Add function to check if a date is valid

src/codes_util.cc

@@ -194,3 +194,23 @@ int codes_flush_sync_close_file(FILE* f)
     }
     return GRIB_SUCCESS;
 }
+
+// Return 1 if input date is valid. Otherwise 0
+int is_date_valid(long year, long month, long day, long hour, long minute, double second)
+{
+    // Convert input date to Julian number
+    double result = 0; // Julian number in units of days
+    long year1, month1, day1, hour1, minute1, lSecond1;
+
+    // For validating the date/time, we specify seconds as an integer
+    long lSecond = (long)second;
+    grib_datetime_to_julian(year, month, day, hour, minute, lSecond, &result);
+
+    // Check conversion worked by going other way
+    grib_julian_to_datetime(result, &year1, &month1, &day1, &hour1, &minute1, &lSecond1);
+    if (year1 != year || month1 != month || day1 != day || minute1 != minute || lSecond1 != lSecond) {
+        return 0; // bad date
+    }
+
+    return 1;
+}

src/eccodes_prototypes.h

@@ -1427,6 +1427,7 @@ int path_is_directory(const char* filename);
 char* codes_getenv(const char* name);
 int codes_check_grib_ieee_packing_value(int value);
 int codes_flush_sync_close_file(FILE* f);
+int is_date_valid(long year, long month, long day, long hour, long minute, double second);
 
 /* grib_util.cc*/
 grib_handle* grib_util_sections_copy(grib_handle* hfrom, grib_handle* hto, int what, int* err);

tests/unit_tests.cc

@@ -1654,11 +1654,45 @@ static void test_parse_keyval_string()
     free( (void*)values3[0].name );
 }
 
+static void test_dates()
+{
+    printf("Testing: dates...\n");
+    Assert( is_date_valid(1979,12, 1, 0,0,0) );
+    Assert( is_date_valid(1900, 1, 1, 0,0,0) );
+    Assert( is_date_valid(1964, 4, 6, 0,0,0) );
+    Assert( is_date_valid(2023, 3, 4, 0,0,0) );
+    Assert( is_date_valid(2023, 3, 4, 12,0,0) );
+    Assert( is_date_valid(2023, 3, 4, 0,10,0) );
+    Assert( is_date_valid(2023, 3, 4, 0,0,59) );
+    Assert( is_date_valid(0000, 3, 4, 0,0,0) );
+    Assert( is_date_valid(2020, 2, 29, 0,0,0) );//leap year
+
+    Assert( !is_date_valid(  10, -1, 1, 0,0,0) );// bad months
+    Assert( !is_date_valid(1900, 0,  1, 0,0,0) );
+    Assert( !is_date_valid(1900, 13, 1, 0,0,0) );
+
+    Assert( !is_date_valid(1900, 5,  0, 0,0,0) ); // bad days
+    Assert( !is_date_valid(2000, 5, 32, 0,0,0) );
+    Assert( !is_date_valid(2000, 5, -7, 0,0,0) );
+
+    Assert( !is_date_valid(2000, 5, 8, 99,0,0) );//bad hours
+    Assert( !is_date_valid(2000, 5, 9, -1,0,0) );
+
+    Assert( !is_date_valid(2000, 5, 8, 0, 61,0) );//bad mins
+    Assert( !is_date_valid(2000, 5, 9, 0,-1, 0) );
+
+    Assert( !is_date_valid(2000, 5, 8, 0, 1, -1) );//bad secs
+    Assert( !is_date_valid(2000, 5, 9, 0, 1, 60) );
+
+    Assert( !is_date_valid(2023, 2, 29, 0,0,0) );//Feb
+
+}
 
 int main(int argc, char** argv)
 {
     printf("Doing unit tests. ecCodes version = %ld\n", grib_get_api_version());
 
+    test_dates();
     test_logging_proc();
     test_grib_binary_search();
     test_parse_keyval_string();