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tdutils/td/utils/MovableValue.h

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+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library 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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#pragma once
+
+namespace td {
+
+template <class T, T empty_val = T()>
+class MovableValue {
+ public:
+  MovableValue() = default;
+  MovableValue(T val) : val_(val) {
+  }
+  MovableValue(MovableValue &&other) : val_(other.val_) {
+    other.clear();
+  }
+  MovableValue &operator=(MovableValue &&other) {
+    val_ = other.val_;
+    other.clear();
+    return *this;
+  }
+  MovableValue(const MovableValue &) = delete;
+  MovableValue &operator=(const MovableValue &) = delete;
+  ~MovableValue() = default;
+
+  void clear() {
+    val_ = empty_val;
+  }
+  const T &get() const {
+    return val_;
+  }
+
+ private:
+  T val_ = empty_val;
+};
+
+}  // namespace td