Base32::decode

static function decode($base32String)
{
	if (!$base32String)
		return '';

	if (!is_string($base32String))
		throw new ArgumentTypeException('base32String', 'string');

	$base32String = mb_strtoupper($base32String);
	$base32Array = str_split($base32String);

	$string = '';

	foreach ($base32Array as $str)
	{
		// skip padding
		if ($str === '=')
			continue;

		if (!isset(self::$alphabet[$str]))
			throw new DecodingException(sprintf('Illegal character: %s', $str));

		$char = self::$alphabet[$str];
		$char = decbin($char);
		$string .= str_pad($char, 5, 0, STR_PAD_LEFT);
	}

	while (strlen($string) % 8 !== 0)
	{
		$string = substr($string, 0, -1);
	}

	$binaryArray = self::chunk($string, 8);

	$realString = '';

	foreach ($binaryArray as $bin)
	{
		// Pad each value to 8 bits
		$bin = str_pad($bin, 8, 0, STR_PAD_RIGHT);
		// Convert binary strings to ASCII
		$realString .= chr(bindec($bin));
	}

	return $realString;
}