Implement C++17 P0025 clamp.

2016-07-15  Edward Smith-Rowland  <3dw4rd@verizon.net>

	Implement C++17 P0025 clamp.
	* include/bits/algorithmfwd.h: Declare clamp overloads.
	* include/bits/stl_algo.h: Implement clamp.  Feature __cpp_lib_clamp.
	* testsuite/25_algorithms/clamp/1.cc: New test.
	* testsuite/25_algorithms/clamp/2.cc: New test.
	* testsuite/25_algorithms/clamp/constexpr.cc: New test.
	* testsuite/25_algorithms/clamp/requirements/explicit_instantiation/
	1.cc: New test.
	* testsuite/25_algorithms/clamp/requirements/explicit_instantiation/
	pod.cc: New test.

From-SVN: r238383

8 files changed, 329 insertions, 1 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 2386300..25b8191 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,16 @@
+2016-07-15  Edward Smith-Rowland  <3dw4rd@verizon.net>
+
+	Implement C++17 P0025 clamp.
+	* include/bits/algorithmfwd.h: Declare clamp overloads.
+	* include/bits/stl_algo.h: Implement clamp.  Feature __cpp_lib_clamp.
+	* testsuite/25_algorithms/clamp/1.cc: New test.
+	* testsuite/25_algorithms/clamp/2.cc: New test.
+	* testsuite/25_algorithms/clamp/constexpr.cc: New test.
+	* testsuite/25_algorithms/clamp/requirements/explicit_instantiation/
+	1.cc: New test.
+	* testsuite/25_algorithms/clamp/requirements/explicit_instantiation/
+	pod.cc: New test.
+
 2016-07-14  Ville Voutilainen  <ville.voutilainen@gmail.com>
 
 	Fix the constraints for any's assignment operator template to properly
diff --git a/libstdc++-v3/include/bits/algorithmfwd.h b/libstdc++-v3/include/bits/algorithmfwd.h
index cd98fe0..1defb1d 100644
--- a/libstdc++-v3/include/bits/algorithmfwd.h
+++ b/libstdc++-v3/include/bits/algorithmfwd.h
@@ -48,6 +48,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     all_of (C++0x)
     any_of (C++0x)
     binary_search
+    clamp (C++17)
     copy
     copy_backward
     copy_if (C++0x)
@@ -208,6 +209,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     bool 
     binary_search(_FIter, _FIter, const _Tp&, _Compare);
 
+#if __cplusplus > 201402L
+  template<typename _Tp>
+    _GLIBCXX14_CONSTEXPR
+    const _Tp&
+    clamp(const _Tp&, const _Tp&, const _Tp&);
+
+  template<typename _Tp, typename _Compare>
+    _GLIBCXX14_CONSTEXPR
+    const _Tp&
+    clamp(const _Tp&, const _Tp&, const _Tp&, _Compare);
+#endif
+
   template<typename _IIter, typename _OIter>
     _OIter 
     copy(_IIter, _IIter, _OIter);
diff --git a/libstdc++-v3/include/bits/stl_algo.h b/libstdc++-v3/include/bits/stl_algo.h
index c2ac031..a0820d4 100644
--- a/libstdc++-v3/include/bits/stl_algo.h
+++ b/libstdc++-v3/include/bits/stl_algo.h
@@ -3698,7 +3698,46 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       return std::__is_permutation(__first1, __last1, __first2, __last2,
 				   __gnu_cxx::__ops::__iter_comp_iter(__pred));
     }
-#endif
+
+#if __cplusplus > 201402L
+
+#define __cpp_lib_clamp 201603
+
+  /**
+   *  @brief  Returns the value clamped between lo and hi.
+   *  @ingroup sorting_algorithms
+   *  @param  __val  A value of arbitrary type.
+   *  @param  __lo   A lower limit of arbitrary type.
+   *  @param  __hi   An upper limit of arbitrary type.
+   *  @return max(__val, __lo) if __val < __hi or min(__val, __hi) otherwise.
+   */
+  template<typename _Tp>
+    constexpr const _Tp&
+    clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi)
+    {
+      __glibcxx_assert(!(__hi < __lo));
+      return (__val < __lo) ? __lo : (__hi < __val) ? __hi : __val;
+    }
+
+  /**
+   *  @brief  Returns the value clamped between lo and hi.
+   *  @ingroup sorting_algorithms
+   *  @param  __val   A value of arbitrary type.
+   *  @param  __lo    A lower limit of arbitrary type.
+   *  @param  __hi    An upper limit of arbitrary type.
+   *  @param  __comp  A comparison functor.
+   *  @return max(__val, __lo, __comp) if __comp(__val, __hi)
+   *	      or min(__val, __hi, __comp) otherwise.
+   */
+  template<typename _Tp, typename _Compare>
+    constexpr const _Tp&
+    clamp(const _Tp& __val, const _Tp& __lo, const _Tp& __hi, _Compare __comp)
+    {
+      __glibcxx_assert(!__comp(__hi, __lo));
+      return __comp(__val, __lo) ? __lo : __comp(__hi, __val) ? __hi : __val;
+    }
+#endif // C++17
+#endif // C++14
 
