if ( !isset($chr[1]) ) {
    trigger_error('Short sequence - at least 2 bytes expected, only 1 seen');
    return FALSE;
}

$ord1 = ord($chr[1]);

if ( !isset($chr[2]) ) {
    trigger_error('Short sequence - at least 3 bytes expected, only 2 seen');
    return FALSE;
}

$ord2 = ord($chr[2]);

if ( !isset($chr[3]) ) {
    trigger_error('Short sequence - at least 4 bytes expected, only 3 seen');
    return FALSE;
}

$ord3 = ord($chr[3]);

if ( !isset($chr[4]) ) {
    trigger_error('Short sequence - at least 5 bytes expected, only 4 seen');
    return FALSE;
}

$ord4 = ord($chr[4]);

if ( !isset($chr[5]) ) {
    trigger_error('Short sequence - at least 6 bytes expected, only 5 seen');
    return FALSE;
}