Standalone imp (#2791)

* Moved ui elements to common folder in standalone, and add screen parameters to the api v4

* pass it as a pointer, so if standalone app supports it can change

firmware/standalone/common/ui/optional.hpp

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2016 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of PortaPack.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __OPTIONAL_H__
+#define __OPTIONAL_H__
+
+#include <utility>
+
+template <typename T>
+class Optional {
+   public:
+    constexpr Optional()
+        : value_{}, valid_{false} {}
+    constexpr Optional(const T& value)
+        : value_{value}, valid_{true} {}
+    constexpr Optional(T&& value)
+        : value_{std::move(value)}, valid_{true} {}
+
+    constexpr Optional& operator=(const T& value) {
+        value_ = value;
+        valid_ = true;
+        return *this;
+    }
+    constexpr Optional& operator=(T&& value) {
+        value_ = std::move(value);
+        valid_ = true;
+        return *this;
+    }
+
+    bool is_valid() const { return valid_; }
+    operator bool() const { return valid_; }
+
+    // TODO: Throw if not valid?
+    T& value() & { return value_; }
+    T& operator*() & { return value_; }
+    const T& value() const& { return value_; }
+    const T& operator*() const& { return value_; }
+
+    T&& value() && { return std::move(value_); }
+    T&& operator*() && { return std::move(value_); }
+
+    T* operator->() { return &value_; }
+    const T* operator->() const { return &value_; }
+
+   private:
+    T value_;
+    bool valid_;
+};
+
+#endif /*__OPTIONAL_H__*/