This closes #1212, init support for 1900 or 1904 date system

10 files changed, 94 insertions, 49 deletions

diff --git a/cell.go b/cell.go
index 3c44af4..1d6ed84 100644
--- a/cell.go
+++ b/cell.go
@@ -109,8 +109,12 @@ func (f *File) GetCellType(sheet, axis string) (CellType, error) {
 //    bool
 //    nil
 //
-// Note that default date format is m/d/yy h:mm of time.Time type value. You can
-// set numbers format by SetCellStyle() method.
+// Note that default date format is m/d/yy h:mm of time.Time type value. You
+// can set numbers format by SetCellStyle() method. If you need to set the
+// specialized date in Excel like January 0, 1900 or February 29, 1900, these
+// times can not representation in Go language time.Time data type. Please set
+// the cell value as number 0 or 60, then create and bind the date-time number
+// format style for the cell.
 func (f *File) SetCellValue(sheet, axis string, value interface{}) error {
 	var err error
 	switch v := value.(type) {
@@ -240,7 +244,7 @@ func setCellTime(value time.Time) (t string, b string, isNum bool, err error) {
 // setCellDuration prepares cell type and value by given Go time.Duration type
 // time duration.
 func setCellDuration(value time.Duration) (t string, v string) {
-	v = strconv.FormatFloat(value.Seconds()/86400.0, 'f', -1, 32)
+	v = strconv.FormatFloat(value.Seconds()/86400, 'f', -1, 32)
 	return
 }
 
@@ -752,26 +756,8 @@ func (f *File) SetCellHyperLink(sheet, axis, link, linkType string, opts ...Hype
 	return nil
 }
 
-// GetCellRichText provides a function to get rich text of cell by given
-// worksheet.
-func (f *File) GetCellRichText(sheet, cell string) (runs []RichTextRun, err error) {
-	ws, err := f.workSheetReader(sheet)
-	if err != nil {
-		return
-	}
-	cellData, _, _, err := f.prepareCell(ws, cell)
-	if err != nil {
-		return
-	}
-	siIdx, err := strconv.Atoi(cellData.V)
-	if err != nil || cellData.T != "s" {
-		return
-	}
-	sst := f.sharedStringsReader()
-	if len(sst.SI) <= siIdx || siIdx < 0 {
-		return
-	}
-	si := sst.SI[siIdx]
+// getCellRichText returns rich text of cell by given string item.
+func getCellRichText(si *xlsxSI) (runs []RichTextRun) {
 	for _, v := range si.R {
 		run := RichTextRun{
 			Text: v.T.Val,
@@ -803,6 +789,29 @@ func (f *File) GetCellRichText(sheet, cell string) (runs []RichTextRun, err erro
 	return
 }
 
+// GetCellRichText provides a function to get rich text of cell by given
+// worksheet.
+func (f *File) GetCellRichText(sheet, cell string) (runs []RichTextRun, err error) {
+	ws, err := f.workSheetReader(sheet)
+	if err != nil {
+		return
+	}
+	cellData, _, _, err := f.prepareCell(ws, cell)
+	if err != nil {
+		return
+	}
+	siIdx, err := strconv.Atoi(cellData.V)
+	if err != nil || cellData.T != "s" {
+		return
+	}
+	sst := f.sharedStringsReader()
+	if len(sst.SI) <= siIdx || siIdx < 0 {
+		return
+	}
+	runs = getCellRichText(&sst.SI[siIdx])
+	return
+}
+
 // newRpr create run properties for the rich text by given font format.
 func newRpr(fnt *Font) *xlsxRPr {
 	rpr := xlsxRPr{}
@@ -1099,17 +1108,20 @@ func (f *File) formattedValue(s int, v string, raw bool) string {
 	if styleSheet.CellXfs.Xf[s].NumFmtID != nil {
 		numFmtID = *styleSheet.CellXfs.Xf[s].NumFmtID
 	}
-
+	date1904, wb := false, f.workbookReader()
+	if wb != nil && wb.WorkbookPr != nil {
+		date1904 = wb.WorkbookPr.Date1904
+	}
 	ok := builtInNumFmtFunc[numFmtID]
 	if ok != nil {
-		return ok(v, builtInNumFmt[numFmtID])
+		return ok(v, builtInNumFmt[numFmtID], date1904)
 	}
 	if styleSheet == nil || styleSheet.NumFmts == nil {
 		return v
 	}
 	for _, xlsxFmt := range styleSheet.NumFmts.NumFmt {
 		if xlsxFmt.NumFmtID == numFmtID {
-			return format(v, xlsxFmt.FormatCode)
+			return format(v, xlsxFmt.FormatCode, date1904)
 		}
 	}
 	return v
diff --git a/chart.go b/chart.go
index f740a2b..7b7162b 100644
--- a/chart.go
+++ b/chart.go
@@ -479,8 +479,8 @@ func parseFormatChartSet(formatSet string) (*formatChart, error) {
 		},
 		Format: formatPicture{
 			FPrintsWithSheet: true,
-			XScale:           1.0,
-			YScale:           1.0,
+			XScale:           1,
+			YScale:           1,
 		},
 		Legend: formatChartLegend{
 			Position: "bottom",
diff --git a/date.go b/date.go
index 83d23cc..1574af7 100644
--- a/date.go
+++ b/date.go
@@ -36,7 +36,7 @@ func timeToExcelTime(t time.Time) (float64, error) {
 	// TODO in future this should probably also handle date1904 and like TimeFromExcelTime
 
