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import datetime
from calendar import isleap
from typing import Any, Generator, Optional, Union
def parse_date_args(value: Any, fmt: str) -> Generator:
if not isinstance(value, str):
raise ValueError("")
parser = DateTimeParser(value.strip(), fmt)
return parser.parse()
def calculate_timezone(offset: Optional[int]) -> Optional[datetime.timezone]:
if offset is None:
return None
if offset == 0:
return datetime.timezone.utc
return datetime.timezone(datetime.timedelta(minutes=offset))
def calculate_offset(obj: Union[datetime.time, datetime.datetime]) -> Optional[int]:
offset = obj.utcoffset()
if offset is None:
return None
return int(offset.total_seconds() // 60)
def format_date(year: int, month: int, day: int) -> str:
if year < 0:
year = -year
sign = "-"
else:
sign = ""
return f"{sign}{year:04d}-{month:02d}-{day:02d}"
def format_time(hour: int, minute: int, second: int, fractional_second: int) -> str:
if not fractional_second:
return f"{hour:02d}:{minute:02d}:{second:02d}"
microsecond, nano = divmod(fractional_second, 1000)
if nano:
return f"{hour:02d}:{minute:02d}:{second:02d}.{fractional_second:09d}"
milli, micro = divmod(microsecond, 1000)
if micro:
return f"{hour:02d}:{minute:02d}:{second:02d}.{microsecond:06d}"
return f"{hour:02d}:{minute:02d}:{second:02d}.{milli:03d}"
def format_offset(offset: Optional[int]) -> str:
if offset is None:
return ""
if offset == 0:
return "Z"
if offset < 0:
sign = "-"
offset = -offset
else:
sign = "+"
hh, mm = divmod(offset, 60)
return f"{sign}{hh:02d}:{mm:02d}"
# Copied from calendar.monthlen for some reason it's not exported
mdays = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
def monthlen(year: int, month: int) -> int:
return mdays[month] + (month == 2 and isleap(year))
def validate_date(year: int, month: int, day: int):
if not 1 <= month <= 12:
raise ValueError("Month must be in 1..12")
max_days = monthlen(year, month)
if not 1 <= day <= max_days:
raise ValueError(f"Day must be in 1..{max_days}")
def validate_time(hour: int, minute: int, second: int, franctional_second: int):
if not 0 <= hour <= 24:
raise ValueError("Hour must be in 0..24")
if hour == 24 and (minute != 0 or second != 0 or franctional_second != 0):
raise ValueError("Day time exceeded")
if not 0 <= minute <= 59:
raise ValueError("Minute must be in 0..59")
if not 0 <= second <= 59:
raise ValueError("Second must be in 0..59")
if not 0 <= franctional_second <= 999999999:
raise ValueError("Fractional second must be in 0..999999999")
SIMPLE_TWO_DIGITS_FORMATS = ("d", "m", "H", "M")
class DateTimeParser:
def __init__(self, value: str, fmt: str):
self.format = fmt
self.value = value
self.vlen = len(value)
self.flen = len(fmt)
self.vidx = 0
self.fidx = 0
def parse(self):
try:
while self.fidx < self.flen:
char = self.next_format_char()
if char != "%":
self.skip(char)
else:
var = self.next_format_char()
yield from self.parse_var(var)
if self.vidx != self.vlen:
raise ValueError()
except Exception:
raise ValueError(
f"String '{self.value}' does not match format '{self.format}'"
)
def next_format_char(self) -> str:
char = self.format[self.fidx]
self.fidx += 1
return char
def has_more(self) -> bool:
return self.vidx < self.vlen
def peek(self) -> str:
return self.value[self.vidx]
def skip(self, char: str):
if not self.has_more() or self.peek() != char:
raise ValueError()
self.vidx += 1
def parse_var(self, var: str):
if var in SIMPLE_TWO_DIGITS_FORMATS:
yield self.parse_digits(2)
elif var == "Y":
yield self.parse_year()
elif var == "S":
yield self.parse_digits(2)
yield self.parse_fractional_second()
elif var == "z":
yield self.parse_offset()
else:
raise ValueError()
def parse_year(self) -> int:
negative = False
if self.peek() == "-":
self.vidx += 1
negative = True
start = self.vidx
year = self.parse_minimum_digits(4)
end = self.vidx
raw = self.value[start:end]
leading_zeros = len(raw) - len(raw.lstrip("0"))
if (
(leading_zeros == 1 and year > 999)
or (leading_zeros == 2 and year > 99)
or (leading_zeros == 3 and year > 9)
or (leading_zeros == 4 and year > 0)
or (leading_zeros > 4)
):
raise ValueError()
if negative:
return -year
return year
def parse_fractional_second(self) -> int:
if self.has_more() and self.peek() == ".":
self.vidx += 1
return self.parse_fixed_digits(9)
else:
return 0
def parse_digits(self, digits: int) -> int:
start = self.vidx
self.vidx += digits
return int(self.value[start : self.vidx])
def parse_minimum_digits(self, min_digits: int) -> int:
start = self.vidx
self.vidx += min_digits
while self.has_more() and self.peek().isdigit():
self.vidx += 1
return int(self.value[start : self.vidx])
def parse_fixed_digits(self, max_digits: int) -> int:
start = self.vidx
just = max_digits
while max_digits and self.has_more() and self.peek().isdigit():
self.vidx += 1
max_digits -= 1
return int(self.value[start : self.vidx].ljust(just, "0"))
def parse_offset(self) -> Optional[int]:
if not self.has_more():
return None
ctrl = self.peek()
if ctrl == "Z":
self.vidx += 1
return 0
if ctrl == "-" or ctrl == "+":
self.vidx += 1
offset = self.parse_digits(2) * 60
self.skip(":")
offset += self.parse_digits(2)
offset *= -1 if ctrl == "-" else 1
return offset
raise ValueError()
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