Made lxw_datetime_to_excel_date() function public.

include/xlsxwriter/utility.h

@@ -171,10 +171,32 @@ void lxw_rowcol_to_formula_abs(char *formula, const char *sheetname,
 
 uint32_t lxw_name_to_row(const char *row_str);
 uint16_t lxw_name_to_col(const char *col_str);
+
 uint32_t lxw_name_to_row_2(const char *row_str);
 uint16_t lxw_name_to_col_2(const char *col_str);
 
-double lxw_datetime_to_excel_date(lxw_datetime *datetime, uint8_t date_1904);
+/**
+ * @brief Converts a #lxw_datetime to an Excel datetime number.
+ *
+ * @param datetime A pointer to a #lxw_datetime struct.
+ *
+ * @return A double representing an Excel datetime.
+ *
+ * The `%lxw_datetime_to_excel_datetime()` function converts a datetime in
+ * #lxw_datetime to and Excel datetime number:
+ *
+ * @code
+ *     lxw_datetime datetime = {2013, 2, 28, 12, 0, 0.0};
+ *
+ *     double excel_datetime = lxw_datetime_to_excel_date(&datetime);
+ * @endcode
+ *
+ * See @ref working_with_dates for more details on the Excel datetime format.
+ */
+double lxw_datetime_to_excel_datetime(lxw_datetime *datetime);
+
+double lxw_datetime_to_excel_date_epoch(lxw_datetime *datetime,
+                                        uint8_t date_1904);
 
 char *lxw_strdup(const char *str);
 char *lxw_strdup_formula(const char *formula);

src/core.c

@@ -50,7 +50,7 @@ lxw_core_free(lxw_core *core)
 }
 
 /*
- * Convert a time_t struct to a ISO 8601 style "2010-01-01T00:00:00Z" date.
+ * Convert a time_t to a ISO 8601 style "2010-01-01T00:00:00Z" date.
  */
 static void
 _datetime_to_iso8601_date(time_t *timer, char *str, size_t size)

src/utility.c

@@ -314,10 +314,11 @@ lxw_name_to_col_2(const char *col_str)
 }
 
 /*
- * Convert a lxw_datetime struct to an Excel serial date.
+ * Convert a lxw_datetime struct to an Excel serial date, with a 1900
+ * or 1904 epoch.
  */
 double
-lxw_datetime_to_excel_date(lxw_datetime *datetime, uint8_t date_1904)
+lxw_datetime_to_excel_date_epoch(lxw_datetime *datetime, uint8_t date_1904)
 {
     int year = datetime->year;
     int month = datetime->month;
@@ -409,6 +410,15 @@ lxw_datetime_to_excel_date(lxw_datetime *datetime, uint8_t date_1904)
     return days + seconds;
 }
 
+/*
+ * Convert a lxw_datetime struct to an Excel serial date, for the 1900 epoch.
+ */
+double
+lxw_datetime_to_excel_datetime(lxw_datetime *datetime)
+{
+    return lxw_datetime_to_excel_date_epoch(datetime, LXW_FALSE);
+}
+
 /* Simple strdup() implementation since it isn't ANSI C. */
 char *
 lxw_strdup(const char *str)

src/worksheet.c

@@ -6935,7 +6935,7 @@ worksheet_write_datetime(lxw_worksheet *self,
     if (err)
         return err;
 
-    excel_date = lxw_datetime_to_excel_date(datetime, LXW_EPOCH_1900);
+    excel_date = lxw_datetime_to_excel_date_epoch(datetime, LXW_EPOCH_1900);
 
     cell = _new_number_cell(row_num, col_num, excel_date, format);
 
