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420 lines
15 KiB
Python
420 lines
15 KiB
Python
import re
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import sys
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from webencodings import ascii_lower
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from .ast import ( # isort: skip
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AtKeywordToken, Comment, CurlyBracketsBlock, DimensionToken, FunctionBlock,
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HashToken, IdentToken, LiteralToken, NumberToken, ParenthesesBlock, ParseError,
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PercentageToken, SquareBracketsBlock, StringToken, UnicodeRangeToken, URLToken,
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WhitespaceToken)
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from .serializer import serialize_string_value, serialize_url
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_NUMBER_RE = re.compile(r'[-+]?([0-9]*\.)?[0-9]+([eE][+-]?[0-9]+)?')
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_HEX_ESCAPE_RE = re.compile(r'([0-9A-Fa-f]{1,6})[ \n\t]?')
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def parse_component_value_list(css, skip_comments=False):
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"""Parse a list of component values.
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:type css: :obj:`str`
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:param css: A CSS string.
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:type skip_comments: :obj:`bool`
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:param skip_comments:
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Ignore CSS comments.
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The return values (and recursively its blocks and functions)
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will not contain any :class:`~tinycss2.ast.Comment` object.
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:returns: A list of :term:`component values`.
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"""
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css = (css.replace('\0', '\uFFFD')
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# This turns out to be faster than a regexp:
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.replace('\r\n', '\n').replace('\r', '\n').replace('\f', '\n'))
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length = len(css)
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token_start_pos = pos = 0 # Character index in the css source.
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line = 1 # First line is line 1.
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last_newline = -1
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root = tokens = []
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end_char = None # Pop the stack when encountering this character.
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stack = [] # Stack of nested blocks: (tokens, end_char) tuples.
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while pos < length:
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newline = css.rfind('\n', token_start_pos, pos)
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if newline != -1:
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line += 1 + css.count('\n', token_start_pos, newline)
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last_newline = newline
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# First character in a line is in column 1.
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column = pos - last_newline
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token_start_pos = pos
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c = css[pos]
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if c in ' \n\t':
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pos += 1
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while css.startswith((' ', '\n', '\t'), pos):
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pos += 1
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value = css[token_start_pos:pos]
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tokens.append(WhitespaceToken(line, column, value))
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continue
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elif (c in 'Uu' and pos + 2 < length and css[pos + 1] == '+' and
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css[pos + 2] in '0123456789abcdefABCDEF?'):
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start, end, pos = _consume_unicode_range(css, pos + 2)
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tokens.append(UnicodeRangeToken(line, column, start, end))
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continue
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elif css.startswith('-->', pos): # Check before identifiers
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tokens.append(LiteralToken(line, column, '-->'))
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pos += 3
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continue
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elif _is_ident_start(css, pos):
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value, pos = _consume_ident(css, pos)
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if not css.startswith('(', pos): # Not a function
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tokens.append(IdentToken(line, column, value))
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continue
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pos += 1 # Skip the '('
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if ascii_lower(value) == 'url':
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url_pos = pos
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while css.startswith((' ', '\n', '\t'), url_pos):
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url_pos += 1
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if url_pos >= length or css[url_pos] not in ('"', "'"):
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value, pos, error = _consume_url(css, pos)
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if value is not None:
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repr = 'url({})'.format(serialize_url(value))
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if error is not None:
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error_key = error[0]
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if error_key == 'eof-in-string':
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repr = repr[:-2]
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else:
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assert error_key == 'eof-in-url'
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repr = repr[:-1]
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tokens.append(URLToken(line, column, value, repr))
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if error is not None:
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tokens.append(ParseError(line, column, *error))
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continue
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arguments = []
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tokens.append(FunctionBlock(line, column, value, arguments))
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stack.append((tokens, end_char))
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end_char = ')'
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tokens = arguments
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continue
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match = _NUMBER_RE.match(css, pos)
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if match:
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pos = match.end()
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repr_ = css[token_start_pos:pos]
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value = float(repr_)
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int_value = int(repr_) if not any(match.groups()) else None
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if pos < length and _is_ident_start(css, pos):
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unit, pos = _consume_ident(css, pos)
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tokens.append(DimensionToken(
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line, column, value, int_value, repr_, unit))
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elif css.startswith('%', pos):
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pos += 1
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tokens.append(PercentageToken(line, column, value, int_value, repr_))
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else:
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tokens.append(NumberToken(line, column, value, int_value, repr_))
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elif c == '@':
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pos += 1
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if pos < length and _is_ident_start(css, pos):
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value, pos = _consume_ident(css, pos)
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tokens.append(AtKeywordToken(line, column, value))
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else:
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tokens.append(LiteralToken(line, column, '@'))
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elif c == '#':
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pos += 1
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if pos < length and (
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css[pos] in '0123456789abcdefghijklmnopqrstuvwxyz'
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'-_ABCDEFGHIJKLMNOPQRSTUVWXYZ' or
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ord(css[pos]) > 0x7F or # Non-ASCII
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# Valid escape:
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(css[pos] == '\\' and not css.startswith('\\\n', pos))):
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is_identifier = _is_ident_start(css, pos)
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value, pos = _consume_ident(css, pos)
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tokens.append(HashToken(line, column, value, is_identifier))
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else:
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tokens.append(LiteralToken(line, column, '#'))
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elif c == '{':
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content = []
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tokens.append(CurlyBracketsBlock(line, column, content))
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stack.append((tokens, end_char))
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end_char = '}'
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tokens = content
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pos += 1
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elif c == '[':
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content = []
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tokens.append(SquareBracketsBlock(line, column, content))
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stack.append((tokens, end_char))
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end_char = ']'
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tokens = content
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pos += 1
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elif c == '(':
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content = []
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tokens.append(ParenthesesBlock(line, column, content))
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stack.append((tokens, end_char))
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end_char = ')'
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tokens = content
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pos += 1
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elif c == end_char: # Matching }, ] or )
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# The top-level end_char is None (never equal to a character),
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# so we never get here if the stack is empty.
