EthernetUdpV2_0.h

/*
    Udp.cpp: Library to send/receive UDP packets with the Arduino ethernet shield.
    This version only offers minimal wrapping of socket.c/socket.h
    Drop Udp.h/.cpp into the Ethernet library directory at hardware/libraries/Ethernet/

    NOTE: UDP is fast, but has some important limitations (thanks to Warren Gray for mentioning these)
    1) UDP does not guarantee the order in which assembled UDP packets are received. This
    might not happen often in practice, but in larger network topologies, a UDP
    packet can be received out of sequence.
    2) UDP does not guard against lost packets - so packets *can* disappear without the sender being
    aware of it. Again, this may not be a concern in practice on small local networks.
    For more information, see http://www.cafeaulait.org/course/week12/35.html

    MIT License:
    Copyright (c) 2008 Bjoern Hartmann
    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.

    bjoern@cs.stanford.edu 12/30/2008
*/

#ifndef ethernetudp_h
#define ethernetudp_h

#include <Udp.h>

#define UDP_TX_PACKET_MAX_SIZE 24

class EthernetUDP : public UDP {
  private:
    uint8_t _sock;  // socket ID for Wiz5100
    uint16_t _port; // local port to listen on
    IPAddress _remoteIP; // remote IP address for the incoming packet whilst it's being processed
    uint16_t _remotePort; // remote port for the incoming packet whilst it's being processed
    uint16_t _offset; // offset into the packet being sent
    uint16_t _remaining; // remaining bytes of incoming packet yet to be processed

  public:
    EthernetUDP();  // Constructor
    virtual uint8_t begin(
        uint16_t);	// initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
    virtual void stop();  // Finish with the UDP socket

    // Sending UDP packets

    // Start building up a packet to send to the remote host specific in ip and port
    // Returns 1 if successful, 0 if there was a problem with the supplied IP address or port
    virtual int beginPacket(IPAddress ip, uint16_t port);
    // Start building up a packet to send to the remote host specific in host and port
    // Returns 1 if successful, 0 if there was a problem resolving the hostname or port
    virtual int beginPacket(const char* host, uint16_t port);
    // Finish off this packet and send it
    // Returns 1 if the packet was sent successfully, 0 if there was an error
    virtual int endPacket();
    // Write a single byte into the packet
    virtual size_t write(uint8_t);
    // Write size bytes from buffer into the packet
    virtual size_t write(const uint8_t* buffer, size_t size);

    using Print::write;

    // Start processing the next available incoming packet
    // Returns the size of the packet in bytes, or 0 if no packets are available
    virtual int parsePacket();
    // Number of bytes remaining in the current packet
    virtual int available();
    // Read a single byte from the current packet
    virtual int read();
    // Read up to len bytes from the current packet and place them into buffer
    // Returns the number of bytes read, or 0 if none are available
    virtual int read(unsigned char* buffer, size_t len);
    // Read up to len characters from the current packet and place them into buffer
    // Returns the number of characters read, or 0 if none are available
    virtual int read(char* buffer, size_t len) {
        return read((unsigned char*)buffer, len);
    };
    // Return the next byte from the current packet without moving on to the next byte
    virtual int peek();
    virtual void flush();	// Finish reading the current packet

    // Return the IP address of the host who sent the current incoming packet
    virtual IPAddress remoteIP() {
        return _remoteIP;
    };
    // Return the port of the host who sent the current incoming packet
    virtual uint16_t remotePort() {
        return _remotePort;
    };
};

#endif