/*

 * Copyright (c) 2016-2017 Spotify AB

 *

 * Licensed under the Apache License, Version 2.0 (the "License"); you may not

 * use this file except in compliance with the License. You may obtain a copy of

 * the License at

 *

 * http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT

 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the

 * License for the specific language governing permissions and limitations under

 * the License.

 */

#pragma once

#include <array>

#include <cassert>

#include <cstddef>

#include <memory>

#include <vector>

#include <spotify/json/detail/macros.hpp>

namespace spotify {

namespace json {

namespace detail {

template <typename T, std::size_t inline_capacity>

struct stack {

  void push(T value) {

    if (json_unlikely(_vector)) {

      _vector->push_back(std::move(value));

    } else if (json_likely(_inline_size < inline_capacity)) {

      _array[_inline_size++] = std::move(value);

    } else {

      _vector.reset(new std::vector<T>(_array.begin(), _array.end()));

      _vector->push_back(std::move(value));

    }

  }

  T pop() {

    if (json_unlikely(_vector)) {

      auto top = _vector->back();

      _vector->pop_back();

      return top;

    } else {

      assert(_inline_size);

      return _array[--_inline_size];

    }

  }

 private:

  std::array<T, inline_capacity> _array;

  std::unique_ptr<std::vector<T>> _vector;

  std::size_t _inline_size = 0;

};

}  // namespace detail

}  // namespace json

}  // namespace spotify