Source code for charset_normalizer.utils

try:
    import unicodedata2 as unicodedata
except ImportError:
    import unicodedata  # type: ignore[no-redef]
import importlib
import logging
from codecs import IncrementalDecoder
from encodings.aliases import aliases
from functools import lru_cache
from re import findall
from typing import List, Optional, Set, Tuple, Union
from _multibytecodec import MultibyteIncrementalDecoder  # type: ignore
from .constant import (
    ENCODING_MARKS,
    IANA_SUPPORTED_SIMILAR,
    RE_POSSIBLE_ENCODING_INDICATION,
    UNICODE_RANGES_COMBINED,
    UNICODE_SECONDARY_RANGE_KEYWORD,
    UTF8_MAXIMAL_ALLOCATION,
)
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_accentuated(character: str) -> bool:
    try:
        description = unicodedata.name(character)  # type: str
    except ValueError:
        return False
    return (
        "WITH GRAVE" in description
        or "WITH ACUTE" in description
        or "WITH CEDILLA" in description
        or "WITH DIAERESIS" in description
        or "WITH CIRCUMFLEX" in description
        or "WITH TILDE" in description
    )
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def remove_accent(character: str) -> str:
    decomposed = unicodedata.decomposition(character)  # type: str
    if not decomposed:
        return character
    codes = decomposed.split(" ")  # type: List[str]
    return chr(int(codes[0], 16))
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def unicode_range(character: str) -> Optional[str]:
    """
    Retrieve the Unicode range official name from a single character.
    """
    character_ord = ord(character)  # type: int
    for range_name, ord_range in UNICODE_RANGES_COMBINED.items():
        if character_ord in ord_range:
            return range_name
    return None
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_latin(character: str) -> bool:
    try:
        description = unicodedata.name(character)  # type: str
    except ValueError:
        return False
    return "LATIN" in description
[docs]def is_ascii(character: str) -> bool:
    try:
        character.encode("ascii")
    except UnicodeEncodeError:
        return False
    return True
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_punctuation(character: str) -> bool:
    character_category = unicodedata.category(character)  # type: str
    if "P" in character_category:
        return True
    character_range = unicode_range(character)  # type: Optional[str]
    if character_range is None:
        return False
    return "Punctuation" in character_range
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_symbol(character: str) -> bool:
    character_category = unicodedata.category(character)  # type: str
    if "S" in character_category or "N" in character_category:
        return True
    character_range = unicode_range(character)  # type: Optional[str]
    if character_range is None:
        return False
    return "Forms" in character_range
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_emoticon(character: str) -> bool:
    character_range = unicode_range(character)  # type: Optional[str]
    if character_range is None:
        return False
    return "Emoticons" in character_range
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_separator(character: str) -> bool:
    if character.isspace() or character in {"｜", "+", ",", ";", "<", ">"}:
        return True
    character_category = unicodedata.category(character)  # type: str
    return "Z" in character_category
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_case_variable(character: str) -> bool:
    return character.islower() != character.isupper()
[docs]def is_private_use_only(character: str) -> bool:
    character_category = unicodedata.category(character)  # type: str
    return character_category == "Co"
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_cjk(character: str) -> bool:
    try:
        character_name = unicodedata.name(character)
    except ValueError:
        return False
    return "CJK" in character_name
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_hiragana(character: str) -> bool:
    try:
        character_name = unicodedata.name(character)
    except ValueError:
        return False
    return "HIRAGANA" in character_name
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_katakana(character: str) -> bool:
    try:
        character_name = unicodedata.name(character)
    except ValueError:
        return False
    return "KATAKANA" in character_name
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_hangul(character: str) -> bool:
    try:
        character_name = unicodedata.name(character)
    except ValueError:
        return False
    return "HANGUL" in character_name
[docs]@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_thai(character: str) -> bool:
    try:
        character_name = unicodedata.name(character)
    except ValueError:
        return False
    return "THAI" in character_name
[docs]@lru_cache(maxsize=len(UNICODE_RANGES_COMBINED))
def is_unicode_range_secondary(range_name: str) -> bool:
    return any(keyword in range_name for keyword in UNICODE_SECONDARY_RANGE_KEYWORD)
[docs]def any_specified_encoding(sequence: bytes, search_zone: int = 4096) -> Optional[str]:
    """
    Extract using ASCII-only decoder any specified encoding in the first n-bytes.
