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try:
import unicodedata2 as unicodedata
except ImportError:
import unicodedata
from codecs import IncrementalDecoder
from re import findall
from typing import Optional, Tuple, Union, List, Set
import importlib
from _multibytecodec import MultibyteIncrementalDecoder # type: ignore
from encodings.aliases import aliases
from functools import lru_cache
from charset_normalizer.constant import UNICODE_RANGES_COMBINED, UNICODE_SECONDARY_RANGE_KEYWORD, \
RE_POSSIBLE_ENCODING_INDICATION, ENCODING_MARKS, UTF8_MAXIMAL_ALLOCATION, IANA_SUPPORTED_SIMILAR
@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
@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
)
)
@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
@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
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 = 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
@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
@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
@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 = unicodedata.category(character) # type: str
return "Co" == character_category
@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:
for keyword in UNICODE_SECONDARY_RANGE_KEYWORD:
if keyword in range_name:
return True
return False
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[:seq_len if seq_len <= search_zone else 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
@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
)
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""
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('-', '_')
for encoding_alias, encoding_iana in aliases.items():
if cp_name == encoding_alias or cp_name == 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() # 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.
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(0, 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
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]
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