libstdc++
hash_exponential_size_policy_imp.hpp
Go to the documentation of this file.
1 // -*- C++ -*-
2 
3 // Copyright (C) 2005, 2006, 2009 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 hash_exponential_size_policy_imp.hpp
38  * Contains a resize size policy implementation.
39  */
40 
41 PB_DS_CLASS_T_DEC
42 PB_DS_CLASS_C_DEC::
43 hash_exponential_size_policy(size_type start_size, size_type grow_factor) :
44  m_start_size(start_size),
45  m_grow_factor(grow_factor)
46 { }
47 
48 PB_DS_CLASS_T_DEC
49 void
50 PB_DS_CLASS_C_DEC::
51 swap(PB_DS_CLASS_C_DEC& other)
52 {
53  std::swap(m_start_size, other.m_start_size);
54  std::swap(m_grow_factor, other.m_grow_factor);
55 }
56 
57 PB_DS_CLASS_T_DEC
58 typename PB_DS_CLASS_C_DEC::size_type
59 PB_DS_CLASS_C_DEC::
60 get_nearest_larger_size(size_type size) const
61 {
62  size_type ret = m_start_size;
63  while (ret <= size)
64  {
65  const size_type next_ret = ret* m_grow_factor;
66  if (next_ret < ret)
67  __throw_insert_error();
68  ret = next_ret;
69  }
70  return ret;
71 }
72 
73 PB_DS_CLASS_T_DEC
74 typename PB_DS_CLASS_C_DEC::size_type
75 PB_DS_CLASS_C_DEC::
76 get_nearest_smaller_size(size_type size) const
77 {
78  size_type ret = m_start_size;
79  while (true)
80  {
81  const size_type next_ret = ret* m_grow_factor;
82  if (next_ret < ret)
83  __throw_resize_error();
84  if (next_ret >= size)
85  return (ret);
86  ret = next_ret;
87  }
88  return ret;
89 }
90