path: root/libs/charset_normalizer/utils.py

import importlib
import logging
import unicodedata
from codecs import IncrementalDecoder
from encodings.aliases import aliases
from functools import lru_cache
from re import findall
from typing import Generator, List, Optional, Set, Tuple, Union

from _multibytecodec import MultibyteIncrementalDecoder

from .constant import (
    ENCODING_MARKS,
    IANA_SUPPORTED_SIMILAR,
    RE_POSSIBLE_ENCODING_INDICATION,
    UNICODE_RANGES_COMBINED,
    UNICODE_SECONDARY_RANGE_KEYWORD,
    UTF8_MAXIMAL_ALLOCATION,
)


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_accentuated(character: str) -> bool:
    try:
        description: str = unicodedata.name(character)
    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
    )


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def remove_accent(character: str) -> str:
    decomposed: str = unicodedata.decomposition(character)
    if not decomposed:
        return character

    codes: List[str] = decomposed.split(" ")

    return chr(int(codes[0], 16))


@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: int = ord(character)

    for range_name, ord_range in UNICODE_RANGES_COMBINED.items():
        if character_ord in ord_range:
            return range_name

    return None


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_latin(character: str) -> bool:
    try:
        description: str = unicodedata.name(character)
    except ValueError:
        return False
    return "LATIN" in description


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_ascii(character: str) -> bool:
    try:
        character.encode("ascii")
    except UnicodeEncodeError:
        return False
    return True


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_punctuation(character: str) -> bool:
    character_category: str = unicodedata.category(character)

    if "P" in character_category:
        return True

    character_range: Optional[str] = unicode_range(character)

    if character_range is None:
        return False

    return "Punctuation" in character_range


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_symbol(character: str) -> bool:
    character_category: str = unicodedata.category(character)

    if "S" in character_category or "N" in character_category:
        return True

    character_range: Optional[str] = unicode_range(character)

    if character_range is None:
        return False

    return "Forms" in character_range


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_emoticon(character: str) -> bool:
    character_range: Optional[str] = unicode_range(character)

    if character_range is None:
        return False

    return "Emoticons" in character_range


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_separator(character: str) -> bool:
    if character.isspace() or character in {"｜", "+", ",", ";", "<", ">"}:
        return True

    character_category: str = unicodedata.category(character)

    return "Z" in character_category


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_case_variable(character: str) -> bool:
    return character.islower() != character.isupper()


def is_private_use_only(character: str) -> bool:
    character_category: str = unicodedata.category(character)

    return character_category == "Co"


@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


@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


@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


@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


@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


@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)


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_unprintable(character: str) -> bool:
    return (
        character.isspace() is False  # includes \n \t \r \v
        and character.isprintable() is False
        and character != "\x1A"  # Why? Its the ASCII substitute character.
        and character != "\ufeff"  # bug discovered in Python,
        # Zero Width No-Break Space located in 	Arabic Presentation Forms-B, Unicode 1.1 not acknowledged as space.
    )


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: int = len(sequence)

    results: List[str] = findall(
        RE_POSSIBLE_ENCODING_INDICATION,
        sequence[: min(seq_len, search_zone)].decode("ascii", errors="ignore"),
    )

    if len(results) == 0:
        return None

    for specified_encoding in results:
        specified_encoding = specified_encoding.lower().replace("-", "_")

        encoding_alias: str
        encoding_iana: str

        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


@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,
        MultibyteIncrementalDecoder,
    )


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: Union[bytes, List[bytes]] = ENCODING_MARKS[iana_encoding]

        if isinstance(marks, bytes):
            marks = [marks]

        for mark in marks:
            if sequence.startswith(mark):
                return iana_encoding, mark

    return None, b""


def should_strip_sig_or_bom(iana_encoding: str) -> bool:
    return iana_encoding not in {"utf_16", "utf_32"}


def iana_name(cp_name: str, strict: bool = True) -> str:
    cp_name = cp_name.lower().replace("-", "_")

    encoding_alias: str
    encoding_iana: str

    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


def range_scan(decoded_sequence: str) -> List[str]:
    ranges: Set[str] = set()

    for character in decoded_sequence:
        character_range: Optional[str] = unicode_range(character)

        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
    decoder_b = importlib.import_module(
        "encodings.{}".format(iana_name_b)
    ).IncrementalDecoder

    id_a: IncrementalDecoder = decoder_a(errors="ignore")
    id_b: IncrementalDecoder = decoder_b(errors="ignore")

    character_match_count: int = 0

    for i in range(255):
        to_be_decoded: bytes = bytes([i])
        if id_a.decode(to_be_decoded) == id_b.decode(to_be_decoded):
            character_match_count += 1

    return character_match_count / 254


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]
    )


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)


def cut_sequence_chunks(
    sequences: bytes,
    encoding_iana: str,
    offsets: range,
    chunk_size: int,
    bom_or_sig_available: bool,
    strip_sig_or_bom: bool,
    sig_payload: bytes,
    is_multi_byte_decoder: bool,
    decoded_payload: Optional[str] = None,
) -> Generator[str, None, None]:
    if decoded_payload and is_multi_byte_decoder is False:
        for i in offsets:
            chunk = decoded_payload[i : i + chunk_size]
            if not chunk:
                break
            yield chunk
    else:
        for i in offsets:
            chunk_end = i + chunk_size
            if chunk_end > len(sequences) + 8:
                continue

            cut_sequence = sequences[i : i + chunk_size]

            if bom_or_sig_available and strip_sig_or_bom is False:
                cut_sequence = sig_payload + cut_sequence

            chunk = cut_sequence.decode(
                encoding_iana,
                errors="ignore" if is_multi_byte_decoder else "strict",
            )

            # multi-byte bad cutting detector and adjustment
            # not the cleanest way to perform that fix but clever enough for now.
            if is_multi_byte_decoder and i > 0:
                chunk_partial_size_chk: int = min(chunk_size, 16)

                if (
                    decoded_payload
                    and chunk[:chunk_partial_size_chk] not in decoded_payload
                ):
                    for j in range(i, i - 4, -1):
                        cut_sequence = sequences[j:chunk_end]

                        if bom_or_sig_available and strip_sig_or_bom is False:
                            cut_sequence = sig_payload + cut_sequence

                        chunk = cut_sequence.decode(encoding_iana, errors="ignore")

                        if chunk[:chunk_partial_size_chk] in decoded_payload:
                            break

            yield chunk