PR77994 Convert std::sample size argument to suitable type

PR libstdc++/77994
	* include/bits/stl_algo.h (sample): Convert size argument to iterator
	difference type.
	* include/experimental/algorithm (experimental::sample): Likewise.
	* testsuite/25_algorithms/sample/2.cc: New test.

From-SVN: r241245
This commit is contained in:
Jonathan Wakely 2016-10-17 15:39:23 +01:00 committed by Jonathan Wakely
parent 44b00dbca0
commit 12d3f34b33
4 changed files with 77 additions and 2 deletions

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@ -1,3 +1,11 @@
2016-10-17 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/77994
* include/bits/stl_algo.h (sample): Convert size argument to iterator
difference type.
* include/experimental/algorithm (experimental::sample): Likewise.
* testsuite/25_algorithms/sample/2.cc: New test.
2016-10-17 Paolo Carlini <paolo.carlini@oracle.com>
* testsuite/unordered_map/insert/57619.C: Rename to 57619.cc.

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@ -5730,8 +5730,9 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
static_assert(is_integral<_Distance>::value,
"sample size must be an integer type");
typename iterator_traits<_PopulationIterator>::difference_type __d = __n;
return std::__sample(__first, __last, __pop_cat{}, __out, __samp_cat{},
__n, std::forward<_UniformRandomBitGenerator>(__g));
__d, std::forward<_UniformRandomBitGenerator>(__g));
}
#endif // C++17
#endif // C++14

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@ -76,8 +76,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static_assert(is_integral<_Distance>::value,
"sample size must be an integer type");
typename iterator_traits<_PopulationIterator>::difference_type __d = __n;
return std::__sample(__first, __last, __pop_cat{}, __out, __samp_cat{},
__n,
__d,
std::forward<_UniformRandomNumberGenerator>(__g));
}

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@ -0,0 +1,65 @@
// Copyright (C) 2016 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/>.
// { dg-options "-std=gnu++17" }
// { dg-do run { target c++1z } }
#ifndef _GLIBCXX_ASSERTIONS
// Make std::uniform_int_distribution check its parameters
# define _GLIBCXX_ASSERTIONS
#endif
#include <algorithm>
#include <random>
#include <climits>
#include <testsuite_hooks.h>
#include <testsuite_iterators.h>
std::mt19937 rng;
using std::sample;
using __gnu_test::test_container;
using __gnu_test::output_iterator_wrapper;
void
test01()
{
int pop[UCHAR_MAX] = { };
for (int i = SCHAR_MAX; i < UCHAR_MAX; ++i)
pop[i] = 1;
const signed char sample_size = SCHAR_MAX; // PR libstdc++/77994
int out[sample_size] = { };
// random access iterators for both population and result
// (uses reservoir sampling)
auto it = sample(std::begin(pop), std::end(pop), out, sample_size, rng);
auto sum = std::accumulate(out, it, 0);
VERIFY( sum != 0 ); // exceedingly unlikely!
// random access iterator for population and output iterator for result
// (uses selection sampling)
test_container<int, output_iterator_wrapper> samp2(out);
sample(std::begin(pop), std::end(pop), samp2.begin(), sample_size, rng);
sum = std::accumulate(std::begin(out), std::end(out), 0);
VERIFY( sum != 0 );
}
int
main()
{
test01();
}