[gcc(refs/users/ppalka/heads/libstdcxx-constrained-algos)] Add ranges::generate and ranges::generate_n

Patrick Palka ppalka@gcc.gnu.org
Mon Jan 20 21:56:00 GMT 2020


https://gcc.gnu.org/g:ab6b00691cc74a16faedfef691b267563d5ca679

commit ab6b00691cc74a16faedfef691b267563d5ca679
Author: Patrick Palka <ppalka@gcc.gnu.org>
Date:   Mon Jan 20 16:46:38 2020 -0500

    Add ranges::generate and ranges::generate_n

Diff:
---
 libstdc++-v3/include/bits/ranges_algo.h            | 30 ++++++++
 .../25_algorithms/generate/constrained.cc          | 77 ++++++++++++++++++++
 .../25_algorithms/generate_n/constrained.cc        | 84 ++++++++++++++++++++++
 3 files changed, 191 insertions(+)

diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
index 6856439..da81196 100644
--- a/libstdc++-v3/include/bits/ranges_algo.h
+++ b/libstdc++-v3/include/bits/ranges_algo.h
@@ -1250,6 +1250,36 @@ namespace ranges
 	return ranges::fill(ranges::begin(__r), ranges::end(__r), __value);
       }
 
+    template<input_or_output_iterator _Out, copy_constructible _F>
+      requires invocable<_F&> && writable<_Out, invoke_result_t<_F&>>
+      constexpr _Out
+      generate_n(_Out __first, iter_difference_t<_Out> __n, _F __gen)
+      {
+	for (; __n > 0; --__n, (void)++__first)
+	  *__first = std::__invoke(__gen);
+	return __first;
+      }
+
+    template<input_or_output_iterator _Out, sentinel_for<_Out> _Sent,
+	     copy_constructible _F>
+      requires invocable<_F&> && writable<_Out, invoke_result_t<_F&>>
+      constexpr _Out
+      generate(_Out __first, _Sent __last, _F __gen)
+      {
+	for (; __first != __last; ++__first)
+	  *__first = std::__invoke(__gen);
+	return __first;
+      }
+
+    template<typename _Range, copy_constructible _F>
+      requires invocable<_F&> && output_range<_Range, invoke_result_t<_F&>>
+      constexpr safe_iterator_t<_Range>
+      generate(_Range&& __r, _F __gen)
+      {
+	return ranges::generate(ranges::begin(__r), ranges::end(__r),
+				std::move(__gen));
+      }
+
 } // namespace ranges
 _GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
diff --git a/libstdc++-v3/testsuite/25_algorithms/generate/constrained.cc b/libstdc++-v3/testsuite/25_algorithms/generate/constrained.cc
new file mode 100644
index 0000000..71bcbaa
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/generate/constrained.cc
@@ -0,0 +1,77 @@
+// Copyright (C) 2020 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++2a" }
+// { dg-do run { target c++2a } }
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+using __gnu_test::test_container;
+using __gnu_test::test_range;
+using __gnu_test::input_iterator_wrapper;
+using __gnu_test::output_iterator_wrapper;
+using __gnu_test::forward_iterator_wrapper;
+
+namespace ranges = std::ranges;
+
+void
+test01()
+{
+  const int c[6] = { 1, 2, 3, 4, 5, 6 };
+
+    {
+      int x[6];
+      int a = 1;
+      VERIFY( ranges::generate(x, [&] { return a++; }) == x+6 );
+      VERIFY( ranges::equal(x, c) );
+    }
+
+    {
+      int x[6];
+      int a = 1;
+      test_container<int, forward_iterator_wrapper> cx(x);
+      VERIFY( ranges::generate(cx, [&] { return a++; }) == cx.end() );
+      VERIFY( ranges::equal(cx, c) );
+    }
+
+    {
+      int x[6];
+      int a = 1;
+      test_range<int, output_iterator_wrapper> rx(x);
+      VERIFY( ranges::generate(rx, [&] { return a++; }) == rx.end() );
+      VERIFY( ranges::equal(x, c) );
+    }
+}
+
+constexpr bool
+test02()
+{
+  const int c[6] = { 1, 2, 3, 4, 5, 6 };
+  int x[6];
+  int a = 1;
+  ranges::generate(x, [&] { return a++; });
+  return ranges::equal(x, c);
+}
+
+int
+main()
+{
+  test01();
+  static_assert(test02());
+}
diff --git a/libstdc++-v3/testsuite/25_algorithms/generate_n/constrained.cc b/libstdc++-v3/testsuite/25_algorithms/generate_n/constrained.cc
new file mode 100644
index 0000000..ff894ad
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/generate_n/constrained.cc
@@ -0,0 +1,84 @@
+// Copyright (C) 2020 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++2a" }
+// { dg-do run { target c++2a } }
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+using __gnu_test::test_container;
+using __gnu_test::test_range;
+using __gnu_test::input_iterator_wrapper;
+using __gnu_test::output_iterator_wrapper;
+using __gnu_test::forward_iterator_wrapper;
+
+namespace ranges = std::ranges;
+
+void
+test01()
+{
+  const int c[6] = { 1, 2, 3, 4, 5, 6 };
+
+    {
+      int x[6] = { 7, 8, 9, 4, 5, 6 };
+      int a = 1;
+      VERIFY( ranges::generate_n(x, 3, [&] { return a++; }) == x+3 );
+      VERIFY( ranges::equal(x, c) );
+    }
+
+    {
+      int x[6] = { 7, 8, 9, 4, 5, 6 };
+      int a = 1;
+      test_container<int, forward_iterator_wrapper> cx(x);
+      VERIFY( *ranges::generate_n(cx.begin(), 3, [&] { return a++; })
+	       == 4 );
+      VERIFY( ranges::equal(cx, c) );
+    }
+
+    {
+      int x[6] = { 7, 8, 9, 4, 5, 6 };
+      int a = 1;
+      test_range<int, output_iterator_wrapper> rx(x);
+      ranges::generate_n(ranges::begin(rx), 3, [&] { return a++; });
+      VERIFY( ranges::equal(x, c) );
+    }
+}
+
+constexpr bool
+test02()
+{
+  bool ok = true;
+  int c[6] = { 1, 2, 3, 4, 5, 6 };
+  int x[6];
+  int a = 1;
+  ranges::generate_n(x, 6, [&] { return a++; });
+  ok &= ranges::equal(x, c);
+  ranges::generate_n(c, 0, [] { return -1; });
+  ok &= ranges::equal(x, c);
+  ranges::generate_n(c, -2, [] { return -1; });
+  ok &= ranges::equal(x, c);
+  return ok;
+}
+
+int
+main()
+{
+  test01();
+  static_assert(test02());
+}



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