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tokens, end_char = stack.pop()
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pos += 1
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elif c in '}])':
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tokens.append(ParseError(line, column, c, 'Unmatched ' + c))
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pos += 1
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elif c in ('"', "'"):
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value, pos, error = _consume_quoted_string(css, pos)
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if value is not None:
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repr = '"{}"'.format(serialize_string_value(value))
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if error is not None:
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repr = repr[:-1]
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tokens.append(StringToken(line, column, value, repr))
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if error is not None:
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tokens.append(ParseError(line, column, *error))
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elif css.startswith('/*', pos): # Comment
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pos = css.find('*/', pos + 2)
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if pos == -1:
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if not skip_comments:
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tokens.append(Comment(line, column, css[token_start_pos + 2:]))
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break
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if not skip_comments:
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tokens.append(Comment(line, column, css[token_start_pos + 2:pos]))
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pos += 2
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elif css.startswith('<!--', pos):
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tokens.append(LiteralToken(line, column, '<!--'))
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pos += 4
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elif css.startswith('||', pos):
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tokens.append(LiteralToken(line, column, '||'))
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pos += 2
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elif c in '~|^$*':
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pos += 1
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if css.startswith('=', pos):
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pos += 1
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tokens.append(LiteralToken(line, column, c + '='))
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else:
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tokens.append(LiteralToken(line, column, c))
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else:
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tokens.append(LiteralToken(line, column, c))
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pos += 1
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return root
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def _is_name_start(css, pos):
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"""Return true if the given character is a name-start code point."""
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# https://www.w3.org/TR/css-syntax-3/#name-start-code-point
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c = css[pos]
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return (
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c in 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_' or
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ord(c) > 0x7F)
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def _is_ident_start(css, pos):
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"""Return True if the given position is the start of a CSS identifier."""
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# https://drafts.csswg.org/css-syntax/#would-start-an-identifier
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if _is_name_start(css, pos):
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return True
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elif css[pos] == '-':
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pos += 1
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return (
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# Name-start code point or hyphen:
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(pos < len(css) and (_is_name_start(css, pos) or css[pos] == '-')) or
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# Valid escape:
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(css.startswith('\\', pos) and not css.startswith('\\\n', pos)))
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elif css[pos] == '\\':
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return not css.startswith('\\\n', pos)
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return False
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def _consume_ident(css, pos):
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"""Return (unescaped_value, new_pos).
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Assumes pos starts at a valid identifier. See :func:`_is_ident_start`.
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"""
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# http://dev.w3.org/csswg/css-syntax/#consume-a-name
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chunks = []
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length = len(css)
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start_pos = pos
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while pos < length:
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c = css[pos]
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if c in ('abcdefghijklmnopqrstuvwxyz-_0123456789'
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'ABCDEFGHIJKLMNOPQRSTUVWXYZ') or ord(c) > 0x7F:
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pos += 1
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elif c == '\\' and not css.startswith('\\\n', pos):
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# Valid escape
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chunks.append(css[start_pos:pos])
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c, pos = _consume_escape(css, pos + 1)
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chunks.append(c)
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start_pos = pos
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else:
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break
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chunks.append(css[start_pos:pos])
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return ''.join(chunks), pos
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def _consume_quoted_string(css, pos):
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"""Return (unescaped_value, new_pos)."""
