public static function LV($str, $len = 1, $lrev = false)
    {
        $l = static::i2b($len, strlen($str));
        if ($lrev) {
            $l = strrev($l);
        }
        return $l . $str;
    }
public static function LV($str, $len = 1, $lrev = false)
    {
        $l = static::i2b($len, strlen($str));
        if ($lrev) {
            $l = strrev($l);
        }
        return $l . $str;
    }
public static function LV ( $ str , $ len = 1 , $ lrev = false ) { $ l = static :: i2b ( $ len , strlen ( $ str ) ) ; if ( $ lrev ) { $ l = strrev ( $ l ) ; } return $ l . $ str ; }
Build length-value binary snippet.

@param string $str Data.
@param int $len Number of bytes to encode length, defaults to 1.
@return string
Build length - value binary snippet .