txCommands.c TxGetInputEvent() rework main loop to iterate less

Original version would iterate exhaustively, even when it was not
necessary.

This version seeks to do the minimum amount of iteration work based
on the information available.

textio/txCommands.c

@@ -1021,22 +1021,33 @@ TxGetInputEvent(
 	    perror("magic");
 	}
 
-	for (i = 0; numReady && i < txLastInputEntry; i++)
+	/* 0..1023 using numReady==0 to terminate early */
+	for (fd = 0; numReady && fd <= txInputDescriptors_nfds; fd++)
 	{
-	    /* This device has data on its file descriptor, call
-	     * it so that it can add events to the input queue.
-	     */
-	    for (fd = 0; fd <= txInputDescriptors_nfds; fd++) {
-		if (FD_ISSET(fd, &inputs) &&
-			    FD_ISSET(fd, &txInputDevice[i].tx_fdmask)) {
-		    lastNum = txNumInputEvents;
-		    (*(txInputDevice[i].tx_inputProc))
-			(fd, txInputDevice[i].tx_cdata); /** @invoke cb_textio_input_t */
-		    FD_CLR(fd, &inputs);
-		    /* Did this driver choose to add an event? */
-		    if (txNumInputEvents != lastNum) gotSome = TRUE;
-		    numReady--;
-		}
+	    if (!FD_ISSET(fd, &inputs))
+		continue; /* this fd is was not monitored or is not ready */
+
+	    /* find the input device receiver entry */
+	    for (i = 0; i < txLastInputEntry; i++)
+	    {
+		if (!FD_ISSET(fd, &txInputDevice[i].tx_fdmask))
+		    continue;
+
+		/* This device has data on its file descriptor, call
+		 * it so that it can add events to the input queue.
+		 */
+		lastNum = txNumInputEvents;
+
+		(*txInputDevice[i].tx_inputProc)(fd, txInputDevice[i].tx_cdata);
+
+		/* Did this driver choose to add an event? */
+		if (txNumInputEvents != lastNum) gotSome = TRUE;
+		numReady--;
+
+		/* original code would FD_CLR() which would effectively break here
+		 * so this only allows the first found receiver to receive the data
+		 */
+		break;
 	    }
 	}
 	/*