 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
   /**
diff --git a/libstdc++-v3/testsuite/25_algorithms/clamp/1.cc b/libstdc++-v3/testsuite/25_algorithms/clamp/1.cc
new file mode 100644
index 0000000..cf2e131
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/clamp/1.cc
@@ -0,0 +1,48 @@
+// { dg-options "-std=gnu++17" }
+
+// Copyright (C) 2016 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/>.
+
+#include <algorithm>
+#include <functional>
+#include <testsuite_hooks.h>
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  const int x = std::clamp(1, 2, 4);
+  const int y = std::clamp(3, 2, 4);
+  const int z = std::clamp(5, 2, 4);
+  VERIFY( x == 2 );
+  VERIFY( y == 3 );
+  VERIFY( z == 4 );
+
+  const int xc = std::clamp(1, 2, 4, std::greater<int>());
+  const int yc = std::clamp(3, 2, 4, std::greater<int>());
+  const int zc = std::clamp(5, 2, 4, std::greater<int>());
+  VERIFY( xc == 4 );
+  VERIFY( yc == 2 );
+  VERIFY( zc == 2 );
+}
+
+int
+main()
+{
+  test01();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/25_algorithms/clamp/2.cc b/libstdc++-v3/testsuite/25_algorithms/clamp/2.cc
new file mode 100644
index 0000000..50c1a51
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/clamp/2.cc
@@ -0,0 +1,102 @@
+// { dg-options "-std=gnu++17" }
+
+// Copyright (C) 2000-2016 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/>.
+
+#include <algorithm>
+#include <functional>
+#include <testsuite_hooks.h>
+
+template<typename T>
+  struct A { static const T a; };
+
+template<typename T>
+const T A<T>::a = T(3);
+
+void test02()
+{
+  bool test __attribute__((unused)) = true;
+
+  VERIFY( 3 == std::clamp(A<int>::a, 2, 4) );
+  VERIFY( 2 == std::clamp(A<int>::a, 1, 2) );
+  VERIFY( 4 == std::clamp(A<int>::a, 4, 6) );
+
+  VERIFY( 3u == std::clamp(A<unsigned int>::a, 2u, 4u) );
+  VERIFY( 2u == std::clamp(A<unsigned int>::a, 1u, 2u) );
+  VERIFY( 4u == std::clamp(A<unsigned int>::a, 4u, 6u) );
+
+  VERIFY( 3l == std::clamp(A<long>::a, 2l, 4l) );
+  VERIFY( 2l == std::clamp(A<long>::a, 1l, 2l) );
+  VERIFY( 4l == std::clamp(A<long>::a, 4l, 6l) );
+
+  VERIFY( 3ul == std::clamp(A<unsigned long>::a, 2ul, 4ul) );
+  VERIFY( 2ul == std::clamp(A<unsigned long>::a, 1ul, 2ul) );
+  VERIFY( 4ul == std::clamp(A<unsigned long>::a, 4ul, 6ul) );
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+  VERIFY( 3ll == std::clamp(A<long long>::a, 2ll, 4ll) );
+  VERIFY( 2ll == std::clamp(A<long long>::a, 1ll, 2ll) );
+  VERIFY( 4ll == std::clamp(A<long long>::a, 4ll, 6ll) );
+
+  VERIFY( 3ull == std::clamp(A<unsigned long long>::a, 2ull, 4ull) );
+  VERIFY( 2ull == std::clamp(A<unsigned long long>::a, 1ull, 2ull) );
+  VERIFY( 4ull == std::clamp(A<unsigned long long>::a, 4ull, 6ull) );
+#endif
+
+  VERIFY( (short)3 == std::clamp(A<short>::a, (short)2, (short)4) );
+  VERIFY( (short)2 == std::clamp(A<short>::a, (short)1, (short)2) );
+  VERIFY( (short)4 == std::clamp(A<short>::a, (short)4, (short)6) );
+
+  VERIFY( (unsigned short)3 == std::clamp(A<unsigned short>::a, (unsigned short)2, (unsigned short)4) );
+  VERIFY( (unsigned short)2 == std::clamp(A<unsigned short>::a, (unsigned short)1, (unsigned short)2) );
+  VERIFY( (unsigned short)4 == std::clamp(A<unsigned short>::a, (unsigned short)4, (unsigned short)6) );
+
+  VERIFY( (char)3 == std::clamp(A<char>::a, (char)2, (char)4) );
+  VERIFY( (char)2 == std::clamp(A<char>::a, (char)1, (char)2) );
+  VERIFY( (char)4 == std::clamp(A<char>::a, (char)4, (char)6) );
+
+  VERIFY( (signed char)3 == std::clamp(A<signed char>::a, (signed char)2, (signed char)4) );
+  VERIFY( (signed char)2 == std::clamp(A<signed char>::a, (signed char)1, (signed char)2) );
+  VERIFY( (signed char)4 == std::clamp(A<signed char>::a, (signed char)4, (signed char)6) );
+
+  VERIFY( (unsigned char)3 == std::clamp(A<unsigned char>::a, (unsigned char)2, (unsigned char)4) );
