Add Serial.room()

teensy3/usb_seremu.c

 #endif
 }
 
+int usb_seremu_room(void)
+{
+	uint32_t len;
+
+	tx_noautoflush = 1;
+	if (!tx_packet) {
+		if (!usb_configuration ||
+		  usb_tx_packet_count(SEREMU_TX_ENDPOINT) >= TX_PACKET_LIMIT ||
+		  (tx_packet = usb_malloc()) == NULL) {
+			tx_noautoflush = 0;
+			return 0;
+		}
+	}
+	len = SEREMU_TX_SIZE - tx_packet->index;
+	tx_noautoflush = 0;
+	return len;
+}
+
 void usb_seremu_flush_output(void)
 {
 	int i;

teensy3/usb_seremu.h

 void usb_seremu_flush_input(void);
 int usb_seremu_putchar(uint8_t c);
 int usb_seremu_write(const void *buffer, uint32_t size);
+int usb_seremu_room(void);
 void usb_seremu_flush_output(void);
 void usb_seremu_flush_callback(void);
 extern volatile uint8_t usb_seremu_transmit_flush_timer;
         size_t write(long n) { return write((uint8_t)n); }
         size_t write(unsigned int n) { return write((uint8_t)n); }
         size_t write(int n) { return write((uint8_t)n); }
+	int room() { return usb_seremu_room(); }
 	using Print::write;
         void send_now(void) { usb_seremu_flush_output(); };
         uint32_t baud(void) { return 9600; }
 	size_t write(long n) { return 1; }
 	size_t write(unsigned int n) { return 1; }
 	size_t write(int n) { return 1; }
+	int room() { return 0; }
 	using Print::write;
 	void send_now(void) { }
 	uint32_t baud(void) { return 0; }

teensy3/usb_serial.c

 	return 0;
 }
 
+int usb_serial_room(void)
+{
+	uint32_t len;
+
+	tx_noautoflush = 1;
+	if (!tx_packet) {
+		if (!usb_configuration ||
+		  usb_tx_packet_count(CDC_TX_ENDPOINT) >= TX_PACKET_LIMIT ||
+		  (tx_packet = usb_malloc()) == NULL) {
+			tx_noautoflush = 0;
+			return 0;
+		}
+	}
+	len = CDC_TX_SIZE - tx_packet->index;
+	tx_noautoflush = 0;
+	return len;
+}
+
 void usb_serial_flush_output(void)
 {
 	if (!usb_configuration) return;

teensy3/usb_serial.h

 void usb_serial_flush_input(void);
 int usb_serial_putchar(uint8_t c);
 int usb_serial_write(const void *buffer, uint32_t size);
+int usb_serial_room(void);
 void usb_serial_flush_output(void);
 extern uint32_t usb_cdc_line_coding[2];
 extern volatile uint8_t usb_cdc_line_rtsdtr;
 	size_t write(long n) { return write((uint8_t)n); }
 	size_t write(unsigned int n) { return write((uint8_t)n); }
 	size_t write(int n) { return write((uint8_t)n); }
+	int room() { return usb_serial_room(); }
 	using Print::write;
         void send_now(void) { usb_serial_flush_output(); }
         uint32_t baud(void) { return usb_cdc_line_coding[0]; }
 	size_t write(long n) { return 1; }
 	size_t write(unsigned int n) { return 1; }
 	size_t write(int n) { return 1; }
+	int room() { return 0; }
 	using Print::write;
         void send_now(void) { }
         uint32_t baud(void) { return 0; }