feat: embed template xmls

pack.go

@@ -2,29 +2,37 @@ package docxlib
 
 import (
 	"archive/zip"
+	"bytes"
 	"encoding/xml"
-	"strings"
 )
 
 // This receives a zip file writer (word documents are a zip with multiple xml inside)
 // and writes the relevant files. Some of them come from the empty_constants file,
 // others from the actual in-memory structure
 func (f *Docx) pack(zipWriter *zip.Writer) (err error) {
-	files := map[string]string{}
+	fileslst := []string{
+		"_rels/.rels",
+		"docProps/app.xml",
+		"docProps/core.xml",
+		"word/theme/theme1.xml",
+		"word/styles.xml",
+		"[Content_Types].xml",
+	}
+	files := make(map[string][]byte, 64)
 
-	files["_rels/.rels"] = TEMP_REL
-	files["docProps/app.xml"] = TEMP_DOCPROPS_APP
-	files["docProps/core.xml"] = TEMP_DOCPROPS_CORE
-	files["word/theme/theme1.xml"] = TEMP_WORD_THEME_THEME
-	files["word/styles.xml"] = TEMP_WORD_STYLE
-	files["[Content_Types].xml"] = TEMP_CONTENT
+	for _, name := range fileslst {
+		files[name], err = TEMP_XML_FS.ReadFile("xml/" + name)
+		if err != nil {
+			return
+		}
+	}
 	files["word/_rels/document.xml.rels"], err = marshal(f.DocRelation)
 	if err != nil {
-		return err
+		return
 	}
 	files["word/document.xml"], err = marshal(f.Document)
 	if err != nil {
-		return err
+		return
 	}
 
 	for path, data := range files {
@@ -33,7 +41,7 @@ func (f *Docx) pack(zipWriter *zip.Writer) (err error) {
 			return err
 		}
 
-		_, err = w.Write(StringToBytes(data))
+		_, err = w.Write(data)
 		if err != nil {
 			return err
 		}
@@ -42,13 +50,13 @@ func (f *Docx) pack(zipWriter *zip.Writer) (err error) {
 	return
 }
 
-func marshal(data interface{}) (out string, err error) {
-	sb := strings.Builder{}
-	sb.WriteString(xml.Header)
-	err = xml.NewEncoder(&sb).Encode(data)
+func marshal(data interface{}) (out []byte, err error) {
+	buf := bytes.NewBuffer(make([]byte, 0, 1024))
+	buf.WriteString(xml.Header)
+	err = xml.NewEncoder(buf).Encode(data)
 	if err != nil {
 		return
 	}
-	out = sb.String()
+	out = buf.Bytes()
 	return
 }