helpers/SStringHelper.php5

<?php
abstract class SStringHelper extends SObject {

    // Diff algorithm based on  Paul's Simple Diff Algorithm v 0.1
    // (C) Paul Butler 2007 <http://www.paulbutler.org/>
    protected static function diffHelper($old, $new){
        $maxlen = 0;
        foreach($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(
            self::diffHelper(array_slice($old, 0, $omax), array_slice($new, 0, $nmax)),
            array_slice($new, $nmax, $maxlen),
            self::diffHelper(array_slice($old, $omax + $maxlen), array_slice($new, $nmax + $maxlen)));
    }
    public static function diff($old, $new){
        $diff = self::diffHelper(explode(' ', $old), explode(' ', $new));
        $ret = '';
        foreach($diff as $k){
            if(is_array($k))
                $ret .= (!empty($k['d'])?"<del>".implode(' ',$k['d'])."</del> ":'').
                    (!empty($k['i'])?"<ins>".implode(' ',$k['i'])."</ins> ":'');
            else $ret .= $k . ' ';
        }
        return $ret;
    }
    public function toHTML($string) {
        $string = str_replace('\r', '<br />', $string);
        $string = str_replace('\n', '<br />', $string);
        $string = str_replace('
', '<br />', $string);
        return $string;
    }
}

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