+  VERIFY( (unsigned char)2 == std::clamp(A<unsigned char>::a, (unsigned char)1, (unsigned char)2) );
+  VERIFY( (unsigned char)4 == std::clamp(A<unsigned char>::a, (unsigned char)4, (unsigned char)6) );
+
+  VERIFY( (wchar_t)3 == std::clamp(A<wchar_t>::a, (wchar_t)2, (wchar_t)4) );
+  VERIFY( (wchar_t)2 == std::clamp(A<wchar_t>::a, (wchar_t)1, (wchar_t)2) );
+  VERIFY( (wchar_t)4 == std::clamp(A<wchar_t>::a, (wchar_t)4, (wchar_t)6) );
+
+  VERIFY( 3.0 == std::clamp(A<double>::a, 2.0, 4.0) );
+  VERIFY( 2.0 == std::clamp(A<double>::a, 1.0, 2.0) );
+  VERIFY( 4.0 == std::clamp(A<double>::a, 4.0, 6.0) );
+
+  VERIFY( 3.0f == std::clamp(A<float>::a, 2.0f, 4.0f) );
+  VERIFY( 2.0f == std::clamp(A<float>::a, 1.0f, 2.0f) );
+  VERIFY( 4.0f == std::clamp(A<float>::a, 4.0f, 6.0f) );
+
+  VERIFY( 3.0l == std::clamp(A<long double>::a, 2.0l, 4.0l) );
+  VERIFY( 2.0l == std::clamp(A<long double>::a, 1.0l, 2.0l) );
+  VERIFY( 4.0l == std::clamp(A<long double>::a, 4.0l, 6.0l) );
+}
+
+int
+main()
+{
+  test02();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/25_algorithms/clamp/constexpr.cc b/libstdc++-v3/testsuite/25_algorithms/clamp/constexpr.cc
new file mode 100644
index 0000000..4ff8798
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/clamp/constexpr.cc
@@ -0,0 +1,31 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do compile }
+
+// Copyright (C) 2016 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/>.
+
+#include <algorithm>
+#include <functional>
+
+#ifndef __cpp_lib_clamp
+# error "Feature-test macro for clamp missing"
+#elif __cpp_lib_clamp != 201603
+# error "Feature-test macro for clamp has wrong value"
+#endif
+
+static_assert(std::clamp(2, 0, 1) == 1, "");
+static_assert(std::clamp(2, 0, 1, std::greater<int>()) == 0, "");
diff --git a/libstdc++-v3/testsuite/25_algorithms/clamp/requirements/explicit_instantiation/1.cc b/libstdc++-v3/testsuite/25_algorithms/clamp/requirements/explicit_instantiation/1.cc
new file mode 100644
index 0000000..d8bf8d6
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/clamp/requirements/explicit_instantiation/1.cc
@@ -0,0 +1,44 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do compile }
+
+// Copyright (C) 2016 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/>.
+
+#include <algorithm>
+#include <functional>
+#include <testsuite_api.h>
+
+#ifndef __cpp_lib_clamp
+# error "Feature-test macro for clamp missing"
+#elif __cpp_lib_clamp != 201603
+# error "Feature-test macro for clamp has wrong value"
+#endif
+
+namespace std
+{
+  using __gnu_test::NonDefaultConstructible;
+
+  typedef NonDefaultConstructible	value_type;
+  typedef value_type*			iterator_type;
+  typedef std::less<value_type>		compare_type;
+
+  template const value_type& clamp(const value_type&,
+				   const value_type&, const value_type&);
+  template const value_type& clamp(const value_type&,
+				   const value_type&, const value_type&,
+				   compare_type);
+}
diff --git a/libstdc++-v3/testsuite/25_algorithms/clamp/requirements/explicit_instantiation/pod.cc b/libstdc++-v3/testsuite/25_algorithms/clamp/requirements/explicit_instantiation/pod.cc
new file mode 100644
index 0000000..acb6d0f
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/clamp/requirements/explicit_instantiation/pod.cc
@@ -0,0 +1,38 @@
+// { dg-options "-std=gnu++17" }
+// { dg-do compile }
+
+// Copyright (C) 2016 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/>.
+
+
+#include <algorithm>
+#include <testsuite_character.h>
+
+namespace std
+{
+  using __gnu_test::pod_int;
+
+  typedef pod_int 		value_type;
+  typedef value_type* 		iterator_type;
+  typedef std::less<value_type> compare_type;
+
+  template const value_type& clamp(const value_type&,
+				   const value_type&, const value_type&);
+  template const value_type& clamp(const value_type&,
+				   const value_type&, const value_type&,
+				   compare_type);
+}