re PR libstdc++/61374 (string_view::operator string() is buggy)

	PR libstdc++/61374
	* include/experimental/string_view (operator basic_string): Correct
	order of arguments.
	(to_string): Replace with member function.
	Add inline specifiers. Remove unused header. Remove _S_empty_rep and
	allow _M_str to be null.
	* testsuite/experimental/string_view/cons/char/1.cc: Adjust to new
	default constructor semantics.
	* testsuite/experimental/string_view/cons/wchar_t/1.cc: Likewise.
	* testsuite/experimental/string_view/operations/copy/char/1.cc: Fix
	copyright dates. Remove unused header.
	* testsuite/experimental/string_view/operations/copy/wchar_t/1.cc:
	Likewise.
	* testsuite/experimental/string_view/operations/data/char/1.cc:
	Fix copyright dates. Adjust to new default constructor semantics.
	* testsuite/experimental/string_view/operations/data/wchar_t/1.cc:
	Likewise.
	* testsuite/experimental/string_view/operations/to_string/1.cc: New.

From-SVN: r211113

10 files changed, 129 insertions, 87 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 203ea7d..4d69c25 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,24 @@
+2014-06-01  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/61374
+	* include/experimental/string_view (operator basic_string): Correct
+	order of arguments.
+	(to_string): Replace with member function.
+	Add inline specifiers. Remove unused header. Remove _S_empty_rep and
+	allow _M_str to be null.
+	* testsuite/experimental/string_view/cons/char/1.cc: Adjust to new
+	default constructor semantics.
+	* testsuite/experimental/string_view/cons/wchar_t/1.cc: Likewise.
+	* testsuite/experimental/string_view/operations/copy/char/1.cc: Fix
+	copyright dates. Remove unused header.
+	* testsuite/experimental/string_view/operations/copy/wchar_t/1.cc:
+	Likewise.
+	* testsuite/experimental/string_view/operations/data/char/1.cc:
+	Fix copyright dates. Adjust to new default constructor semantics.
+	* testsuite/experimental/string_view/operations/data/wchar_t/1.cc:
+	Likewise.
+	* testsuite/experimental/string_view/operations/to_string/1.cc: New.
+
 2014-05-30  Jonathan Wakely  <jwakely@redhat.com>
 
 	* testsuite/lib/libstdc++.exp (libstdc++_init): Adjust regexp to
diff --git a/libstdc++-v3/include/experimental/string_view b/libstdc++-v3/include/experimental/string_view
index 6b6588b..49f46af 100644
--- a/libstdc++-v3/include/experimental/string_view
+++ b/libstdc++-v3/include/experimental/string_view
@@ -39,7 +39,6 @@
 # include <bits/c++14_warning.h>
 #else
 
-#include <debug/debug.h>
 #include <string>
 #include <limits>
 
@@ -66,18 +65,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
    *    _CharT*    _M_str
    *    size_t     _M_len
    *  @endcode
-   *
-   *  A basic_string_view represents an empty string with a static constexpr
-   *  length one string:
-   *
-   *  @code
-   *    static constexpr value_type _S_empty_str[1]{0};
-   *  @endcode
    */
-  template<typename _CharT, typename _Traits = char_traits<_CharT>>
+  template<typename _CharT, typename _Traits = std::char_traits<_CharT>>
     class basic_string_view
     {
-
     public:
 
       // types
@@ -99,7 +90,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       constexpr
       basic_string_view() noexcept
-      : _M_len{0}, _M_str{_S_empty_str}
+      : _M_len{0}, _M_str{nullptr}
       { }
 
       constexpr basic_string_view(const basic_string_view&) noexcept = default;
@@ -112,12 +103,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       constexpr basic_string_view(const _CharT* __str)
       : _M_len{__str == nullptr ? 0 : traits_type::length(__str)},
-	_M_str{__str == nullptr ? _S_empty_str : __str}
+	_M_str{__str}
       { }
 
       constexpr basic_string_view(const _CharT* __str, size_type __len)
-      : _M_len{__str == nullptr ? 0 :__len},
-        _M_str{__str == nullptr ? _S_empty_str : __str}
+      : _M_len{__len},
+        _M_str{__str}
       { }
 
       basic_string_view&
@@ -143,19 +134,19 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       const_reverse_iterator
       rbegin() const noexcept
-      { return std::reverse_iterator<const_iterator>(this->end()); }
+      { return const_reverse_iterator(this->end()); }
 
       const_reverse_iterator
       rend() const noexcept
-      { return std::reverse_iterator<const_iterator>(this->begin()); }
+      { return const_reverse_iterator(this->begin()); }
 
       const_reverse_iterator
       crbegin() const noexcept
-      { return std::reverse_iterator<const_iterator>(this->end()); }
+      { return const_reverse_iterator(this->end()); }
 
       const_reverse_iterator
       crend() const noexcept
-      { return std::reverse_iterator<const_iterator>(this->begin()); }
+      { return const_reverse_iterator(this->begin()); }
 
       // [string.view.capacity], capacity
 
@@ -169,8 +160,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       constexpr size_type
       max_size() const noexcept
-      { return ((npos - sizeof(size_type) - sizeof(void*))
-		/ sizeof(value_type) / 4); }
+      {
+	return (npos - sizeof(size_type) - sizeof(void*))
+		/ sizeof(value_type) / 4;
+      }
 
       constexpr bool
       empty() const noexcept
@@ -195,7 +188,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 					     "(which is %zu) >= this->size() "
 					     "(which is %zu)"),
 					 __pos, this->size()),
-		_S_empty_str[0]);
+		*this->_M_str);
       }
 
       constexpr const _CharT&
@@ -219,11 +212,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { return this->_M_str; }
 
