RE: [xml] Problems with the character & and saving/loading XML files

["Daniel Gehriger" <bulk linkcad com>]

Use something like the code below. The function copies the escaped input
string to the output buffer of size "len" (including terminating '\0').
It's up to you to ensure that the output buffer is large enough, or the
data will be truncated.

- Daniel

---------------------------------------------------
#include <string.h>

#ifndef MIN
#define MIN(a, b) ((a)<(b)?(a):(b))
#endif

void escape(const char* in, char* out, size_t len)
{
  const char * const chars = "<>&'\"";
  const char * const entities[] = { "&lt;", "&gt;", "&amp;", "&apos;",
"&quot;" };
  const char *mark, *set, *end;
  size_t l;

  end  = out + len - 1;
  mark = in;
  while (*in && out != end) {
    set = strstr(chars, in);
    if (set) {
      /* copy unescaped chars */
      l = MIN(in-mark, end-out);
      strncpy(out, mark, l);
      out += l;
      mark = in + 1;

      /* insert escaped char */
      l = MIN(strlen(entities[set - chars]), end-out);
      strncpy(out, entities[set - chars], l);
      out += l;
    }

    ++in;
  }

  /* copy remaining unescaped chars */
  l = MIN(in-mark, end-out);
  strncpy(out, mark, l);
  out += l;

  /* need to append '\0', strncpy doesn't always */
  *out = '\0';
}
--------------------------------------------------------------

> -----Original Message-----
> From: Philip Van Hoof [mailto:freax pandora be] 
> Sent: Friday, 19 April, 2002 16:45
> To: Daniel Gehriger
> Cc: 'Philip Van Hoof'; xml gnome org
> Subject: Re: [xml] Problems with the character & and 
> saving/loading XML files
>
>
> On 2002.04.19 15:20 Daniel Gehriger wrote:
>
>
> > The following two characters must be escaped: '<' and '&'. 
> You could 
> > also use a CDATA section, like this:
> > <mydata><![CDATA[   ANY DATA   ]]></mydata>
> > , but then you mustn't use "]]>" inside the CDATA section, 
> and there's 
> > no way to escape this sequence. You better don't use CDATA for this 
> > reason.  Here's a link with more information:
>
> > http://www.w3schools.com/xml/xml_cdata.asp
>
> Okay, thanks a lot..
> How do I use <![CDATA[ in the libxml ? When I do something
> like this then "<" and ">" will get escaped :
>
> gchar *data;
> data = g_strdup_printf("<![CDATA[%s]]>", item->data); 
> xmlNewChild (itemnode,NULL,"data", data);
>
> And if I don't want to use the <![CDATA[ ]]> tag. What
> would be the best way to search/replace the "special" 
> characters in C ? Normal regular expression, sed like 
> search/replace ? s/&/&amp;/g ?
>
>
> --
> Philip Van Hoof