[libcxx] r279948 - Implement C++17 std::sample.
Eric Fiselier via cfe-commits
cfe-commits at lists.llvm.org
Sun Aug 28 15:14:38 PDT 2016
Author: ericwf
Date: Sun Aug 28 17:14:37 2016
New Revision: 279948
URL: http://llvm.org/viewvc/llvm-project?rev=279948&view=rev
Log:
Implement C++17 std::sample.
This patch implements the std::sample function added to C++17 from LFTS. It
also removes the std::experimental::sample implementation which now forwards
to std::sample.
Added:
libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/
libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp
libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp
Modified:
libcxx/trunk/include/algorithm
libcxx/trunk/include/experimental/algorithm
libcxx/trunk/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp
libcxx/trunk/test/support/test_iterators.h
Modified: libcxx/trunk/include/algorithm
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/algorithm?rev=279948&r1=279947&r2=279948&view=diff
==============================================================================
--- libcxx/trunk/include/algorithm (original)
+++ libcxx/trunk/include/algorithm Sun Aug 28 17:14:37 2016
@@ -288,6 +288,12 @@ template <class RandomAccessIterator, cl
random_shuffle(RandomAccessIterator first, RandomAccessIterator last,
RandomNumberGenerator& rand); // deprecated in C++14
+template<class PopulationIterator, class SampleIterator,
+ class Distance, class UniformRandomBitGenerator>
+ SampleIterator sample(PopulationIterator first, PopulationIterator last,
+ SampleIterator out, Distance n,
+ UniformRandomBitGenerator&& g); // C++17
+
template<class RandomAccessIterator, class UniformRandomNumberGenerator>
void shuffle(RandomAccessIterator first, RandomAccessIterator last,
UniformRandomNumberGenerator&& g);
@@ -3142,6 +3148,78 @@ random_shuffle(_RandomAccessIterator __f
}
}
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+ class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+ _PopulationIterator __last, _SampleIterator __out,
+ _Distance __n,
+ _UniformRandomNumberGenerator & __g,
+ input_iterator_tag) {
+
+ _Distance __k = 0;
+ for (; __first != __last && __k < __n; ++__first, (void)++__k)
+ __out[__k] = *__first;
+ _Distance __sz = __k;
+ for (; __first != __last; ++__first, (void)++__k) {
+ _Distance __r = _VSTD::uniform_int_distribution<_Distance>(0, __k)(__g);
+ if (__r < __sz)
+ __out[__r] = *__first;
+ }
+ return __out + _VSTD::min(__n, __k);
+}
+
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+ class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+ _PopulationIterator __last, _SampleIterator __out,
+ _Distance __n,
+ _UniformRandomNumberGenerator& __g,
+ forward_iterator_tag) {
+ _Distance __unsampled_sz = _VSTD::distance(__first, __last);
+ for (__n = _VSTD::min(__n, __unsampled_sz); __n != 0; ++__first) {
+ _Distance __r =
+ _VSTD::uniform_int_distribution<_Distance>(0, --__unsampled_sz)(__g);
+ if (__r < __n) {
+ *__out++ = *__first;
+ --__n;
+ }
+ }
+ return __out;
+}
+
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+ class _UniformRandomNumberGenerator>
+_LIBCPP_INLINE_VISIBILITY
+_SampleIterator __sample(_PopulationIterator __first,
+ _PopulationIterator __last, _SampleIterator __out,
+ _Distance __n, _UniformRandomNumberGenerator& __g) {
+ typedef typename iterator_traits<_PopulationIterator>::iterator_category
+ _PopCategory;
+ typedef typename iterator_traits<_PopulationIterator>::difference_type
+ _Difference;
+ static_assert(__is_forward_iterator<_PopulationIterator>::value ||
+ __is_random_access_iterator<_SampleIterator>::value,
+ "SampleIterator must meet the requirements of RandomAccessIterator");
+ typedef typename common_type<_Distance, _Difference>::type _CommonType;
+ _LIBCPP_ASSERT(__n >= 0, "N must be a positive number.");
+ return _VSTD::__sample(
+ __first, __last, __out, _CommonType(__n),
