SDLnetselect.c

/*
    SDL_net:  An example cross-platform network library for use with SDL
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/* $Id: SDLnetselect.c 1192 2004-01-04 17:41:55Z slouken $ */

#include "SDLnetsys.h"
#include "SDL_net.h"

/* The select() API for network sockets */

struct SDLNet_Socket {
	int ready;
	SOCKET channel;
#ifdef MACOS_OPENTRANSPORT
	OTEventCode curEvent;
#endif
};

struct _SDLNet_SocketSet {
	int numsockets;
	int maxsockets;
	struct SDLNet_Socket **sockets;
};

/* Allocate a socket set for use with SDLNet_CheckSockets() 
   This returns a socket set for up to 'maxsockets' sockets, or NULL if 
   the function ran out of memory. 
 */
SDLNet_SocketSet SDLNet_AllocSocketSet(int maxsockets)
{
	struct _SDLNet_SocketSet *set;
	int i;

	set = (struct _SDLNet_SocketSet *)malloc(sizeof(*set));
	if ( set != NULL ) {
		set->numsockets = 0;
		set->maxsockets = maxsockets;
		set->sockets = (struct SDLNet_Socket **)malloc
					(maxsockets*sizeof(*set->sockets));
		if ( set->sockets != NULL ) {
			for ( i=0; i<maxsockets; ++i ) {
				set->sockets[i] = NULL;
			}
		} else {
			free(set);
			set = NULL;
		}
	}
	return(set);
}

/* Add a socket to a set of sockets to be checked for available data */
int SDLNet_AddSocket(SDLNet_SocketSet set, SDLNet_GenericSocket sock)
{
	if ( sock != NULL ) {
		if ( set->numsockets == set->maxsockets ) {
			SDLNet_SetError("socketset is full");
			return(-1);
		}
		set->sockets[set->numsockets++] = (struct SDLNet_Socket *)sock;
	}
	return(set->numsockets);
}

/* Remove a socket from a set of sockets to be checked for available data */
int SDLNet_DelSocket(SDLNet_SocketSet set, SDLNet_GenericSocket sock)
{
	int i;

	if ( sock != NULL ) {
		for ( i=0; i<set->numsockets; ++i ) {
			if ( set->sockets[i] == (struct SDLNet_Socket *)sock ) {
				break;
			}
		}
		if ( i == set->numsockets ) {
			SDLNet_SetError("socket not found in socketset");
			return(-1);
		}
		--set->numsockets;
		for ( ; i<set->numsockets; ++i ) {
			set->sockets[i] = set->sockets[i+1];
		}
	}
	return(set->numsockets);
}

/* This function checks to see if data is available for reading on the
   given set of sockets.  If 'timeout' is 0, it performs a quick poll,
   otherwise the function returns when either data is available for
   reading, or the timeout in milliseconds has elapsed, which ever occurs
   first.  This function returns the number of sockets ready for reading,
   or -1 if there was an error with the select() system call.
*/
#ifdef MACOS_OPENTRANSPORT
int SDLNet_CheckSockets(SDLNet_SocketSet set, Uint32 timeout)
{
Uint32	stop;
int 	numReady;

	/* Loop, polling the network devices */
	
	stop = SDL_GetTicks() + timeout;
	
	do 
	{
	OTResult status;
	size_t	numBytes;
	int 	i;
		
		numReady = 0;
	
		for (i = set->numsockets-1;i >= 0;--i) 
		{
			status = OTLook( set->sockets[i]->channel );
			if( status > 0 )
			{
				switch( status )
				{
					case T_UDERR:
						OTRcvUDErr( set->sockets[i]->channel , nil);
						break;
					case T_DISCONNECT:
						OTRcvDisconnect( set->sockets[i]->channel, nil );
						break;
					case T_ORDREL:
						OTRcvOrderlyDisconnect(set->sockets[i]->channel );
						break;
					case T_CONNECT:
						OTRcvConnect( set->sockets[i]->channel, nil );
						break;
					
				
					default:
						set->sockets[i]->ready = 1;
						++numReady;
				}
			}
			else if( OTCountDataBytes(set->sockets[i]->channel, &numBytes ) != kOTNoDataErr )
			{
				set->sockets[i]->ready = 1;
				++numReady;
			}
			else
				set->sockets[i]->ready = 0;
		}
		
	} while (!numReady && (SDL_GetTicks() < stop));

	return(numReady);
}
#else
int SDLNet_CheckSockets(SDLNet_SocketSet set, Uint32 timeout)
{
	int i;
	SOCKET maxfd;
	int retval;
	struct timeval tv;
	fd_set mask;

	/* Find the largest file descriptor */
	maxfd = 0;
	for ( i=set->numsockets-1; i>=0; --i ) {
		if ( set->sockets[i]->channel > maxfd ) {
			maxfd = set->sockets[i]->channel;
		}
	}

	/* Check the file descriptors for available data */
	do {
		errno = 0;

		/* Set up the mask of file descriptors */
		FD_ZERO(&mask);
		for ( i=set->numsockets-1; i>=0; --i ) {
			FD_SET(set->sockets[i]->channel, &mask);
		}

		/* Set up the timeout */
		tv.tv_sec = timeout/1000;
		tv.tv_usec = (timeout%1000)*1000;

		/* Look! */
		retval = select(maxfd+1, &mask, NULL, NULL, &tv);
	} while ( errno == EINTR );

	/* Mark all file descriptors ready that have data available */
	if ( retval > 0 ) {
		for ( i=set->numsockets-1; i>=0; --i ) {
			if ( FD_ISSET(set->sockets[i]->channel, &mask) ) {
				set->sockets[i]->ready = 1;
			}
		}
	}
	return(retval);
}
#endif /* MACOS_OPENTRANSPORT */
   
/* Free a set of sockets allocated by SDL_NetAllocSocketSet() */
extern void SDLNet_FreeSocketSet(SDLNet_SocketSet set)
{
	if ( set ) {
		free(set->sockets);
		free(set);
	}
}