/*

    File:       UDPEcho.h

    Contains:   A class that implements a UDP echo protocol client and server.

    Written by: DTS

    Copyright:  Copyright (c) 2010-12 Apple Inc. All Rights Reserved.

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                The Apple Software is provided by Apple on an "AS IS" basis. 

                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING

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*/

#import <Foundation/Foundation.h>

#if TARGET_OS_EMBEDDED || TARGET_IPHONE_SIMULATOR

    #import <CFNetwork/CFNetwork.h>

#else

    #import <CoreServices/CoreServices.h>

#endif

@protocol UDPEchoDelegate;

@interface UDPEcho : NSObject

- (id)init;

- (void)startServerOnPort:(NSUInteger)port;

    // Starts an echo server on the specified port.  Will call the 

    // -echo:didStartWithAddress: delegate method on success and the 

    // -echo:didStopWithError: on failure.  After that, the various 

    // 'data' delegate methods may be called.

- (void)startConnectedToHostName:(NSString *)hostName port:(NSUInteger)port;

    // Starts a client targetting the specified host and port.  

    // Will call -echo:didStartWithAddress: delegate method on success and 

    // the -echo:didStopWithError: on failure.  At that point you can call 

    // -sendData: to send data to the server and the various 'data' delegate 

    // methods may be called.

- (void)sendData:(NSData *)data;

    // On the client, sends the specified data to the server.  The 

    // -echo:didSendData:toAddress: or -echo:didFailToSendData:toAddress:error: 

    // delegate method will be called to indicate the success or failure 

    // of the send, and the -echo:didReceiveData:fromAddress: delegate method 

    // will be called if a response is received.

- (void)stop;

    // Will stop the object, preventing any future network operations or delegate 

    // method calls until the next start call.

@property (nonatomic, weak,   readwrite) id<UDPEchoDelegate>    delegate;

@property (nonatomic, assign, readonly, getter=isServer) BOOL   server;

@property (nonatomic, copy,   readonly ) NSString *             hostName;       // valid in client mode

@property (nonatomic, copy,   readonly ) NSData *               hostAddress;    // valid in client mode after successful start

@property (nonatomic, assign, readonly ) NSUInteger             port;           // valid in client and server mode

@end

@protocol UDPEchoDelegate <NSObject>

@optional

// In all cases an address is an NSData containing some form of (struct sockaddr), 

// specifically a (struct sockaddr_in) or (struct sockaddr_in6).

- (void)echo:(UDPEcho *)echo didReceiveData:(NSData *)data fromAddress:(NSData *)addr;

    // Called after successfully receiving data.  On a server object this data will 

    // automatically be echoed back to the sender.

    //

    // assert(echo != nil);

    // assert(data != nil);

    // assert(addr != nil);

- (void)echo:(UDPEcho *)echo didReceiveError:(NSError *)error;

    // Called after a failure to receive data.

    //

    // assert(echo != nil);

    // assert(error != nil);

- (void)echo:(UDPEcho *)echo didSendData:(NSData *)data toAddress:(NSData *)addr;

    // Called after successfully sending data.  On the server side this is typically 

    // the result of an echo.

    //

    // assert(echo != nil);

    // assert(data != nil);

    // assert(addr != nil);

- (void)echo:(UDPEcho *)echo didFailToSendData:(NSData *)data toAddress:(NSData *)addr error:(NSError *)error;

    // Called after a failure to send data.

    //

    // assert(echo != nil);

    // assert(data != nil);

    // assert(addr != nil);

    // assert(error != nil);

- (void)echo:(UDPEcho *)echo didStartWithAddress:(NSData *)address;

    // Called after the object has successfully started up.  On the client addresses 

    // is the list of addresses associated with the host name passed to 

    // -startConnectedToHostName:port:.  On the server, this is the local address 

    // to which the server is bound.

    //

    // assert(echo != nil);

    // assert(address != nil);

- (void)echo:(UDPEcho *)echo didStopWithError:(NSError *)error;

    // Called after the object stops spontaneously (that is, after some sort of failure, 

    // but now after a call to -stop).

    //

    // assert(echo != nil);

    // assert(error != nil);

@end