cc_hash_max_collision_check_resize_trigger_imp.hpp
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// -*- C++ -*-
// Copyright (C) 2005-2013 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
// <http://www.gnu.org/licenses/>.
// 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 cc_hash_max_collision_check_resize_trigger_imp.hpp
* Contains a resize trigger implementation.
*/
PB_DS_CLASS_T_DEC
PB_DS_CLASS_C_DEC::
cc_hash_max_collision_check_resize_trigger(float load) :
m_load(load),
m_size(0),
m_num_col(0),
m_max_col(0),
m_resize_needed(false)
{ }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_find_search_start()
{ }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_find_search_collision()
{ }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_find_search_end()
{ }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_insert_search_start()
{ m_num_col = 0; }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_insert_search_collision()
{ ++m_num_col; }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_insert_search_end()
{ calc_resize_needed(); }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_erase_search_start()
{ }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_erase_search_collision()
{ }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_erase_search_end()
{ }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_inserted(size_type)
{ }
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
notify_erased(size_type)
{ m_resize_needed = true; }
PB_DS_CLASS_T_DEC
void
PB_DS_CLASS_C_DEC::
notify_cleared()
{ m_resize_needed = false; }
PB_DS_CLASS_T_DEC
inline bool
PB_DS_CLASS_C_DEC::
is_resize_needed() const
{ return m_resize_needed; }
PB_DS_CLASS_T_DEC
inline bool
PB_DS_CLASS_C_DEC::
is_grow_needed(size_type /*size*/, size_type /*num_used_e*/) const
{ return m_num_col >= m_max_col; }
PB_DS_CLASS_T_DEC
void
PB_DS_CLASS_C_DEC::
notify_resized(size_type new_size)
{
m_size = new_size;
#ifdef PB_DS_HT_MAP_RESIZE_TRACE_
std::cerr << "chmccrt::notify_resized "
<< static_cast<unsigned long>(new_size) << std::endl;
#endif
calc_max_num_coll();
calc_resize_needed();
m_num_col = 0;
}
PB_DS_CLASS_T_DEC
void
PB_DS_CLASS_C_DEC::
calc_max_num_coll()
{
// max_col <-- \sqrt{2 load \ln( 2 m \ln( m ) ) }
const double ln_arg = 2 * m_size * std::log(double(m_size));
m_max_col = size_type(std::ceil(std::sqrt(2 * m_load * std::log(ln_arg))));
#ifdef PB_DS_HT_MAP_RESIZE_TRACE_
std::cerr << "chmccrt::calc_max_num_coll "
<< static_cast<unsigned long>(m_size) << " "
<< static_cast<unsigned long>(m_max_col) << std::endl;
#endif
}
PB_DS_CLASS_T_DEC
void
PB_DS_CLASS_C_DEC::
notify_externally_resized(size_type new_size)
{ notify_resized(new_size); }
PB_DS_CLASS_T_DEC
void
PB_DS_CLASS_C_DEC::
swap(PB_DS_CLASS_C_DEC& other)
{
std::swap(m_load, other.m_load);
std::swap(m_size, other.m_size);
std::swap(m_num_col, other.m_num_col);
std::swap(m_max_col, other.m_max_col);
std::swap(m_resize_needed, other.m_resize_needed);
}
PB_DS_CLASS_T_DEC
inline float
PB_DS_CLASS_C_DEC::
get_load() const
{
PB_DS_STATIC_ASSERT(access, external_load_access);
return m_load;
}
PB_DS_CLASS_T_DEC
inline void
PB_DS_CLASS_C_DEC::
calc_resize_needed()
{ m_resize_needed = m_resize_needed || m_num_col >= m_max_col; }
PB_DS_CLASS_T_DEC
void
PB_DS_CLASS_C_DEC::
set_load(float load)
{
PB_DS_STATIC_ASSERT(access, external_load_access);
m_load = load;
calc_max_num_coll();
calc_resize_needed();
}