save bytes on memory instead of string

1 files changed, 11 insertions, 8 deletions

diff --git a/lib.go b/lib.go
index c0426d6..a168781 100644
--- a/lib.go
+++ b/lib.go
@@ -12,8 +12,8 @@ import (
 
 // ReadZipReader can be used to read an XLSX in memory without touching the
 // filesystem.
-func ReadZipReader(r *zip.Reader) (map[string]string, int, error) {
-	fileList := make(map[string]string)
+func ReadZipReader(r *zip.Reader) (map[string][]byte, int, error) {
+	fileList := make(map[string][]byte)
 	worksheets := 0
 	for _, v := range r.File {
 		fileList[v.Name] = readFile(v)
@@ -27,21 +27,24 @@ func ReadZipReader(r *zip.Reader) (map[string]string, int, error) {
 }
 
 // readXML provides function to read XML content as string.
-func (f *File) readXML(name string) string {
+func (f *File) readXML(name string) []byte {
 	if content, ok := f.XLSX[name]; ok {
 		return content
 	}
-	return ""
+	return []byte{}
 }
 
 // saveFileList provides function to update given file content in file list of
 // XLSX.
-func (f *File) saveFileList(name, content string) {
-	f.XLSX[name] = XMLHeader + content
+func (f *File) saveFileList(name string, content []byte) {
+	newContent := make([]byte, 0, len(XMLHeader)+len(content))
+	newContent = append(newContent, []byte(XMLHeader)...)
+	newContent = append(newContent, content...)
+	f.XLSX[name] = newContent
 }
 
 // Read file content as string in a archive file.
-func readFile(file *zip.File) string {
+func readFile(file *zip.File) []byte {
 	rc, err := file.Open()
 	if err != nil {
 		log.Fatal(err)
@@ -49,7 +52,7 @@ func readFile(file *zip.File) string {
 	buff := bytes.NewBuffer(nil)
 	io.Copy(buff, rc)
 	rc.Close()
-	return string(buff.Bytes())
+	return buff.Bytes()
 }
 
 // ToAlphaString provides function to convert integer to Excel sheet column