Converting delphi statement to c#

Question

I have a Delphi statement that I need to convert to C#, but I am not sure how the pointer dereferencing works in this circumstance.

var
  myarray : array[0..15] of WORD8;
  pBuf : PWORD32Buf;
begin
  ...
  pBuf := @myarray;
  Result := pBuf^[0] xor pBuf^[1] xor pBuf^[2] xor pBuf^[3];
end;

I understand that pBuf points to myarray and that pBuf^[0] should therefore be the 32 bit value represented by the first 4 bytes of the array. But I am not clear what 4 bytes would be represented by pBuf^[1] .

Would this be bytes 4 to 7 of myarray ?

Answer 1

You can use BitConverter.ToIn32 to acheive this:

byte[] myarray = new byte[16];

var result = BitConverter.ToInt32(myarray, 0) ^ 
             BitConverter.ToInt32(myarray, 4) ^
             BitConverter.ToInt32(myarray, 8) ^
             BitConverter.ToInt32(myarray, 12) ;

If you want to make an unsigned number then use ToUInt32 rather than ToInt32

Answer 2

We can only guess at the answer, because we don't know what PWORD32Buf is. Presumably it is a pointer to an array of DWORD , where DWORD is an unsigned 32 bit integer. And we also need to guess what WORD8 is, presumably an 8 byte type, probably unsigned.

In which case pBuf^[0] is bytes 0 to 3, pBuf^[1] is bytes 4 to 7, and so on. That would make sense because it would mean that all 16 bytes are included in the xor expression.