Text_Diff_Engine_xdiff

16class Text_Diff_Engine_xdiff {17 18    /**19     */20    function diff($from_lines, $to_lines)21    {22        array_walk($from_lines, array('Text_Diff', 'trimNewlines'));23        array_walk($to_lines, array('Text_Diff', 'trimNewlines'));24 25        /* Convert the two input arrays into strings for xdiff processing. */26        $from_string = implode("\n", $from_lines);27        $to_string = implode("\n", $to_lines);28 29        /* Diff the two strings and convert the result to an array. */30        $diff = xdiff_string_diff($from_string, $to_string, count($to_lines));31        $diff = explode("\n", $diff);32 33        /* Walk through the diff one line at a time.  We build the $edits34         * array of diff operations by reading the first character of the35         * xdiff output (which is in the "unified diff" format).36         *37         * Note that we don't have enough information to detect "changed"38         * lines using this approach, so we can't add Text_Diff_Op_changed39         * instances to the $edits array.  The result is still perfectly40         * valid, albeit a little less descriptive and efficient. */41        $edits = array();42        foreach ($diff as $line) {43            if (!strlen($line)) {44                continue;45            }46            switch ($line[0]) {47            case ' ':48                $edits[] = new Text_Diff_Op_copy(array(substr($line, 1)));49                break;50 51            case '+':52                $edits[] = new Text_Diff_Op_add(array(substr($line, 1)));53                break;54 55            case '-':56                $edits[] = new Text_Diff_Op_delete(array(substr($line, 1)));57                break;58            }59        }60 61        return $edits;62    }63 64}