Upgraded hid interface

src/ergodox.cpp

@@ -1,7 +1,6 @@
 #include "ergodox.hpp"
 
 
-
 Ergodox::Ergodox(
 	unsigned short vendor_id,
 	unsigned short product_id,
@@ -64,6 +63,9 @@ Ergodox::~Ergodox() {
 Try to open this keyboard's hid device.
 Throws a runtime error if device is already open,
 or if we can't find a device with the given params.
+
+If we successfully open a device, this method sends a
+CMD_HELLO packet.
 */
 void Ergodox::open() {
 	if (handle != NULL) {
@@ -94,6 +96,10 @@ void Ergodox::open() {
 		hid_free_enumeration(devs);
 		throw std::runtime_error("Could not open hid device");
 	}
+
+	hid_set_nonblocking(handle, 1);
+
+	write(CMD_HELLO, NULL, 0);
 }
 
 
@@ -108,14 +114,64 @@ void Ergodox::close() {
 /*
 Send data to Ergodox.
 
+@param cmd Command byte
 @param data Data to send
-@param length How many bytes to send
-@returns Actual number of bytes written, or -1 on error.
+@returns data_len Data length. Must be shorter than packet_size.
 */
-int Ergodox::write(uint8_t* data, size_t length) const {
+int Ergodox::write(uint8_t cmd, const uint8_t* data, uint8_t data_len) const {
 	if (handle == NULL) {
 		throw std::runtime_error("Cannot write, device is not open!");
 	}
 
-	return hid_write(handle, data, length);
+	if (data_len > packet_size) {
+		throw std::runtime_error("Data length exceeds packet size");
+	}
+
+	if (data == NULL) {
+		data = {0x00};
+	}
+
+	uint8_t packet[packet_size];
+	packet[0] = 0x00; // Report number. Not seen by keyboard.
+	packet[1] = cmd;  // First byte is always command
+
+	// Copy data into rest of packet
+	std::copy(data, data + data_len, packet + 2);
+
+	return hid_write(handle, packet, packet_size + 1);
+}
+
+
+/*
+Read data from Ergodox into read_buf. If a CMD_SEND_STATE packet is received, process it and return false.
+
+@returns True if a new command was received, false otherwise.
+*/
+bool Ergodox::read() {
+	if (handle == NULL) {
+		throw std::runtime_error("Cannot write, device is not open!");
+	}
+	ssize_t res;
+	res = hid_read(handle, read_buf, packet_size);
+
+	if (res == 0) {
+		return false;
+	} else if (res < 0) {
+		throw std::runtime_error("Read failed.");
+	}
+
+	switch(read_buf[0]) {
+
+		// If keyboard sends a state packet, parse it.
+		case CMD_SEND_STATE:
+			if (animation_mode != read_buf[1]) {
+				wprintf(L"Mode set to %#x\n", read_buf[1]);
+				animation_mode = read_buf[1];
+			}
+
+			// Main code should not parse state packets.
+			return false;
+	}
+
+	return res > 0;
 }