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			673 lines
		
	
	
	
		
			23 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			673 lines
		
	
	
	
		
			23 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
"""A parser for HTML and XHTML."""
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# This file is based on sgmllib.py, but the API is slightly different.
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# XXX There should be a way to distinguish between PCDATA (parsed
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# character data -- the normal case), RCDATA (replaceable character
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# data -- only char and entity references and end tags are special)
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# and CDATA (character data -- only end tags are special).
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import re
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import string
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# Regular expressions used for parsing
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interesting_normal = re.compile('[&<]')
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interesting_cdata = re.compile(r'<(/|\Z)')
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incomplete = re.compile('&[a-zA-Z#]')
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entityref = re.compile('&([a-zA-Z][-.a-zA-Z0-9]*)[^a-zA-Z0-9]')
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charref = re.compile('&#(?:[0-9]+|[xX][0-9a-fA-F]+)[^0-9a-fA-F]')
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starttagopen = re.compile('<[a-zA-Z]')
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piopen = re.compile(r'<\?')
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piclose = re.compile('>')
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endtagopen = re.compile('</')
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declopen = re.compile('<!')
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special = re.compile('<![^<>]*>')
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commentopen = re.compile('<!--')
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commentclose = re.compile(r'--\s*>')
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tagfind = re.compile('[a-zA-Z][-.a-zA-Z0-9:_]*')
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attrfind = re.compile(
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    r'\s*([a-zA-Z_][-.:a-zA-Z_0-9]*)(\s*=\s*'
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    r'(\'[^\']*\'|"[^"]*"|[-a-zA-Z0-9./:;+*%?!&$\(\)_#=~]*))?')
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locatestarttagend = re.compile(r"""
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  <[a-zA-Z][-.a-zA-Z0-9:_]*          # tag name
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  (?:\s+                             # whitespace before attribute name
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    (?:[a-zA-Z_][-.:a-zA-Z0-9_]*     # attribute name
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      (?:\s*=\s*                     # value indicator
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        (?:'[^']*'                   # LITA-enclosed value
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          |\"[^\"]*\"                # LIT-enclosed value
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          |[^'\">\s]+                # bare value
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         )
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       )?
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     )
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   )*
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  \s*                                # trailing whitespace
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""", re.VERBOSE)
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endstarttag = re.compile(r"\s*/?>")
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endendtag = re.compile('>')
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endtagfind = re.compile('</\s*([a-zA-Z][-.a-zA-Z0-9:_]*)\s*>')
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declname = re.compile(r'[a-zA-Z][-_.a-zA-Z0-9]*\s*')
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declstringlit = re.compile(r'(\'[^\']*\'|"[^"]*")\s*')
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class HTMLParseError(Exception):
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    """Exception raised for all parse errors."""
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    def __init__(self, msg, position=(None, None)):
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        assert msg
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        self.msg = msg
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        self.lineno = position[0]
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        self.offset = position[1]
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    def __str__(self):
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        result = self.msg
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        if self.lineno is not None:
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            result = result + ", at line %d" % self.lineno
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        if self.offset is not None:
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            result = result + ", column %d" % (self.offset + 1)
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        return result
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class HTMLParser:
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    """Find tags and other markup and call handler functions.
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    Usage:
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        p = HTMLParser()
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        p.feed(data)
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        ...
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        p.close()
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    Start tags are handled by calling self.handle_starttag() or
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    self.handle_startendtag(); end tags by self.handle_endtag().  The
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    data between tags is passed from the parser to the derived class
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    by calling self.handle_data() with the data as argument (the data
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    may be split up in arbitrary chunks).  Entity references are
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    passed by calling self.handle_entityref() with the entity
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    reference as the argument.  Numeric character references are
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    passed to self.handle_charref() with the string containing the
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    reference as the argument.
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    """
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    CDATA_CONTENT_ELEMENTS = ("script", "style")
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    def __init__(self):
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        """Initialize and reset this instance."""
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        self.reset()
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    def reset(self):
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        """Reset this instance.  Loses all unprocessed data."""
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        self.rawdata = ''
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        self.stack = []
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        self.lasttag = '???'
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        self.lineno = 1
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        self.offset = 0
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        self.interesting = interesting_normal
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    def feed(self, data):
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        """Feed data to the parser.
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        Call this as often as you want, with as little or as much text
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        as you want (may include '\n').
