Reuse fromtimestamp for 0 values, and timedelta() instead of casting time_t to int.

Author: jhohm

Lib/_pydatetime.py

@@ -1039,9 +1039,7 @@ def fromtimestamp(cls, t):
             raise TypeError("'NoneType' object cannot be interpreted as an integer")
         if t < 0 and os.name == 'nt':
             # Windows converters throw an OSError for negative values.
-            y, m, d, hh, mm, ss, weekday, jday, dst = _time.localtime(0)
-            result = cls(y, m, d)
-            return result + timedelta(seconds=t)
+            return cls.fromtimestamp(0) + timedelta(seconds=t)
         y, m, d, hh, mm, ss, weekday, jday, dst = _time.localtime(t)
         return cls(y, m, d)
 
@@ -1859,6 +1857,10 @@ def _fromtimestamp(cls, t, utc, tz):
 
         A timezone info object may be passed in as well.
         """
+        if t < 0 and os.name == 'nt':
+            # Windows converters throw an OSError for negative values.
+            return cls._fromtimestamp(0, utc, tz) + timedelta(seconds=t)
+
         frac, t = _math.modf(t)
         us = round(frac * 1e6)
         if us >= 1000000:
@@ -1869,11 +1871,6 @@ def _fromtimestamp(cls, t, utc, tz):
             us += 1000000
 
         converter = _time.gmtime if utc else _time.localtime
-        if t < 0 and os.name == 'nt':
-            # Windows converters throw an OSError for negative values.
-            y, m, d, hh, mm, ss, weekday, jday, dst = converter(0)
-            result = cls(y, m, d, hh, mm, ss, 0, tz)
-            return result + timedelta(seconds=t, microseconds=us)
         y, m, d, hh, mm, ss, weekday, jday, dst = converter(t)
         ss = min(ss, 59)    # clamp out leap seconds if the platform has them
         result = cls(y, m, d, hh, mm, ss, us, tz)

Modules/_datetimemodule.c

@@ -3262,16 +3262,13 @@ date_fromtimestamp(PyObject *cls, PyObject *obj)
         if (_PyTime_localtime(0, &tm) != 0)
             return NULL;
 
-        int normalize = 1, negate = 0;
-        PyObject *date = new_date_subclass_ex(tm.tm_year + 1900,
-                                              tm.tm_mon + 1,
-                                              tm.tm_mday,
-                                              cls);
+        int negate = 0;
+        PyObject *date = date_fromtimestamp(cls, _PyLong_GetZero());
         if (date == NULL) {
             return NULL;
         }
         PyObject *result = NULL;
-        PyObject *delta = new_delta(0, (int)t, 0, normalize);
+        PyObject *delta = PyObject_CallFunction((PyObject*)&DELTA_TYPE(NO_STATE), "iO", 0, obj);
         if (delta == NULL) {
             Py_DECREF(date);
             return NULL;
@@ -5565,13 +5562,13 @@ datetime_from_timestamp(PyObject *cls, TM_FUNC f, PyObject *timestamp,
 
 #ifdef MS_WINDOWS
     if (timet < 0) {
-        int normalize = 1, factor = 1;
+        int factor = 1;
         PyObject *dt = datetime_from_timet_and_us(cls, f, 0, 0, tzinfo);
         if (dt == NULL) {
             return NULL;
         }
         PyObject *result = NULL;
-        PyObject *delta = new_delta(0, (int)timet, us, normalize);
+        PyObject *delta = PyObject_CallFunction((PyObject*)&DELTA_TYPE(NO_STATE), "iO", 0, timestamp);
         if (delta == NULL) {
             Py_DECREF(dt);
             return NULL;