libstdc++-v3/include/ext/pb_ds/detail/resize_policy/cc_hash_max_collision_check_resize_trigger_imp.hpp

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005-2023 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the terms
   7 // of the GNU General Public License as published by the Free Software
   8 // Foundation; either version 3, or (at your option) any later
   9 // version.
  10
  11 // This library is distributed in the hope that it will be useful, but
  12 // WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 // General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  26
  27 // Permission to use, copy, modify, sell, and distribute this software
  28 // is hereby granted without fee, provided that the above copyright
  29 // notice appears in all copies, and that both that copyright notice
  30 // and this permission notice appear in supporting documentation. None
  31 // of the above authors, nor IBM Haifa Research Laboratories, make any
  32 // representation about the suitability of this software for any
  33 // purpose. It is provided "as is" without express or implied
  34 // warranty.
  35
  36 /**
  37  * @file cc_hash_max_collision_check_resize_trigger_imp.hpp
  38  * Contains a resize trigger implementation.
  39  */
  40
  41 #ifdef PB_DS_CLASS_C_DEC
  42
  43 PB_DS_CLASS_T_DEC
  44 PB_DS_CLASS_C_DEC::
  45 cc_hash_max_collision_check_resize_trigger(float load) :
  46   m_load(load),
  47   m_size(0),
  48   m_num_col(0),
  49   m_max_col(0),
  50   m_resize_needed(false)
  51 { }
  52
  53 PB_DS_CLASS_T_DEC
  54 inline void
  55 PB_DS_CLASS_C_DEC::
  56 notify_find_search_start()
  57 { }
  58
  59 PB_DS_CLASS_T_DEC
  60 inline void
  61 PB_DS_CLASS_C_DEC::
  62 notify_find_search_collision()
  63 { }
  64
  65 PB_DS_CLASS_T_DEC
  66 inline void
  67 PB_DS_CLASS_C_DEC::
  68 notify_find_search_end()
  69 { }
  70
  71 PB_DS_CLASS_T_DEC
  72 inline void
  73 PB_DS_CLASS_C_DEC::
  74 notify_insert_search_start()
  75 { m_num_col = 0; }
  76
  77 PB_DS_CLASS_T_DEC
  78 inline void
  79 PB_DS_CLASS_C_DEC::
  80 notify_insert_search_collision()
  81 { ++m_num_col; }
  82
  83 PB_DS_CLASS_T_DEC
  84 inline void
  85 PB_DS_CLASS_C_DEC::
  86 notify_insert_search_end()
  87 { calc_resize_needed(); }
  88
  89 PB_DS_CLASS_T_DEC
  90 inline void
  91 PB_DS_CLASS_C_DEC::
  92 notify_erase_search_start()
  93 { }
  94
  95 PB_DS_CLASS_T_DEC
  96 inline void
  97 PB_DS_CLASS_C_DEC::
  98 notify_erase_search_collision()
  99 { }
 100
 101 PB_DS_CLASS_T_DEC
 102 inline void
 103 PB_DS_CLASS_C_DEC::
 104 notify_erase_search_end()
 105 { }
 106
 107 PB_DS_CLASS_T_DEC
 108 inline void
 109 PB_DS_CLASS_C_DEC::
 110 notify_inserted(size_type)
 111 { }
 112
 113 PB_DS_CLASS_T_DEC
 114 inline void
 115 PB_DS_CLASS_C_DEC::
 116 notify_erased(size_type)
 117 { m_resize_needed = true; }
 118
 119 PB_DS_CLASS_T_DEC
 120 void
 121 PB_DS_CLASS_C_DEC::
 122 notify_cleared()
 123 { m_resize_needed = false; }
 124
 125 PB_DS_CLASS_T_DEC
 126 inline bool
 127 PB_DS_CLASS_C_DEC::
 128 is_resize_needed() const
 129 { return m_resize_needed; }
 130
 131 PB_DS_CLASS_T_DEC
 132 inline bool
 133 PB_DS_CLASS_C_DEC::
 134 is_grow_needed(size_type /*size*/, size_type /*num_used_e*/) const
 135 { return m_num_col >= m_max_col; }
 136
 137 PB_DS_CLASS_T_DEC
 138 void
 139 PB_DS_CLASS_C_DEC::
 140 notify_resized(size_type new_size)
 141 {
 142   m_size = new_size;
 143
 144 #ifdef PB_DS_HT_MAP_RESIZE_TRACE_
 145   std::cerr << "chmccrt::notify_resized "
 146             << static_cast<unsigned long>(new_size) << std::endl;
 147 #endif
 148
 149   calc_max_num_coll();
 150   calc_resize_needed();
 151   m_num_col = 0;
 152 }
 153
 154 PB_DS_CLASS_T_DEC
 155 void
 156 PB_DS_CLASS_C_DEC::
 157 calc_max_num_coll()
 158 {
 159   // max_col <-- \sqrt{2 load \ln( 2 m \ln( m ) ) }
 160   const double ln_arg = 2 * m_size * std::log(double(m_size));
 161   m_max_col = size_type(std::ceil(std::sqrt(2 * m_load * std::log(ln_arg))));
 162
 163 #ifdef PB_DS_HT_MAP_RESIZE_TRACE_
 164   std::cerr << "chmccrt::calc_max_num_coll "
 165             << static_cast<unsigned long>(m_size) <<    "    "
 166             << static_cast<unsigned long>(m_max_col) << std::endl;
 167 #endif
 168 }
 169
 170 PB_DS_CLASS_T_DEC
 171 void
 172 PB_DS_CLASS_C_DEC::
 173 notify_externally_resized(size_type new_size)
 174 { notify_resized(new_size); }
 175
 176 PB_DS_CLASS_T_DEC
 177 void
 178 PB_DS_CLASS_C_DEC::
 179 swap(PB_DS_CLASS_C_DEC& other)
 180 {
 181   std::swap(m_load, other.m_load);
 182   std::swap(m_size, other.m_size);
 183   std::swap(m_num_col, other.m_num_col);
 184   std::swap(m_max_col, other.m_max_col);
 185   std::swap(m_resize_needed, other.m_resize_needed);
 186 }
 187
 188 PB_DS_CLASS_T_DEC
 189 inline float
 190 PB_DS_CLASS_C_DEC::
 191 get_load() const
 192 {
 193   PB_DS_STATIC_ASSERT(access, external_load_access);
 194   return m_load;
 195 }
 196
 197 PB_DS_CLASS_T_DEC
 198 inline void
 199 PB_DS_CLASS_C_DEC::
 200 calc_resize_needed()
 201 { m_resize_needed = m_resize_needed || m_num_col >= m_max_col; }
 202
 203 PB_DS_CLASS_T_DEC
 204 void
 205 PB_DS_CLASS_C_DEC::
 206 set_load(float load)
 207 {
 208   PB_DS_STATIC_ASSERT(access, external_load_access);
 209   m_load = load;
 210   calc_max_num_coll();
 211   calc_resize_needed();
 212 }
 213
 214 #endif