[PHP] whats wrong with this function

[Adrian Murphy]

whats wrong with this.
it's getting stuck somewhere



function urls_clickable($string) { 
for($n=0; $n < strlen($string); $n++) 
{ 
if(strtolower($string[$n]) == 'h') { 
if(!strcmp("http://";, strtolower($string[$n]) . strtolower($string[$n+1]) . 
strtolower($string[$n+2]) . strtolower($string[$n+3]) . $string[$n+4] . $string[$n+5] 
. $string[$n+6])) { 
$startpos = $n; 
while($n < strlen($string) && eregi("[a-z0-9\.\:\?\/\~\-\_\&\=\%\+\'\"]", 
$string[$n])) $n++; 
if(!eregi("[a-z0-9]", $string[$n-1])) $n--; 
$link = substr($string, $startpos, ($n-$startpos)); 
$link = $link; 
$string_tmp = $string; 
$string = substr($string_tmp, 0, $startpos); 
$string .= "<a href=\"$link\" target=\"_blank\">$link</a>"; 
$string .= substr($string_tmp, $n, strlen($string_tmp)); 
$n = $n + 15; 
} 
} 
} 
return $string; 
}

$text = "http://www.somewhere.org <br><br>";
echo urls_clickable($text);