Encode HTML Characters in C - c

Question

I am reading data over a socket and parsing it with LibXML.
The problem that I am currently having is that sometimes there is a web link in the data which breaks the parser.
http://example.com/?key=value&key2=value
Is there any way to convert that to html characters?
Something like the above to
http://example.com/?key=value&key2=value
Example of socket data:
<node link="http://example.com/?key=value&key2=value" />
EDIT:
Found a solution that works for my problem here

Answer 1

You are going to have to do a pre-filter here. Contrary to other indications, search and replace just won't cut it. Consider your search side is &, which matches too much.
Construct the following finite state machine:
NORMAL:
if next matches "<" then TAG
TAG:
if next matches "![CDATA[" then CDATA
TAGSCAN
TAGSCAN:
if next matches whitespace then TAGSCAN2
if next matches > or next matches /> then NORMAL
TAGSCAN2:
if next matches whitespace then TAGSCAN2
if next matches SRC= or next matches HREF= then URL
TAGSCAN
URL:
we found an attribute with a URL in it. Do your search and replace
on the contents of the URL attribute value, advance past the URL and
go back to TAGSCAN
CDATA:
if next doesn't match ]]> then CDATA
NORMAL

Answer 2

I have found a nice solution using the code from
Find and Replace that uses a Find and Replace method suggested by bolov.
retval = str_replace(message, size, "&", "&");
if (!retval) {
printf("Not enough room to replace & with `&'\n");
}