reserveddeque.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
 
// SPDX-FileCopyrightText: Copyright © DUNE Project contributors, see file AUTHORS.md
// SPDX-License-Identifier: LicenseRef-GPL-2.0-only-with-DUNE-exception OR LGPL-3.0-or-later
 
#ifndef DUNE_FUNCTIONS_COMMON_RESERVEDDEQUE_HH
#define DUNE_FUNCTIONS_COMMON_RESERVEDDEQUE_HH
 
#include <algorithm>
#include <iostream>
#include <cstddef>
#include <initializer_list>
 
#include <dune/common/genericiterator.hh>
 
#ifdef CHECK_RESERVEDDEQUE
#define CHECKSIZE(X) assert(X)
#else
#define CHECKSIZE(X) {}
#endif
 
namespace Dune {
namespace Functions {
 
  template<class T, int n>
  class ReservedDeque
  {
  public:
 
    typedef T value_type;
    typedef T* pointer;
    typedef T& reference;
    typedef const T& const_reference;
    typedef size_t size_type;
    typedef std::ptrdiff_t difference_type;
    typedef Dune::GenericIterator<ReservedDeque, value_type> iterator;
    typedef Dune::GenericIterator<const ReservedDeque, const value_type> const_iterator;
 
    ReservedDeque() :
      size_(0),
      first_(0)
    {}
 
    ReservedDeque(std::initializer_list<T> const &l)
    {
      assert(l.size() <= n);// Actually, this is not needed any more!
      size_ = l.size();
      std::copy_n(l.begin(), size_, data_);
    }
 
    void clear()
    {
      first_ = 0;
      size_ = 0;
    }
 
    void resize(size_t s)
    {
      CHECKSIZE(s<=n);
      size_ = s;
    }
 
    void push_back(const T& t)
    {
      CHECKSIZE(size_<n);
      data_[size_++ % n] = t;
    }
 
    void push_front(const T& t)
    {
      CHECKSIZE(size_<n);
      ++size_;
      first_ = (first_+(n-1)) % n;
      data_[first_] = t;
    }
 
    void pop_back()
    {
      if (! empty())
        size_--;
    }
 
    void pop_front()
    {
      if (! empty())
      {
        size_--;
        first_ = (++first_) % n;
      }
    }
 
    iterator begin(){
      return iterator(*this, 0);
    }
 
    const_iterator begin() const {
      return const_iterator(*this, 0);
    }
 
    iterator end(){
      return iterator(*this, size_);
    }
 
    const_iterator end() const {
      return const_iterator(*this, size_);
    }
 
    reference operator[] (size_type i)
    {
      CHECKSIZE(size_>i);
      return data_[(first_ + i) % n];
    }
 
    const_reference operator[] (size_type i) const
    {
      CHECKSIZE(size_>i);
      return data_[(first_ + i) % n];
    }
 
    reference front()
    {
      CHECKSIZE(size_>0);
      return data_[first_];
    }
 
    const_reference front() const
    {
      CHECKSIZE(size_>0);
      return data_[first_];
    }
 
    reference back()
    {
      CHECKSIZE(size_>0);
      return data_[(first_ + size_-1) % n];
    }
 
    const_reference back() const
    {
      CHECKSIZE(size_>0);
      return data_[(first_ + size_-1) % n];
    }
 
    size_type size () const
    {
      return size_;
    }
 
    bool empty() const
    {
      return size_==0;
    }
 
    static constexpr size_type capacity()
    {
      return n;
    }
 
    static constexpr size_type max_size()
    {
      return n;
    }
 
    friend std::ostream& operator<< (std::ostream& s, const ReservedDeque& v)
    {
      for (size_t i=0; i<v.size(); i++)
        s << v[i] << "  ";
      return s;
    }
 
  private:
    T data_[n];
    size_type first_;
    size_type size_;
  };
 
} // end namespace Functions
} // end namespace Dune
 
#undef CHECKSIZE
 
#endif // DUNE_FUNCTIONS_COMMON_RESERVEDDEQUE_HH