Int128 in .Net?

Question

I need to do some large integer math. Are there any classes or structs out there that represent a 128-bit integer and implement all of the usual operators?

BTW, I realize that decimal can be used to represent a 96-bit int.

Answer 1

No, there's nothing in .NET <= 3.5. I'm hoping/expecting that BigInteger will make its return in .NET 4.0. (It was cut from .NET 3.5.)

Answer 2

I believe Mono has a BigInteger implementation that you should be able to track down the source for.

Answer 3

Here's an implementation of big integer from .net matters.

http://msdn.microsoft.com/en-us/magazine/cc163696.aspx

Answer 4

You might be able to use Microsoft.FSharp.Math.BigInt. As Jon points out, with any luck we may see an authorized version in .NET 4.0.

Update: It's here in System.Numerics. "The BigInteger type is an immutable type that represents an arbitrarily large integer whose value in theory has no upper or lower bounds."

var i = System.Numerics.BigInteger.Parse("10000000000000000000000000000000");

Answer 5

There's a BigInteger class defined as part of IronPython that you could use.

Answer 6

If you don't mind making reference to the J# library (vjslib.dll included with VS by default) there is already and implementation of BigInteger in .NET

using java.math;

public static void Main(){
    BigInteger biggy = new BigInteger(....)

}