python/samba/nt_time.py

   1 #
   2 # NT Time utility functions.
   3 #
   4 # Copyright (C) Catalyst.Net Ltd 2023
   5 #
   6 # This program is free software: you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation, either version 3 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  18 #
  19
  20 import datetime
  21 from typing import NewType
  22
  23
  24 NtTime = NewType("NtTime", int)
  25 NtTimeDelta = NewType("NtTimeDelta", int)
  26
  27
  28 NT_EPOCH = datetime.datetime(
  29     1601, 1, 1, 0, 0, 0, 0, tzinfo=datetime.timezone.utc
  30 )
  31 NT_TICKS_PER_μSEC = 10
  32 NT_TICKS_PER_SEC = NT_TICKS_PER_μSEC * 10**6
  33
  34
  35 def _validate_nt_time(nt_time: NtTime) -> None:
  36     if not isinstance(nt_time, int):
  37         raise ValueError(f"{nt_time} is not an integer")
  38     if not 0 <= nt_time < 2**64:
  39         raise ValueError(f"{nt_time} is out of range")
  40
  41
  42 def nt_time_from_datetime(tm: datetime.datetime) -> NtTime:
  43     time_since_epoch = tm - NT_EPOCH
  44     nt_time = NtTime(round(time_since_epoch.total_seconds() * NT_TICKS_PER_SEC))
  45     _validate_nt_time(nt_time)
  46     return nt_time
  47
  48
  49 def datetime_from_nt_time(nt_time: NtTime) -> datetime.datetime:
  50     _validate_nt_time(nt_time)
  51     time_since_epoch = datetime.timedelta(microseconds=nt_time / NT_TICKS_PER_μSEC)
  52     return NT_EPOCH + time_since_epoch
  53
  54
  55 def nt_time_delta_from_datetime(dt: datetime.timedelta) -> NtTimeDelta:
  56     return NtTimeDelta(round(dt.total_seconds() * NT_TICKS_PER_SEC))
  57
  58
  59 def timedelta_from_nt_time_delta(nt_time_delta: NtTimeDelta) -> datetime.timedelta:
  60     return datetime.timedelta(microseconds=nt_time_delta / NT_TICKS_PER_μSEC)