#ifndef PTR_STACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66
#define PTR_STACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66

#if defined(_MSC_VER) ||                                            \
    (defined(__GNUC__) && (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) || \
     (__GNUC__ >= 4))  // GCC supports "pragma once" correctly since 3.4
#pragma once
#endif

#include <cstddef>
#include <cstdlib>
#include <memory>
#include <vector>

#include "yaml-cpp/noncopyable.h"

template <typename T>
class ptr_stack : private YAML::noncopyable {
 public:
  ptr_stack() {}
  ~ptr_stack() { clear(); }

  void clear() {
    for (std::size_t i = 0; i < m_data.size(); i++)
      delete m_data[i];
    m_data.clear();
  }

  std::size_t size() const { return m_data.size(); }
  bool empty() const { return m_data.empty(); }

  void push(std::auto_ptr<T> t) {
    m_data.push_back(NULL);
    m_data.back() = t.release();
  }
  std::auto_ptr<T> pop() {
    std::auto_ptr<T> t(m_data.back());
    m_data.pop_back();
    return t;
  }
  T& top() { return *m_data.back(); }
  const T& top() const { return *m_data.back(); }

  T& top(std::ptrdiff_t diff) { return **(m_data.end() - 1 + diff); }
  const T& top(std::ptrdiff_t diff) const {
    return **(m_data.end() - 1 + diff);
  }

 private:
  std::vector<T*> m_data;
};

#endif  // PTR_STACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66
