Add user-defined USB receive callback

Allows the user to respond to received USB packet data immediately after it has been parsed by the library.

Author: dmadison

keywords.txt

@@ -47,6 +47,8 @@ getRumbleRight	KEYWORD2
 
 getLEDPatternID	KEYWORD2
 
+setReceiveCallback	KEYWORD2
+
 # USB I/O
 connected	KEYWORD2
 send	KEYWORD2

src/XInput.cpp

@@ -317,6 +317,10 @@ uint8_t XInputGamepad::getLEDPatternID() const {
 	return (uint8_t)ledPattern;
 }
 
+void XInputGamepad::setReceiveCallback(RecvCallbackType cback) {
+	recvCallback = cback;
+}
+
 boolean XInputGamepad::connected() {
 #ifdef USB_XINPUT
 	return XInputUSB::connected();
@@ -359,6 +363,12 @@ size_t XInputGamepad::receive() {
 	else if (PacketType == (uint8_t) XInputReceiveType::LEDs) {
 		parseLED(rx[2]);
 	}
+
+	// User-defined receive callback
+	if (recvCallback != nullptr) {
+		recvCallback(PacketType);
+	}
+
 	return bytesRecv;
 #else
 	return 0;
@@ -446,6 +456,9 @@ void XInputGamepad::reset() {
 	// Reset rescale ranges
 	setTriggerRange(XInputMap_Trigger::range.min, XInputMap_Trigger::range.max);
 	setJoystickRange(XInputMap_Joystick::range.min, XInputMap_Joystick::range.max);
+
+	// Clear user-set receive callback
+	recvCallback = nullptr;
 }
 
 void XInputGamepad::printDebug(Print &output) const {

src/XInput.h

@@ -108,6 +108,10 @@ class XInputGamepad {
 	uint8_t getLEDPatternID() const;  // Returns LED pattern ID #
 	XInputLEDPattern getLEDPattern() const;  // Returns LED pattern type
 
+	// Received Data Callback
+	using RecvCallbackType = void(*)(uint8_t packetType);
+	void setReceiveCallback(RecvCallbackType);
+
 	// USB IO
 	boolean connected();
 	size_t send();
@@ -131,6 +135,7 @@ class XInputGamepad {
 	uint8_t tx[20];  // USB transmit data
 	boolean newData;  // Flag for tx data changed
 
+	RecvCallbackType recvCallback;
 	uint8_t player;  // Gamepad player #, buffered
 	uint8_t rumble[2];  // Rumble motor data in, buffered
 	XInputLEDPattern ledPattern;  // LED pattern data in, buffered