46 lines
1.5 KiB
Python
46 lines
1.5 KiB
Python
# Copyright (c) PARRRATE T&V 2021. All rights reserved.
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from io import BytesIO
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from typing import Iterable, Type, TypeVar
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from bu4.parsing.abstractparser import AbstractParser
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from bu4.parsing.extensions.abstractextension import AbstractExtension
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from bu4.parsing.extensions.extension import Extension
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from bu4.parsing.states.parsingread import ParsingRead
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from bu4.transform.states.transformstate import TransformState
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__all__ = ('Parser',)
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T = TypeVar('T')
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class Parser(AbstractParser[T]):
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def __init__(self, source: bytes, extensions: Iterable[Type[Extension[T]]]):
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self.__source = BytesIO(source)
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self.__extensions: dict[int, Extension[T]] = {}
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for extension in extensions:
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if extension.code in self.__extensions:
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raise ValueError('code overload')
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self.__extensions[extension.code] = extension(self)
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def read(self) -> int:
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bytes_ = self.__source.read(1)
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return bytes_[0] if bytes_ else 0
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def parse_name(self) -> bytes:
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s = BytesIO()
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while True:
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c = self.read()
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if not c:
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return s.getvalue()
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s.write(bytes([c]))
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def extension_for(self, code: int) -> AbstractExtension[T]:
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extension = self.__extensions.get(code)
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if extension is None:
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raise ValueError(f'unknown control: {hex(code)}')
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return extension
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def parse(self) -> TransformState[T]:
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return ParsingRead(self)
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