BigInteger Parse Octal String?

Question

In Java, I could do

//Parsing Octal String
BigInteger b = new BigInteger(\"16304103460644701340432043410021040424210140423204\",8);

Then f

Answer 1

A simple implementation for hex (and all bases up to 16); expand it by adding characters to the string constant (credit where credit is due; this is based on Douglas's answer):

private const string digits = "0123456789ABCDEF";
private readonly Dictionary values
    = digits.ToDictionary(c => c, c => (BigInteger)digits.IndexOf(c));
public BigInteger ParseBigInteger(string value, BigInteger baseOfValue)
{
    return value.Aggregate(
        new BigInteger,
        (current, digit) => current * baseOfValue + values[digit]);
}

It is likely that arithmetic where one operand is an int is faster than if both operands are BigInteger. In that case:

private readonly Dictionary values
    = digits.ToDictionary(c => c, c => digits.IndexOf(c));
public BigInteger ParseBigInteger(string value, int baseOfValue)
{
    return value.Aggregate(
        new BigInteger,
        (current, digit) => current * baseOfValue + values[digit]);
}