Format strings with inline HTML tags.

Hi, thank you for the script, it is a very good work. I am using it to find the difference between two strings generated by an Editor wich contains inline HTML tags for formatings and the result i get is that the new string is wrapet completly as a new string and the old one completly as a deleted string.

Can you help me with any idea? Thank you in advance.

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Do you can provide example input and output?

/**
* Highlights the Difference between two strings
*
* @PARAM $o Old String
* @PARAM $n New String
* @return array
*/
public function getDecoratedDiff($o, $n){

    $ol = str_replace('>', '> ', $o);
    $old = str_replace('<', ' <', $ol);

    $ne = str_replace('>', '> ', $n);
    $new = str_replace('<', ' <', $ne);

    $ret = array(
        'old'   => '',
        'new'   => ''
    );

    $diff = $this->stringDiff(preg_split("/[\s]+/", $old), preg_split("/[\s]+/", $new));

    foreach($diff as $k){
        if(is_array($k)){
            if( !empty($k['d']) ){
                $ret['old'] .= "<del style='background-color: #ff000d'>".implode(' ',$k['d'])."</del> ";
            } else {
                $ret['old'] .= '';
            }

            if( !empty($k['i']) ){
                $ret['new'] .= "<ins style='background-color: #0091ff'>".implode(' ',$k['i'])."</ins> ";
            } else {
                $ret['new'] .= '';
            }
        } else {
            $ret['old'] .= $k . ' ';
            $ret['new'] .= $k . ' ';
        }
    }
    return $ret;
}

public function stringDiff($old, $new){
    $matrix = array();
    $maxlen = 0;
    foreach($old as $oindex => $ovalue){
        $nkeys = array_keys($new, $ovalue);
        foreach($nkeys as $nindex){
            $matrix[$oindex][$nindex] = isset($matrix[$oindex - 1][$nindex - 1]) ?
                $matrix[$oindex - 1][$nindex - 1] + 1 : 1;
            if($matrix[$oindex][$nindex] > $maxlen){
                $maxlen = $matrix[$oindex][$nindex];
                $omax = $oindex + 1 - $maxlen;
                $nmax = $nindex + 1 - $maxlen;
            }
        }
    }
    if($maxlen == 0) return array(array('d'=>$old, 'i'=>$new));
    return array_merge(
        $this->stringDiff(
            array_slice($old, 0, $omax),
            array_slice($new, 0, $nmax)
        ),
        array_slice($new, $nmax, $maxlen),
        $this->stringDiff(
            array_slice($old, $omax + $maxlen),
            array_slice($new, $nmax + $maxlen)
        )
    );
}

Now i get 2 Strings, the old one with the deleted strings marked and the new one with the added strings marked. And the HTML tags are escaped by putting a space in them so it wont catch them like:
Old: <span style="padding-left: 20px">Old Text</span>
New: <span style="padding-left: 30px">Old Text</span>
And the new output would be: <span style="padding-left: <ins style="color: blue;">>20px">Old</ins> Text</span>

Hope it helps :) For me it did.