Base32::encode

static function encode($string)
{
	if (!$string)
		return '';

	if (!is_string($string))
		throw new ArgumentTypeException('string', 'string');

	if (self::$encodeAlphabet === null)
		self::$encodeAlphabet = array_flip(self::$alphabet);

	// Convert string to binary
	$binaryString = '';

	foreach (str_split($string) as $s)
	{
		// Return each character as an 8-bit binary string
		$s = decbin(ord($s));
		$binaryString .= str_pad($s, 8, 0, STR_PAD_LEFT);
	}

	// Break into 5-bit chunks, then break that into an array
	$binaryArray = self::chunk($binaryString, 5);

	// Pad array to be divisible by 8
	while (count($binaryArray) % 8 !== 0)
	{
		$binaryArray[] = null;
	}

	$base32String = '';

	// Encode in base32
	foreach ($binaryArray as $bin)
	{
		$char = 32;

		if (!is_null($bin))
		{
			// Pad the binary strings
			$bin = str_pad($bin, 5, 0, STR_PAD_RIGHT);
			$char = bindec($bin);
		}

		// Base32 character
		$base32String .= self::$encodeAlphabet[$char];
	}

	return $base32String;
}