added new screens and getting ready for networking, looking at SDL_net for cross platfrom networking so i dont have to touch windows

SDL2_net-2.2.0/SDLnetselect.c

@@ -0,0 +1,160 @@
+/*
+  SDL_net:  An example cross-platform network library for use with SDL
+  Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+#include "SDLnetsys.h"
+#include "SDL_net.h"
+
+/* The select() API for network sockets */
+
+struct SDLNet_Socket {
+    int ready;
+    SOCKET channel;
+};
+
+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 *)SDL_malloc(sizeof(*set));
+    if ( set != NULL ) {
+        set->numsockets = 0;
+        set->maxsockets = maxsockets;
+        set->sockets = (struct SDLNet_Socket **)SDL_malloc
+                    (maxsockets*sizeof(*set->sockets));
+        if ( set->sockets != NULL ) {
+            for ( i=0; i<maxsockets; ++i ) {
+                set->sockets[i] = NULL;
+            }
+        } else {
+            SDL_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.
+*/
+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 {
+        SDLNet_SetLastError(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 ( SDLNet_GetLastError() == 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);
+}
+
+/* Free a set of sockets allocated by SDL_NetAllocSocketSet() */
+void SDLNet_FreeSocketSet(SDLNet_SocketSet set)
+{
+    if ( set ) {
+        SDL_free(set->sockets);
+        SDL_free(set);
+    }
+}