from datetime import ( timedelta, timezone, ) from pandas.compat._optional import import_optional_dependency try: # py39+ import zoneinfo from zoneinfo import ZoneInfo except ImportError: zoneinfo = None ZoneInfo = None from cpython.datetime cimport ( datetime, timedelta, tzinfo, ) # dateutil compat from dateutil.tz import ( gettz as dateutil_gettz, tzfile as _dateutil_tzfile, tzlocal as _dateutil_tzlocal, tzutc as _dateutil_tzutc, ) import numpy as np import pytz from pytz.tzinfo import BaseTzInfo as _pytz_BaseTzInfo cimport numpy as cnp from numpy cimport int64_t cnp.import_array() # ---------------------------------------------------------------------- from pandas._libs.tslibs.util cimport ( get_nat, is_integer_object, ) cdef int64_t NPY_NAT = get_nat() cdef tzinfo utc_stdlib = timezone.utc cdef tzinfo utc_pytz = pytz.utc cdef tzinfo utc_dateutil_str = dateutil_gettz("UTC") # NB: *not* the same as tzutc() cdef tzinfo utc_zoneinfo = None # ---------------------------------------------------------------------- cdef bint is_utc_zoneinfo(tzinfo tz): # Workaround for cases with missing tzdata # https://github.com/pandas-dev/pandas/pull/46425#discussion_r830633025 if tz is None or zoneinfo is None: return False global utc_zoneinfo if utc_zoneinfo is None: try: utc_zoneinfo = ZoneInfo("UTC") except zoneinfo.ZoneInfoNotFoundError: return False # Warn if tzdata is too old, even if there is a system tzdata to alert # users about the mismatch between local/system tzdata import_optional_dependency("tzdata", errors="warn", min_version="2022.1") return tz is utc_zoneinfo cpdef inline bint is_utc(tzinfo tz): return ( tz is utc_pytz or tz is utc_stdlib or isinstance(tz, _dateutil_tzutc) or tz is utc_dateutil_str or is_utc_zoneinfo(tz) ) cdef bint is_zoneinfo(tzinfo tz): if ZoneInfo is None: return False return isinstance(tz, ZoneInfo) cdef bint is_tzlocal(tzinfo tz): return isinstance(tz, _dateutil_tzlocal) cdef bint treat_tz_as_pytz(tzinfo tz): return (hasattr(tz, "_utc_transition_times") and hasattr(tz, "_transition_info")) cdef bint treat_tz_as_dateutil(tzinfo tz): return hasattr(tz, "_trans_list") and hasattr(tz, "_trans_idx") # Returns str or tzinfo object cpdef inline object get_timezone(tzinfo tz): """ We need to do several things here: 1) Distinguish between pytz and dateutil timezones 2) Not be over-specific (e.g. US/Eastern with/without DST is same *zone* but a different tz object) 3) Provide something to serialize when we're storing a datetime object in pytables. We return a string prefaced with dateutil if it's a dateutil tz, else just the tz name. It needs to be a string so that we can serialize it with UJSON/pytables. maybe_get_tz (below) is the inverse of this process. """ if tz is None: raise TypeError("tz argument cannot be None") if is_utc(tz): return tz else: if treat_tz_as_dateutil(tz): if ".tar.gz" in tz._filename: raise ValueError( "Bad tz filename. Dateutil on python 3 on windows has a " "bug which causes tzfile._filename to be the same for all " "timezone files. Please construct dateutil timezones " 'implicitly by passing a string like "dateutil/Europe' '/London" when you construct your pandas objects instead ' "of passing a timezone object. See " "https://github.com/pandas-dev/pandas/pull/7362") return "dateutil/" + tz._filename else: # tz is a pytz timezone or unknown. try: zone = tz.zone if zone is None: return tz return zone except AttributeError: return tz cpdef inline tzinfo maybe_get_tz(object tz): """ (Maybe) Construct a timezone object from a string. If tz is a string, use it to construct a timezone object. Otherwise, just return tz. """ if isinstance(tz, str): if tz == "tzlocal()": tz = _dateutil_tzlocal() elif tz.startswith("dateutil/"): zone = tz[9:] tz = dateutil_gettz(zone) # On Python 3 on Windows, the filename is not always set correctly. if isinstance(tz, _dateutil_tzfile) and ".tar.gz" in tz._filename: tz._filename = zone elif tz[0] in {"-", "+"}: hours = int(tz[0:3]) minutes = int(tz[0] + tz[4:6]) tz = timezone(timedelta(hours=hours, minutes=minutes)) elif tz[0:4] in {"UTC-", "UTC+"}: hours = int(tz[3:6]) minutes = int(tz[3] + tz[7:9]) tz = timezone(timedelta(hours=hours, minutes=minutes)) elif tz == "UTC" or tz == "utc": tz = utc_stdlib else: tz = pytz.timezone(tz) elif is_integer_object(tz): tz = timezone(timedelta(seconds=tz)) elif isinstance(tz, tzinfo): pass elif tz is None: pass else: raise TypeError(type(tz)) return tz def _p_tz_cache_key(tz: tzinfo): """ Python interface for cache function to facilitate testing. """ return tz_cache_key(tz) # Timezone data caches, key is the pytz string or dateutil file name. dst_cache = {} cdef object tz_cache_key(tzinfo tz): """ Return the key in the cache for the timezone info object or None if unknown. The key is currently the tz string for pytz timezones, the filename for dateutil timezones. Notes ----- This cannot just be the hash of a timezone object. Unfortunately, the hashes of two dateutil tz objects which represent the same timezone are not equal (even though the tz objects will compare equal and represent the same tz file). Also, pytz objects are not always hashable so we use str(tz) instead. """ if isinstance(tz, _pytz_BaseTzInfo): return tz.zone elif isinstance(tz, _dateutil_tzfile): if ".tar.gz" in tz._filename: raise ValueError("Bad tz filename. Dateutil on python 3 on " "windows has a bug which causes tzfile._filename " "to be the same for all timezone files. Please " "construct dateutil timezones implicitly by " 'passing a string like "dateutil/Europe/London" ' "when you construct your pandas objects instead " "of passing a timezone object. See " "https://github.com/pandas-dev/pandas/pull/7362") return "dateutil" + tz._filename else: return None # ---------------------------------------------------------------------- # UTC Offsets cdef timedelta get_utcoffset(tzinfo tz, datetime obj): try: return tz._utcoffset except AttributeError: return tz.utcoffset(obj) cpdef inline bint is_fixed_offset(tzinfo tz): if treat_tz_as_dateutil(tz): if len(tz._trans_idx) == 0 and len(tz._trans_list) == 0: return 1 else: return 0 elif treat_tz_as_pytz(tz): if (len(tz._transition_info) == 0 and len(tz._utc_transition_times) == 0): return 1 else: return 0 elif is_zoneinfo(tz): return 0 # This also implicitly accepts datetime.timezone objects which are # considered fixed return 1 cdef object _get_utc_trans_times_from_dateutil_tz(tzinfo tz): """ Transition times in dateutil timezones are stored in local non-dst time. This code converts them to UTC. It's the reverse of the code in dateutil.tz.tzfile.__init__. """ new_trans = list(tz._trans_list) last_std_offset = 0 for i, (trans, tti) in enumerate(zip(tz._trans_list, tz._trans_idx)): if not tti.isdst: last_std_offset = tti.offset new_trans[i] = trans - last_std_offset return new_trans cdef int64_t[::1] unbox_utcoffsets(object transinfo): cdef: Py_ssize_t i, sz int64_t[::1] arr sz = len(transinfo) arr = np.empty(sz, dtype="i8") for i in range(sz): arr[i] = int(transinfo[i][0].total_seconds()) * 1_000_000_000 return arr # ---------------------------------------------------------------------- # Daylight Savings cdef object get_dst_info(tzinfo tz): """ Returns ------- ndarray[int64_t] Nanosecond UTC times of DST transitions. ndarray[int64_t] Nanosecond UTC offsets corresponding to DST transitions. str Describing the type of tzinfo object. """ cache_key = tz_cache_key(tz) if cache_key is None: # e.g. pytz.FixedOffset, matplotlib.dates._UTC, # psycopg2.tz.FixedOffsetTimezone num = int(get_utcoffset(tz, None).total_seconds()) * 1_000_000_000 # If we have e.g. ZoneInfo here, the get_utcoffset call will return None, # so the total_seconds() call will raise AttributeError. return (np.array([NPY_NAT + 1], dtype=np.int64), np.array([num], dtype=np.int64), "unknown") if cache_key not in dst_cache: if treat_tz_as_pytz(tz): trans = np.array(tz._utc_transition_times, dtype="M8[ns]") trans = trans.view("i8") if tz._utc_transition_times[0].year == 1: trans[0] = NPY_NAT + 1 deltas = unbox_utcoffsets(tz._transition_info) typ = "pytz" elif treat_tz_as_dateutil(tz): if len(tz._trans_list): # get utc trans times trans_list = _get_utc_trans_times_from_dateutil_tz(tz) trans = np.hstack([ np.array([0], dtype="M8[s]"), # place holder for 1st item np.array(trans_list, dtype="M8[s]")]).astype( "M8[ns]") # all trans listed trans = trans.view("i8") trans[0] = NPY_NAT + 1 # deltas deltas = np.array([v.offset for v in ( tz._ttinfo_before,) + tz._trans_idx], dtype="i8") deltas *= 1_000_000_000 typ = "dateutil" elif is_fixed_offset(tz): trans = np.array([NPY_NAT + 1], dtype=np.int64) deltas = np.array([tz._ttinfo_std.offset], dtype="i8") * 1_000_000_000 typ = "fixed" else: # 2018-07-12 this is not reached in the tests, and this case # is not handled in any of the functions that call # get_dst_info. If this case _were_ hit the calling # functions would then hit an IndexError because they assume # `deltas` is non-empty. # (under the just-deleted code that returned empty arrays) raise AssertionError("dateutil tzinfo is not a FixedOffset " "and has an empty `_trans_list`.", tz) else: # static tzinfo, we can get here with pytz.StaticTZInfo # which are not caught by treat_tz_as_pytz trans = np.array([NPY_NAT + 1], dtype=np.int64) num = int(get_utcoffset(tz, None).total_seconds()) * 1_000_000_000 deltas = np.array([num], dtype=np.int64) typ = "static" dst_cache[cache_key] = (trans, deltas, typ) return dst_cache[cache_key] def infer_tzinfo(datetime start, datetime end): if start is not None and end is not None: tz = start.tzinfo if not tz_compare(tz, end.tzinfo): raise AssertionError(f"Inputs must both have the same timezone, " f"{tz} != {end.tzinfo}") elif start is not None: tz = start.tzinfo elif end is not None: tz = end.tzinfo else: tz = None return tz cpdef bint tz_compare(tzinfo start, tzinfo end): """ Compare string representations of timezones The same timezone can be represented as different instances of timezones. For example `` and `` are essentially same timezones but aren't evaluated such, but the string representation for both of these is `'Europe/Paris'`. This exists only to add a notion of equality to pytz-style zones that is compatible with the notion of equality expected of tzinfo subclasses. Parameters ---------- start : tzinfo end : tzinfo Returns: ------- bool """ # GH 18523 if is_utc(start): # GH#38851 consider pytz/dateutil/stdlib UTCs as equivalent return is_utc(end) elif is_utc(end): # Ensure we don't treat tzlocal as equal to UTC when running in UTC return False elif start is None or end is None: return start is None and end is None return get_timezone(start) == get_timezone(end) def tz_standardize(tz: tzinfo) -> tzinfo: """ If the passed tz is a pytz timezone object, "normalize" it to the a consistent version Parameters ---------- tz : tzinfo Returns ------- tzinfo Examples -------- >>> from datetime import datetime >>> from pytz import timezone >>> tz = timezone('US/Pacific').normalize( ... datetime(2014, 1, 1, tzinfo=pytz.utc) ... ).tzinfo >>> tz >>> tz_standardize(tz) >>> tz = timezone('US/Pacific') >>> tz >>> tz_standardize(tz) """ if treat_tz_as_pytz(tz): return pytz.timezone(str(tz)) return tz