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        """
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        self.rawdata = self.rawdata + data
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        self.goahead(0)
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    def close(self):
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        """Handle any buffered data."""
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        self.goahead(1)
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    # Internal -- update line number and offset.  This should be
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    # called for each piece of data exactly once, in order -- in other
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    # words the concatenation of all the input strings to this
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    # function should be exactly the entire input.
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    def updatepos(self, i, j):
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        if i >= j:
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            return j
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        rawdata = self.rawdata
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        nlines = string.count(rawdata, "\n", i, j)
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        if nlines:
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            self.lineno = self.lineno + nlines
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            pos = string.rindex(rawdata, "\n", i, j) # Should not fail
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            self.offset = j-(pos+1)
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        else:
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            self.offset = self.offset + j-i
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        return j
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    def getpos(self):
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        """Return current line number and offset."""
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        return self.lineno, self.offset
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    __starttag_text = None
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    def get_starttag_text(self):
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        """Return full source of start tag: '<...>'."""
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        return self.__starttag_text
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    def set_cdata_mode(self):
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        self.interesting = interesting_cdata
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    def clear_cdata_mode(self):
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        self.interesting = interesting_normal
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    # Internal -- handle data as far as reasonable.  May leave state
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    # and data to be processed by a subsequent call.  If 'end' is
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    # true, force handling all data as if followed by EOF marker.
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    def goahead(self, end):
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        rawdata = self.rawdata
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        i = 0
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        n = len(rawdata)
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        while i < n:
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            match = self.interesting.search(rawdata, i) # < or &
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            if match:
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                j = match.start()
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            else:
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                j = n
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            if i < j: self.handle_data(rawdata[i:j])
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            i = self.updatepos(i, j)
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            if i == n: break
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            if rawdata[i] == '<':
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                if starttagopen.match(rawdata, i): # < + letter
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                    k = self.parse_starttag(i)
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                elif endtagopen.match(rawdata, i): # </
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                    k = self.parse_endtag(i)
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                    if k >= 0:
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                        self.clear_cdata_mode()
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                elif commentopen.match(rawdata, i): # <!--
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                    k = self.parse_comment(i)
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                elif piopen.match(rawdata, i): # <?
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                    k = self.parse_pi(i)
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                elif declopen.match(rawdata, i): # <!
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                    k = self.parse_declaration(i)
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                elif (i + 1) < n:
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                    self.handle_data("<")
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                    k = i + 1
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                else:
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                    break
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                if k < 0:
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                    if end:
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                        raise HTMLParseError("EOF in middle of construct",
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                                             self.getpos())
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                    break
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                i = self.updatepos(i, k)
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            elif rawdata[i:i+2] == "&#":
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                match = charref.match(rawdata, i)
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                if match:
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                    name = match.group()[2:-1]
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                    self.handle_charref(name)
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                    k = match.end()
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                    if rawdata[k-1] != ';':
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                        k = k - 1
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                    i = self.updatepos(i, k)
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                    continue
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                else:
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                    break
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            elif rawdata[i] == '&':
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                match = entityref.match(rawdata, i)
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                if match:
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                    name = match.group(1)
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                    self.handle_entityref(name)
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                    k = match.end()
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                    if rawdata[k-1] != ';':
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                        k = k - 1
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                    i = self.updatepos(i, k)
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                    continue
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                match = incomplete.match(rawdata, i)
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                if match:
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                    # match.group() will contain at least 2 chars
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                    rest = rawdata[i:]
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                    if end and match.group() == rest:
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                        raise HTMLParseError(
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                            "EOF in middle of entity or char ref",
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                            self.getpos())
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                    # incomplete
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                    break
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                elif (i + 1) < n:
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                    # not the end of the buffer, and can't be confused
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                    # with some other construct
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                    self.handle_data("&")
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                    i = self.updatepos(i, i + 1)
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                else:
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                    break
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            else:
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                assert 0, "interesting.search() lied"
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        # end while
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        if end and i < n:
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            self.handle_data(rawdata[i:n])
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            i = self.updatepos(i, n)
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        self.rawdata = rawdata[i:]
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    # Internal -- parse comment, return end or -1 if not terminated
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    def parse_comment(self, i, report=1):
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        rawdata = self.rawdata
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        assert rawdata[i:i+4] == '<!--', 'unexpected call to parse_comment()'
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        match = commentclose.search(rawdata, i+4)
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        if not match:
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            return -1
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        if report:
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            j = match.start()
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            self.handle_comment(rawdata[i+4: j])
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        j = match.end()
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        return j
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    # Internal -- parse declaration.
