Question

Previous question was to encode two Int32 into one Int64 [C# – Making one Int64 from two Int32s

Question: How to decode one Int64 back to two Int32 ?

Answer 1

Here’s a (cheap) solution that will work for both conversions.

[StructLayout(LayoutKind.Explicit)]
public struct UnionInt64Int32 {
    public UnionInt64Int32(Int64 value) {
        Value32H = 0; Value32L = 0;
        Value64 = value;
    }
    public UnionInt64Int32(Int32 value1, Int32 value2) {
        Value64 = 0;
        Value32H = value1; Value32L = value2;
    }
    [FieldOffset(0)] public Int64 Value64;
    [FieldOffset(0)] public Int32 Value32H;
    [FieldOffset(4)] public Int32 Value32L;
}

An obvious drawback to this though, it’s unportable. The Value32H and value32L will be reversed on different endian platforms.