# -*- coding: utf-8 -*-
"""TCP Header Flags
======================
.. module:: pcapkit.vendor.tcp.flags
This module contains the vendor crawler for **TCP Header Flags**,
which is automatically generating :class:`pcapkit.const.tcp.flags.Flags`.
"""
import csv
import re
import sys
from typing import TYPE_CHECKING
from pcapkit.vendor.default import Vendor
if TYPE_CHECKING:
from typing import Callable
__all__ = ['Flags']
#: TCP header flags' abbreviation.
DATA = {
15: 'FIN',
14: 'SYN',
13: 'RST',
12: 'PSH',
11: 'ACK',
10: 'URG',
9: 'ECE',
8: 'CWR',
}
#: Default constant template of enumeration registry from IANA CSV.
LINE = lambda NAME, DOCS, FLAG, ENUM, MODL: f'''\
# -*- coding: utf-8 -*-
# pylint: disable=line-too-long
"""{(name := DOCS.split(' [', maxsplit=1)[0])}
{'=' * (len(name) + 6)}
.. module:: {MODL.replace('vendor', 'const')}
This module contains the constant enumeration for **{name}**,
which is automatically generated from :class:`{MODL}.{NAME}`.
"""
from typing import TYPE_CHECKING
from aenum import IntFlag
from pcapkit.corekit.enum import EnumRegistry
from pcapkit.utilities.exceptions import EnumValueError
if TYPE_CHECKING:
from typing import Any
__all__ = ['{NAME}']
class {NAME}(EnumRegistry, IntFlag):
"""[{NAME}] {DOCS}
.. versionchanged:: 1.5.0
A value outside the 16-bit field raises :exc:`ValueError`, where
:mod:`aenum` composed a pseudo-member for any integer.
"""
{ENUM}
@classmethod
def _validate_value(cls, value: 'Any') -> 'None':
"""Reject ``value`` unless it passes the range check :meth:`_missing_` makes.
Overrides :meth:`~pcapkit.corekit.enum.EnumLookup._validate_value`
with that check and the message it raises, so
:meth:`~pcapkit.corekit.enum.EnumRegistry.register` refuses exactly the
values :meth:`~pcapkit.corekit.enum.EnumLookup.get` refuses, in the
same words (:issue:`1816`).
Args:
value: Value about to be looked up or minted.
Raises:
EnumValueError: If ``value`` fails that check. A
:exc:`ValueError`, so an ``except ValueError`` caller is
unaffected.
"""
if not ({FLAG}):
raise EnumValueError(f'{{value!r}} is not a valid {{cls.__name__}}')
@classmethod
def _missing_(cls, value: 'int') -> '{NAME}':
"""Lookup function used when value is not found.
Args:
value: Value to get enum item.
"""
if not ({FLAG}):
raise ValueError(f'{{value!r}} is not a valid {{cls.__name__}}')
return super()._missing_(value)
'''.strip() # type: Callable[[str, str, str, str, str], str]
[docs]
class Flags(Vendor):
"""TCP Header Flags"""
#: Value limit checker. The registry indexes *bit offsets* 4 through 15,
#: but the members it generates are ``1 << offset``, so the value domain a
#: lookup has to accept is the 16-bit field those bits live in -- a
#: composite such as ``SYN | ACK`` is a legitimate value and only the
#: composite path reaches :meth:`~pcapkit.const.tcp.flags.Flags._missing_`.
FLAG = 'isinstance(value, int) and 0 <= value <= 0xFFFF'
#: Link to registry.
LINK = 'https://www.iana.org/assignments/tcp-parameters/tcp-header-flags.csv'
def process(self, data: 'list[str]') -> 'list[str]': # type: ignore[override]
"""Process CSV data.
Args:
data: CSV data.
Returns:
Enumeration fields.
"""
reader = csv.reader(data)
next(reader) # header
enum = [] # type: list[str]
for item in reader:
dscp = item[1]
rfcs = item[2]
temp = [] # type: list[str]
for rfc in self.split_references(rfcs):
if re.match(r'\d+', rfc):
continue
if 'RFC' in rfc and re.match(r'\d+', rfc[3:]):
# temp.append(f'[{rfc[:3]} {rfc[3:]}]')
temp.append(f'[:rfc:`{rfc[3:]}`]')
else:
temp.append(f'[{rfc}]'.replace('_', ' '))
tmp1 = f" {''.join(temp)}" if rfcs else ''
desc = self.wrap_comment(re.sub(r'\r*\n', ' ', f'{dscp}{tmp1}', flags=re.MULTILINE))
code = item[0]
name = DATA.get(int(code), dscp.split(' (')[0]).replace('Reserved for future use', 'Reserved')
renm = self.rename(name or 'Unassigned', code, original=dscp)
pres = f"{renm} = 1 << {code}"
sufs = f'#: {desc}'
# if len(pres) > 74:
# sufs = f"\n{' '*80}{sufs}"
# enum.append(f'{pres.ljust(76)}{sufs}')
enum.append(f'{sufs}\n {pres}')
return enum
def context(self, data: 'list[str]') -> 'str':
"""Generate constant context.
Args:
data: CSV data.
Returns:
Constant context.
"""
enum = self.process(data)
ENUM = '\n\n '.join(map(lambda s: s.rstrip(), enum)).strip()
return LINE(self.NAME, self.DOCS, self.FLAG, ENUM, self.__module__)
if __name__ == '__main__':
sys.exit(Flags()) # type: ignore[arg-type]