1 files changed, 111 insertions, 0 deletions

diff --git a/src/hid_core/frontend/input_interpreter.h b/src/hid_core/frontend/input_interpreter.h
new file mode 100644
index 000000000..3569aac93
--- /dev/null
+++ b/src/hid_core/frontend/input_interpreter.h
@@ -0,0 +1,111 @@
+// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <array>
+
+#include "common/common_types.h"
+
+namespace Core {
+class System;
+}
+
+namespace Core::HID {
+enum class NpadButton : u64;
+}
+
+namespace Service::HID {
+class NPad;
+}
+
+/**
+ * The InputInterpreter class interfaces with HID to retrieve button press states.
+ * Input is intended to be polled every 50ms so that a button is considered to be
+ * held down after 400ms has elapsed since the initial button press and subsequent
+ * repeated presses occur every 50ms.
+ */
+class InputInterpreter {
+public:
+    explicit InputInterpreter(Core::System& system);
+    virtual ~InputInterpreter();
+
+    /// Gets a button state from HID and inserts it into the array of button states.
+    void PollInput();
+
+    /// Resets all the button states to their defaults.
+    void ResetButtonStates();
+
+    /**
+     * Checks whether the button is pressed.
+     *
+     * @param button The button to check.
+     *
+     * @returns True when the button is pressed.
+     */
+    [[nodiscard]] bool IsButtonPressed(Core::HID::NpadButton button) const;
+
+    /**
+     * Checks whether any of the buttons in the parameter list is pressed.
+     *
+     * @tparam HIDButton The buttons to check.
+     *
+     * @returns True when at least one of the buttons is pressed.
+     */
+    template <Core::HID::NpadButton... T>
+    [[nodiscard]] bool IsAnyButtonPressed() {
+        return (IsButtonPressed(T) || ...);
+    }
+
+    /**
+     * The specified button is considered to be pressed once
+     * if it is currently pressed and not pressed previously.
+     *
+     * @param button The button to check.
+     *
+     * @returns True when the button is pressed once.
+     */
+    [[nodiscard]] bool IsButtonPressedOnce(Core::HID::NpadButton button) const;
+
+    /**
+     * Checks whether any of the buttons in the parameter list is pressed once.
+     *
+     * @tparam T The buttons to check.
+     *
+     * @returns True when at least one of the buttons is pressed once.
+     */
+    template <Core::HID::NpadButton... T>
+    [[nodiscard]] bool IsAnyButtonPressedOnce() const {
+        return (IsButtonPressedOnce(T) || ...);
+    }
+
+    /**
+     * The specified button is considered to be held down if it is pressed in all 9 button states.
+     *
+     * @param button The button to check.
+     *
+     * @returns True when the button is held down.
+     */
+    [[nodiscard]] bool IsButtonHeld(Core::HID::NpadButton button) const;
+
+    /**
+     * Checks whether any of the buttons in the parameter list is held down.
+     *
+     * @tparam T The buttons to check.
+     *
+     * @returns True when at least one of the buttons is held down.
+     */
+    template <Core::HID::NpadButton... T>
+    [[nodiscard]] bool IsAnyButtonHeld() const {
+        return (IsButtonHeld(T) || ...);
+    }
+
+private:
+    std::shared_ptr<Service::HID::NPad> npad;
+
+    /// Stores 9 consecutive button states polled from HID.
+    std::array<Core::HID::NpadButton, 9> button_states{};
+
+    std::size_t previous_index{};
+    std::size_t current_index{};
+};