D:/DRISSI/arduino-0022/arduino-0022/libraries/Ethernet/Udp.h
00001 /*
00002  *  Udp.cpp: Library to send/receive UDP packets with the Arduino ethernet shield.
00003  *  This version only offers minimal wrapping of socket.c/socket.h
00004  *  Drop Udp.h/.cpp into the Ethernet library directory at hardware/libraries/Ethernet/ 
00005  *
00006  * NOTE: UDP is fast, but has some important limitations (thanks to Warren Gray for mentioning these)
00007  * 1) UDP does not guarantee the order in which assembled UDP packets are received. This
00008  * might not happen often in practice, but in larger network topologies, a UDP
00009  * packet can be received out of sequence. 
00010  * 2) UDP does not guard against lost packets - so packets *can* disappear without the sender being
00011  * aware of it. Again, this may not be a concern in practice on small local networks.
00012  * For more information, see http://www.cafeaulait.org/course/week12/35.html
00013  *
00014  * MIT License:
00015  * Copyright (c) 2008 Bjoern Hartmann
00016  * Permission is hereby granted, free of charge, to any person obtaining a copy
00017  * of this software and associated documentation files (the "Software"), to deal
00018  * in the Software without restriction, including without limitation the rights
00019  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00020  * copies of the Software, and to permit persons to whom the Software is
00021  * furnished to do so, subject to the following conditions:
00022  * 
00023  * The above copyright notice and this permission notice shall be included in
00024  * all copies or substantial portions of the Software.
00025  * 
00026  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00027  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00028  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00029  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00030  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00031  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
00032  * THE SOFTWARE.
00033  *
00034  * bjoern@cs.stanford.edu 12/30/2008
00035  */
00036 
00037 #ifndef udp_h
00038 #define udp_h
00039 
00040 #define UDP_TX_PACKET_MAX_SIZE 24
00041 
00042 class UdpClass {
00043 private:
00044   uint8_t _sock;  // socket ID for Wiz5100
00045   uint16_t _port; // local port to listen on
00046 
00047 public:
00048   void begin(uint16_t);                         // initialize, start listening on specified port
00049   int available();                                                              // has data been received?
00050 
00051   // C-style buffer-oriented functions
00052   uint16_t sendPacket(uint8_t *, uint16_t, uint8_t *, uint16_t); //send a packet to specified peer 
00053   uint16_t sendPacket(const char[], uint8_t *, uint16_t);  //send a string as a packet to specified peer
00054   int readPacket(uint8_t *, uint16_t);          // read a received packet 
00055   int readPacket(uint8_t *, uint16_t, uint8_t *, uint16_t *);           // read a received packet, also return sender's ip and port     
00056   // readPacket that fills a character string buffer
00057   int readPacket(char *, uint16_t, uint8_t *, uint16_t &);
00058 
00059 };
00060 
00061 extern UdpClass Udp;
00062 
00063 #endif