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    def parse_declaration(self, i):
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        # This is some sort of declaration; in "HTML as
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        # deployed," this should only be the document type
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        # declaration ("<!DOCTYPE html...>").
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        rawdata = self.rawdata
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        j = i + 2
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        assert rawdata[i:j] == "<!", "unexpected call to parse_declaration"
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        if rawdata[j:j+1] in ("-", ""):
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            # Start of comment followed by buffer boundary,
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            # or just a buffer boundary.
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            return -1
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        # in practice, this should look like: ((name|stringlit) S*)+ '>'
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        n = len(rawdata)
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        decltype, j = self.scan_name(j, i)
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        if j < 0:
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            return j
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        if decltype.lower() != "doctype":
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            raise HTMLParseError("unknown declaration: '%s'" % decltype,
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                                 self.getpos())
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        while j < n:
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            c = rawdata[j]
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            if c == ">":
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                # end of declaration syntax
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                data = rawdata[i+2:j]
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                self.handle_decl(data)
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                return j + 1
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            if c in "\"'":
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                m = declstringlit.match(rawdata, j)
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                if not m:
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                    return -1 # incomplete
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                j = m.end()
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            elif c in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ":
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                name, j = self.scan_name(j, i)
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            elif c == "[" and decltype == "doctype":
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                j = self.parse_doctype_subset(j + 1, i)
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            else:
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                raise HTMLParseError(
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                    "unexpected char in declaration: %s" % `rawdata[j]`,
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                    self.getpos())
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            if j < 0:
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                return j
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        return -1 # incomplete
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    # Internal -- scan past the internal subset in a <!DOCTYPE declaration,
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    # returning the index just past any whitespace following the trailing ']'.
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    def parse_doctype_subset(self, i, declstartpos):
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        rawdata = self.rawdata
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        n = len(rawdata)
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        j = i
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        while j < n:
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            c = rawdata[j]
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            if c == "<":
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                s = rawdata[j:j+2]
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                if s == "<":
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                    # end of buffer; incomplete
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                    return -1
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                if s != "<!":
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                    self.updatepos(declstartpos, j + 1)
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                    raise HTMLParseError("unexpect char in internal subset",
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                                         self.getpos())
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                if (j + 2) == n:
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                    # end of buffer; incomplete
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                    return -1
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                if (j + 4) > n:
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                    # end of buffer; incomplete
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                    return -1
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                if rawdata[j:j+4] == "<!--":
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                    j = self.parse_comment(j, report=0)
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                    if j < 0:
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                        return j
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                    continue
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                name, j = self.scan_name(j + 2, declstartpos)
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                if j == -1:
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                    return -1
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                if name not in ("attlist", "element", "entity", "notation"):
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                    self.updatepos(declstartpos, j + 2)
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                    raise HTMLParseError(
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                        "unknown declaration %s in internal subset" % `name`,
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                        self.getpos())
