int_t select(int_t nfds, fd_set *readfds, fd_set *writefds,
fd_set *exceptfds, const timeval *timeout)
{
int_t i;
int_t j;
int_t n;
int_t s;
time_t time;
uint_t eventMask;
uint_t eventFlags;
OsEvent *event;
fd_set *fds;
//Create an event object to get notified of socket events
event = osEventCreate(FALSE, FALSE);
//Any error to report?
if(event == OS_INVALID_HANDLE)
{
socketError(NULL, ERROR_OUT_OF_RESOURCES);
return SOCKET_ERROR;
}
//Parse all the descriptor sets
for(i = 0; i < 3; i ++)
{
//Select the suitable descriptor set
switch(i)
{
case 0:
//Set of sockets to be checked for readability
fds = readfds;
eventMask = SOCKET_EVENT_RX_READY;
break;
case 1:
//Set of sockets to be checked for writability
fds = writefds;
eventMask = SOCKET_EVENT_TX_READY;
break;
default:
//Set of sockets to be checked for errors
fds = exceptfds;
eventMask = SOCKET_EVENT_CLOSED;
break;
}
//Each descriptor is optional and may be omitted
if(fds != NULL)
{
//Parse the current set of sockets
for(j = 0; j < fds->fd_count; j++)
{
//Get the descriptor associated with the current entry
s = fds->fd_array[j];
//Subscribe to the requested events
socketRegisterEvents(&socketTable[s], event, eventMask);
}
}
}
//Retrieve timeout value
if(timeout != NULL)
time = timeout->tv_sec * 1000 + timeout->tv_usec / 1000;
else
time = INFINITE_DELAY;
//Block the current task until an event occurs
osEventWait(event, time);
//Count the number of events in the signaled state
n = 0;
//Parse all the descriptor sets
for(i = 0; i < 3; i ++)
{
//Select the suitable descriptor set
switch(i)
{
case 0:
//Set of sockets to be checked for readability
fds = readfds;
eventMask = SOCKET_EVENT_RX_READY;
break;
case 1:
//Set of sockets to be checked for writability
fds = writefds;
eventMask = SOCKET_EVENT_TX_READY;
break;
default:
//Set of sockets to be checked for errors
fds = exceptfds;
eventMask = SOCKET_EVENT_CLOSED;
break;
}
//Each descriptor is optional and may be omitted
if(fds != NULL)
{
//Parse the current set of sockets
for(j = 0; j < fds->fd_count; )
{
//Get the descriptor associated with the current entry
s = fds->fd_array[j];
//Retrieve event flags for the current socket
socketGetEvents(&socketTable[s], &eventFlags);
//Unsubscribe previously registered events
socketUnregisterEvents(&socketTable[s]);
//Event flag is set?
if(eventFlags & eventMask)
{
//Track the number of events in the signaled state
n++;
//Jump to the next socket descriptor
j++;
}
else
{
//Remove descriptor from the current set
selectFdClr(fds, s);
}
}
}
}
//Close event
osEventClose(event);
//Return the number of events in the signaled state
return n;
}
error_t socketPoll(SocketEventDesc *eventDesc, uint_t size, OsEvent *extEvent, systime_t timeout)
{
uint_t i;
bool_t status;
OsEvent *event;
OsEvent eventObject;
//Check parameters
if(!eventDesc || !size)
return ERROR_INVALID_PARAMETER;
//Try to use the supplied event object to receive notifications
if(!extEvent)
{
//Create an event object only if necessary
if(!osCreateEvent(&eventObject))
{
//Report an error
return ERROR_OUT_OF_RESOURCES;
}
//Reference to the newly created event
event = &eventObject;
}
else
{
//Reference to the external event
event = extEvent;
}
//Loop through descriptors
for(i = 0; i < size; i++)
{
//Clear event flags
eventDesc[i].eventFlags = 0;
//Subscribe to the requested events
socketRegisterEvents(eventDesc[i].socket, event, eventDesc[i].eventMask);
}
//Block the current task until an event occurs
status = osWaitForEvent(event, timeout);
//Any socket event is in the signaled state?
if(status)
{
//Loop through descriptors
for(i = 0; i < size; i++)
{
//Retrieve event flags for the current socket
socketGetEvents(eventDesc[i].socket, &eventDesc[i].eventFlags);
//Clear unnecessary flags
eventDesc[i].eventFlags &= eventDesc[i].eventMask;
}
}
//Unsubscribe previously registered events
for(i = 0; i < size; i++)
socketUnregisterEvents(eventDesc[i].socket);
//Reset event object before exiting...
osResetEvent(event);
//Release previously allocated resources
if(!extEvent)
osDeleteEvent(&eventObject);
//Return status code
return status ? NO_ERROR : ERROR_TIMEOUT;
}