+ __g, _PopCategory());
+}
+
+#if _LIBCPP_STD_VER > 14
+template <class _PopulationIterator, class _SampleIterator, class _Distance,
+ class _UniformRandomNumberGenerator>
+inline _LIBCPP_INLINE_VISIBILITY
+_SampleIterator sample(_PopulationIterator __first,
+ _PopulationIterator __last, _SampleIterator __out,
+ _Distance __n, _UniformRandomNumberGenerator&& __g) {
+ return _VSTD::__sample(__first, __last, __out, __n, __g);
+}
+#endif // _LIBCPP_STD_VER > 14
+
template<class _RandomAccessIterator, class _UniformRandomNumberGenerator>
void shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,
#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
Modified: libcxx/trunk/include/experimental/algorithm
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/experimental/algorithm?rev=279948&r1=279947&r2=279948&view=diff
==============================================================================
--- libcxx/trunk/include/experimental/algorithm (original)
+++ libcxx/trunk/include/experimental/algorithm Sun Aug 28 17:14:37 2016
@@ -58,64 +58,11 @@ _ForwardIterator search(_ForwardIterator
template <class _PopulationIterator, class _SampleIterator, class _Distance,
class _UniformRandomNumberGenerator>
-_LIBCPP_INLINE_VISIBILITY
-_SampleIterator __sample(_PopulationIterator __first,
- _PopulationIterator __last, _SampleIterator __out,
- _Distance __n,
- _UniformRandomNumberGenerator &&__g,
- input_iterator_tag) {
-
- _Distance __k = 0;
- for (; __first != __last && __k < __n; ++__first, (void)++__k)
- __out[__k] = *__first;
- _Distance __sz = __k;
- for (; __first != __last; ++__first, (void)++__k) {
- _Distance __r = _VSTD::uniform_int_distribution<_Distance>(0, __k)(__g);
- if (__r < __sz)
- __out[__r] = *__first;
- }
- return __out + _VSTD::min(__n, __k);
-}
-
-template <class _PopulationIterator, class _SampleIterator, class _Distance,
- class _UniformRandomNumberGenerator>
-_LIBCPP_INLINE_VISIBILITY
-_SampleIterator __sample(_PopulationIterator __first,
- _PopulationIterator __last, _SampleIterator __out,
- _Distance __n,
- _UniformRandomNumberGenerator &&__g,
- forward_iterator_tag) {
- _Distance __unsampled_sz = _VSTD::distance(__first, __last);
- for (__n = _VSTD::min(__n, __unsampled_sz); __n != 0; ++__first) {
- _Distance __r =
- _VSTD::uniform_int_distribution<_Distance>(0, --__unsampled_sz)(__g);
- if (__r < __n) {
- *__out++ = *__first;
- --__n;
- }
- }
- return __out;
-}
-
-template <class _PopulationIterator, class _SampleIterator, class _Distance,
- class _UniformRandomNumberGenerator>
-_LIBCPP_INLINE_VISIBILITY
-_SampleIterator sample(_PopulationIterator __first,
- _PopulationIterator __last, _SampleIterator __out,
- _Distance __n, _UniformRandomNumberGenerator &&__g) {
- typedef typename iterator_traits<_PopulationIterator>::iterator_category
- _PopCategory;
- typedef typename iterator_traits<_PopulationIterator>::difference_type
- _Difference;
- static_assert(__is_forward_iterator<_PopulationIterator>::value ||
- __is_random_access_iterator<_SampleIterator>::value,
- "SampleIterator must meet the requirements of RandomAccessIterator");
- typedef typename common_type<_Distance, _Difference>::type _CommonType;
- _LIBCPP_ASSERT(__n >= 0, "N must be a positive number.");
- return _VSTD_LFTS::__sample(
- __first, __last, __out, _CommonType(__n),
- _VSTD::forward<_UniformRandomNumberGenerator>(__g),
- _PopCategory());
+inline _LIBCPP_INLINE_VISIBILITY
+_SampleIterator sample(_PopulationIterator __first, _PopulationIterator __last,
+ _SampleIterator __out, _Distance __n,
+ _UniformRandomNumberGenerator &&__g) {
+ return _VSTD::__sample(__first, __last, __out, __n, __g);
}
_LIBCPP_END_NAMESPACE_LFTS
Added: libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp?rev=279948&view=auto
==============================================================================
--- libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp (added)
+++ libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.fail.cpp Sun Aug 28 17:14:37 2016
@@ -0,0 +1,41 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <algorithm>
+
+// template <class PopulationIterator, class SampleIterator, class Distance,
+// class UniformRandomNumberGenerator>
+// SampleIterator sample(PopulationIterator first, PopulationIterator last,
+// SampleIterator out, Distance n,
+// UniformRandomNumberGenerator &&g);
+
+#include <algorithm>
+#include <random>
+#include <cassert>
+
+#include "test_iterators.h"
+
+template <class PopulationIterator, class SampleIterator> void test() {
+ int ia[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+ const unsigned is = sizeof(ia) / sizeof(ia[0]);
+ const unsigned os = 4;
+ int oa[os];
+ std::minstd_rand g;
+ std::sample(PopulationIterator(ia), PopulationIterator(ia + is),
+ SampleIterator(oa), os, g);
+}
+
+int main() {
+ // expected-error at algorithm:* {{static_assert failed "SampleIterator must meet the requirements of RandomAccessIterator"}}
+ // expected-error at algorithm:* 2 {{does not provide a subscript operator}}
+ // expected-error at algorithm:* {{invalid operands}}
+ test<input_iterator<int *>, output_iterator<int *> >();
+}
Added: libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp?rev=279948&view=auto
==============================================================================
--- libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp (added)
+++ libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.pass.cpp Sun Aug 28 17:14:37 2016
@@ -0,0 +1,148 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <algorithm>
+
+// template <class PopulationIterator, class SampleIterator, class Distance,
+// class UniformRandomNumberGenerator>
+// SampleIterator sample(PopulationIterator first, PopulationIterator last,
+// SampleIterator out, Distance n,
+// UniformRandomNumberGenerator &&g);
+
+#include <algorithm>
+#include <random>
+#include <cassert>
+
+#include "test_iterators.h"
+
+struct ReservoirSampleExpectations {
+ enum { os = 4 };
+ static int oa1[os];
+ static int oa2[os];
+};
+
+int ReservoirSampleExpectations::oa1[] = {10, 5, 9, 4};
+int ReservoirSampleExpectations::oa2[] = {5, 2, 10, 4};
+
+struct SelectionSampleExpectations {
+ enum { os = 4 };
+ static int oa1[os];
+ static int oa2[os];
+};
+
+int SelectionSampleExpectations::oa1[] = {1, 4, 6, 7};
+int SelectionSampleExpectations::oa2[] = {1, 2, 6, 8};
+
+template <class IteratorCategory> struct TestExpectations
+ : public SelectionSampleExpectations {};
+
+template <>
+struct TestExpectations<std::input_iterator_tag>
+ : public ReservoirSampleExpectations {};
+
+template <template<class...> class PopulationIteratorType, class PopulationItem,
+ template<class...> class SampleIteratorType, class SampleItem>
+void test() {
+ typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
+ typedef SampleIteratorType<SampleItem *> SampleIterator;
+ PopulationItem ia[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+ const unsigned is = sizeof(ia) / sizeof(ia[0]);
+ typedef TestExpectations<typename std::iterator_traits<
+ PopulationIterator>::iterator_category> Expectations;
+ const unsigned os = Expectations::os;
+ SampleItem oa[os];
+ const int *oa1 = Expectations::oa1;
+ const int *oa2 = Expectations::oa2;
+ std::minstd_rand g;
+ SampleIterator end;
+ end = std::sample(PopulationIterator(ia),
+ PopulationIterator(ia + is),
+ SampleIterator(oa), os, g);
+ assert(end.base() - oa == std::min(os, is));
+ assert(std::equal(oa, oa + os, oa1));
+ end = std::sample(PopulationIterator(ia),
+ PopulationIterator(ia + is),
+ SampleIterator(oa), os, std::move(g));
+ assert(end.base() - oa == std::min(os, is));
+ assert(std::equal(oa, oa + os, oa2));
+}
+
+template <template<class...> class PopulationIteratorType, class PopulationItem,