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                # handle the individual names
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                meth = getattr(self, "parse_doctype_" + name)
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                j = meth(j, declstartpos)
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                if j < 0:
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                    return j
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            elif c == "%":
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                # parameter entity reference
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                if (j + 1) == n:
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                    # end of buffer; incomplete
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                    return -1
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                s, j = self.scan_name(j + 1, declstartpos)
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                if j < 0:
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                    return j
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                if rawdata[j] == ";":
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                    j = j + 1
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            elif c == "]":
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                j = j + 1
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                while j < n and rawdata[j] in string.whitespace:
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                    j = j + 1
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                if j < n:
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                    if rawdata[j] == ">":
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                        return j
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                    self.updatepos(declstartpos, j)
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                    raise HTMLParseError(
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                        "unexpected char after internal subset",
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                        self.getpos())
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                else:
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                    return -1
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            elif c in string.whitespace:
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                j = j + 1
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            else:
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                self.updatepos(declstartpos, j)
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                raise HTMLParseError(
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                    "unexpected char %s in internal subset" % `c`,
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                    self.getpos())
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        # end of buffer reached
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        return -1
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    def parse_doctype_element(self, i, declstartpos):
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        rawdata = self.rawdata
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        n = len(rawdata)
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        name, j = self.scan_name(i, declstartpos)
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        if j == -1:
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            return -1
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        # style content model; just skip until '>'
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        if '>' in rawdata[j:]:
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            return string.find(rawdata, ">", j) + 1
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        return -1
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    def parse_doctype_attlist(self, i, declstartpos):
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        rawdata = self.rawdata
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        name, j = self.scan_name(i, declstartpos)
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        c = rawdata[j:j+1]
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        if c == "":
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            return -1
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        if c == ">":
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            return j + 1
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        while 1:
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            # scan a series of attribute descriptions; simplified:
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            #   name type [value] [#constraint]
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            name, j = self.scan_name(j, declstartpos)
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            if j < 0:
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                return j
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            c = rawdata[j:j+1]
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            if c == "":
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                return -1
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            if c == "(":
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                # an enumerated type; look for ')'
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                if ")" in rawdata[j:]:
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                    j = string.find(rawdata, ")", j) + 1
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                else:
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                    return -1
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                while rawdata[j:j+1] in string.whitespace:
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                    j = j + 1
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                if not rawdata[j:]:
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                    # end of buffer, incomplete
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                    return -1
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            else:
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                name, j = self.scan_name(j, declstartpos)
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            c = rawdata[j:j+1]
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            if not c:
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                return -1
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            if c in "'\"":
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                m = declstringlit.match(rawdata, j)
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                if m:
