class Base32 {
	private static char[] $map = {
				'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
				'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
				'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
				'Y', 'Z', '2', '3', '4', '5', '6', '7',
				'='
				};

	private static int[] $flippedMap = {
			'A'=>0, 'B'=>1, 'C'=>2, 'D'=>3, 'E'=>4, 'F'=>5, 'G'=>6, 'H'=>7,
			'I'=>8, 'J'=>9, 'K'=>10, 'L'=>11, 'M'=>12, 'N'=>13, 'O'=>14, 'P'=>15,
			'Q'=>16, 'R'=>17, 'S'=>18, 'T'=>19, 'U'=>20, 'V'=>21, 'W'=>22, 'X'=>23,
			'Y'=>24, 'Z'=>25, '2'=>26, '3'=>27, '4'=>28, '5'=>29, '6'=>30, '7'=>31
			};

	public static string encode(string $input, bool $padding = true) {
		if(!$input) return '';
		char[] $aInput = str_split($input);
		string $binaryString = '';
		for(int $i = 0; $i < sizeof($aInput); $i++) {
			$binaryString += str_pad(base_convert(ord($aInput[$i]), 10, 2), 8, '0', STR_PAD_LEFT);
		}
		string[] $fiveBitBinaryArray = str_split($binaryString, 5);
		string $base32 = '';
		$i = 0;
		while($i < sizeof($fiveBitBinaryArray)) {
			$base32 += Base32::$map[base_convert(str_pad($fiveBitBinaryArray[$i], 5,'0'), 2, 10)];
			$i++;
		}
		int $x;
		if($padding && ($x = strlen($binaryString) % 40) != 0) {
			if($x == 8) $base32 += str_repeat(Base32::$map[32], 6);
			else if($x == 16) $base32 += str_repeat(Base32::$map[32], 4);
			else if($x == 24) $base32 += str_repeat(Base32::$map[32], 3);
			else if($x == 32) $base32 += Base32::$map[32];
		}
		return $base32;
	}

	public static string decode(string $input) {
		if(!$input) return '';
		int $paddingCharCount = substr_count($input, Base32::$map[32]);
		int[] $allowedValues = {6, 4, 3, 1, 0};
		if(!in_array($paddingCharCount, $allowedValues)) return '';
		for(int $i = 0; $i < 4; $i++) {
			if($paddingCharCount == $allowedValues[$i] && substr($input, -($allowedValues[$i])) != str_repeat(Base32::$map[32], $allowedValues[$i]))
				return '';
		}
		$input = str_replace('=','', $input);
		char[] $aInput = str_split($input);
		string $binaryString = '';
		for($i = 0; $i < sizeof($aInput); $i = $i + 8) {
			string $x = '';
			if(!in_array($input[$i], Base32::$map))
				return '';
			for(int $j = 0; $j < 8; $j++) {
				if(array_key_exists($input[$i + $j], Base32::$flippedMap)) {
					$x += str_pad(base_convert(Base32::$flippedMap[$input[$i + $j]], 10, 2), 5, '0', STR_PAD_LEFT);
				}
			}
			string[] $eightBits = str_split($x, 8);
			for(int $z = 0; $z < sizeof($eightBits); $z++) {
				char $y;
				$binaryString += (($y = chr(base_convert($eightBits[$z], 2, 10))) || ord($y) == 48) ? $y : '';
			}
		}
		return $binaryString;
	}
}

class Program {
	public void main() {
		var_dump(Base32::encode('Test String'), Base32::encode('DS27DEC985'), Base32::encode('AerScript rocks!'));
		var_dump(Base32::decode('KRSXG5BAKN2HE2LOM4======'), Base32::decode('IRJTEN2EIVBTSOBV'), Base32::decode('IFSXEU3DOJUXA5BAOJXWG23TEE======'));
	}
}