    """
    if not isinstance(sequence, bytes):
        raise TypeError
    seq_len = len(sequence)  # type: int
    results = findall(
        RE_POSSIBLE_ENCODING_INDICATION,
        sequence[: min(seq_len, search_zone)].decode("ascii", errors="ignore"),
    )  # type: List[str]
    if len(results) == 0:
        return None
    for specified_encoding in results:
        specified_encoding = specified_encoding.lower().replace("-", "_")
        for encoding_alias, encoding_iana in aliases.items():
            if encoding_alias == specified_encoding:
                return encoding_iana
            if encoding_iana == specified_encoding:
                return encoding_iana
    return None
[docs]@lru_cache(maxsize=128)
def is_multi_byte_encoding(name: str) -> bool:
    """
    Verify is a specific encoding is a multi byte one based on it IANA name
    """
    return name in {
        "utf_8",
        "utf_8_sig",
        "utf_16",
        "utf_16_be",
        "utf_16_le",
        "utf_32",
        "utf_32_le",
        "utf_32_be",
        "utf_7",
    } or issubclass(
        importlib.import_module("encodings.{}".format(name)).IncrementalDecoder,  # type: ignore
        MultibyteIncrementalDecoder,
    )
[docs]def identify_sig_or_bom(sequence: bytes) -> Tuple[Optional[str], bytes]:
    """
    Identify and extract SIG/BOM in given sequence.
    """
    for iana_encoding in ENCODING_MARKS:
        marks = ENCODING_MARKS[iana_encoding]  # type: Union[bytes, List[bytes]]
        if isinstance(marks, bytes):
            marks = [marks]
        for mark in marks:
            if sequence.startswith(mark):
                return iana_encoding, mark
    return None, b""
[docs]def should_strip_sig_or_bom(iana_encoding: str) -> bool:
    return iana_encoding not in {"utf_16", "utf_32"}
[docs]def iana_name(cp_name: str, strict: bool = True) -> str:
    cp_name = cp_name.lower().replace("-", "_")
    for encoding_alias, encoding_iana in aliases.items():
        if cp_name in [encoding_alias, encoding_iana]:
            return encoding_iana
    if strict:
        raise ValueError("Unable to retrieve IANA for '{}'".format(cp_name))
    return cp_name
[docs]def range_scan(decoded_sequence: str) -> List[str]:
    ranges = set()  # type: Set[str]
    for character in decoded_sequence:
        character_range = unicode_range(character)  # type: Optional[str]
        if character_range is None:
            continue
        ranges.add(character_range)
    return list(ranges)
def cp_similarity(iana_name_a: str, iana_name_b: str) -> float:
    if is_multi_byte_encoding(iana_name_a) or is_multi_byte_encoding(iana_name_b):
        return 0.0
    decoder_a = importlib.import_module("encodings.{}".format(iana_name_a)).IncrementalDecoder  # type: ignore
    decoder_b = importlib.import_module("encodings.{}".format(iana_name_b)).IncrementalDecoder  # type: ignore
    id_a = decoder_a(errors="ignore")  # type: IncrementalDecoder
    id_b = decoder_b(errors="ignore")  # type: IncrementalDecoder
    character_match_count = 0  # type: int
    for i in range(255):
        to_be_decoded = bytes([i])  # type: bytes
        if id_a.decode(to_be_decoded) == id_b.decode(to_be_decoded):
            character_match_count += 1
    return character_match_count / 254
[docs]def is_cp_similar(iana_name_a: str, iana_name_b: str) -> bool:
    """
    Determine if two code page are at least 80% similar. IANA_SUPPORTED_SIMILAR dict was generated using
    the function cp_similarity.
    """
    return (
        iana_name_a in IANA_SUPPORTED_SIMILAR
        and iana_name_b in IANA_SUPPORTED_SIMILAR[iana_name_a]
    )
[docs]def set_logging_handler(
    name: str = "charset_normalizer",
    level: int = logging.INFO,
    format_string: str = "%(asctime)s | %(levelname)s | %(message)s",
) -> None:
    logger = logging.getLogger(name)
    logger.setLevel(level)
    handler = logging.StreamHandler()
    handler.setFormatter(logging.Formatter(format_string))
    logger.addHandler(handler)