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+/*
+ *  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 udp_h
+#define udp_h
+
+#include <Stream.h>
+#include <IPAddress.h>
+
+#define UDP_TX_PACKET_MAX_SIZE 24
+
+class UDP : public Stream {
+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
+
+public:
+  UDP();  // Constructor
+  uint8_t begin(uint16_t);	// initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
+  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
+  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
+  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
+  int endPacket();
+  // Write a single byte into the packet
+  virtual void write(uint8_t);
+  // Write a string of characters into the packet
+  virtual void write(const char *str);
+  // Write size bytes from buffer into the packet
+  virtual void write(const uint8_t *buffer, size_t size);
+
+  // Start processing the next available incoming packet
+  // Returns the size of the packet in bytes, or 0 if no packets are available
+  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
+  IPAddress remoteIP() { return _remoteIP; };
+  // Return the port of the host who sent the current incoming packet
+  uint16_t remotePort() { return _remotePort; };
+};
+
+#endif