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                    j = m.end()
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                else:
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                    return -1
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                c = rawdata[j:j+1]
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                if not c:
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                    return -1
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            if c == "#":
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                if rawdata[j:] == "#":
 | 
						|
                    # end of buffer
 | 
						|
                    return -1
 | 
						|
                name, j = self.scan_name(j + 1, declstartpos)
 | 
						|
                if j < 0:
 | 
						|
                    return j
 | 
						|
                c = rawdata[j:j+1]
 | 
						|
                if not c:
 | 
						|
                    return -1
 | 
						|
            if c == '>':
 | 
						|
                # all done
 | 
						|
                return j + 1
 | 
						|
 | 
						|
    def parse_doctype_notation(self, i, declstartpos):
 | 
						|
        name, j = self.scan_name(i, declstartpos)
 | 
						|
        if j < 0:
 | 
						|
            return j
 | 
						|
        rawdata = self.rawdata
 | 
						|
        while 1:
 | 
						|
            c = rawdata[j:j+1]
 | 
						|
            if not c:
 | 
						|
                # end of buffer; incomplete
 | 
						|
                return -1
 | 
						|
            if c == '>':
 | 
						|
                return j + 1
 | 
						|
            if c in "'\"":
 | 
						|
                m = declstringlit.match(rawdata, j)
 | 
						|
                if not m:
 | 
						|
                    return -1
 | 
						|
                j = m.end()
 | 
						|
            else:
 | 
						|
                name, j = self.scan_name(j, declstartpos)
 | 
						|
                if j < 0:
 | 
						|
                    return j
 | 
						|
 | 
						|
    def parse_doctype_entity(self, i, declstartpos):
 | 
						|
        rawdata = self.rawdata
 | 
						|
        if rawdata[i:i+1] == "%":
 | 
						|
            j = i + 1
 | 
						|
            while 1:
 | 
						|
                c = rawdata[j:j+1]
 | 
						|
                if not c:
 | 
						|
                    return -1
 | 
						|
                if c in string.whitespace:
 | 
						|
                    j = j + 1
 | 
						|
                else:
 | 
						|
                    break
 | 
						|
        else:
 | 
						|
            j = i
 | 
						|
        name, j = self.scan_name(j, declstartpos)
 | 
						|
        if j < 0:
 | 
						|
            return j
 | 
						|
        while 1:
 | 
						|
            c = self.rawdata[j:j+1]
 | 
						|
            if not c:
 | 
						|
                return -1
 | 
						|
            if c in "'\"":
 | 
						|
                m = declstringlit.match(rawdata, j)
 | 
						|
                if m:
 | 
						|
                    j = m.end()
 | 
						|
                else:
 | 
						|
                    return -1    # incomplete
 | 
						|
            elif c == ">":
 | 
						|
                return j + 1
 | 
						|
            else:
 | 
						|
                name, j = self.scan_name(j, declstartpos)
 | 
						|
                if j < 0:
 | 
						|
                    return j
 | 
						|
 | 
						|
    def scan_name(self, i, declstartpos):
 | 
						|
        rawdata = self.rawdata
 | 
						|
        n = len(rawdata)
 | 
						|
        if i == n:
 | 
						|
            return None, -1
 | 
						|
        m = declname.match(rawdata, i)
 | 
						|
        if m:
 | 
						|
            s = m.group()
 | 
						|
            name = s.strip()
 | 
						|
            if (i + len(s)) == n:
 | 
						|
                return None, -1  # end of buffer
 | 
						|
            return name.lower(), m.end()
 | 
						|
        else:
 | 
						|
            self.updatepos(declstartpos, i)
 | 
						|
            raise HTMLParseError("expected name token", self.getpos())
 | 
						|
 | 
						|
    # Internal -- parse processing instr, return end or -1 if not terminated
 | 
						|
    def parse_pi(self, i):
 | 
						|
        rawdata = self.rawdata
 | 
						|
        assert rawdata[i:i+2] == '<?', 'unexpected call to parse_pi()'
 | 
						|
        match = piclose.search(rawdata, i+2) # >
 | 
						|
        if not match:
 | 
						|
            return -1
 | 
						|
        j = match.start()
 | 
						|
        self.handle_pi(rawdata[i+2: j])
 | 
						|
        j = match.end()
 | 
						|
        return j
 | 
						|
 | 
						|
    # Internal -- handle starttag, return end or -1 if not terminated
 | 
						|
    def parse_starttag(self, i):
 | 
						|
        self.__starttag_text = None
 | 
						|
        endpos = self.check_for_whole_start_tag(i)
 | 
						|
        if endpos < 0:
 | 
						|
            return endpos
 | 
						|
        rawdata = self.rawdata
 | 
						|
        self.__starttag_text = rawdata[i:endpos]
 | 
						|
 | 
						|
        # Now parse the data between i+1 and j into a tag and attrs
 | 
						|
        attrs = []
 | 
						|
        match = tagfind.match(rawdata, i+1)
 | 
						|
        assert match, 'unexpected call to parse_starttag()'
 | 
						|
        k = match.end()
 | 
						|
        self.lasttag = tag = string.lower(rawdata[i+1:k])
 | 
						|
 | 
						|
        while k < endpos:
 | 
						|
            m = attrfind.match(rawdata, k)
 | 
						|
            if not m:
 | 
						|
                break
 | 
						|
            attrname, rest, attrvalue = m.group(1, 2, 3)
 | 
						|
            if not rest:
 | 
						|
                attrvalue = None
 | 
						|
            elif attrvalue[:1] == '\'' == attrvalue[-1:] or \
 | 
						|
                 attrvalue[:1] == '"' == attrvalue[-1:]:
 | 
						|
                attrvalue = attrvalue[1:-1]
 | 
						|
                attrvalue = self.unescape(attrvalue)
 | 
						|
            attrs.append((string.lower(attrname), attrvalue))
 | 
						|
            k = m.end()
 | 
						|
 | 
						|
        end = string.strip(rawdata[k:endpos])
 | 
						|
        if end not in (">", "/>"):
 | 
						|
            lineno, offset = self.getpos()
 | 
						|
            if "\n" in self.__starttag_text:
 | 
						|
                lineno = lineno + string.count(self.__starttag_text, "\n")
 | 
						|
                offset = len(self.__starttag_text) \
 | 
						|
                         - string.rfind(self.__starttag_text, "\n")
 | 
						|
            else:
 | 
						|
                offset = offset + len(self.__starttag_text)
 | 
						|
            raise HTMLParseError("junk characters in start tag: %s"
 | 
						|
                                 % `rawdata[k:endpos][:20]`,
 | 
						|
                                 (lineno, offset))
 | 
						|
        if end[-2:] == '/>':
 | 
						|
            # XHTML-style empty tag: <span attr="value" />
 | 
						|
            self.handle_startendtag(tag, attrs)
 | 
						|
        else:
 | 
						|
            self.handle_starttag(tag, attrs)
 | 
						|
            if tag in self.CDATA_CONTENT_ELEMENTS:
 | 
						|
                self.set_cdata_mode()
