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Diffstat (limited to 'libstdc++-v3/testsuite/ext/pb_ds/example/hash_illegal_resize.cc')
-rw-r--r-- | libstdc++-v3/testsuite/ext/pb_ds/example/hash_illegal_resize.cc | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/libstdc++-v3/testsuite/ext/pb_ds/example/hash_illegal_resize.cc b/libstdc++-v3/testsuite/ext/pb_ds/example/hash_illegal_resize.cc new file mode 100644 index 00000000000..9b3e7747488 --- /dev/null +++ b/libstdc++-v3/testsuite/ext/pb_ds/example/hash_illegal_resize.cc @@ -0,0 +1,137 @@ +// -*- C++ -*- + +// Copyright (C) 2005, 2006 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the terms +// of the GNU General Public License as published by the Free Software +// Foundation; either version 2, or (at your option) any later +// version. + +// This library is distributed in the hope that it will be useful, but +// WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this library; see the file COPYING. If not, write to +// the Free Software Foundation, 59 Temple Place - Suite 330, Boston, +// MA 02111-1307, USA. + +// As a special exception, you may use this file as part of a free +// software library without restriction. Specifically, if other files +// instantiate templates or use macros or inline functions from this +// file, or you compile this file and link it with other files to +// produce an executable, this file does not by itself cause the +// resulting executable to be covered by the GNU General Public +// License. This exception does not however invalidate any other +// reasons why the executable file might be covered by the GNU General +// Public License. + +// Copyright (C) 2004 Ami Tavory and Vladimir Dreizin, IBM-HRL. + +// Permission to use, copy, modify, sell, and distribute this software +// is hereby granted without fee, provided that the above copyright +// notice appears in all copies, and that both that copyright notice +// and this permission notice appear in supporting documentation. None +// of the above authors, nor IBM Haifa Research Laboratories, make any +// representation about the suitability of this software for any +// purpose. It is provided "as is" without express or implied +// warranty. + +/** + * @file hash_illegal_resize_example.cpp + * An example of illegally + * externally resizing a hash-based container object. + */ + +/** + * This example shows the case where a hash-based container object is + * resized to a value which it cannot accomodate at runtime. Illegal + * runtime resizes cause an exception. + */ + +#include <ext/pb_ds/assoc_container.hpp> +#include <ext/pb_ds/hash_policy.hpp> +#include <ext/pb_ds/exception.hpp> +#include <cassert> + +using namespace std; +using namespace pb_ds; + +// A simple hash functor. +// hash could serve instead of this functor, but it is not yet +// standard everywhere. +struct int_hash : public unary_function<int, size_t> +{ + inline size_t + operator()(const int& r_i) const + { return r_i; } +}; + + +int main() +{ + // A probing hash table mapping ints to chars. + typedef + gp_hash_table< + int, + int, + int_hash, + equal_to< + int>, + // Combining function. + direct_mod_range_hashing<>, + // Probe function. + quadratic_probe_fn<>, + // Resize policy. + hash_standard_resize_policy< + hash_prime_size_policy, + hash_load_check_resize_trigger<>, + /* Allow external access to size. + * Without setting this to true, external resizing + * is not possible. + */ + true> > + map_t; + + map_t g; + + // Insert some elements. + int i; + + for (i = 0; i < 1000; ++i) + g[i] = 2* i; + + // Check all ok. + assert(g.size() == 1000); + for (i = 0; i < 1000; ++i) + assert(g.find(i) != g.end()&& g.find(i)->second == 2* i); + + // Now attempt to resize the table to 200 (impossible). + bool ex_thrown = false; + + try + { + g.resize(200); + } + catch(pb_ds::resize_error& ) + { + ex_thrown = true; + } + + // Assert an exception was thrown. A probing table cannot contain + // 1000 entries in less than 1000 places. + assert(ex_thrown); + + // Irrespective of the fact that the resize was not successful, the + // container object should still be in a valid state; the following + // checks this. + // Check all ok. + assert(g.size() == 1000); + for (i = 0; i < 1000; ++i) + assert(g.find(i) != g.end()&& g.find(i)->second == 2* i); + + return 0; +} + |