Strip longer text by given length (utf-8 multi-bytes)

/**
 * Strip text longer then given length
 * @param string $text Text to be stripped
 * @param int $length Length of chars to keep
 * @param string $glueChar (optional) Show when length exceeded
 * @return string|null Stripped text | Text was empty
 */
function getCharsByLength ( $text, $length, $glueChar = '...' ) {
	if ( !trim ($text ) ) {
		return null;
	}

	/** @var int $actualLength */
	$actualLength = function_exists('mb_strlen')
		? mb_strlen($text)
		: strlen($text);

	// desired length is same or less, return as it is
	if ( $actualLength <= $length ) {
		return $text;
	}

	return function_exists ( 'mb_substr' )
		? mb_substr ($text, 0, $length, 'utf8' ) . $glueChar
		: substr ($text, 0, $length ) . $glueChar;
}

/************
 * EXAMPLE
 ***********/
getCharsByLength ('Νο εαμ σθμμο vολθτπατ. Εα εστ ομνεσ ιμπερδιετ εφφιcιαντθρ', 10);

/***********
 * OUTPUT
 **********/
# Νο εαμ σθμ...