| // -*- C++ -*- |
| |
| // Copyright (C) 2005, 2006 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 2, 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. |
| |
| // You should have received a copy of the GNU General Public License |
| // along with this library; see the file COPYING. If not, write to |
| // the Free Software Foundation, 59 Temple Place - Suite 330, Boston, |
| // MA 02111-1307, USA. |
| |
| // As a special exception, you may use this file as part of a free |
| // software library without restriction. Specifically, if other files |
| // instantiate templates or use macros or inline functions from this |
| // file, or you compile this file and link it with other files to |
| // produce an executable, this file does not by itself cause the |
| // resulting executable to be covered by the GNU General Public |
| // License. This exception does not however invalidate any other |
| // reasons why the executable file might be covered by the GNU General |
| // Public License. |
| |
| // 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 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 <debug/debug.h> |
| |
| namespace pb_ds |
| { |
| namespace detail |
| { |
| |
| #define PB_DS_CLASS_T_DEC template<typename Size_Type> |
| |
| #define PB_DS_CLASS_C_DEC resize_policy<Size_Type> |
| |
| template<typename Size_Type> |
| class resize_policy |
| { |
| public: |
| typedef Size_Type size_type; |
| |
| enum |
| { |
| min_size = 16 |
| }; |
| |
| public: |
| inline |
| resize_policy(); |
| |
| inline void |
| swap(PB_DS_CLASS_C_DEC& other); |
| |
| inline bool |
| resize_needed_for_grow(size_type size) const; |
| |
| inline bool |
| resize_needed_for_shrink(size_type size) const; |
| |
| inline bool |
| grow_needed(size_type size) const; |
| |
| inline bool |
| shrink_needed(size_type size) const; |
| |
| inline size_type |
| get_new_size_for_grow() const; |
| |
| inline size_type |
| get_new_size_for_shrink() const; |
| |
| size_type |
| get_new_size_for_arbitrary(size_type size) const; |
| |
| inline void |
| notify_grow_resize(); |
| |
| inline void |
| notify_shrink_resize(); |
| |
| void |
| notify_arbitrary(size_type actual_size); |
| |
| #ifdef _GLIBCXX_DEBUG |
| void |
| assert_valid() const; |
| #endif |
| |
| #ifdef PB_DS_BINARY_HEAP_TRACE_ |
| void |
| trace() const; |
| #endif |
| |
| private: |
| enum |
| { |
| ratio = 8, |
| factor = 2 |
| }; |
| |
| private: |
| size_type m_next_shrink_size; |
| size_type m_next_grow_size; |
| }; |
| |
| PB_DS_CLASS_T_DEC |
| inline |
| PB_DS_CLASS_C_DEC:: |
| resize_policy() : |
| m_next_shrink_size(0), |
| m_next_grow_size(min_size) |
| { _GLIBCXX_DEBUG_ONLY(assert_valid();) } |
| |
| PB_DS_CLASS_T_DEC |
| inline void |
| PB_DS_CLASS_C_DEC:: |
| swap(PB_DS_CLASS_C_DEC& other) |
| { |
| std::swap(m_next_shrink_size, other.m_next_shrink_size); |
| std::swap(m_next_grow_size, other.m_next_grow_size); |
| } |
| |
| PB_DS_CLASS_T_DEC |
| inline bool |
| PB_DS_CLASS_C_DEC:: |
| resize_needed_for_grow(size_type size) const |
| { |
| _GLIBCXX_DEBUG_ASSERT(size <= m_next_grow_size); |
| return size == m_next_grow_size; |
| } |
| |
| PB_DS_CLASS_T_DEC |
| inline bool |
| PB_DS_CLASS_C_DEC:: |
| resize_needed_for_shrink(size_type size) const |
| { |
| _GLIBCXX_DEBUG_ASSERT(size <= m_next_grow_size); |
| return size == m_next_shrink_size; |
| } |
| |
| PB_DS_CLASS_T_DEC |
| inline typename PB_DS_CLASS_C_DEC::size_type |
| PB_DS_CLASS_C_DEC:: |
| get_new_size_for_grow() const |
| { return m_next_grow_size* factor; } |
| |
| PB_DS_CLASS_T_DEC |
| inline typename PB_DS_CLASS_C_DEC::size_type |
| PB_DS_CLASS_C_DEC:: |
| get_new_size_for_shrink() const |
| { |
| const size_type half_size = m_next_grow_size / factor; |
| return std::max(static_cast<size_type>(min_size), half_size); |
| } |
| |
| PB_DS_CLASS_T_DEC |
| inline typename PB_DS_CLASS_C_DEC::size_type |
| PB_DS_CLASS_C_DEC:: |
| get_new_size_for_arbitrary(size_type size) const |
| { |
| size_type ret = min_size; |
| while (ret < size) |
| ret *= factor; |
| return ret; |
| } |
| |
| PB_DS_CLASS_T_DEC |
| inline void |
| PB_DS_CLASS_C_DEC:: |
| notify_grow_resize() |
| { |
| _GLIBCXX_DEBUG_ONLY(assert_valid();) |
| _GLIBCXX_DEBUG_ASSERT(m_next_grow_size >= min_size); |
| m_next_grow_size *= factor; |
| m_next_shrink_size = m_next_grow_size / ratio; |
| _GLIBCXX_DEBUG_ONLY(assert_valid();) |
| } |
| |
| PB_DS_CLASS_T_DEC |
| inline void |
| PB_DS_CLASS_C_DEC:: |
| notify_shrink_resize() |
| { |
| _GLIBCXX_DEBUG_ONLY(assert_valid();) |
| m_next_shrink_size /= factor; |
| if (m_next_shrink_size == 1) |
| m_next_shrink_size = 0; |
| |
| m_next_grow_size = |
| std::max(m_next_grow_size / factor, static_cast<size_type>(min_size)); |
| _GLIBCXX_DEBUG_ONLY(assert_valid();) |
| } |
| |
| PB_DS_CLASS_T_DEC |
| inline void |
| PB_DS_CLASS_C_DEC:: |
| notify_arbitrary(size_type actual_size) |
| { |
| m_next_grow_size = actual_size; |
| m_next_shrink_size = m_next_grow_size / ratio; |
| _GLIBCXX_DEBUG_ONLY(assert_valid();) |
| } |
| |
| #ifdef _GLIBCXX_DEBUG |
| PB_DS_CLASS_T_DEC |
| void |
| PB_DS_CLASS_C_DEC:: |
| assert_valid() const |
| { |
| _GLIBCXX_DEBUG_ASSERT(m_next_shrink_size == 0 || |
| m_next_shrink_size* ratio == m_next_grow_size); |
| |
| _GLIBCXX_DEBUG_ASSERT(m_next_grow_size >= min_size); |
| } |
| #endif |
| |
| #ifdef PB_DS_BINARY_HEAP_TRACE_ |
| PB_DS_CLASS_T_DEC |
| void |
| PB_DS_CLASS_C_DEC:: |
| trace() const |
| { |
| std::cerr << "shrink = " << m_next_shrink_size << |
| " grow = " << m_next_grow_size << std::endl; |
| } |
| #endif |
| |
| #undef PB_DS_CLASS_T_DEC |
| #undef PB_DS_CLASS_C_DEC |
| |
| } // namespace detail |
| } // namespace pb_ds |
| |
| #endif |
