installer_files/conda/Lib/site-packages/charset_normalizer/md.py

from functools import lru_cache
from typing import Optional, List

from charset_normalizer.constant import UNICODE_SECONDARY_RANGE_KEYWORD
from charset_normalizer.utils import is_punctuation, is_symbol, unicode_range, is_accentuated, is_latin, \
    remove_accent, is_separator, is_cjk, is_case_variable, is_hangul, is_katakana, is_hiragana, is_ascii, is_thai


class MessDetectorPlugin:
    """
    Base abstract class used for mess detection plugins.
    All detectors MUST extend and implement given methods.
    """

    def eligible(self, character: str) -> bool:
        """
        Determine if given character should be fed in.
        """
        raise NotImplementedError  # pragma: nocover

    def feed(self, character: str) -> None:
        """
        The main routine to be executed upon character.
        Insert the logic in witch the text would be considered chaotic.
        """
        raise NotImplementedError  # pragma: nocover

    def reset(self) -> None:
        """
        Permit to reset the plugin to the initial state.
        """
        raise NotImplementedError  # pragma: nocover

    @property
    def ratio(self) -> float:
        """
        Compute the chaos ratio based on what your feed() has seen.
        Must NOT be lower than 0.; No restriction gt 0.
        """
        raise NotImplementedError  # pragma: nocover


class TooManySymbolOrPunctuationPlugin(MessDetectorPlugin):

    def __init__(self):
        self._punctuation_count = 0  # type: int
        self._symbol_count = 0  # type: int
        self._character_count = 0  # type: int

        self._last_printable_char = None  # type: Optional[str]
        self._frenzy_symbol_in_word = False  # type: bool

    def eligible(self, character: str) -> bool:
        return character.isprintable()

    def feed(self, character: str) -> None:
        self._character_count += 1

        if character != self._last_printable_char and character not in ["<", ">", "=", ":", "/", "&", ";", "{", "}", "[", "]", ",", "|", '"']:
            if is_punctuation(character):
                self._punctuation_count += 1
            elif character.isdigit() is False and is_symbol(character):
                self._symbol_count += 2

        self._last_printable_char = character

    def reset(self) -> None:
        self._punctuation_count = 0
        self._character_count = 0
        self._symbol_count = 0

    @property
    def ratio(self) -> float:
        if self._character_count == 0:
            return 0.

        ratio_of_punctuation = (self._punctuation_count + self._symbol_count) / self._character_count  # type: float

        return ratio_of_punctuation if ratio_of_punctuation >= 0.3 else 0.


class TooManyAccentuatedPlugin(MessDetectorPlugin):

    def __init__(self):
        self._character_count = 0  # type: int
        self._accentuated_count = 0  # type: int

    def eligible(self, character: str) -> bool:
        return character.isalpha()

    def feed(self, character: str) -> None:
        self._character_count += 1

        if is_accentuated(character):
            self._accentuated_count += 1

    def reset(self) -> None:
        self._character_count = 0
        self._accentuated_count = 0

    @property
    def ratio(self) -> float:
        if self._character_count == 0:
            return 0.
        ratio_of_accentuation = self._accentuated_count / self._character_count  # type: float
        return ratio_of_accentuation if ratio_of_accentuation >= 0.35 else 0.


class UnprintablePlugin(MessDetectorPlugin):

    def __init__(self):
        self._unprintable_count = 0  # type: int
        self._character_count = 0  # type: int

    def eligible(self, character: str) -> bool:
        return True

    def feed(self, character: str) -> None:
        if character not in {'\n', '\t', '\r', '\v'} and character.isprintable() is False:
            self._unprintable_count += 1
        self._character_count += 1

    def reset(self) -> None:
        self._unprintable_count = 0

    @property
    def ratio(self) -> float:
        if self._character_count == 0:
            return 0.

        return (self._unprintable_count * 8) / self._character_count


class SuspiciousDuplicateAccentPlugin(MessDetectorPlugin):

    def __init__(self):
        self._successive_count = 0  # type: int
        self._character_count = 0  # type: int

        self._last_latin_character = None  # type: Optional[str]

    def eligible(self, character: str) -> bool:
        return character.isalpha() and is_latin(character)

    def feed(self, character: str) -> None:
        self._character_count += 1
        if self._last_latin_character is not None:
            if is_accentuated(character) and is_accentuated(self._last_latin_character):
                if character.isupper() and self._last_latin_character.isupper():
                    self._successive_count += 1
                # Worse if its the same char duplicated with different accent.
                if remove_accent(character) == remove_accent(self._last_latin_character):
                    self._successive_count += 1
        self._last_latin_character = character

    def reset(self) -> None:
        self._successive_count = 0
        self._character_count = 0
        self._last_latin_character = None

    @property
    def ratio(self) -> float:
        if self._character_count == 0:
            return 0.

