Added ergodox hid manager

src/ergodox.cpp

@@ -0,0 +1,118 @@
+#include "ergodox.hpp"
+
+
+
+Ergodox::Ergodox(
+	unsigned short vendor_id,
+	unsigned short product_id,
+	unsigned short usage,
+	unsigned short usage_page
+) :
+	vendor_id(vendor_id),
+	product_id(product_id),
+	usage(usage),
+	usage_page(usage_page),
+	handle(NULL)
+{
+	hid_init();
+	open();
+}
+
+
+
+/*
+Initialize Ergodox interface.
+
+Should be called once at start of execution. Arguments are the USB parameters of the keyboard.
+
+Returns instance of singleton.
+*/
+Ergodox& Ergodox::init(
+	unsigned short vendor_id,
+	unsigned short product_id,
+	unsigned short usage,
+	unsigned short usage_page
+) {
+	static bool has_been_initialized = false;
+	static Ergodox Instance(
+		vendor_id,
+		product_id,
+		usage,
+		usage_page
+	);
+
+	// This isn't strictly necessary, but there is no reason
+	// to call init() twice.
+	if (has_been_initialized) {
+		has_been_initialized = true;
+		throw std::runtime_error("Ergodox has already been initialized!");
+	}
+
+	return Instance;
+}
+
+Ergodox::~Ergodox() {
+	close();
+	hid_exit();
+}
+
+
+/*
+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.
+*/
+void Ergodox::open() {
+	if (handle != NULL) {
+		throw std::runtime_error("Device already open");
+	}
+
+	struct hid_device_info *devs, *cur_dev;
+	const char *path_to_open = NULL;
+
+	devs = hid_enumerate(vendor_id, product_id);
+	cur_dev = devs;
+	while (cur_dev) {
+		if (cur_dev->vendor_id == vendor_id &&
+			cur_dev->product_id == product_id &&
+			cur_dev->usage == usage &&
+			cur_dev->usage_page == usage_page
+		) {
+			path_to_open = cur_dev->path;
+			break;
+		}
+		cur_dev = cur_dev->next;
+	}
+
+	if (path_to_open) {
+		handle = hid_open_path(path_to_open);
+		hid_free_enumeration(devs);
+	} else {
+		hid_free_enumeration(devs);
+		throw std::runtime_error("Could not open hid device");
+	}
+}
+
+
+// Close hid device if it is open.
+void Ergodox::close() {
+	if (handle != NULL) {
+		hid_close(handle);
+	}
+}
+
+
+/*
+Send data to Ergodox.
+
+@param data Data to send
+@param length How many bytes to send
+@returns Actual number of bytes written, or -1 on error.
+*/
+int Ergodox::write(uint8_t* data, size_t length) const {
+	if (handle == NULL) {
+		throw std::runtime_error("Cannot write, device is not open!");
+	}
+
+	return hid_write(handle, data, length);
+}