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36fed23c | 1 | // -*- C++ -*- |
2 | ||
fbd26352 | 3 | // Copyright (C) 2005-2019 Free Software Foundation, Inc. |
36fed23c | 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 | |
6bc9506f | 8 | // Foundation; either version 3, or (at your option) any later |
36fed23c | 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 | ||
6bc9506f | 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/>. | |
36fed23c | 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_prime_size_policy_imp.hpp | |
38 | * Contains a resize size policy implementation. | |
39 | */ | |
40 | ||
3c28ef9e | 41 | #pragma GCC system_header |
42 | ||
36fed23c | 43 | namespace detail |
44 | { | |
36fed23c | 45 | enum |
46 | { | |
205d962c | 47 | num_distinct_sizes_32_bit = 30, |
48 | num_distinct_sizes_64_bit = 62, | |
49 | num_distinct_sizes = sizeof(std::size_t) != 8 ? | |
50 | num_distinct_sizes_32_bit : num_distinct_sizes_64_bit, | |
36fed23c | 51 | }; |
52 | ||
205d962c | 53 | // Originally taken from the SGI implementation; acknowledged in the docs. |
54 | // Further modified (for 64 bits) from tr1's hashtable. | |
205d962c | 55 | static const std::size_t g_a_sizes[num_distinct_sizes_64_bit] = |
36fed23c | 56 | { |
f6d12374 | 57 | /* 0 */ 5ul, |
58 | /* 1 */ 11ul, | |
59 | /* 2 */ 23ul, | |
60 | /* 3 */ 47ul, | |
61 | /* 4 */ 97ul, | |
62 | /* 5 */ 199ul, | |
63 | /* 6 */ 409ul, | |
64 | /* 7 */ 823ul, | |
65 | /* 8 */ 1741ul, | |
66 | /* 9 */ 3469ul, | |
67 | /* 10 */ 6949ul, | |
68 | /* 11 */ 14033ul, | |
69 | /* 12 */ 28411ul, | |
70 | /* 13 */ 57557ul, | |
71 | /* 14 */ 116731ul, | |
72 | /* 15 */ 236897ul, | |
73 | /* 16 */ 480881ul, | |
74 | /* 17 */ 976369ul, | |
75 | /* 18 */ 1982627ul, | |
76 | /* 19 */ 4026031ul, | |
77 | /* 20 */ 8175383ul, | |
78 | /* 21 */ 16601593ul, | |
79 | /* 22 */ 33712729ul, | |
80 | /* 23 */ 68460391ul, | |
81 | /* 24 */ 139022417ul, | |
82 | /* 25 */ 282312799ul, | |
83 | /* 26 */ 573292817ul, | |
84 | /* 27 */ 1164186217ul, | |
85 | /* 28 */ 2364114217ul, | |
86 | /* 29 */ 4294967291ul, | |
87 | /* 30 */ (std::size_t)8589934583ull, | |
88 | /* 31 */ (std::size_t)17179869143ull, | |
89 | /* 32 */ (std::size_t)34359738337ull, | |
90 | /* 33 */ (std::size_t)68719476731ull, | |
91 | /* 34 */ (std::size_t)137438953447ull, | |
92 | /* 35 */ (std::size_t)274877906899ull, | |
93 | /* 36 */ (std::size_t)549755813881ull, | |
94 | /* 37 */ (std::size_t)1099511627689ull, | |
95 | /* 38 */ (std::size_t)2199023255531ull, | |
96 | /* 39 */ (std::size_t)4398046511093ull, | |
97 | /* 40 */ (std::size_t)8796093022151ull, | |
98 | /* 41 */ (std::size_t)17592186044399ull, | |
99 | /* 42 */ (std::size_t)35184372088777ull, | |
100 | /* 43 */ (std::size_t)70368744177643ull, | |
101 | /* 44 */ (std::size_t)140737488355213ull, | |
102 | /* 45 */ (std::size_t)281474976710597ull, | |
103 | /* 46 */ (std::size_t)562949953421231ull, | |
104 | /* 47 */ (std::size_t)1125899906842597ull, | |
105 | /* 48 */ (std::size_t)2251799813685119ull, | |
106 | /* 49 */ (std::size_t)4503599627370449ull, | |
107 | /* 50 */ (std::size_t)9007199254740881ull, | |
108 | /* 51 */ (std::size_t)18014398509481951ull, | |
109 | /* 52 */ (std::size_t)36028797018963913ull, | |
110 | /* 53 */ (std::size_t)72057594037927931ull, | |
111 | /* 54 */ (std::size_t)144115188075855859ull, | |
112 | /* 55 */ (std::size_t)288230376151711717ull, | |
113 | /* 56 */ (std::size_t)576460752303423433ull, | |
114 | /* 57 */ (std::size_t)1152921504606846883ull, | |
115 | /* 58 */ (std::size_t)2305843009213693951ull, | |
116 | /* 59 */ (std::size_t)4611686018427387847ull, | |
117 | /* 60 */ (std::size_t)9223372036854775783ull, | |
118 | /* 61 */ (std::size_t)18446744073709551557ull, | |
36fed23c | 119 | }; |
120 | ||
121 | } // namespace detail | |
122 | ||
123 | PB_DS_CLASS_T_DEC | |
124 | inline | |
125 | PB_DS_CLASS_C_DEC:: | |
ce8b0a77 | 126 | hash_prime_size_policy(size_type n) : m_start_size(n) |
127 | { m_start_size = get_nearest_larger_size(n); } | |
36fed23c | 128 | |
129 | PB_DS_CLASS_T_DEC | |
130 | inline void | |
131 | PB_DS_CLASS_C_DEC:: | |
132 | swap(PB_DS_CLASS_C_DEC& other) | |
59ae0c9c | 133 | { std::swap(m_start_size, other.m_start_size); } |
36fed23c | 134 | |
135 | PB_DS_CLASS_T_DEC | |
136 | inline PB_DS_CLASS_C_DEC::size_type | |
137 | PB_DS_CLASS_C_DEC:: | |
ce8b0a77 | 138 | get_nearest_larger_size(size_type n) const |
36fed23c | 139 | { |
59ae0c9c | 140 | const std::size_t* const p_upper = std::upper_bound(detail::g_a_sizes, |
ce8b0a77 | 141 | detail::g_a_sizes + detail::num_distinct_sizes, n); |
36fed23c | 142 | |
143 | if (p_upper == detail::g_a_sizes + detail::num_distinct_sizes) | |
c4f08cc0 | 144 | __throw_resize_error(); |
59ae0c9c | 145 | return *p_upper; |
36fed23c | 146 | } |
147 | ||
148 | PB_DS_CLASS_T_DEC | |
149 | inline PB_DS_CLASS_C_DEC::size_type | |
150 | PB_DS_CLASS_C_DEC:: | |
ce8b0a77 | 151 | get_nearest_smaller_size(size_type n) const |
36fed23c | 152 | { |
e4bb1925 | 153 | const std::size_t* p_lower = std::lower_bound(detail::g_a_sizes, |
ce8b0a77 | 154 | detail::g_a_sizes + detail::num_distinct_sizes, n); |
36fed23c | 155 | |
ce8b0a77 | 156 | if (*p_lower >= n && p_lower != detail::g_a_sizes) |
36fed23c | 157 | --p_lower; |
36fed23c | 158 | if (*p_lower < m_start_size) |
59ae0c9c | 159 | return m_start_size; |
160 | return *p_lower; | |
36fed23c | 161 | } |