Module refinery.lib.dt

Date and time related functoins.

"""
Date and time related functoins.
"""
from __future__ import annotations

from datetime import datetime, timedelta, timezone


def isodate(iso: str) -> datetime | None:
    """
    Convert an input date string in ISO format to a `datetime` object. Contains fallbacks for early
    Python versions.
    """
    if len(iso) not in range(16, 25):
        return None
    iso = iso[:19].replace(' ', 'T', 1)
    try:
        try:
            return datetime.fromisoformat(iso)
        except AttributeError:
            return datetime.strptime(iso, "%Y-%m-%dT%H:%M:%S")
    except ValueError:
        return None


def pdfdate(value: str) -> datetime | None:
    """
    Parse a PDF date string in the ISO 32000 format `D:YYYYMMDDHHmmSS+hh'mm'`. The result is a
    timezone-aware `datetime` when the string specifies a UTC offset, and naive otherwise.
    """
    import re
    iso32 = R'D?:?(\d{4})' + 5 * R'(\d{2})?' + R'(?:([Zz+-])(\d{2})?\'?(\d{2})?\'?)?'
    if (match := re.match(iso32, value.strip())) is None:
        return None
    *dt, sgn, tzh, tzm = match.groups()
    parsed = [int(g) for g in dt if g is not None]
    while len(parsed) < 3:
        parsed.append(1)
    if sgn is None:
        tzinfo = None
    elif sgn in 'Zz':
        tzinfo = timezone.utc
    else:
        offset = timedelta(hours=int(tzh or 0), minutes=int(tzm or 0))
        tzinfo = timezone(offset if sgn == '+' else -offset)
    try:
        return datetime(*parsed, tzinfo=tzinfo)
    except ValueError:
        return None


def date_from_timestamp(ts: int | float):
    """
    Convert a UTC timestamp to a datetime object.
    """
    return datetime.fromtimestamp(ts, timezone.utc).replace(tzinfo=None)


def filetime(value: int) -> datetime | None:
    """
    Convert a Windows `FILETIME` value, which counts 100-nanosecond intervals since January 1st of
    1601 in UTC, to a `datetime` object in the UTC time zone. The value zero marks an unset time,
    and it converts to `None` like every value that no `datetime` object can represent.
    """
    if value <= 0:
        return None
    try:
        return datetime(1601, 1, 1, tzinfo=timezone.utc) + timedelta(microseconds=value // 10)
    except OverflowError:
        return None


def dostime(stamp: int) -> datetime:
    """
    Parses a given DOS timestamp into a datetime object.
    """
    d, t = stamp >> 16, stamp & 0xFFFF
    s = (t & 0x1F) << 1

    return datetime(
        year   = ((d & 0xFE00) >> 0x9) + 1980,  # noqa
        month  = ((d & 0x01E0) >> 0x5),         # noqa
        day    = ((d & 0x001F) >> 0x0),         # noqa
        hour   = ((t & 0xF800) >> 0xB),         # noqa
        minute = ((t & 0x07E0) >> 0x5),         # noqa
        second = 59 if s == 60 else s,          # noqa
    )

Functions

def isodate(iso)

Convert an input date string in ISO format to a datetime object. Contains fallbacks for early Python versions.

Expand source code Browse git

def isodate(iso: str) -> datetime | None:
    """
    Convert an input date string in ISO format to a `datetime` object. Contains fallbacks for early
    Python versions.
    """
    if len(iso) not in range(16, 25):
        return None
    iso = iso[:19].replace(' ', 'T', 1)
    try:
        try:
            return datetime.fromisoformat(iso)
        except AttributeError:
            return datetime.strptime(iso, "%Y-%m-%dT%H:%M:%S")
    except ValueError:
        return None

def pdfdate(value)

Parse a PDF date string in the ISO 32000 format D:YYYYMMDDHHmmSS+hh'mm'. The result is a timezone-aware datetime when the string specifies a UTC offset, and naive otherwise.

Expand source code Browse git

def pdfdate(value: str) -> datetime | None:
    """
    Parse a PDF date string in the ISO 32000 format `D:YYYYMMDDHHmmSS+hh'mm'`. The result is a
    timezone-aware `datetime` when the string specifies a UTC offset, and naive otherwise.
    """
    import re
    iso32 = R'D?:?(\d{4})' + 5 * R'(\d{2})?' + R'(?:([Zz+-])(\d{2})?\'?(\d{2})?\'?)?'
    if (match := re.match(iso32, value.strip())) is None:
        return None
    *dt, sgn, tzh, tzm = match.groups()
    parsed = [int(g) for g in dt if g is not None]
    while len(parsed) < 3:
        parsed.append(1)
    if sgn is None:
        tzinfo = None
    elif sgn in 'Zz':
        tzinfo = timezone.utc
    else:
        offset = timedelta(hours=int(tzh or 0), minutes=int(tzm or 0))
        tzinfo = timezone(offset if sgn == '+' else -offset)
    try:
        return datetime(*parsed, tzinfo=tzinfo)
    except ValueError:
        return None

def date_from_timestamp(ts)

Convert a UTC timestamp to a datetime object.

Expand source code Browse git

def date_from_timestamp(ts: int | float):
    """
    Convert a UTC timestamp to a datetime object.
    """
    return datetime.fromtimestamp(ts, timezone.utc).replace(tzinfo=None)

def filetime(value)

Convert a Windows FILETIME value, which counts 100-nanosecond intervals since January 1st of 1601 in UTC, to a datetime object in the UTC time zone. The value zero marks an unset time, and it converts to None like every value that no datetime object can represent.

Expand source code Browse git

def filetime(value: int) -> datetime | None:
    """
    Convert a Windows `FILETIME` value, which counts 100-nanosecond intervals since January 1st of
    1601 in UTC, to a `datetime` object in the UTC time zone. The value zero marks an unset time,
    and it converts to `None` like every value that no `datetime` object can represent.
    """
    if value <= 0:
        return None
    try:
        return datetime(1601, 1, 1, tzinfo=timezone.utc) + timedelta(microseconds=value // 10)
    except OverflowError:
        return None

def dostime(stamp)

Parses a given DOS timestamp into a datetime object.

Expand source code Browse git

def dostime(stamp: int) -> datetime:
    """
    Parses a given DOS timestamp into a datetime object.
    """
    d, t = stamp >> 16, stamp & 0xFFFF
    s = (t & 0x1F) << 1

    return datetime(
        year   = ((d & 0xFE00) >> 0x9) + 1980,  # noqa
        month  = ((d & 0x01E0) >> 0x5),         # noqa
        day    = ((d & 0x001F) >> 0x0),         # noqa
        hour   = ((t & 0xF800) >> 0xB),         # noqa
        minute = ((t & 0x07E0) >> 0x5),         # noqa
        second = 59 if s == 60 else s,          # noqa
    )