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// -*- C++ -*-

// Copyright (C) 2005-2015 Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library 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 3, or (at your option) any later

// version.

// This 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

// General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional

// permissions described in the GCC Runtime Library Exception, version

// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and

// a copy of the GCC Runtime Library Exception along with this program;

// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

// .

// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.

// Permission to use, copy, modify, sell, and distribute this software

// is hereby granted without fee, provided that the above copyright

// notice appears in all copies, and that both that copyright notice

// and this permission notice appear in supporting documentation. None

// of the above authors, nor IBM Haifa Research Laboratories, make any

// representation about the suitability of this software for any

// purpose. It is provided "as is" without express or implied

// warranty.

/**

 * @file binary_heap_/resize_policy.hpp

 * Contains an implementation class for a binary_heap.

 */

#ifndef PB_DS_BINARY_HEAP_RESIZE_POLICY_HPP

#define PB_DS_BINARY_HEAP_RESIZE_POLICY_HPP

#include 

namespace __gnu_pbds

{

  namespace detail

  {

    /// Resize policy for binary heap.

    template

    class resize_policy

    {

    private:

      enum

	{

	  ratio = 8,

	  factor = 2

	};

      /// Next shrink size.

      _Tp 		m_shrink_size;

      /// Next grow size.

      _Tp 		m_grow_size;

    public:

      typedef _Tp	size_type;

      static const _Tp	min_size = 16;

      resize_policy() : m_shrink_size(0), m_grow_size(min_size)

      { PB_DS_ASSERT_VALID((*this)) }

      resize_policy(const resize_policy& other)

      : m_shrink_size(other.m_shrink_size), m_grow_size(other.m_grow_size)

      { PB_DS_ASSERT_VALID((*this)) }

      inline void

      swap(resize_policy<_Tp>&);

      inline bool

      resize_needed_for_grow(size_type) const;

      inline bool

      resize_needed_for_shrink(size_type) const;

      inline bool

      grow_needed(size_type) const;

      inline bool

      shrink_needed(size_type) const;

      inline size_type

      get_new_size_for_grow() const;

      inline size_type

      get_new_size_for_shrink() const;

      inline size_type

      get_new_size_for_arbitrary(size_type) const;

      inline void

      notify_grow_resize();

      inline void

      notify_shrink_resize();

      void

      notify_arbitrary(size_type);

#ifdef _GLIBCXX_DEBUG

      void

      assert_valid(const char*, int) const;

#endif

#ifdef PB_DS_BINARY_HEAP_TRACE_

      void

      trace() const;

#endif

    };

    template

      const _Tp resize_policy<_Tp>::min_size;

    template

    inline void

    resize_policy<_Tp>::

    swap(resize_policy<_Tp>& other)

    {

      std::swap(m_shrink_size, other.m_shrink_size);

      std::swap(m_grow_size, other.m_grow_size);

    }

    template

    inline bool

    resize_policy<_Tp>::

    resize_needed_for_grow(size_type size) const

    {

      _GLIBCXX_DEBUG_ASSERT(size <= m_grow_size);

      return size == m_grow_size;

    }

    template

    inline bool

    resize_policy<_Tp>::

    resize_needed_for_shrink(size_type size) const

    {

      _GLIBCXX_DEBUG_ASSERT(size <= m_grow_size);

      return size == m_shrink_size;

    }

    template

    inline typename resize_policy<_Tp>::size_type

    resize_policy<_Tp>::

    get_new_size_for_grow() const

    { return m_grow_size * factor; }

    template

    inline typename resize_policy<_Tp>::size_type

    resize_policy<_Tp>::

    get_new_size_for_shrink() const

    {

      const size_type half_size = m_grow_size / factor;

      return std::max(min_size, half_size);

    }

    template

    inline typename resize_policy<_Tp>::size_type

    resize_policy<_Tp>::

    get_new_size_for_arbitrary(size_type size) const

    {

      size_type ret = min_size;

      while (ret < size)

	ret *= factor;

      return ret;

    }

    template

    inline void

    resize_policy<_Tp>::

    notify_grow_resize()

    {

      PB_DS_ASSERT_VALID((*this))

      _GLIBCXX_DEBUG_ASSERT(m_grow_size >= min_size);

      m_grow_size *= factor;

      m_shrink_size = m_grow_size / ratio;

      PB_DS_ASSERT_VALID((*this))

    }

    template

    inline void

    resize_policy<_Tp>::

    notify_shrink_resize()

    {

      PB_DS_ASSERT_VALID((*this))

      m_shrink_size /= factor;

      if (m_shrink_size == 1)

	m_shrink_size = 0;

      m_grow_size = std::max(m_grow_size / factor, min_size);

      PB_DS_ASSERT_VALID((*this))

    }

    template

    inline void

    resize_policy<_Tp>::

    notify_arbitrary(size_type actual_size)

    {

      m_grow_size = actual_size;

      m_shrink_size = m_grow_size / ratio;

      PB_DS_ASSERT_VALID((*this))

    }

#ifdef _GLIBCXX_DEBUG

    template

    void

    resize_policy<_Tp>::

    assert_valid(const char* __file, int __line) const

    {

      PB_DS_DEBUG_VERIFY(m_shrink_size == 0

			 || m_shrink_size * ratio == m_grow_size);

      PB_DS_DEBUG_VERIFY(m_grow_size >= min_size);

    }

#endif

#ifdef PB_DS_BINARY_HEAP_TRACE_

    template

    void

    resize_policy<_Tp>::

    trace() const

    {

      std::cerr << "shrink = " << m_shrink_size

		<< " grow = " << m_grow_size << std::endl;

    }

#endif

} // namespace detail

} // namespace __gnu_pbds

#endif