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Re: 26-Jul-99 bug: Bad <font> in <tr> causes crash

From: Dave Raggett <dsr@w3.org>
Date: Sun, 15 Aug 1999 14:09:05 +0100 (GMT Daylight Time)
To: Terry Teague <teague@mailandnews.com>
cc: HTML Tidy Mailing List <html-tidy@w3.org>
Message-ID: <Pine.WNT.4.10.9908151406590.-308917@hazel.hpl.hp.com>
On Sat, 31 Jul 1999, Terry Teague wrote:

> At 11:45 AM -0600 7/27/99, Randy Waki wrote:
> >Thanks for the new release!  Incidentally, the bugs I recently reported in
> >the 7-Jul-99 Tidy are reproducible in the new 29-Jul-99 version.
> >
> >Here's a new bug report:
> >
> >The HTML document below has a table row containing a bad <font> tag with no
> >content, no ending </font> tag, and no enclosing table cell.  26-Jul-99 Tidy
> >crashes (on Windows NT, at least) trying to access an illegal address.  Andy
> >Quick's 7-Jul-99 Java version also crashes (with a NullPointerException),
> >suggesting that the problem in the C version is with the value of prev in
> >parser.c, TrimInitialSpace(), line 194:
> >
> >    if (prev->type == TextNode)
> >
> >-------- Example HTML document --------
> ><html>
> >  <head>
> >    <title>t</title>
> >  </head>
> >  <body>
> >    <table summary="s">
> >      <tr>
> >        <font>
> >      </tr>
> >    </table>
> >  </body>
> ></html>
> >---------------------------------------

This is caused by a bug in TrimInitialSpace() in parser.c
which failed when the element is the first in the content.
The revised routine is as follows:

void TrimInitialSpace(Lexer *lexer, Node *element, Node *text)
{
    Node *prev, *node;

    if (text->type == TextNode && lexer->lexbuf[text->start] == ' ')
    {
        if (element->tag->model & CM_INLINE &&
            element->parent->content != element)
        {
            prev = element->prev;

            if (prev && prev->type == TextNode)
            {
                if (lexer->lexbuf[prev->end - 1] != ' ')
                    lexer->lexbuf[(prev->end)++] = ' ';

                ++(element->start);
            }
            else /* create new node */
            {
                node = NewNode();
                node->start = (element->start)++;
                node->end = element->start;
                lexer->lexbuf[node->start] = ' ';
                node->prev = prev;

                if (prev)
                    prev->next = node;

                node->next = element;
                element->prev = node;
                node->parent = element->parent;
            }
        }

        /* discard the space  in current node */
        ++(text->start);
    }
}


Regards,

-- Dave Raggett <dsr@w3.org> http://www.w3.org/People/Raggett
phone: +44 122 578 2984 (or 2521) +44 385 320 444 (gsm mobile)
World Wide Web Consortium (on assignment from HP Labs)
Received on Sunday, 15 August 1999 09:06:09 GMT

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