@ func writeDiffToCSV(buf []byte) {
 		usage(err.Error())
 	}
 	defer output_csv_file.Close()
-
 	outCSV := bufio.NewWriter(output_csv_file)
 	outCSV.WriteString(strings.Join(csvHeaderData, ","))
 	outCSV.WriteString("\n")

utils/csvutils.go

@@ -1,60 +1,68 @@
 package utils
 
 import (
+	"bufio"
+	"bytes"
 	"encoding/csv"
 	"fmt"
 	"os"
+	"strings"
 )
 
 //ColumnReorder is to reorder the CSV columns
 func ColumnReorder(filePath string, columns []int) {
-	file, err := os.Open(filePath)
-	defer file.Close()
 
+	buf := bytes.Buffer{}
+	//defer buf.Reset()
+
+	file, err := os.Open(filePath)
 	if err != nil {
 		_ = fmt.Errorf("error in reading file %s", err)
 	}
+	defer file.Close()
 
 	reader := csv.NewReader(file)
 	var newColumn []string
 
-	writer, wFile := getWriter(filePath)
-	defer wFile.Close()
+	/*writer, wFile := getWriter(filePath)
+	defer wFile.Close()*/
 
 	for line, err := reader.Read(); err == nil; line, err = reader.Read() {
 		for _, v := range columns {
 			newColumn = append(newColumn, line[v])
 		}
 
-		if err = writer.Write(newColumn); err != nil {
+		if _, err = buf.WriteString(strings.Join(newColumn, ",") + "\n"); err != nil {
 			fmt.Println("Error:", err)
 			break
 		}
-		writer.Flush()
+
+		/*if err = writer.Write(newColumn); err != nil {
+			fmt.Println("Error:", err)
+			break
+		}
+		writer.Flush()*/
+
 		newColumn = newColumn[:0]
 	}
-}
 
-/*func writeDiffCSVDelta(buf *bytes.Buffer, line []byte) {
-	buf.Write(line)
-	buf.WriteString("\n")
+	writeToFile(filePath+".colreordered", buf.Bytes())
 }
 
 func writeToFile(filePath string, buf []byte) {
-	wFile, err := os.Create(filePath) //".colreordered"
+	wFile, err := os.Create(filePath)
 	if err != nil {
-		usage(err.Error())
+		fmt.Println("writeToFile Error: ", err)
+		return
 	}
-	defer output_csv_file.Close()
+	defer wFile.Close()
 
-	outCSV := bufio.NewWriter(output_csv_file)
-	outCSV.WriteString(strings.Join(csvHeaderData, ","))
-	outCSV.WriteString("\n")
-	outCSV.Write(buf)
-	outCSV.Flush()
-}*/
+	outFile := bufio.NewWriter(wFile)
+	outFile.Write(buf)
+	outFile.Flush()
+}
 
-func getWriter(filePath string) (*csv.Writer, *os.File) {
+/*func getWriter(filePath string) (*csv.Writer, *os.File) {
 	// Creating csv writer
 	wFile, err := os.Create(filePath + ".colreordered")
 	if err != nil {
@@ -64,7 +72,7 @@ func getWriter(filePath string) (*csv.Writer, *os.File) {
 
 	writer := csv.NewWriter(wFile)
 	return writer, wFile
-}
+}*/
 
 //GetColumnCount : return the CSV column count
 func GetColumnCount(filePath string) int {