        return (self._successive_count * 2) / self._character_count


class SuspiciousRange(MessDetectorPlugin):

    def __init__(self):
        self._suspicious_successive_range_count = 0  # type: int
        self._character_count = 0  # type: int
        self._last_printable_seen = None  # type: Optional[str]

    def eligible(self, character: str) -> bool:
        return character.isprintable()

    def feed(self, character: str) -> None:
        self._character_count += 1

        if character.isspace() or is_punctuation(character):
            self._last_printable_seen = None
            return

        if self._last_printable_seen is None:
            self._last_printable_seen = character
            return

        unicode_range_a = unicode_range(self._last_printable_seen)  # type: Optional[str]
        unicode_range_b = unicode_range(character)  # type: Optional[str]

        if is_suspiciously_successive_range(unicode_range_a, unicode_range_b):
            self._suspicious_successive_range_count += 1

        self._last_printable_seen = character

    def reset(self) -> None:
        self._character_count = 0
        self._suspicious_successive_range_count = 0
        self._last_printable_seen = None

    @property
    def ratio(self) -> float:
        if self._character_count == 0:
            return 0.

        ratio_of_suspicious_range_usage = (self._suspicious_successive_range_count * 2) / self._character_count  # type: float

        if ratio_of_suspicious_range_usage < 0.1:
            return 0.

        return ratio_of_suspicious_range_usage


class SuperWeirdWordPlugin(MessDetectorPlugin):

    def __init__(self):
        self._word_count = 0  # type: int
        self._bad_word_count = 0  # type: int
        self._is_current_word_bad = False  # type: bool
        self._foreign_long_watch = False  # type: bool

        self._character_count = 0  # type: int
        self._bad_character_count = 0  # type: int

        self._buffer = ""  # type: str
        self._buffer_accent_count = 0  # type: int

    def eligible(self, character: str) -> bool:
        return True

    def feed(self, character: str) -> None:
        if character.isalpha():
            self._buffer = "".join([self._buffer, character])
            if is_accentuated(character):
                self._buffer_accent_count += 1
            if self._foreign_long_watch is False and is_latin(character) is False and is_cjk(character) is False and is_hangul(character) is False and is_katakana(character) is False and is_hiragana(character) is False and is_thai(character) is False:
                self._foreign_long_watch = True
            return
        if not self._buffer:
            return
        if (character.isspace() or is_punctuation(character) or is_separator(character)) and self._buffer:
            self._word_count += 1
            buffer_length = len(self._buffer)  # type: int

            self._character_count += buffer_length

            if buffer_length >= 4 and self._buffer_accent_count / buffer_length >= 0.3:
                self._is_current_word_bad = True
            if buffer_length >= 24 and self._foreign_long_watch:
                self._is_current_word_bad = True

            if self._is_current_word_bad:
                self._bad_word_count += 1
                self._bad_character_count += len(self._buffer)
                self._is_current_word_bad = False

            self._foreign_long_watch = False
            self._buffer = ""
            self._buffer_accent_count = 0
        elif character not in {"<", ">", "-", "="} and character.isdigit() is False and is_symbol(character):
            self._is_current_word_bad = True
            self._buffer += character

    def reset(self) -> None:
        self._buffer = ""
        self._is_current_word_bad = False
        self._foreign_long_watch = False
        self._bad_word_count = 0
        self._word_count = 0
        self._character_count = 0
        self._bad_character_count = 0

    @property
    def ratio(self) -> float:
        if self._word_count <= 10:
            return 0.

        return self._bad_character_count / self._character_count


class CjkInvalidStopPlugin(MessDetectorPlugin):
    """
    GB(Chinese) based encoding often render the stop incorrectly when the content does not fit and can be easily detected.
    Searching for the overuse of '丅' and '丄'.
    """

    def __init__(self):
        self._wrong_stop_count = 0  # type: int
        self._cjk_character_count = 0  # type: int

    def eligible(self, character: str) -> bool:
        return True

    def feed(self, character: str) -> None:
        if character in ["丅", "丄"]:
            self._wrong_stop_count += 1
            return
        if is_cjk(character):
            self._cjk_character_count += 1

    def reset(self) -> None:
        self._wrong_stop_count = 0
        self._cjk_character_count = 0