 	if t.Before(excelMinTime1900) {
-		return 0.0, nil
+		return 0, nil
 	}
 
 	tt := t
@@ -58,7 +58,7 @@ func timeToExcelTime(t time.Time) (float64, error) {
 	// program that had the majority market share at the time; Lotus 1-2-3.
 	// https://www.myonlinetraininghub.com/excel-date-and-time
 	if t.After(excelBuggyPeriodStart) {
-		result += 1.0
+		result++
 	}
 	return result, nil
 }
diff --git a/numfmt.go b/numfmt.go
index 6cb7fc7..5503027 100644
--- a/numfmt.go
+++ b/numfmt.go
@@ -34,7 +34,7 @@ type numberFormat struct {
 	section                                                                 []nfp.Section
 	t                                                                       time.Time
 	sectionIdx                                                              int
-	isNumeric, hours, seconds                                               bool
+	date1904, isNumeric, hours, seconds                                     bool
 	number                                                                  float64
 	ap, afterPoint, beforePoint, localCode, result, value, valueSectionType string
 }
@@ -287,9 +287,9 @@ func (nf *numberFormat) prepareNumberic(value string) {
 // format provides a function to return a string parse by number format
 // expression. If the given number format is not supported, this will return
 // the original cell value.
-func format(value, numFmt string) string {
+func format(value, numFmt string, date1904 bool) string {
 	p := nfp.NumberFormatParser()
-	nf := numberFormat{section: p.Parse(numFmt), value: value}
+	nf := numberFormat{section: p.Parse(numFmt), value: value, date1904: date1904}
 	nf.number, nf.valueSectionType = nf.getValueSectionType(value)
 	nf.prepareNumberic(value)
 	for i, section := range nf.section {
@@ -315,7 +315,7 @@ func format(value, numFmt string) string {
 // positiveHandler will be handling positive selection for a number format
 // expression.
 func (nf *numberFormat) positiveHandler() (result string) {
-	nf.t, nf.hours, nf.seconds = timeFromExcelTime(nf.number, false), false, false
+	nf.t, nf.hours, nf.seconds = timeFromExcelTime(nf.number, nf.date1904), false, false
 	for i, token := range nf.section[nf.sectionIdx].Items {
 		if inStrSlice(supportedTokenTypes, token.TType, true) == -1 || token.TType == nfp.TokenTypeGeneral {
 			result = nf.value
diff --git a/numfmt_test.go b/numfmt_test.go
index 7dc3f77..5cdf56b 100644
--- a/numfmt_test.go
+++ b/numfmt_test.go
@@ -1005,7 +1005,7 @@ func TestNumFmt(t *testing.T) {
 		{"-8.0450685976001E-21", "0_);[Red]\\(0\\)", "(0)"},
 		{"-8.04506", "0_);[Red]\\(0\\)", "(8)"},
 	} {
-		result := format(item[0], item[1])
+		result := format(item[0], item[1], false)
 		assert.Equal(t, item[2], result, item)
 	}
 }
diff --git a/picture.go b/picture.go
index 919262c..5e8f6b8 100644
--- a/picture.go
+++ b/picture.go
@@ -31,8 +31,8 @@ import (
 func parseFormatPictureSet(formatSet string) (*formatPicture, error) {
 	format := formatPicture{
 		FPrintsWithSheet: true,
-		XScale:           1.0,
-		YScale:           1.0,
+		XScale:           1,
+		YScale:           1,
 	}
 	err := json.Unmarshal(parseFormatSet(formatSet), &format)
 	return &format, err
diff --git a/shape.go b/shape.go
index db76867..6d86f38 100644
--- a/shape.go
+++ b/shape.go
@@ -25,8 +25,8 @@ func parseFormatShapeSet(formatSet string) (*formatShape, error) {
 		Height: 160,
 		Format: formatPicture{
 			FPrintsWithSheet: true,
-			XScale:           1.0,
-			YScale:           1.0,
+			XScale:           1,
+			YScale:           1,
 		},
 		Line: formatLine{Width: 1},
 	}
diff --git a/styles.go b/styles.go
index 11f6f75..6ef7dcb 100644
--- a/styles.go
+++ b/styles.go
@@ -754,7 +754,7 @@ var currencyNumFmt = map[int]string{
 
