- Performance optimization 20% faster, 14% memory savings on set cell values;

- Using the canonical syntax in issue template and contributing guide;
- go test has been updated

.github/ISSUE_TEMPLATE.md

@@ -21,19 +21,17 @@ Briefly describe the problem you are having in a few paragraphs.
 
 **Describe the results you received:**
 
-
 **Describe the results you expected:**
 
-
 **Output of `go version`:**
 
-```
+```text
 (paste your output here)
 ```
 
 **Excelize version or commit ID:**
 
-```
+```text
 (paste here)
 ```
 

CONTRIBUTING.md

@@ -25,7 +25,6 @@ Security reports are greatly appreciated and we will publicly thank you for it.
 We currently do not offer a paid security bounty program, but are not
 ruling it out in the future.
 
-
 ## Reporting other issues
 
 A great way to contribute to the project is to send a detailed report when you
@@ -44,7 +43,7 @@ When reporting issues, always include the output of `go env`.
 
 Also include the steps required to reproduce the problem if possible and
 applicable. This information will help us review and fix your issue faster.
-When sending lengthy log-files, consider posting them as a gist (https://gist.github.com).
+When sending lengthy log-files, consider posting them as a gist [https://gist.github.com](https://gist.github.com).
 Don't forget to remove sensitive data from your logfiles before posting (you can
 replace those parts with "REDACTED").
 
@@ -77,9 +76,9 @@ However, there might be a way to implement that feature *on top of* excelize.
 
 Fork the repository and make changes on your fork in a feature branch:
 
-- If it's a bug fix branch, name it XXXX-something where XXXX is the number of
+* If it's a bug fix branch, name it XXXX-something where XXXX is the number of
     the issue.
-- If it's a feature branch, create an enhancement issue to announce
+* If it's a feature branch, create an enhancement issue to announce
     your intentions, and name it XXXX-something where XXXX is the number of the
     issue.
 
@@ -194,7 +193,7 @@ signature certifies that you wrote the patch or otherwise have the right to pass
 it on as an open-source patch. The rules are pretty simple: if you can certify
 the below (from [developercertificate.org](http://developercertificate.org/)):
 
-```
+```text
 Developer Certificate of Origin
 Version 1.1
 
@@ -242,14 +241,14 @@ Use your real name (sorry, no pseudonyms or anonymous contributions.)
 If you set your `user.name` and `user.email` git configs, you can sign your
 commit automatically with `git commit -s`.
 
-### How can I become a maintainer?
+### How can I become a maintainer
 
 First, all maintainers have 3 things
 
-- They share responsibility in the project's success.
-- They have made a long-term, recurring time investment to improve the project.
-- They spend that time doing whatever needs to be done, not necessarily what
-is the most interesting or fun.
+* They share responsibility in the project's success.
+* They have made a long-term, recurring time investment to improve the project.
+* They spend that time doing whatever needs to be done, not necessarily what
+ is the most interesting or fun.
 
 Maintainers are often under-appreciated, because their work is harder to appreciate.
 It's easy to appreciate a really cool and technically advanced feature. It's harder

excelize_test.go

@@ -85,6 +85,9 @@ func TestOpenFile(t *testing.T) {
 	xlsx.SetCellValue("Sheet2", "F17", complex64(5+10i))
 	t.Log(letterOnlyMapF('x'))
 	t.Log(deepCopy(nil, nil))
+	shiftJulianToNoon(1, -0.6)
+	timeFromExcelTime(61, true)
+	timeFromExcelTime(62, true)
 	// Test boolean write
 	booltest := []struct {
 		value    bool

sheet.go

@@ -94,13 +94,15 @@ func (f *File) worksheetWriter() {
 
 // trimCell provides function to trim blank cells which created by completeCol.
 func trimCell(column []xlsxC) []xlsxC {
-	col := []xlsxC{}
+	col := make([]xlsxC, len(column))
+	i := 0
 	for _, c := range column {
 		if c.S != 0 || c.V != "" || c.F != nil || c.T != "" {
-			col = append(col, c)
+			col[i] = c
+			i++
 		}
 	}
-	return col
+	return col[0:i]
 }
 
 // Read and update property of contents type of XLSX.
@@ -641,8 +643,16 @@ func (f *File) GetSheetVisible(name string) bool {
 // trimSheetName provides function to trim invaild characters by given worksheet
 // name.
 func trimSheetName(name string) string {
-	r := strings.NewReplacer(":", "", "\\", "", "/", "", "?", "", "*", "", "[", "", "]", "")
-	name = r.Replace(name)
+	r := []rune{}
+	for _, v := range []rune(name) {
+		switch v {
+		case 58, 92, 47, 63, 42, 91, 93: // replace :\/?*[]
+			continue
+		default:
+			r = append(r, v)
+		}
+	}
+	name = string(r)
 	if utf8.RuneCountInString(name) > 31 {
 		name = string([]rune(name)[0:31])
 	}