+ template<class...> class SampleIteratorType, class SampleItem>
+void test_empty_population() {
+ typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
+ typedef SampleIteratorType<SampleItem *> SampleIterator;
+ PopulationItem ia[] = {42};
+ const unsigned os = 4;
+ SampleItem oa[os];
+ std::minstd_rand g;
+ SampleIterator end =
+ std::sample(PopulationIterator(ia), PopulationIterator(ia),
+ SampleIterator(oa), os, g);
+ assert(end.base() == oa);
+}
+
+template <template<class...> class PopulationIteratorType, class PopulationItem,
+ template<class...> class SampleIteratorType, class SampleItem>
+void test_empty_sample() {
+ typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
+ typedef SampleIteratorType<SampleItem *> SampleIterator;
+ PopulationItem ia[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+ const unsigned is = sizeof(ia) / sizeof(ia[0]);
+ SampleItem oa[1];
+ std::minstd_rand g;
+ SampleIterator end =
+ std::sample(PopulationIterator(ia), PopulationIterator(ia + is),
+ SampleIterator(oa), 0, g);
+ assert(end.base() == oa);
+}
+
+template <template<class...> class PopulationIteratorType, class PopulationItem,
+ template<class...> class SampleIteratorType, class SampleItem>
+void test_small_population() {
+ // The population size is less than the sample size.
+ typedef PopulationIteratorType<PopulationItem *> PopulationIterator;
+ typedef SampleIteratorType<SampleItem *> SampleIterator;
+ PopulationItem ia[] = {1, 2, 3, 4, 5};
+ const unsigned is = sizeof(ia) / sizeof(ia[0]);
+ const unsigned os = 8;
+ SampleItem oa[os];
+ const SampleItem oa1[] = {1, 2, 3, 4, 5};
+ std::minstd_rand g;
+ SampleIterator end;
+ end = std::sample(PopulationIterator(ia),
+ PopulationIterator(ia + is),
+ SampleIterator(oa), os, g);
+ assert(end.base() - oa == std::min(os, is));
+ assert(std::equal(oa, end.base(), oa1));
+}
+
+int main() {
+ test<input_iterator, int, random_access_iterator, int>();
+ test<forward_iterator, int, output_iterator, int>();
+ test<forward_iterator, int, random_access_iterator, int>();
+
+ test<input_iterator, int, random_access_iterator, double>();
+ test<forward_iterator, int, output_iterator, double>();
+ test<forward_iterator, int, random_access_iterator, double>();
+
+ test_empty_population<input_iterator, int, random_access_iterator, int>();
+ test_empty_population<forward_iterator, int, output_iterator, int>();
+ test_empty_population<forward_iterator, int, random_access_iterator, int>();
+
+ test_empty_sample<input_iterator, int, random_access_iterator, int>();
+ test_empty_sample<forward_iterator, int, output_iterator, int>();
+ test_empty_sample<forward_iterator, int, random_access_iterator, int>();
+
+ test_small_population<input_iterator, int, random_access_iterator, int>();
+ test_small_population<forward_iterator, int, output_iterator, int>();
+ test_small_population<forward_iterator, int, random_access_iterator, int>();
+}
Added: libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp?rev=279948&view=auto
==============================================================================
--- libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp (added)
+++ libcxx/trunk/test/std/algorithms/alg.modifying.operations/alg.random.sample/sample.stable.pass.cpp Sun Aug 28 17:14:37 2016
@@ -0,0 +1,55 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14
+
+// <algorithm>
+
+// template <class PopulationIterator, class SampleIterator, class Distance,
+// class UniformRandomNumberGenerator>
+// SampleIterator sample(PopulationIterator first, PopulationIterator last,
+// SampleIterator out, Distance n,
+// UniformRandomNumberGenerator &&g);
+
+#include <algorithm>
+#include <random>
+#include <cassert>
+
+#include "test_iterators.h"
+
+// Stable if and only if PopulationIterator meets the requirements of a
+// ForwardIterator type.
