1// <experimental/algorithm> -*- C++ -*-
3// Copyright (C) 2014-2016 Free Software Foundation, Inc.
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
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
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.
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/>.
25/** @file experimental/algorithm
26 * This is a TS C++ Library header.
29#ifndef _GLIBCXX_EXPERIMENTAL_ALGORITHM
30#define _GLIBCXX_EXPERIMENTAL_ALGORITHM 1
32#pragma GCC system_header
34#if __cplusplus <= 201103L
35# include <bits/c++14_warning.h>
40#include <experimental/bits/lfts_config.h>
42namespace std _GLIBCXX_VISIBILITY(default)
46inline namespace fundamentals_v1
48_GLIBCXX_BEGIN_NAMESPACE_VERSION
50 template<typename _ForwardIterator, typename _Searcher>
51 inline _ForwardIterator
52 search(_ForwardIterator __first, _ForwardIterator __last,
53 const _Searcher& __searcher)
54 { return __searcher(__first, __last); }
56#define __cpp_lib_experimental_sample 201402
58 /// Reservoir sampling algorithm.
59 template<typename _InputIterator, typename _RandomAccessIterator,
60 typename _Size, typename _UniformRandomNumberGenerator>
62 __sample(_InputIterator __first, _InputIterator __last, input_iterator_tag,
63 _RandomAccessIterator __out, random_access_iterator_tag,
64 _Size __n, _UniformRandomNumberGenerator&& __g)
66 using __distrib_type = std::uniform_int_distribution<_Size>;
67 using __param_type = typename __distrib_type::param_type;
69 _Size __sample_sz = 0;
70 while (__first != __last && __sample_sz != __n)
72 __out[__sample_sz++] = *__first;
75 for (auto __pop_sz = __sample_sz; __first != __last;
76 ++__first, (void)++__pop_sz)
78 const auto __k = __d(__g, __param_type{0, __pop_sz});
80 __out[__k] = *__first;
82 return __out + __sample_sz;
85 /// Selection sampling algorithm.
86 template<typename _ForwardIterator, typename _OutputIterator, typename _Cat,
87 typename _Size, typename _UniformRandomNumberGenerator>
89 __sample(_ForwardIterator __first, _ForwardIterator __last,
91 _OutputIterator __out, _Cat,
92 _Size __n, _UniformRandomNumberGenerator&& __g)
94 using __distrib_type = std::uniform_int_distribution<_Size>;
95 using __param_type = typename __distrib_type::param_type;
97 _Size __unsampled_sz = std::distance(__first, __last);
98 for (__n = std::min(__n, __unsampled_sz); __n != 0; ++__first)
99 if (__d(__g, __param_type{0, --__unsampled_sz}) < __n)
107 /// Take a random sample from a population.
108 template<typename _PopulationIterator, typename _SampleIterator,
109 typename _Distance, typename _UniformRandomNumberGenerator>
111 sample(_PopulationIterator __first, _PopulationIterator __last,
112 _SampleIterator __out, _Distance __n,
113 _UniformRandomNumberGenerator&& __g)
115 using __pop_cat = typename
116 std::iterator_traits<_PopulationIterator>::iterator_category;
117 using __samp_cat = typename
118 std::iterator_traits<_SampleIterator>::iterator_category;
121 __or_<is_convertible<__pop_cat, forward_iterator_tag>,
122 is_convertible<__samp_cat, random_access_iterator_tag>>::value,
123 "output range must use a RandomAccessIterator when input range"
124 " does not meet the ForwardIterator requirements");
126 static_assert(is_integral<_Distance>::value,
127 "sample size must be an integer type");
129 typename iterator_traits<_PopulationIterator>::difference_type __d = __n;
130 return std::experimental::__sample(
131 __first, __last, __pop_cat{}, __out, __samp_cat{},
132 __d, std::forward<_UniformRandomNumberGenerator>(__g));
135_GLIBCXX_END_NAMESPACE_VERSION
136} // namespace fundamentals_v1
137} // namespace experimental
142#endif // _GLIBCXX_EXPERIMENTAL_ALGORITHM