source/charset_normalizer/utils.py

from __future__ import annotations

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

from _multibytecodec import (  # type: ignore[import-not-found,import]
    MultibyteIncrementalDecoder,
)

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


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_accentuated(character: str) -> bool:
    try:
        description: str = unicodedata.name(character)
    except ValueError:  # Defensive: unicode database outdated?
        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
        or "WITH MACRON" in description
        or "WITH RING ABOVE" 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) -> str | None:
    """
    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    except ValueError:  # Defensive: unicode database outdated?
        return False
    return "LATIN" in description


@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: str | None = 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: str | None = unicode_range(character)

    if character_range is None:
        return False

    return "Forms" in character_range and character_category != "Lo"


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_emoticon(character: str) -> bool:
    character_range: str | None = unicode_range(character)

    if character_range is None:
        return False

    return "Emoticons" in character_range or "Pictographs" 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 or character_category in {"Po", "Pd", "Pc"}


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


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_cjk(character: str) -> bool:
    try:
        character_name = unicodedata.name(character)
    except ValueError:  # Defensive: unicode database outdated?
        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:  # Defensive: unicode database outdated?
        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:  # Defensive: unicode database outdated?
        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:  # Defensive: unicode database outdated?
        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:  # Defensive: unicode database outdated?
        return False

    return "THAI" in character_name


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_arabic(character: str) -> bool:
    try:
        character_name = unicodedata.name(character)
    except ValueError:  # Defensive: unicode database outdated?
        return False

    return "ARABIC" in character_name


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_arabic_isolated_form(character: str) -> bool:
    try:
        character_name = unicodedata.name(character)
    except ValueError:  # Defensive: unicode database outdated?
        return False

    return "ARABIC" in character_name and "ISOLATED FORM" in character_name


@lru_cache(maxsize=UTF8_MAXIMAL_ALLOCATION)
def is_cjk_uncommon(character: str) -> bool:
    return character not in COMMON_CJK_CHARACTERS


@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 = 8192) -> str | None:
    """
    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(f"encodings.{name}").IncrementalDecoder,
        MultibyteIncrementalDecoder,
    )


def identify_sig_or_bom(sequence: bytes) -> tuple[str | None, bytes]:
    """
    Identify and extract SIG/BOM in given sequence.
    """

    for iana_encoding in ENCODING_MARKS:
        marks: 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:
    """Returns the Python normalized encoding name (Not the IANA official name)."""
    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(f"Unable to retrieve IANA for '{cp_name}'")

    return cp_name


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(f"encodings.{iana_name_a}").IncrementalDecoder
    decoder_b = importlib.import_module(f"encodings.{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: str | None = 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