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PR libstdc++/91748 fix std::for_each_n for random access iterators

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PR libstdc++/91748
	* include/bits/stl_algo.h (for_each_n): Fix random access iterator
	case.
	* testsuite/25_algorithms/for_each/for_each_n.cc: Test with random
	access iterators.

From-SVN: r275683
This commit is contained in:
Jonathan Wakely 2019-09-12 11:51:39 +01:00 • committed by Jonathan Wakely
parent 58cc98767a
commit 52f6afe06d
3 changed files with 45 additions and 2 deletions
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8
libstdc++-v3/ChangeLog
View file

@ -1,3 +1,11 @@
2019-09-12 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/91748
* include/bits/stl_algo.h (for_each_n): Fix random access iterator
case.
* testsuite/25_algorithms/for_each/for_each_n.cc: Test with random
access iterators.
2019-09-11 Jonathan Wakely <jwakely@redhat.com>
* python/libstdcxx/v6/xmethods.py (SharedPtrUseCountWorker.__call__):

6
libstdc++-v3/include/bits/stl_algo.h
View file

@ -3993,7 +3993,11 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
auto __n2 = std::__size_to_integer(__n);
using _Cat = typename iterator_traits<_InputIterator>::iterator_category;
if constexpr (is_base_of_v<random_access_iterator_tag, _Cat>)
return std::for_each(__first, __first + __n2, __f);
{
auto __last = __first + __n2;
std::for_each(__first, __last, std::move(__f));
return __last;
}
else
{
while (__n2-->0)

33
libstdc++-v3/testsuite/25_algorithms/for_each/for_each_n.cc
View file

@ -47,11 +47,42 @@ void test01()
};
auto res = std::for_each_n(con.begin(), Size(con.size()), Func(sum));
VERIFY( res.ptr == con.end().ptr );
VERIFY( res == con.end() );
VERIFY( sum == 15 );
}
void
test02()
{
using __gnu_test::test_container;
using __gnu_test::random_access_iterator_wrapper;
int array[5] = { 2, 4, 6, 8, 10 };
test_container<int, random_access_iterator_wrapper> con(array);
int prod = 1;
struct Func
{
Func(int& i) : i(i) { }
Func(Func&&) = default;
Func& operator=(Func&&) = delete;
void operator()(int n) const { i *= n; }
int& i;
};
struct Size
{
Size(short v) : val(v) { }
operator short() const { return val; }
short val;
};
auto res = std::for_each_n(con.begin(), Size(con.size()), Func(prod));
VERIFY( res == con.end() );
VERIFY( prod == 3840 );
}
int main()
{
test01();
test02();
}