    @property
    def ratio(self) -> float:
        if self._cjk_character_count < 16:
            return 0.
        return self._wrong_stop_count / self._cjk_character_count


class ArchaicUpperLowerPlugin(MessDetectorPlugin):

    def __init__(self):
        self._buf = False  # type: bool

        self._character_count_since_last_sep = 0  # type: int

        self._successive_upper_lower_count = 0  # type: int
        self._successive_upper_lower_count_final = 0  # type: int

        self._character_count = 0  # type: int

        self._last_alpha_seen = None  # type: Optional[str]
        self._current_ascii_only = True  # type: bool

    def eligible(self, character: str) -> bool:
        return True

    def feed(self, character: str) -> None:
        is_concerned = character.isalpha() and is_case_variable(character)
        chunk_sep = is_concerned is False

        if chunk_sep and self._character_count_since_last_sep > 0:
            if self._character_count_since_last_sep <= 64 and character.isdigit() is False and self._current_ascii_only is False:
                self._successive_upper_lower_count_final += self._successive_upper_lower_count

            self._successive_upper_lower_count = 0
            self._character_count_since_last_sep = 0
            self._last_alpha_seen = None
            self._buf = False
            self._character_count += 1
            self._current_ascii_only = True

            return

        if self._current_ascii_only is True and is_ascii(character) is False:
            self._current_ascii_only = False

        if self._last_alpha_seen is not None:
            if (character.isupper() and self._last_alpha_seen.islower()) or (character.islower() and self._last_alpha_seen.isupper()):
                if self._buf is True:
                    self._successive_upper_lower_count += 2
                    self._buf = False
                else:
                    self._buf = True
            else:
                self._buf = False

        self._character_count += 1
        self._character_count_since_last_sep += 1
        self._last_alpha_seen = character

    def reset(self) -> None:
        self._character_count = 0
        self._character_count_since_last_sep = 0
        self._successive_upper_lower_count = 0
        self._successive_upper_lower_count_final = 0
        self._last_alpha_seen = None
        self._buf = False
        self._current_ascii_only = True

    @property
    def ratio(self) -> float:
        if self._character_count == 0:
            return 0.

        return self._successive_upper_lower_count_final / self._character_count


def is_suspiciously_successive_range(unicode_range_a: Optional[str], unicode_range_b: Optional[str]) -> bool:
    """
    Determine if two Unicode range seen next to each other can be considered as suspicious.
    """
    if unicode_range_a is None or unicode_range_b is None:
        return True

    if unicode_range_a == unicode_range_b:
        return False

    if "Latin" in unicode_range_a and "Latin" in unicode_range_b:
        return False

    if "Emoticons" in unicode_range_a or "Emoticons" in unicode_range_b:
        return False

    keywords_range_a, keywords_range_b = unicode_range_a.split(" "), unicode_range_b.split(" ")

    for el in keywords_range_a:
        if el in UNICODE_SECONDARY_RANGE_KEYWORD:
            continue
        if el in keywords_range_b:
            return False

    # Japanese Exception
    if unicode_range_a in ['Katakana', 'Hiragana'] and unicode_range_b in ['Katakana', 'Hiragana']:
        return False

    if unicode_range_a in ['Katakana', 'Hiragana'] or unicode_range_b in ['Katakana', 'Hiragana']:
        if "CJK" in unicode_range_a or "CJK" in unicode_range_b:
            return False

    if "Hangul" in unicode_range_a or "Hangul" in unicode_range_b:
        if "CJK" in unicode_range_a or "CJK" in unicode_range_b:
            return False
        if unicode_range_a == "Basic Latin" or unicode_range_b == "Basic Latin":
            return False

    # Chinese/Japanese use dedicated range for punctuation and/or separators.
    if ('CJK' in unicode_range_a or 'CJK' in unicode_range_b) or (unicode_range_a in ['Katakana', 'Hiragana'] and unicode_range_b in ['Katakana', 'Hiragana']):
        if 'Punctuation' in unicode_range_a or 'Punctuation' in unicode_range_b:
            return False
        if 'Forms' in unicode_range_a or 'Forms' in unicode_range_b:
            return False

    return True


@lru_cache(maxsize=2048)
def mess_ratio(decoded_sequence: str, maximum_threshold: float = 0.2, debug: bool = False) -> float:
    """
    Compute a mess ratio given a decoded bytes sequence. The maximum threshold does stop the computation earlier.
    """
    detectors = []  # type: List[MessDetectorPlugin]

    for md_class in MessDetectorPlugin.__subclasses__():
        detectors.append(
            md_class()
        )

    length = len(decoded_sequence)  # type: int

    mean_mess_ratio = 0.  # type: float

    if length < 512:
        intermediary_mean_mess_ratio_calc = 32  # type: int
    elif length <= 1024:
        intermediary_mean_mess_ratio_calc = 64
    else:
        intermediary_mean_mess_ratio_calc = 128

    for character, index in zip(decoded_sequence, range(0, length)):
        for detector in detectors:
            if detector.eligible(character):
                detector.feed(character)

        if (index > 0 and index % intermediary_mean_mess_ratio_calc == 0) or index == length-1:
            mean_mess_ratio = sum(
                [
                    dt.ratio for dt in detectors
                ]
            )

            if mean_mess_ratio >= maximum_threshold:
                break

    if debug:
        for dt in detectors:  # pragma: nocover
            print(
                dt.__class__,
                dt.ratio
            )

    return round(
        mean_mess_ratio,
        3
    )