# -*- coding: utf-8 -*-
"""Delphi TDateTime implementation."""
import decimal
from dfdatetime import definitions
from dfdatetime import factory
from dfdatetime import interface
[docs]
class DelphiDateTimeEpoch(interface.DateTimeEpoch):
"""Delphi TDateTime epoch."""
[docs]
def __init__(self):
"""Initializes a Delphi TDateTime epoch."""
super(DelphiDateTimeEpoch, self).__init__(1899, 12, 30)
[docs]
class DelphiDateTime(interface.DateTimeValues):
"""Delphi TDateTime timestamp.
The Delphi TDateTime timestamp is a floating point value that contains
the number of days since 1899-12-30 00:00:00 (also known as the epoch).
Negative values represent date and times predating the epoch.
The maximal correct date supported by TDateTime values is limited to:
9999-12-31 23:59:59.999
Attributes:
is_local_time (bool): True if the date and time value is in local time.
"""
# The difference between December 30, 1899 and January 1, 1970 in days.
_DELPHI_TO_POSIX_BASE = 25569
_EPOCH = DelphiDateTimeEpoch()
[docs]
def __init__(self, precision=None, time_zone_offset=None, timestamp=None):
"""Initializes a Delphi TDateTime timestamp.
Args:
precision (Optional[str]): precision of the date and time value, which
should be one of the PRECISION_VALUES in definitions.
time_zone_offset (Optional[int]): time zone offset in number of minutes
from UTC or None if not set.
timestamp (Optional[float]): Delphi TDateTime timestamp.
"""
super(DelphiDateTime, self).__init__(
precision=precision or definitions.PRECISION_1_MILLISECOND,
time_zone_offset=time_zone_offset)
self._timestamp = timestamp
@property
def timestamp(self):
"""float: Delphi TDateTime timestamp or None if not set."""
return self._timestamp
def _GetNormalizedTimestamp(self):
"""Retrieves the normalized timestamp.
Returns:
decimal.Decimal: normalized timestamp, which contains the number of
seconds since January 1, 1970 00:00:00 and a fraction of second used
for increased precision, or None if the normalized timestamp cannot be
determined.
"""
if self._normalized_timestamp is None:
if self._timestamp is not None:
self._normalized_timestamp = (
decimal.Decimal(self._timestamp) - self._DELPHI_TO_POSIX_BASE)
self._normalized_timestamp *= definitions.SECONDS_PER_DAY
if self._time_zone_offset:
self._normalized_timestamp -= self._time_zone_offset * 60
return self._normalized_timestamp
[docs]
def CopyFromDateTimeString(self, time_string):
"""Copies a Delphi TDateTime timestamp from a string.
Args:
time_string (str): date and time value formatted as:
YYYY-MM-DD hh:mm:ss.######[+-]##:##
Where # are numeric digits ranging from 0 to 9 and the seconds
fraction can be either 3, 6 or 9 digits. The time of day, seconds
fraction and time zone offset are optional. The default time zone
is UTC.
Raises:
ValueError: if the time string is invalid or not supported.
"""
date_time_values = self._CopyDateTimeFromString(time_string)
year = date_time_values.get('year', 0)
month = date_time_values.get('month', 0)
day_of_month = date_time_values.get('day_of_month', 0)
hours = date_time_values.get('hours', 0)
minutes = date_time_values.get('minutes', 0)
seconds = date_time_values.get('seconds', 0)
nanoseconds = date_time_values.get('nanoseconds', 0)
time_zone_offset = date_time_values.get('time_zone_offset', None)
if year > 9999:
raise ValueError(f'Unsupported year value: {year:d}.')
timestamp = self._GetNumberOfSecondsFromElements(
year, month, day_of_month, hours, minutes, seconds)
timestamp = float(timestamp) / definitions.SECONDS_PER_DAY
timestamp += self._DELPHI_TO_POSIX_BASE
timestamp += float(nanoseconds) / definitions.NANOSECONDS_PER_DAY
self._normalized_timestamp = None
self._timestamp = timestamp
self._time_zone_offset = time_zone_offset
[docs]
def CopyToDateTimeString(self):
"""Copies the Delphi TDateTime timestamp to a date and time string.
Returns:
str: date and time value formatted as: "YYYY-MM-DD hh:mm:ss.######" or
None if the timestamp is missing.
"""
if self._timestamp is None:
return None
number_of_seconds = self._timestamp * definitions.SECONDS_PER_DAY
number_of_days, hours, minutes, seconds = self._GetTimeValues(
int(number_of_seconds))
# The maximum date supported by TDateTime values is limited to:
# 9999-12-31 23:59:59.999 (approximate 2958465 days since epoch).
# The minimum date is unknown hence assuming it is limited to:
# 0001-01-01 00:00:00.000 (approximate -693593 days since epoch).
if number_of_days < -693593 or number_of_days > 2958465:
return None
year, month, day_of_month = self._GetDateValuesWithEpoch(
number_of_days, self._EPOCH)
microseconds = int(
(number_of_seconds % 1) * definitions.MICROSECONDS_PER_SECOND)
return (f'{year:04d}-{month:02d}-{day_of_month:02d} '
f'{hours:02d}:{minutes:02d}:{seconds:02d}.{microseconds:06d}')
factory.Factory.RegisterDateTimeValues(DelphiDateTime)