Marshalling a big-endian byte collection into a struct in order to pull out values

Posted by Pat on Stack Overflow See other posts from Stack Overflow or by Pat
Published on 2010-03-19T19:41:42Z Indexed on 2010/03/19 20:01 UTC
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There is an insightful question about reading a C/C++ data structure in C# from a byte array, but I cannot get the code to work for my collection of big-endian (network byte order) bytes. (EDIT: Note that my real struct has more than just one field.) Is there a way to marshal the bytes into a big-endian version of the structure and then pull out the values in the endianness of the framework (that of the host, which is usually little-endian)?

This should summarize what I'm looking for (LE=LittleEndian, BE=BigEndian):

void Main()
{
    var leBytes = new byte[] {1, 0};
    var beBytes = new byte[] {0, 1};
    Foo fooLe = ByteArrayToStructure<Foo>(leBytes);
    Foo fooBe = ByteArrayToStructureBigEndian<Foo>(beBytes);
    Assert.AreEqual(fooLe, fooBe);
}

[StructLayout(LayoutKind.Explicit, Size=2)]
public struct Foo  {
    [FieldOffset(0)] 
    public ushort firstUshort;
}

T ByteArrayToStructure<T>(byte[] bytes) where T: struct 
{
    GCHandle handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
    T stuff = (T)Marshal.PtrToStructure(handle.AddrOfPinnedObject(),typeof(T));
    handle.Free();
    return stuff;
}

T ByteArrayToStructureBigEndian<T>(byte[] bytes) where T: struct 
{
    ???
}

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