Shrink input buffer in xmlParseCharDataComplex

Avoid "huge input lookup" error when parsing large text nodes with
complex data.

parser.c

@@ -4571,6 +4571,7 @@ xmlParseCharDataComplex(xmlParserCtxtPtr ctxt, int cdata) {
 	}
 	count++;
 	if (count > 50) {
+            SHRINK;
 	    GROW;
 	    count = 0;
             if (ctxt->instate == XML_PARSER_EOF)

[Mike Dalessio]

I think this change needs to also be made in xmlParseCommentComplex. Happy to create a test case if you'd like to see it.

[Mike Dalessio]

This change also needs to be made in xmlParseCDSect, see https://github.com/sparklemotion/nokogiri/issues/2132 which provides a test case.

Extrapolating, this same logic appears in a few more functions and may need to change there, too:

• xmlParseSystemLiteral
• xmlParsePubidLiteral
• xmlParsePI
• xmlParseCommentComplex as noted in my previous comment