code: function decode(str) {
  	// FIXME: Check for multiplication overflow
  	if (str.length > 12) {
  		throw new TypeError("Number encoded is too large");
  	}
  
  	var num = new UInt64();
  	for (let i=0; i<str.length; i++) {
  		let n = CHARS.indexOf(str[i]);
  		if (n === -1) {
  			throw new TypeError("Unknown character in string");
  		}
  		num.multiply(SIXTY_TWO);
  		num.add(new UInt64(n));
  	}
  
  	var buf = new Buffer(8);
  	num.div(UINT32_CAPACITY);
  	buf.writeUInt32BE(parseInt(num.toString()), 0);
  	buf.writeUInt32BE(num.remainder, 4);
  	return buf;
  }
docs: /*
  Decodes a base 62 string into an 8-byte buffer.