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

   1 // -*- C++ -*-
   2
   3 // Copyright (C) 2005, 2006 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 2, 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 // You should have received a copy of the GNU General Public License
  17 // along with this library; see the file COPYING.  If not, write to
  18 // the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
  19 // MA 02111-1307, USA.
  20
  21 // As a special exception, you may use this file as part of a free
  22 // software library without restriction.  Specifically, if other files
  23 // instantiate templates or use macros or inline functions from this
  24 // file, or you compile this file and link it with other files to
  25 // produce an executable, this file does not by itself cause the
  26 // resulting executable to be covered by the GNU General Public
  27 // License.  This exception does not however invalidate any other
  28 // reasons why the executable file might be covered by the GNU General
  29 // Public License.
  30
  31 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
  32
  33 // Permission to use, copy, modify, sell, and distribute this software
  34 // is hereby granted without fee, provided that the above copyright
  35 // notice appears in all copies, and that both that copyright notice
  36 // and this permission notice appear in supporting documentation. None
  37 // of the above authors, nor IBM Haifa Research Laboratories, make any
  38 // representation about the suitability of this software for any
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  40 // warranty.
  41
  42 /**
  43  * @file hash_exponential_size_policy_imp.hpp
  44  * Contains a resize size policy implementation.
  45  */
  46
  47 PB_DS_CLASS_T_DEC
  48 PB_DS_CLASS_C_DEC::
  49 hash_exponential_size_policy(size_type start_size, size_type grow_factor) :
  50   m_start_size(start_size),
  51   m_grow_factor(grow_factor)
  52 { }
  53
  54 PB_DS_CLASS_T_DEC
  55 void
  56 PB_DS_CLASS_C_DEC::
  57 swap(PB_DS_CLASS_C_DEC& other)
  58 {
  59   std::swap(m_start_size, other.m_start_size);
  60   std::swap(m_grow_factor, other.m_grow_factor);
  61 }
  62
  63 PB_DS_CLASS_T_DEC
  64 typename PB_DS_CLASS_C_DEC::size_type
  65 PB_DS_CLASS_C_DEC::
  66 get_nearest_larger_size(size_type size) const
  67 {
  68   size_type ret = m_start_size;
  69   while (ret <= size)
  70     {
  71       const size_type next_ret = ret*  m_grow_factor;
  72       if (next_ret < ret)
  73         throw insert_error();
  74       ret = next_ret;
  75     }
  76   return ret;
  77 }
  78
  79 PB_DS_CLASS_T_DEC
  80 typename PB_DS_CLASS_C_DEC::size_type
  81 PB_DS_CLASS_C_DEC::
  82 get_nearest_smaller_size(size_type size) const
  83 {
  84   size_type ret = m_start_size;
  85   while (true)
  86     {
  87       const size_type next_ret = ret*  m_grow_factor;
  88       if (next_ret < ret)
  89         throw resize_error();
  90       if (next_ret >= size)
  91         return (ret);
  92       ret = next_ret;
  93     }
  94   return ret;
  95 }
  96