@@ -9042,16 +9042,18 @@ worksheet_data_validation_range(lxw_worksheet *self, lxw_row_t first_row,
         || validation->validate == LXW_VALIDATION_TYPE_TIME) {
         if (is_between) {
             copy->value_number =
-                lxw_datetime_to_excel_date(&validation->minimum_datetime,
-                                           LXW_EPOCH_1900);
+                lxw_datetime_to_excel_date_epoch(&validation->
+                                                 minimum_datetime,
+                                                 LXW_EPOCH_1900);
             copy->maximum_number =
-                lxw_datetime_to_excel_date(&validation->maximum_datetime,
-                                           LXW_EPOCH_1900);
+                lxw_datetime_to_excel_date_epoch(&validation->
+                                                 maximum_datetime,
+                                                 LXW_EPOCH_1900);
         }
         else {
             copy->value_number =
-                lxw_datetime_to_excel_date(&validation->value_datetime,
-                                           LXW_EPOCH_1900);
+                lxw_datetime_to_excel_date_epoch(&validation->value_datetime,
+                                                 LXW_EPOCH_1900);
         }
     }
 

test/unit/helper.h

@@ -76,7 +76,7 @@
 
 
 #define TEST_ROWCOL_TO_FORMULA_ABS(sheet, row1, col1, row2, col2, exp) \
-    lxw_rowcol_to_formula_abs(got, sheet, row1, col1, row2, col2);  \
+    lxw_rowcol_to_formula_abs(got, sheet, row1, col1, row2, col2);     \
     ASSERT_STR(exp, got);
 
 
@@ -86,7 +86,7 @@
     datetime->min   = _min;                                         \
     datetime->sec   = _sec;                                         \
                                                                     \
-    got = lxw_datetime_to_excel_date(datetime, 0);                  \
+    got = lxw_datetime_to_excel_datetime(datetime);                 \
                                                                     \
     ASSERT_DOUBLE(exp, got);                                        \
     free(datetime);
@@ -97,7 +97,7 @@
     datetime->month = _month;                                       \
     datetime->day   = _day;                                         \
                                                                     \
-    got = lxw_datetime_to_excel_date(datetime, 0);                  \
+    got = lxw_datetime_to_excel_datetime(datetime);                 \
                                                                     \
     ASSERT_DOUBLE(exp, got);                                        \
     free(datetime);
@@ -108,7 +108,7 @@
     datetime->month = _month;                                       \
     datetime->day   = _day;                                         \
                                                                     \
-    got = lxw_datetime_to_excel_date(datetime, 1);                  \
+    got = lxw_datetime_to_excel_date_epoch(datetime, 1);            \
                                                                     \
     ASSERT_DOUBLE(exp, got);                                        \
     free(datetime);
@@ -122,7 +122,7 @@
     datetime->min   = _min;                                         \
     datetime->sec   = _sec;                                         \
                                                                     \
-    got = lxw_datetime_to_excel_date(datetime, 0);                  \
+    got = lxw_datetime_to_excel_datetime(datetime);                 \
                                                                     \
     ASSERT_DOUBLE(exp, got);                                        \
     free(datetime);

test/unit/worksheet/test_worksheet_conditional_format10.c

@@ -70,7 +70,7 @@ CTEST(worksheet, worksheet_condtional_format10) {
 
     conditional_format->type     = LXW_CONDITIONAL_TYPE_CELL;
     conditional_format->criteria = LXW_CONDITIONAL_CRITERIA_GREATER_THAN;
-    conditional_format->value    = lxw_datetime_to_excel_date(&datetime1, LXW_FALSE);
+    conditional_format->value    = lxw_datetime_to_excel_datetime(&datetime1);
     conditional_format->format   = NULL;
     worksheet_conditional_format_range(worksheet, RANGE("A1:A4"), conditional_format);
 

test/unit/worksheet/test_worksheet_conditional_format11.c

@@ -72,8 +72,8 @@ CTEST(worksheet, worksheet_condtional_format11) {
 
     conditional_format->type      = LXW_CONDITIONAL_TYPE_CELL;
     conditional_format->criteria  = LXW_CONDITIONAL_CRITERIA_BETWEEN;
-    conditional_format->min_value = lxw_datetime_to_excel_date(&datetime1, LXW_FALSE);;
-    conditional_format->max_value = lxw_datetime_to_excel_date(&datetime2, LXW_FALSE);;
+    conditional_format->min_value = lxw_datetime_to_excel_datetime(&datetime1);
+    conditional_format->max_value = lxw_datetime_to_excel_datetime(&datetime2);
     worksheet_conditional_format_range(worksheet, RANGE("A1:A4"), conditional_format);