Add std::copy_n istreambuf_iterator specialization

	* include/bits/stl_algo.h
	(__copy_n_a(_IIte, _Size, _OIte)): New.
	(__copy_n_a(istreambuf_iterator<>, _Size, _CharT*)): New declaration.
	(__copy_n(_IIte, _Size, _OIte, input_iterator_tag)): Adapt to use
	latter.
	* include/bits/streambuf_iterator.h (istreambuf_iterator<>): Declare
	std::__copy_n_a friend.
	(__copy_n_a(istreambuf_iterator<>, _Size, _CharT*)): New.
	* testsuite/25_algorithms/copy_n/istreambuf_iterator/1.cc: New.
	* testsuite/25_algorithms/copy_n/istreambuf_iterator/1_neg.cc: New.
	* testsuite/25_algorithms/copy_n/istreambuf_iterator/2_neg.cc: New.

From-SVN: r276638

libstdc++-v3/ChangeLog

 2019-10-06  François Dumont  <fdumont@gcc.gnu.org>
 
+	* include/bits/stl_algo.h
+	(__copy_n_a(_IIte, _Size, _OIte)): New.
+	(__copy_n_a(istreambuf_iterator<>, _Size, _CharT*)): New declaration.
+	(__copy_n(_IIte, _Size, _OIte, input_iterator_tag)): Adapt to use
+	latter.
+	* include/bits/streambuf_iterator.h (istreambuf_iterator<>): Declare
+	std::__copy_n_a friend.
+	(__copy_n_a(istreambuf_iterator<>, _Size, _CharT*)): New.
+	* testsuite/25_algorithms/copy_n/istreambuf_iterator/1.cc: New.
+	* testsuite/25_algorithms/copy_n/istreambuf_iterator/1_neg.cc: New.
+	* testsuite/25_algorithms/copy_n/istreambuf_iterator/2_neg.cc: New.
+
 	* include/bits/stl_iterator_base_types.h (__iterator_category_t): Define
 	for C++11.
 	(_RequireInputIte): Likewise and use __enable_if_t.

libstdc++-v3/include/bits/stl_algo.h

@@ -880,7 +880,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);
     }
-#endif
+#endif // C++11
 
   template<typename _ForwardIterator, typename _Predicate>
     _GLIBCXX20_CONSTEXPR

libstdc++-v3/include/bits/streambuf_iterator.h

@@ -80,6 +80,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	__copy_move_a2(istreambuf_iterator<_CharT2>,
 		       istreambuf_iterator<_CharT2>, _CharT2*);
 
+#if __cplusplus >= 201103L
+      template<typename _CharT2, typename _Size>
+	friend __enable_if_t<__is_char<_CharT2>::__value, _CharT2*>
+	__copy_n_a(istreambuf_iterator<_CharT2>, _Size, _CharT2*);
+#endif
+
       template<typename _CharT2>
 	friend typename __gnu_cxx::__enable_if<__is_char<_CharT2>::__value,
 				    istreambuf_iterator<_CharT2> >::__type
@@ -367,6 +373,26 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       return __result;
     }
 
+#if __cplusplus >= 201103L
+  template<typename _CharT, typename _Size>
+    __enable_if_t<__is_char<_CharT>::__value, _CharT*>
+    __copy_n_a(istreambuf_iterator<_CharT> __it, _Size __n, _CharT* __result)
+    {
+      if (__n == 0)
+	return __result;
+
+      __glibcxx_requires_cond(__it._M_sbuf,
+			      _M_message(__gnu_debug::__msg_inc_istreambuf)
+			      ._M_iterator(__it));
+      _CharT* __beg = __result;
+      __result += __it._M_sbuf->sgetn(__beg, __n);
+      __glibcxx_requires_cond(__result - __beg == __n,
+			      _M_message(__gnu_debug::__msg_inc_istreambuf)
+			      ._M_iterator(__it));
+      return __result;
+    }
+#endif // C++11
+
   template<typename _CharT>
     typename __gnu_cxx::__enable_if<__is_char<_CharT>::__value,
 		  		    istreambuf_iterator<_CharT> >::__type

libstdc++-v3/testsuite/25_algorithms/copy_n/istreambuf_iterator/1.cc

+// Copyright (C) 2019 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-do run { target c++11 } }
+
+#include <algorithm>
+#include <sstream>
+#include <iterator>
+
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  std::stringstream ss("12345");
+
+  std::string ostr(5, '0');
+  typedef std::istreambuf_iterator<char> istrb_ite;
+  auto res = std::copy_n(istrb_ite(ss), 0, ostr.begin());
+  VERIFY( res == ostr.begin() );
+  VERIFY( ostr.front() == '0' );
+
+  res = std::copy_n(istrb_ite(ss), 2, ostr.begin());
+  VERIFY( res == ostr.begin() + 2 );
+  VERIFY( ostr == "12000" );
+
+  res = std::copy_n(istrb_ite(ss), 3, ostr.begin() + 2);
+  VERIFY( res == ostr.begin() + 5 );
+  VERIFY( ostr == "12345" );
+}
+
+void test02()
+{
+  std::stringstream ss("12345");
+
+  std::string ostr(5, '0');
+  typedef std::istreambuf_iterator<char> istrb_ite;
+
+  istrb_ite ibfit(ss);
+  auto res = std::copy_n(ibfit, 3, std::copy_n(ibfit, 2, ostr.begin()));
+  VERIFY( res == ostr.begin() + 5 );
+  VERIFY( ostr == "12345" );
+}
+
+void test03()
+{
+  std::string ostr(5, '0');
+  typedef std::istreambuf_iterator<char> istrb_ite;
+
+  auto res = std::copy_n(istrb_ite(), 0, ostr.begin());
+  VERIFY( res == ostr.begin() );
+}
+
+int main()
+{
+  test01();
+  test02();
+  test03();
+  return 0;
+}

libstdc++-v3/testsuite/25_algorithms/copy_n/istreambuf_iterator/1_neg.cc

+// Copyright (C) 2019 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-do run { target c++11 xfail *-*-* } }
+// { dg-require-debug-mode { } }
+
+#include <algorithm>
+#include <sstream>
+#include <iterator>
+
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  std::stringstream ss("12345");
+
+  std::string ostr(10, '0');
+  typedef std::istreambuf_iterator<char> istrb_ite;
+  std::copy_n(istrb_ite(ss), 10, ostr.begin());
+}
+
+int main()
+{
+  test01();
+  return 0;
+}

libstdc++-v3/testsuite/25_algorithms/copy_n/istreambuf_iterator/2_neg.cc

+// Copyright (C) 2019 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-do run { target c++11 xfail *-*-* } }
+// { dg-require-debug-mode { } }
+
+#include <algorithm>
+#include <sstream>
+#include <iterator>
+
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  std::string ostr(10, '0');
+  typedef std::istreambuf_iterator<char> istrb_ite;
+  std::copy_n(istrb_ite(), 10, ostr.begin());
+}
+
+int main()
+{
+  test01();
+  return 0;
+}