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/*
* Udp.cpp: Library to send/receive UDP packets.
*
* 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>
class UDP : public Stream {
public:
virtual uint8_t begin(uint16_t) =0; // initialize, start listening on specified port. Returns 1 if successful, 0 if there are no sockets available to use
virtual void stop() =0; // 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) =0;
// 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) =0;
// Finish off this packet and send it
// Returns 1 if the packet was sent successfully, 0 if there was an error
virtual int endPacket() =0;
// Write a single byte into the packet
virtual size_t write(uint8_t) =0;
// Write a string of characters into the packet
virtual size_t write(const char *str) =0;
// Write size bytes from buffer into the packet
virtual size_t write(const uint8_t *buffer, size_t size) =0;
// 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() =0;
// Number of bytes remaining in the current packet
virtual int available() =0;
// Read a single byte from the current packet
virtual int read() =0;
// 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) =0;
// 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) =0;
// Return the next byte from the current packet without moving on to the next byte
virtual int peek() =0;
virtual void flush() =0; // Finish reading the current packet
// Return the IP address of the host who sent the current incoming packet
virtual IPAddress remoteIP() =0;
// Return the port of the host who sent the current incoming packet
virtual uint16_t remotePort() =0;
protected:
uint8_t* rawIPAddress(IPAddress& addr) { return addr.raw_address(); };
};
#endif
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