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Re: XML Parser has no support for DTD [message #13406 is a reply to message #13397]

Fri, 04 January 2008 09:53

cbpporter
Messages: 1427
Registered: September 2007

Ultimate Contributor

luzr wrote on Thu, 03 January 2008 21:46

IMO, no need. Just skip the damned thing Smile

Mirek

The fix was easy. I did ignore it, just inserted the whole thing into a "nested" tag content, so in the previous example you would get a node with type of XML_DECL and content:

DOCTYPE note [
  <!ELEMENT note (to,from,heading,body)>
  <!ELEMENT to      (#PCDATA)>
  <!ELEMENT from    (#PCDATA)>
  <!ELEMENT heading (#PCDATA)>
  <!ELEMENT body    (#PCDATA)>
]

I tested it with the provided XmlViewer on this example and some other ones, including a 12MB XML, and it seems to work fine with well formatted XMLs.

Which brings me to my next problem. The XML parser code looks pretty efficient, and while it could be improved, the results wouldn't be that different. And loading that 12MB XML takes a lot (but less than in other programs I tried capable of loading an XML tree Razz

). I need a way to speed up thing, and the only thing I can think right now is a binary cache of the XML data.

Here is my fix:

void XmlParser::Next()
{
	nattr.Clear();
	nattr1 = nattrval1 = Null;
	if(empty_tag) {
		empty_tag = false;
		type = XML_END;
		return;
	}
	text.Clear();
	type = XML_EOF;
	if(!npreserve)
		SkipWhites();
	if(*term == '<') {
		term++;
		if(*term == '!') {
			type = XML_DECL;
			term++;
			if(term[0] == '-' && term[1] == '-') {
				type = XML_COMMENT;
				term += 2;
				for(;;) {
					if(term[0] == '-' && term[1] == '-' && term[2] == '>')
						break;
					if(*term == '\0') {
						throw XmlError("Unterminated comment");
						type = XML_EOF;
						return;
					}
					if(*term == '\n')
						line++;
					text.Cat(*term++);
				}
				term += 3;
				return;
			}
			bool intdt = false;
			for(;;) {
				if (*term == '[') 
					intdt = true;
				if(*term == '>' && intdt == false) {
					term++;
					break;
				}
				if(intdt == true && term[0] == ']' && term[1] == '>') {
					text.Cat(*term++);
					term++;
					break;
				}
				if(*term == '\0')
					throw XmlError("Unterminated declaration");
				if(*term == '\n')
					line++;
				text.Cat(*term++);
			}
		}
		else
		if(*term == '?') {
			type = XML_PI;
			term++;
			for(;;) {
				if(term[0] == '?' && term[1] == '>') {
					term += 2;
					return;
				}
				if(*term == '\0')
					throw XmlError("Unterminated processing info");
				if(*term == '\n')
					line++;
				text.Cat(*term++);
			}
		}
		else
		if(*term == '/') {
			type = XML_END;
			term++;
			const char *t = term;
			while(IsXmlNameChar(*term))
				term++;
			text = String(t, term);
			if(*term != '>')
				throw XmlError("Unterminated end-tag");
			term++;
		}
		else {
			type = XML_TAG;
			const char *t = term;
			while(IsXmlNameChar(*term))
				term++;
			text = String(t, term);
			for(;;) {
				SkipWhites();
				if(*term == '>') {
					term++;
					break;
				}
				if(term[0] == '/' && term[1] == '>') {
					empty_tag = true;
					term += 2;
					break;
				}
				if(*term == '\0')
					throw XmlError("Unterminated tag");
				const char *t = term++;
				while((byte)*term > ' ' && *term != '=' && *term != '>')
					term++;
				String attr(t, term);
				SkipWhites();
				if(*term == '=') {
					term++;
					SkipWhites();
					StringBuffer attrval;
					if(*term == '\"') {
						term++;
						while(*term && *term != '\"')
							if(*term == '&')
								Ent(attrval);
							else {
								const char *e = term;
								while(*++e && *e != '&' && *e != '\"')
									;
								attrval.Cat(term, (int)(e - term));
								term = e;
							}
						if(*term == '\"')
							term++;
					}
					else {
						while((byte)*term > ' ' && *term != '>')
							if(*term == '&')
								Ent(attrval);
							else {
								const char *e = term;
								while((byte)*++e > ' ' && *e != '>' && *e != '&')
									;
								attrval.Cat(term,(int) (e - term));
								term = e;
							}
					}
					if(attr == "xml:space" && attrval.GetLength() == 8 && !memcmp(~attrval, "preserve", 8))
						npreserve = true;
					String aval = FromUtf8(~attrval, attrval.GetLength()).ToString();
					if(IsNull(nattr1)) {
						nattr1 = attr;
						nattrval1 = aval;
					}
					else
						nattr.Add(attr, aval);
				}
			}
		}
	}
	else if(*term == 0)
		type = XML_EOF;
	else {
		StringBuffer raw_text;
		while(*term != '<' && *term) {
			if(*term == '\n')
				line++;
			if(*term == '&')
				Ent(raw_text);
			else {
				const char *e = term;
				while(*++e && *e != '&' && *e != '<')
					;
				raw_text.Cat(term, (int)(e - term));
				term = e;
			}
		}
		const char *re = raw_text.End();
		if(!npreserve) {
			while(re > raw_text.Begin() && (byte)re[-1] <= ' ')
				re--;
		}
		text = FromUtf8(~raw_text, (int)(re - ~raw_text)).ToString();
		type = XML_TEXT;
	}
}

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