offsets.py 文件源码

def apply(self, other):
        base = other
        n = self.n

        if n > 0:
            while n > 0:
                if not self._offset.onOffset(other):
                    qtr_lens = self.get_weeks(other)
                    start = other - self._offset
                else:
                    start = other
                    qtr_lens = self.get_weeks(other + self._offset)

                for weeks in qtr_lens:
                    start += relativedelta(weeks=weeks)
                    if start > other:
                        other = start
                        n -= 1
                        break

        else:
            n = -n
            while n > 0:
                if not self._offset.onOffset(other):
                    qtr_lens = self.get_weeks(other)
                    end = other + self._offset
                else:
                    end = other
                    qtr_lens = self.get_weeks(other)

                for weeks in reversed(qtr_lens):
                    end -= relativedelta(weeks=weeks)
                    if end < other:
                        other = end
                        n -= 1
                        break
        other = datetime(other.year, other.month, other.day,
                         base.hour, base.minute, base.second, base.microsecond)
        return other