 | 
						|
        return endpos
 | 
						|
 | 
						|
    # Internal -- check to see if we have a complete starttag; return end
 | 
						|
    # or -1 if incomplete.
 | 
						|
    def check_for_whole_start_tag(self, i):
 | 
						|
        rawdata = self.rawdata
 | 
						|
        m = locatestarttagend.match(rawdata, i)
 | 
						|
        if m:
 | 
						|
            j = m.end()
 | 
						|
            next = rawdata[j:j+1]
 | 
						|
            if next == ">":
 | 
						|
                return j + 1
 | 
						|
            if next == "/":
 | 
						|
                s = rawdata[j:j+2]
 | 
						|
                if s == "/>":
 | 
						|
                    return j + 2
 | 
						|
                if s == "/":
 | 
						|
                    # buffer boundary
 | 
						|
                    return -1
 | 
						|
                # else bogus input
 | 
						|
                self.updatepos(i, j + 1)
 | 
						|
                raise HTMLParseError("malformed empty start tag",
 | 
						|
                                     self.getpos())
 | 
						|
            if next == "":
 | 
						|
                # end of input
 | 
						|
                return -1
 | 
						|
            if next in ("abcdefghijklmnopqrstuvwxyz=/"
 | 
						|
                        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"):
 | 
						|
                # end of input in or before attribute value, or we have the
 | 
						|
                # '/' from a '/>' ending
 | 
						|
                return -1
 | 
						|
            self.updatepos(i, j)
 | 
						|
            raise HTMLParseError("malformed start tag", self.getpos())
 | 
						|
        raise AssertionError("we should not gt here!")
 | 
						|
 | 
						|
    # Internal -- parse endtag, return end or -1 if incomplete
 | 
						|
    def parse_endtag(self, i):
 | 
						|
        rawdata = self.rawdata
 | 
						|
        assert rawdata[i:i+2] == "</", "unexpected call to parse_endtag"
 | 
						|
        match = endendtag.search(rawdata, i+1) # >
 | 
						|
        if not match:
 | 
						|
            return -1
 | 
						|
        j = match.end()
 | 
						|
        match = endtagfind.match(rawdata, i) # </ + tag + >
 | 
						|
        if not match:
 | 
						|
            raise HTMLParseError("bad end tag: %s" % `rawdata[i:j]`,
 | 
						|
                                 self.getpos())
 | 
						|
        tag = match.group(1)
 | 
						|
        self.handle_endtag(string.lower(tag))
 | 
						|
        return j
 | 
						|
 | 
						|
    # Overridable -- finish processing of start+end tag: <tag.../>
 | 
						|
    def handle_startendtag(self, tag, attrs):
 | 
						|
        self.handle_starttag(tag, attrs)
 | 
						|
        self.handle_endtag(tag)
 | 
						|
 | 
						|
    # Overridable -- handle start tag
 | 
						|
    def handle_starttag(self, tag, attrs):
 | 
						|
        pass
 | 
						|
 | 
						|
    # Overridable -- handle end tag
 | 
						|
    def handle_endtag(self, tag):
 | 
						|
        pass
 | 
						|
 | 
						|
    # Overridable -- handle character reference
 | 
						|
    def handle_charref(self, name):
 | 
						|
        pass
 | 
						|
 | 
						|
    # Overridable -- handle entity reference
 | 
						|
    def handle_entityref(self, name):
 | 
						|
        pass
 | 
						|
 | 
						|
    # Overridable -- handle data
 | 
						|
    def handle_data(self, data):
 | 
						|
        pass
 | 
						|
 | 
						|
    # Overridable -- handle comment
 | 
						|
    def handle_comment(self, data):
 | 
						|
        pass
 | 
						|
 | 
						|
    # Overridable -- handle declaration
 | 
						|
    def handle_decl(self, decl):
 | 
						|
        pass
 | 
						|
 | 
						|
    # Overridable -- handle processing instruction
 | 
						|
    def handle_pi(self, data):
 | 
						|
        pass
 | 
						|
 | 
						|
    # Internal -- helper to remove special character quoting
 | 
						|
    def unescape(self, s):
 | 
						|
        if '&' not in s:
 | 
						|
            return s
 | 
						|
        s = string.replace(s, "<", "<")
 | 
						|
        s = string.replace(s, ">", ">")
 | 
						|
        s = string.replace(s, "'", "'")
 | 
						|
        s = string.replace(s, """, '"')
 | 
						|
        s = string.replace(s, "&", "&") # Must be last
 | 
						|
        return s
 |