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// -*- C++ -*-
// Copyright (C) 2005-2022 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 3, 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 COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// 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 testsuite_rng.h
*/
#ifndef _GLIBCXX_TESTSUITE_RNG_H
#define _GLIBCXX_TESTSUITE_RNG_H
#include <ctime>
#include <climits>
#include <debug/debug.h>
#include <tr1/random>
namespace __gnu_pbds
{
namespace test
{
class twister_rand_gen
{
public:
twister_rand_gen(unsigned int seed =
static_cast<unsigned int>(std::time(0)))
: m_base_generator(seed)
{
// Do nothing.
}
void
init(unsigned int seed)
{ m_base_generator.seed(seed); }
static unsigned int
get_time_determined_seed()
{ return(static_cast<unsigned int>(std::time(0))); }
unsigned long
get_unsigned_long(unsigned long min = 0,
unsigned long max = UINT_MAX - 1)
{
_GLIBCXX_DEBUG_ASSERT(max >= min);
const double prob = get_prob();
const unsigned long r = (unsigned long)((max - min + 1) * prob) + min;
_GLIBCXX_DEBUG_ASSERT(r <= max);
return r;
}
double
get_prob()
{
const double min = m_base_generator.min();
const double max = m_base_generator.max();
const double range = static_cast<double>(max - min);
const double res = static_cast<double>(m_base_generator() - min);
const double ret = res / range;
_GLIBCXX_DEBUG_ASSERT(ret >= 0 && ret <= 1);
return ret;
}
private:
typedef std::tr1::mt19937 base_generator_t;
base_generator_t m_base_generator;
};
} // namespace test
} // namespace __gnu_pbds
#endif // #ifndef _GLIBCXX_TESTSUITE_RNG_H
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