BlockCopy

[Urs Wigger]

From a socket, I read some data into a bytes buffer.

byte[] bytes = new byte[1024];
int headSize = 8;
int nRead = sock.Receive(bytes, 0, headSize, SocketFlags.Peek);

Next I would like to 'mask' the received data with a struct 'HeaderT'

public struct HeaderT
{
int packetSize;
int type;
};

In C++ this could be done similar to this:
HeaderT *pHead = (HeaderT *)bytes;

In C#, this obviously does not work, so I tried with BlockCopy():

HeaderT header = new HeaderT();
System.Buffer.BlockCopy(bytes, 0, header , 0, headSize);

But then I get the following syntax error
Argument '3': cannot convert from 'HeaderT' to 'System.Array'.

So far I found no solution. Any help would be appreciated
Regards Urs

[Nicholas Paldino [.NET/C# MVP]]

Urs,

You will have to pass an array of type HeaderT into the function, with
one element in it.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Urs Wigger" <ns_urs.wigger@leica-geosystems_ns.com> wrote in message
news:Od*************@TK2MSFTNGP09.phx.gbl...

From a socket, I read some data into a bytes buffer.

byte[] bytes = new byte[1024];
int headSize = 8;
int nRead = sock.Receive(bytes, 0, headSize, SocketFlags.Peek);

Next I would like to 'mask' the received data with a struct 'HeaderT'

public struct HeaderT
{
int packetSize;
int type;
};

In C++ this could be done similar to this:
HeaderT *pHead = (HeaderT *)bytes;

In C#, this obviously does not work, so I tried with BlockCopy():

HeaderT header = new HeaderT();
System.Buffer.BlockCopy(bytes, 0, header , 0, headSize);

But then I get the following syntax error
Argument '3': cannot convert from 'HeaderT' to 'System.Array'.

So far I found no solution. Any help would be appreciated
Regards Urs

[Mattias Sjögren]

You will have to pass an array of type HeaderT into the function, with
one element in it.

I don't think BlockCopy works with UDTs, only with the primitive
types. So I'd do something like this instead

HeaderT header;
header.packetSize = BitConverter.ToInt32( bytes, 0 );
header.type = BitConverter.ToInt32( bytes, 4 );

In C++ this could be done similar to this:
HeaderT *pHead = (HeaderT *)bytes;

In C#, this obviously does not work

Actually you can, in unsafe code. But you may not want to do that.

Mattias

--
Mattias Sjögren [MVP] mattias @ mvps.org
http://www.msjogren.net/dotnet/
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