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 along 17// with this library; see the file COPYING. If not, write to the Free 18// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 19// 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 39// purpose. It is provided "as is" without express or implied 40// warranty. 41 42/** 43 * @file hash_prime_size_policy_imp.hpp 44 * Contains a resize size policy implementation. 45 */ 46 47namespace detail 48{ 49 enum 50 { 51 num_distinct_sizes_32_bit = 30, 52 num_distinct_sizes_64_bit = 62, 53 num_distinct_sizes = sizeof(std::size_t) != 8 ? 54 num_distinct_sizes_32_bit : num_distinct_sizes_64_bit, 55 }; 56 57 // Originally taken from the SGI implementation; acknowledged in the docs. 58 // Further modified (for 64 bits) from tr1's hashtable. 59 static const std::size_t g_a_sizes[num_distinct_sizes_64_bit] = 60 { 61 /* 0 */ 5ul, 62 /* 1 */ 11ul, 63 /* 2 */ 23ul, 64 /* 3 */ 47ul, 65 /* 4 */ 97ul, 66 /* 5 */ 199ul, 67 /* 6 */ 409ul, 68 /* 7 */ 823ul, 69 /* 8 */ 1741ul, 70 /* 9 */ 3469ul, 71 /* 10 */ 6949ul, 72 /* 11 */ 14033ul, 73 /* 12 */ 28411ul, 74 /* 13 */ 57557ul, 75 /* 14 */ 116731ul, 76 /* 15 */ 236897ul, 77 /* 16 */ 480881ul, 78 /* 17 */ 976369ul, 79 /* 18 */ 1982627ul, 80 /* 19 */ 4026031ul, 81 /* 20 */ 8175383ul, 82 /* 21 */ 16601593ul, 83 /* 22 */ 33712729ul, 84 /* 23 */ 68460391ul, 85 /* 24 */ 139022417ul, 86 /* 25 */ 282312799ul, 87 /* 26 */ 573292817ul, 88 /* 27 */ 1164186217ul, 89 /* 28 */ 2364114217ul, 90 /* 29 */ 4294967291ul, 91 /* 30 */ (std::size_t)8589934583ull, 92 /* 31 */ (std::size_t)17179869143ull, 93 /* 32 */ (std::size_t)34359738337ull, 94 /* 33 */ (std::size_t)68719476731ull, 95 /* 34 */ (std::size_t)137438953447ull, 96 /* 35 */ (std::size_t)274877906899ull, 97 /* 36 */ (std::size_t)549755813881ull, 98 /* 37 */ (std::size_t)1099511627689ull, 99 /* 38 */ (std::size_t)2199023255531ull, 100 /* 39 */ (std::size_t)4398046511093ull, 101 /* 40 */ (std::size_t)8796093022151ull, 102 /* 41 */ (std::size_t)17592186044399ull, 103 /* 42 */ (std::size_t)35184372088777ull, 104 /* 43 */ (std::size_t)70368744177643ull, 105 /* 44 */ (std::size_t)140737488355213ull, 106 /* 45 */ (std::size_t)281474976710597ull, 107 /* 46 */ (std::size_t)562949953421231ull, 108 /* 47 */ (std::size_t)1125899906842597ull, 109 /* 48 */ (std::size_t)2251799813685119ull, 110 /* 49 */ (std::size_t)4503599627370449ull, 111 /* 50 */ (std::size_t)9007199254740881ull, 112 /* 51 */ (std::size_t)18014398509481951ull, 113 /* 52 */ (std::size_t)36028797018963913ull, 114 /* 53 */ (std::size_t)72057594037927931ull, 115 /* 54 */ (std::size_t)144115188075855859ull, 116 /* 55 */ (std::size_t)288230376151711717ull, 117 /* 56 */ (std::size_t)576460752303423433ull, 118 /* 57 */ (std::size_t)1152921504606846883ull, 119 /* 58 */ (std::size_t)2305843009213693951ull, 120 /* 59 */ (std::size_t)4611686018427387847ull, 121 /* 60 */ (std::size_t)9223372036854775783ull, 122 /* 61 */ (std::size_t)18446744073709551557ull, 123 }; 124 125} // namespace detail 126 127PB_DS_CLASS_T_DEC 128inline 129PB_DS_CLASS_C_DEC:: 130hash_prime_size_policy(size_type n) : m_start_size(n) 131{ m_start_size = get_nearest_larger_size(n); } 132 133PB_DS_CLASS_T_DEC 134inline void 135PB_DS_CLASS_C_DEC:: 136swap(PB_DS_CLASS_C_DEC& other) 137{ std::swap(m_start_size, other.m_start_size); } 138 139PB_DS_CLASS_T_DEC 140inline PB_DS_CLASS_C_DEC::size_type 141PB_DS_CLASS_C_DEC:: 142get_nearest_larger_size(size_type n) const 143{ 144 const std::size_t* const p_upper = std::upper_bound(detail::g_a_sizes, 145 detail::g_a_sizes + detail::num_distinct_sizes, n); 146 147 if (p_upper == detail::g_a_sizes + detail::num_distinct_sizes) 148 __throw_resize_error(); 149 return *p_upper; 150} 151 152PB_DS_CLASS_T_DEC 153inline PB_DS_CLASS_C_DEC::size_type 154PB_DS_CLASS_C_DEC:: 155get_nearest_smaller_size(size_type n) const 156{ 157 const size_t* p_lower = std::lower_bound(detail::g_a_sizes, 158 detail::g_a_sizes + detail::num_distinct_sizes, n); 159 160 if (*p_lower >= n && p_lower != detail::g_a_sizes) 161 --p_lower; 162 if (*p_lower < m_start_size) 163 return m_start_size; 164 return *p_lower; 165} 166