Added Packet struct and beginnings of packet reading

src/udp/packet.rs

@@ -0,0 +1,66 @@
+use crate::udp::UdpSocket;
+use crate::network::Network;
+use crate::bus::ActiveBus;
+use crate::socket::Socket;
+use crate::IpAddress;
+use byteorder::{BigEndian, ByteOrder};
+
+pub struct UdpPacket<UdpSocket> {
+    udp_socket: UdpSocket,
+    address: IpAddress,
+    remote_port: u16,
+    size: u16,
+    read_pointer: u16,
+}
+
+impl<'a, SpiBus: ActiveBus, NetworkImpl: Network, SocketImpl: Socket> UdpPacket<UdpSocket<'a, SpiBus, NetworkImpl, SocketImpl>>
+{
+    pub fn new(mut udp_socket: UdpSocket<'a, SpiBus, NetworkImpl, SocketImpl>) -> Result<Self, SpiBus::Error> {
+        let receive_size = udp_socket.block_until_receive_size_known()? - 8;
+        // |<-- read_pointer                                read_pointer + received_size -->|
+        // |Destination IP Address | Destination Port | Byte Size of DATA | Actual DATA ... |
+        // |   --- 4 Bytes ---     |  --- 2 Bytes --- |  --- 2 Bytes ---  |      ....       |
+        let read_pointer = udp_socket.socket.get_packet_address(&mut udp_socket.bus)?;
+        let mut header = [0u8; 8];
+        block!(udp_socket.bus.transfer_frame(udp_socket.socket.rx_buffer(), read_pointer, false, &mut header))?;
+        Ok(UdpPacket {
+            udp_socket,
+            address: IpAddress::new(header[0], header[1], header[2], header[3]),
+            remote_port: BigEndian::read_u16(&header[4..5]),
+            size: receive_size,
+            read_pointer,
+        })
+    }
+
+    pub fn get_remote_port(&self) -> u16 {
+        self.remote_port
+    }
+
+    pub fn get_address(&self) -> IpAddress {
+        self.address
+    }
+
+    pub fn read(&self) {
+        // TODO read a byte upon every invocation
+        // w5500.read_from(
+        //     socket.rx_register_at(read_pointer + 8),
+        //     &mut destination[..data_length],
+        // )?;
+    }
+
+    pub fn close(self) -> UdpSocket<'a, SpiBus, NetworkImpl, SocketImpl> {
+        // TODO reset read pointer etc
+
+        // // reset
+        // w5500.write_u16(
+        //     socket.at(SocketRegister::RxReadPointer),
+        //     read_pointer + receive_size as u16,
+        // )?;
+        // w5500.write_u8(
+        //     socket.at(SocketRegister::Command),
+        //     SocketCommand::Recv as u8,
+        // )?;
+        // TODO return Socket
+        self.udp_socket
+    }
+}