To find url given string and replace with anchor tag in php

<?php
$str = "Hi I am using google.com going http://google.com and 
where in https://google.com ahcinkg http://google.co.in else http://google.co";
$ss = "";
$sd = explode(" ",$str);
//print_r($sd);
$c=count($sd)."
";
$i=0;
while($c>$i){
    $regex = "((https?|ftp)\:\/\/)?"; // SCHEME
 $regex .= "([a-z0-9+!*(),;?&=\$_.-]+(\:[a-z0-9+!*(),;?&=\$_.-]+)?@)?"; // User and Pass
 $regex .= "([a-z0-9-.]*)\.([a-z]{2,4})"; // Host or IP
 $regex .= "(\:[0-9]{2,5})?"; // Port
 $regex .= "(\/([a-z0-9+\$_-]\.?)+)*\/?"; // Path
 $regex .= "(\?[a-z+&\$_.-][a-z0-9;:@&%=+\/\$_.-]*)?"; // GET Query
 $regex .= "(#[a-z_.-][a-z0-9+\$_.-]*)?"; // Anchor
 // $regexp = '/^[a-zA-Z0-9][a-zA-Z0-9\-\_]+[a-zA-Z0-9]$/';
 
 if (true == preg_match("/^$regex$/", $sd[$i])) {
  if(!in_array("http", parse_url($sd[$i])) && !in_array("https", parse_url($sd[$i]))) {
   $s1 ="http://".$sd[$i];
   echo $ss ="$sd[$i]  ";
  }elseif(in_array("http", parse_url($sd[$i])) || in_array("https", parse_url($sd[$i]))) {
   echo $ss ="$sd[$i]  ";
  }
 }else{
   echo $sd[$i]."  ";
 }
    $i++;
}
?>