[Ironruby-core] IO#read for socket (SocketStream.cs)

はしもとけんいち ken1hasimoto at gmail.com
Mon Nov 16 03:44:33 EST 2009

Hello, I'm kenichi hashimoto.
I'm Japanese. I don't write english well.

I modified the IronRuby Libirary for reading from the socket to run
the script of the druby-library.
The druby library is contained the standard ruby library.

I wrote two scripts that use the druby, and I tested it.
I saw a exception of the druby when a client script requested to the
server script ( I wrote both the client and the server ) on the
IronRuby 0.9.2.
This exception means that 'the druby library read the datum from the
socket, but size is corrputed'.
Of course, this scripts is not occurred the exception in Matz Ruby
1.8.7 and 1.9.1.

I confirm that protocol of the druby and communication seq, I found
the error that when the druby requests to read the socket with a size,
sometimes the read methods return a data smaller than specify the read
The Ruby IO#Read( size ) MUST recive the buffer required size. If
buffer is reached the request size, IO#read must block.

I found the mistake in the
"_socket.Receive" does NOT block to reach the request size.

        public override int Read(byte[] buffer, int offset, int count) {
            int bytesToRead = _peeked ? count - 1 : count;
            byte[] readBuffer = new byte[bytesToRead];
            long oldPos = _pos;

            if (bytesToRead > 0) {
                int bytesRead = _socket.Receive(readBuffer,
bytesToRead, SocketFlags.None);
                _pos += bytesRead;

I rewrote bellow:

            int updatedOffset = 0;
            while (bytesToRead > 0)
                int bytesRead = 0;
                if (bytesToRead > 0)
                    bytesRead = _socket.Receive(readBuffer,
bytesToRead, SocketFlags.None);
                    _pos += bytesRead;
                    bytesToRead -= bytesRead;

                if (_peeked)
                    // Put the byte we've already peeked at the
beginning of the buffer
                    buffer[offset] = _lastByteRead;
                    // Put the rest of the data afterwards
                    Array.Copy(readBuffer, 0, buffer, offset + 1 +
updatedOffset, bytesRead);
                    _pos += 1;
                    _peeked = false;
                    Array.Copy(readBuffer, 0, buffer, offset +
updatedOffset, bytesRead);
                updatedOffset += bytesRead;

    This code assumes the 'count > 0'.
    And I didn't consider about efficiency of the code.

If my consider is correct, Please modify this problem.

Thank you

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