1 // { dg-timeout-factor 2.0 }
2
3 // -*- C++ -*-
4
5 // Copyright (C) 2005-2021 Free Software Foundation, Inc.
6 //
7 // This file is part of the GNU ISO C++ Library. This library is free
8 // software; you can redistribute it and/or modify it under the terms
9 // of the GNU General Public License as published by the Free Software
10 // Foundation; either version 3, or (at your option) any later
11 // version.
12
13 // This library is distributed in the hope that it will be useful, but
14 // WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 // General Public License for more details.
17
18 // You should have received a copy of the GNU General Public License
19 // along with this library; see the file COPYING3. If not see
20 // <http://www.gnu.org/licenses/>.
21
22
23 // Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL.
24
25 // Permission to use, copy, modify, sell, and distribute this software
26 // is hereby granted without fee, provided that the above copyright
27 // notice appears in all copies, and that both that copyright notice
28 // and this permission notice appear in supporting documentation. None
29 // of the above authors, nor IBM Haifa Research Laboratories, make any
30 // representation about the suitability of this software for any
31 // purpose. It is provided "as is" without express or implied
32 // warranty.
33
34 /**
35 * @file hash_illegal_resize_example.cpp
36 * An example of illegally externally resizing a hash-based container object.
37 */
38
39 /**
40 * This example shows the case where a hash-based container object is
41 * resized to a value which it cannot accommodate at runtime. Illegal
42 * runtime resizes cause an exception.
43 */
44
45 #include <ext/pb_ds/assoc_container.hpp>
46 #include <ext/pb_ds/hash_policy.hpp>
47 #include <ext/pb_ds/exception.hpp>
48 #include <cassert>
49
50 // size of test containers
51 #ifdef _GLIBCXX_DEBUG
52 # define SIZE 100
53 # define RESIZE 20
54 #else
55 # define SIZE 1000
56 # define RESIZE 200
57 #endif
58
59 using namespace std;
60 using namespace __gnu_pbds;
61
62 // A simple hash functor.
63 // hash could serve instead of this functor, but it is not yet
64 // standard everywhere.
65 struct int_hash
66 {
67 size_t
operator ()int_hash68 operator()(const int& r_i) const
69 { return r_i; }
70 };
71
72
main()73 int main()
74 {
75 // A probing hash table mapping ints to chars.
76 typedef
77 gp_hash_table<
78 int,
79 int,
80 int_hash,
81 equal_to<int>,
82 // Combining function.
83 direct_mod_range_hashing<>,
84 // Probe function.
85 quadratic_probe_fn<>,
86 // Resize policy.
87 hash_standard_resize_policy<
88 hash_prime_size_policy,
89 hash_load_check_resize_trigger<>,
90 /* Allow external access to size.
91 * Without setting this to true, external resizing
92 * is not possible.
93 */
94 true> >
95 map_t;
96
97 map_t g;
98
99 // Insert some elements.
100 int i;
101
102 for (i = 0; i < SIZE; ++i)
103 g[i] = 2* i;
104
105 // Check all ok.
106 assert(g.size() == SIZE);
107 for (i = 0; i < SIZE; ++i)
108 assert(g.find(i) != g.end() && g.find(i)->second == 2 * i);
109
110 // Now attempt to resize the table to 200 (impossible).
111 bool ex_thrown = false;
112
113 try
114 {
115 g.resize(RESIZE);
116 }
117 catch(__gnu_pbds::resize_error& )
118 {
119 ex_thrown = true;
120 }
121
122 // Assert an exception was thrown. A probing table cannot contain
123 // 1000 entries in less than 1000 places.
124 assert(ex_thrown);
125
126 // Irrespective of the fact that the resize was not successful, the
127 // container object should still be in a valid state; the following
128 // checks this.
129 // Check all ok.
130 assert(g.size() == SIZE);
131 for (i = 0; i < SIZE; ++i)
132 assert(g.find(i) != g.end() && g.find(i)->second == 2 * i);
133
134 return 0;
135 }
136