fix XLS merged cells and ensure sentinals are correctly saved

commonxl/cell.go

@@ -40,6 +40,8 @@ func (c CellType) String() string {
 		return "date"
 	case HyperlinkStringCell:
 		return "hyperlink"
+	case StaticCell:
+		return "static"
 	default: // StringCell, StaticCell
 		return "string"
 	}

commonxl/sheet.go

@@ -67,6 +67,14 @@ func (s *Sheet) Put(row, col int, value interface{}, fmtNum uint16) {
 		s.Resize(s.NumRows, s.NumCols)
 	}
 
+	if spec, ok := value.(string); ok {
+		if spec == grate.EndRowMerged || spec == grate.EndColumnMerged || spec == grate.ContinueRowMerged || spec == grate.ContinueColumnMerged {
+			s.Rows[row][col] = NewCell(value)
+			s.Rows[row][col][1] = StaticCell
+			return
+		}
+	}
+
 	ct, ok := s.Formatter.getCellType(fmtNum)
 	if !ok || fmtNum == 0 {
 		s.Rows[row][col] = NewCell(value)
@@ -125,6 +133,10 @@ func (s *Sheet) Strings() []string {
 			res[i] = ""
 			continue
 		}
+		if cell.Type() == StaticCell {
+			res[i] = cell.Value().(string)
+			continue
+		}
 		val := cell.Value()
 		fs, ok := s.Formatter.Apply(cell.FormatNo(), val)
 		if !ok {

xls/sheets.go

@@ -386,10 +386,10 @@ func (b *WorkBook) parseSheet(s *boundSheet, ss int) (*commonxl.Sheet, error) {
 			cmcs := binary.LittleEndian.Uint16(r.Data[:2])
 			raw := r.Data[2:]
 			for i := 0; i < int(cmcs); i++ {
-				firstRow := binary.LittleEndian.Uint16(r.Data[:2])
+				firstRow := binary.LittleEndian.Uint16(raw[:2])
-				lastRow := binary.LittleEndian.Uint16(r.Data[2:4])
+				lastRow := binary.LittleEndian.Uint16(raw[2:4])
-				firstCol := binary.LittleEndian.Uint16(r.Data[4:6])
+				firstCol := binary.LittleEndian.Uint16(raw[4:6])
-				lastCol := binary.LittleEndian.Uint16(r.Data[6:])
+				lastCol := binary.LittleEndian.Uint16(raw[6:])
 				raw = raw[8:]
 
 				if lastRow == 0xFFFF { // placeholder value indicate "last"