Input: UDP Client to provide motion and touch controls

An implementation of the cemuhook motion/touch protocol, this adds the
ability for users to connect several different devices to citra to send
direct motion and touch data to citra.

src/input_common/udp/client.h

@@ -0,0 +1,61 @@
+// Copyright 2018 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <mutex>
+#include <string>
+#include <thread>
+#include <tuple>
+#include <vector>
+#include <boost/optional.hpp>
+#include "common/common_types.h"
+#include "common/vector_math.h"
+
+namespace InputCommon::CemuhookUDP {
+
+static constexpr u16 DEFAULT_PORT = 26760;
+static constexpr const char* DEFAULT_ADDR = "127.0.0.1";
+
+class Socket;
+
+namespace Response {
+struct PadData;
+struct PortInfo;
+struct Version;
+} // namespace Response
+
+struct DeviceStatus {
+    std::mutex update_mutex;
+    std::tuple<Math::Vec3<float>, Math::Vec3<float>> motion_status;
+    std::tuple<float, float, bool> touch_status;
+
+    // calibration data for scaling the device's touch area to 3ds
+    struct CalibrationData {
+        u16 min_x;
+        u16 min_y;
+        u16 max_x;
+        u16 max_y;
+    };
+    boost::optional<CalibrationData> touch_calibration;
+};
+
+class Client {
+public:
+    explicit Client(std::shared_ptr<DeviceStatus> status, const std::string& host = DEFAULT_ADDR,
+                    u16 port = DEFAULT_PORT, u32 client_id = 24872);
+    ~Client();
+
+private:
+    void OnVersion(Response::Version);
+    void OnPortInfo(Response::PortInfo);
+    void OnPadData(Response::PadData);
+
+    std::unique_ptr<Socket> socket;
+    std::shared_ptr<DeviceStatus> status;
+    std::thread thread;
+    u64 packet_sequence = 0;
+};
+} // namespace InputCommon::CemuhookUDP