 // builtInNumFmtFunc defined the format conversion functions map. Partial format
 // code doesn't support currently and will return original string.
-var builtInNumFmtFunc = map[int]func(v string, format string) string{
+var builtInNumFmtFunc = map[int]func(v, format string, date1904 bool) string{
 	0:  format,
 	1:  formatToInt,
 	2:  formatToFloat,
@@ -847,7 +847,7 @@ var criteriaType = map[string]string{
 // formatToInt provides a function to convert original string to integer
 // format as string type by given built-in number formats code and cell
 // string.
-func formatToInt(v string, format string) string {
+func formatToInt(v, format string, date1904 bool) string {
 	f, err := strconv.ParseFloat(v, 64)
 	if err != nil {
 		return v
@@ -858,7 +858,7 @@ func formatToInt(v string, format string) string {
 // formatToFloat provides a function to convert original string to float
 // format as string type by given built-in number formats code and cell
 // string.
-func formatToFloat(v string, format string) string {
+func formatToFloat(v, format string, date1904 bool) string {
 	f, err := strconv.ParseFloat(v, 64)
 	if err != nil {
 		return v
@@ -868,7 +868,7 @@ func formatToFloat(v string, format string) string {
 
 // formatToA provides a function to convert original string to special format
 // as string type by given built-in number formats code and cell string.
-func formatToA(v string, format string) string {
+func formatToA(v, format string, date1904 bool) string {
 	f, err := strconv.ParseFloat(v, 64)
 	if err != nil {
 		return v
@@ -883,7 +883,7 @@ func formatToA(v string, format string) string {
 
 // formatToB provides a function to convert original string to special format
 // as string type by given built-in number formats code and cell string.
-func formatToB(v string, format string) string {
+func formatToB(v, format string, date1904 bool) string {
 	f, err := strconv.ParseFloat(v, 64)
 	if err != nil {
 		return v
@@ -896,7 +896,7 @@ func formatToB(v string, format string) string {
 
 // formatToC provides a function to convert original string to special format
 // as string type by given built-in number formats code and cell string.
-func formatToC(v string, format string) string {
+func formatToC(v, format string, date1904 bool) string {
 	f, err := strconv.ParseFloat(v, 64)
 	if err != nil {
 		return v
@@ -907,7 +907,7 @@ func formatToC(v string, format string) string {
 
 // formatToD provides a function to convert original string to special format
 // as string type by given built-in number formats code and cell string.
-func formatToD(v string, format string) string {
+func formatToD(v, format string, date1904 bool) string {
 	f, err := strconv.ParseFloat(v, 64)
 	if err != nil {
 		return v
@@ -918,7 +918,7 @@ func formatToD(v string, format string) string {
 
 // formatToE provides a function to convert original string to special format
 // as string type by given built-in number formats code and cell string.
-func formatToE(v string, format string) string {
+func formatToE(v, format string, date1904 bool) string {
 	f, err := strconv.ParseFloat(v, 64)
 	if err != nil {
 		return v
diff --git a/workbook.go b/workbook.go
index c65397b..417524b 100644
--- a/workbook.go
+++ b/workbook.go
@@ -33,6 +33,10 @@ type WorkbookPrOptionPtr interface {
 }
 
 type (
+	// Date1904 is an option used for WorkbookPrOption, that indicates whether
+	// to use a 1900 or 1904 date system when converting serial date-times in
+	// the workbook to dates
+	Date1904 bool
 	// FilterPrivacy is an option used for WorkbookPrOption
 	FilterPrivacy bool
 )
@@ -116,6 +120,7 @@ func (f *File) workBookWriter() {
 // SetWorkbookPrOptions provides a function to sets workbook properties.
 //
 // Available options:
+//   Date1904(bool)
 //   FilterPrivacy(bool)
 //   CodeName(string)
 func (f *File) SetWorkbookPrOptions(opts ...WorkbookPrOption) error {
@@ -132,6 +137,11 @@ func (f *File) SetWorkbookPrOptions(opts ...WorkbookPrOption) error {
 }
 
