Convert long in base N-arbitrary.java

Convert long in base N-arbitrary.java

public String convert(long num, String code) {
	final int base = code.length();
	String text = "";
	do {
		text = code.charAt((int) (num%base)) + text;
		num /= base;
	} while (num > 0);
	return text;
}

public long toLong(String text, String code) {
	final long base = code.length();
	long num = 0;
	long pow = 1;
	int len = text.length();
	for (int i = 0; i < len; i++) {
		num += code.indexOf(text.charAt(len - i - 1)) * pow;
		pow *= base;
	}
	return num;
}

println(convert(9223372036854775807L,"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"));
println(convert(9223372036854775807L,"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ@=-+*/^%$#&()!?.,:;[]"));
println(toLong("Ns8T$87=uh","0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ@=-+*/^%$#&()!?.,:;[]"));
println(new Date(9223372036854775807L));





    public static String convert(BigInteger num, String code) {
        final BigInteger base = new BigInteger(""+code.length());
        String text = "";
        do {
            text = code.charAt( (num.mod(base) ).intValue()) + text;
            num = num.divide(base);
        } while (num.signum() > 0);
        return text;
    }

    public static BigInteger toLong(String text, String code) {
        final BigInteger base = new BigInteger("" + code.length());
        BigInteger num = BigInteger.ZERO;
        BigInteger pow = BigInteger.ONE;
        int len = text.length();
        for (int i = 0; i < len; i++) {
            BigInteger pos = new BigInteger(""+code.indexOf(text.charAt(len - i - 1)));
            num = num.add(pos.multiply(pow));
            pow = pow.multiply(base);
        }
        return num;
    }