+template <class PopulationIterator, class SampleIterator>
+void test_stability(bool expect_stable) {
+ const unsigned kPopulationSize = 100;
+ int ia[kPopulationSize];
+ for (unsigned i = 0; i < kPopulationSize; ++i)
+ ia[i] = i;
+ PopulationIterator first(ia);
+ PopulationIterator last(ia + kPopulationSize);
+
+ const unsigned kSampleSize = 20;
+ int oa[kPopulationSize];
+ SampleIterator out(oa);
+
+ std::minstd_rand g;
+
+ const int kIterations = 1000;
+ bool unstable = false;
+ for (int i = 0; i < kIterations; ++i) {
+ std::sample(first, last, out, kSampleSize, g);
+ unstable |= !std::is_sorted(oa, oa + kSampleSize);
+ }
+ assert(expect_stable == !unstable);
+}
+
+int main() {
+ test_stability<forward_iterator<int *>, output_iterator<int *> >(true);
+ test_stability<input_iterator<int *>, random_access_iterator<int *> >(false);
+}
Modified: libcxx/trunk/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp?rev=279948&r1=279947&r2=279948&view=diff
==============================================================================
--- libcxx/trunk/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp (original)
+++ libcxx/trunk/test/std/experimental/algorithms/alg.random.sample/sample.fail.cpp Sun Aug 28 17:14:37 2016
@@ -7,6 +7,8 @@
//
//===----------------------------------------------------------------------===//
+// UNSUPPORTED: c++98, c++03
+
// <algorithm>
// template <class PopulationIterator, class SampleIterator, class Distance,
@@ -32,8 +34,8 @@ template <class PopulationIterator, clas
}
int main() {
- // expected-error at experimental/algorithm:* {{static_assert failed "SampleIterator must meet the requirements of RandomAccessIterator"}}
- // expected-error at experimental/algorithm:* 2 {{does not provide a subscript operator}}
- // expected-error at experimental/algorithm:* {{invalid operands}}
+ // expected-error at algorithm:* {{static_assert failed "SampleIterator must meet the requirements of RandomAccessIterator"}}
+ // expected-error at algorithm:* 2 {{does not provide a subscript operator}}
+ // expected-error at algorithm:* {{invalid operands}}
test<input_iterator<int *>, output_iterator<int *> >();
}
Modified: libcxx/trunk/test/support/test_iterators.h
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/support/test_iterators.h?rev=279948&r1=279947&r2=279948&view=diff
==============================================================================
--- libcxx/trunk/test/support/test_iterators.h (original)
+++ libcxx/trunk/test/support/test_iterators.h Sun Aug 28 17:14:37 2016
@@ -57,7 +57,7 @@ template <class It,
class ItTraits = It>
class input_iterator
{
- using Traits = std::iterator_traits<ItTraits>;
+ typedef std::iterator_traits<ItTraits> Traits;
It it_;
template <class U, class T> friend class input_iterator;
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