 // setWorkbookPrOption implements the WorkbookPrOption interface.
+func (o Date1904) setWorkbookPrOption(pr *xlsxWorkbookPr) {
+	pr.Date1904 = bool(o)
+}
+
+// setWorkbookPrOption implements the WorkbookPrOption interface.
 func (o FilterPrivacy) setWorkbookPrOption(pr *xlsxWorkbookPr) {
 	pr.FilterPrivacy = bool(o)
 }
@@ -144,6 +154,7 @@ func (o CodeName) setWorkbookPrOption(pr *xlsxWorkbookPr) {
 // GetWorkbookPrOptions provides a function to gets workbook properties.
 //
 // Available options:
+//   Date1904(bool)
 //   FilterPrivacy(bool)
 //   CodeName(string)
 func (f *File) GetWorkbookPrOptions(opts ...WorkbookPrOptionPtr) error {
@@ -156,7 +167,17 @@ func (f *File) GetWorkbookPrOptions(opts ...WorkbookPrOptionPtr) error {
 }
 
 // getWorkbookPrOption implements the WorkbookPrOption interface and get the
-// filter privacy of thw workbook.
+// date1904 of the workbook.
+func (o *Date1904) getWorkbookPrOption(pr *xlsxWorkbookPr) {
+	if pr == nil {
+		*o = false
+		return
+	}
+	*o = Date1904(pr.Date1904)
+}
+
+// getWorkbookPrOption implements the WorkbookPrOption interface and get the
+// filter privacy of the workbook.
 func (o *FilterPrivacy) getWorkbookPrOption(pr *xlsxWorkbookPr) {
 	if pr == nil {
 		*o = false
@@ -166,7 +187,7 @@ func (o *FilterPrivacy) getWorkbookPrOption(pr *xlsxWorkbookPr) {
 }
 
 // getWorkbookPrOption implements the WorkbookPrOption interface and get the
-// code name of thw workbook.
+// code name of the workbook.
 func (o *CodeName) getWorkbookPrOption(pr *xlsxWorkbookPr) {
 	if pr == nil {
 		*o = ""
diff --git a/workbook_test.go b/workbook_test.go
index e31caf2..18b222c 100644
--- a/workbook_test.go
+++ b/workbook_test.go
@@ -10,6 +10,7 @@ import (
 func ExampleFile_SetWorkbookPrOptions() {
 	f := NewFile()
 	if err := f.SetWorkbookPrOptions(
+		Date1904(false),
 		FilterPrivacy(false),
 		CodeName("code"),
 	); err != nil {
@@ -21,9 +22,13 @@ func ExampleFile_SetWorkbookPrOptions() {
 func ExampleFile_GetWorkbookPrOptions() {
 	f := NewFile()
 	var (
+		date1904      Date1904
 		filterPrivacy FilterPrivacy
 		codeName      CodeName
 	)
+	if err := f.GetWorkbookPrOptions(&date1904); err != nil {
+		fmt.Println(err)
+	}
 	if err := f.GetWorkbookPrOptions(&filterPrivacy); err != nil {
 		fmt.Println(err)
 	}
@@ -31,10 +36,12 @@ func ExampleFile_GetWorkbookPrOptions() {
 		fmt.Println(err)
 	}
 	fmt.Println("Defaults:")
+	fmt.Printf("- date1904: %t\n", date1904)
 	fmt.Printf("- filterPrivacy: %t\n", filterPrivacy)
 	fmt.Printf("- codeName: %q\n", codeName)
 	// Output:
 	// Defaults:
+	// - date1904: false
 	// - filterPrivacy: true
 	// - codeName: ""
 }
@@ -43,6 +50,11 @@ func TestWorkbookPr(t *testing.T) {
 	f := NewFile()
 	wb := f.workbookReader()
 	wb.WorkbookPr = nil
+	var date1904 Date1904
+	assert.NoError(t, f.GetWorkbookPrOptions(&date1904))
+	assert.Equal(t, false, bool(date1904))
+
+	wb.WorkbookPr = nil
 	var codeName CodeName
 	assert.NoError(t, f.GetWorkbookPrOptions(&codeName))
 	assert.Equal(t, "", string(codeName))