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# https://drafts.csswg.org/css-syntax/#consume-a-string-token
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error = None
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quote = css[pos]
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assert quote in ('"', "'")
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pos += 1
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chunks = []
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length = len(css)
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start_pos = pos
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while pos < length:
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c = css[pos]
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if c == quote:
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chunks.append(css[start_pos:pos])
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pos += 1
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break
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elif c == '\\':
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chunks.append(css[start_pos:pos])
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pos += 1
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if pos < length:
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if css[pos] == '\n': # Ignore escaped newlines
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pos += 1
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else:
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c, pos = _consume_escape(css, pos)
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chunks.append(c)
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# else: Escaped EOF, do nothing
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start_pos = pos
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elif c == '\n': # Unescaped newline
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return None, pos, ('bad-string', 'Bad string token')
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else:
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pos += 1
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else:
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error = ('eof-in-string', 'EOF in string')
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chunks.append(css[start_pos:pos])
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return ''.join(chunks), pos, error
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def _consume_escape(css, pos):
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r"""Return (unescaped_char, new_pos).
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Assumes a valid escape: pos is just after '\' and not followed by '\n'.
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"""
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# https://drafts.csswg.org/css-syntax/#consume-an-escaped-character
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hex_match = _HEX_ESCAPE_RE.match(css, pos)
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if hex_match:
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codepoint = int(hex_match.group(1), 16)
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return (
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chr(codepoint) if 0 < codepoint <= sys.maxunicode else '\uFFFD',
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hex_match.end())
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elif pos < len(css):
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return css[pos], pos + 1
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else:
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return '\uFFFD', pos
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def _consume_url(css, pos):
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"""Return (unescaped_url, new_pos)
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The given pos is assumed to be just after the '(' of 'url('.
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"""
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error = None
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length = len(css)
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# https://drafts.csswg.org/css-syntax/#consume-a-url-token
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# Skip whitespace
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while css.startswith((' ', '\n', '\t'), pos):
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pos += 1
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if pos >= length: # EOF
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return '', pos, ('eof-in-url', 'EOF in URL')
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c = css[pos]
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if c in ('"', "'"):
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value, pos, error = _consume_quoted_string(css, pos)
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elif c == ')':
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return '', pos + 1, error
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else:
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chunks = []
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start_pos = pos
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while 1:
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if pos >= length: # EOF
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chunks.append(css[start_pos:pos])
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return ''.join(chunks), pos, ('eof-in-url', 'EOF in URL')
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c = css[pos]
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if c == ')':
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chunks.append(css[start_pos:pos])
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pos += 1
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return ''.join(chunks), pos, error
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elif c in ' \n\t':
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chunks.append(css[start_pos:pos])
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value = ''.join(chunks)
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pos += 1
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break
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elif c == '\\' and not css.startswith('\\\n', pos):
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# Valid escape
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chunks.append(css[start_pos:pos])
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c, pos = _consume_escape(css, pos + 1)
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chunks.append(c)
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start_pos = pos
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elif (c in
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'"\'('
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# https://drafts.csswg.org/css-syntax/#non-printable-character
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'\x00\x01\x02\x03\x04\x05\x06\x07\x08\x0b\x0e'
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'\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19'
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'\x1a\x1b\x1c\x1d\x1e\x1f\x7f'):
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value = None # Parse error
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pos += 1
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break
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else:
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pos += 1
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if value is not None:
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while css.startswith((' ', '\n', '\t'), pos):
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pos += 1
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if pos < length:
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if css[pos] == ')':
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return value, pos + 1, error
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else:
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if error is None:
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error = ('eof-in-url', 'EOF in URL')
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return value, pos, error
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# https://drafts.csswg.org/css-syntax/#consume-the-remnants-of-a-bad-url0
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while pos < length:
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if css.startswith('\\)', pos):
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pos += 2
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elif css[pos] == ')':
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pos += 1
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break
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else:
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pos += 1
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return None, pos, ('bad-url', 'bad URL token')
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def _consume_unicode_range(css, pos):
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"""Return (range, new_pos)
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The given pos is assume to be just after the '+' of 'U+' or 'u+'.
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"""
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# https://drafts.csswg.org/css-syntax/#consume-a-unicode-range-token
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length = len(css)
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start_pos = pos
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max_pos = min(pos + 6, length)
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while pos < max_pos and css[pos] in '0123456789abcdefABCDEF':
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pos += 1
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start = css[start_pos:pos]
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start_pos = pos
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# Same max_pos as before: total of hex digits and question marks <= 6
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while pos < max_pos and css[pos] == '?':
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pos += 1
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question_marks = pos - start_pos
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if question_marks:
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end = start + 'F' * question_marks
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start = start + '0' * question_marks
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elif (pos + 1 < length and css[pos] == '-' and
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css[pos + 1] in '0123456789abcdefABCDEF'):
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pos += 1
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start_pos = pos
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max_pos = min(pos + 6, length)
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while pos < max_pos and css[pos] in '0123456789abcdefABCDEF':
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pos += 1
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end = css[start_pos:pos]
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else:
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end = start
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return int(start, 16), int(end, 16), pos
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