def read_xref_from(self, parser, start, xrefs):
parser.seek(start)<EOL>parser.reset()<EOL>try:<EOL><INDENT>(pos, token) = parser.nexttoken()<EOL><DEDENT>except PSEOF:<EOL><INDENT>raise PDFNoValidXRef('<STR_LIT>')<EOL><DEDENT>if self.debug:<EOL><INDENT>logging.info('<STR_LIT>' % (start, token))<EOL><DEDENT>if isinstance(token, int):<EOL><INDENT>parser.seek(pos)<EOL>parser.reset()<EOL>xref = PDFXRefStream()<EOL>xref.load(parser)<EOL><DEDENT>else:<EOL><INDENT>if token is parser.KEYWORD_XREF:<EOL><INDENT>parser.nextline()<EOL><DEDENT>xref = PDFXRef()<EOL>xref.load(parser)<EOL><DEDENT>xrefs.append(xref)<EOL>trailer = xref.get_trailer()<EOL>if self.debug:<EOL><INDENT>logging.info('<STR_LIT>' % trailer)<EOL><DEDENT>if '<STR_LIT>' in trailer:<EOL><INDENT>pos = int_value(trailer['<STR_LIT>'])<EOL>self.read_xref_from(parser, pos, xrefs)<EOL><DEDENT>if '<STR_LIT>' in trailer:<EOL><INDENT>pos = int_value(trailer['<STR_LIT>'])<EOL>self.read_xref_from(parser, pos, xrefs)<EOL><DEDENT>return<EOL>
Reads XRefs from the given location.