       // [string.view.modifiers], modifiers:
+
       void
       clear() noexcept
       {
 	this->_M_len = 0;
-	this->_M_str = _S_empty_str;
+	this->_M_str = nullptr;
       }
 
       void
@@ -251,8 +245,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       template<typename _Allocator>
         explicit operator basic_string<_CharT, _Traits, _Allocator>() const
         {
-	  return basic_string<_CharT, _Traits, _Allocator>
-					(this->_M_len, this->_M_str);
+	  return { this->_M_str, this->_M_len };
+	}
+
+      template<typename _Allocator = std::allocator<_CharT>>
+	basic_string<_CharT, _Traits, _Allocator>
+	to_string(const _Allocator& __alloc = _Allocator()) const
+	{
+	  return { this->_M_str, this->_M_len, __alloc };
 	}
 
       size_type
@@ -431,8 +431,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	     : static_cast<int>(difference_type{__n1 - __n2});
       }
 
-      static constexpr value_type _S_empty_str[1]{};
-
       size_t	    _M_len;
       const _CharT* _M_str;
     };
@@ -456,131 +454,119 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator==(basic_string_view<_CharT, _Traits> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) == 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator==(basic_string_view<_CharT, _Traits> __x,
                __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
     { return __x.compare(__y) == 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator==(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) == 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator!=(basic_string_view<_CharT, _Traits> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return !(__x == __y); }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator!=(basic_string_view<_CharT, _Traits> __x,
                __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
     { return !(__x == __y); }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator!=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return !(__x == __y); }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator< (basic_string_view<_CharT, _Traits> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) < 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator< (basic_string_view<_CharT, _Traits> __x,
                __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
     { return __x.compare(__y) < 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator< (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) < 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator> (basic_string_view<_CharT, _Traits> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) > 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator> (basic_string_view<_CharT, _Traits> __x,
                __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
     { return __x.compare(__y) > 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator> (__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) > 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator<=(basic_string_view<_CharT, _Traits> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) <= 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator<=(basic_string_view<_CharT, _Traits> __x,
                __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
     { return __x.compare(__y) <= 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator<=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) <= 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator>=(basic_string_view<_CharT, _Traits> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) >= 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator>=(basic_string_view<_CharT, _Traits> __x,
                __detail::__idt<basic_string_view<_CharT, _Traits>> __y) noexcept
     { return __x.compare(__y) >= 0; }
 
   template<typename _CharT, typename _Traits>
-    bool
+    inline bool
     operator>=(__detail::__idt<basic_string_view<_CharT, _Traits>> __x,
                basic_string_view<_CharT, _Traits> __y) noexcept
     { return __x.compare(__y) >= 0; }
 
-  // [string.view.comparison], sufficient additional overloads of comparison functions
-
-  // [string.view.nonmem], other non-member basic_string_view functions
-  template<typename _CharT, typename _Traits = char_traits<_CharT>,
-           typename _Allocator = allocator<_CharT>>
-    basic_string<_CharT, _Traits, _Allocator>
-    to_string(basic_string_view<_CharT, _Traits> __str,
-	      const _Allocator& __alloc = _Allocator())
-    {
-      return basic_string<_CharT, _Traits, _Allocator>
-			(__str.begin(), __str.end(), __alloc);
-    }
-
+  // [string.view.io], Inserters and extractors
   template<typename _CharT, typename _Traits>
-    basic_ostream<_CharT, _Traits>&
-      operator<<(basic_ostream<_CharT, _Traits>& __os,
-                 basic_string_view<_CharT,_Traits> __str)
-      { return __ostream_insert(__os, __str.data(), __str.size()); }
+    inline basic_ostream<_CharT, _Traits>&
+    operator<<(basic_ostream<_CharT, _Traits>& __os,
+	       basic_string_view<_CharT,_Traits> __str)
+    { return __ostream_insert(__os, __str.data(), __str.size()); }
 
 
   // basic_string_view typedef names
diff --git a/libstdc++-v3/include/experimental/string_view.tcc b/libstdc++-v3/include/experimental/string_view.tcc
index 1af3a4d..4456266 100644
--- a/libstdc++-v3/include/experimental/string_view.tcc
+++ b/libstdc++-v3/include/experimental/string_view.tcc
@@ -47,10 +47,6 @@ namespace experimental
 _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   template<typename _CharT, typename _Traits>
-    constexpr _CharT
-    basic_string_view<_CharT, _Traits>::_S_empty_str[1];
-
-  template<typename _CharT, typename _Traits>
     typename basic_string_view<_CharT, _Traits>::size_type
     basic_string_view<_CharT, _Traits>::
     find(const _CharT* __str, size_type __pos, size_type __n) const noexcept
diff --git a/libstdc++-v3/testsuite/experimental/string_view/cons/char/1.cc b/libstdc++-v3/testsuite/experimental/string_view/cons/char/1.cc
index c879cc7..a443b0a 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/cons/char/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/cons/char/1.cc
@@ -33,7 +33,7 @@ test01()
   // basic_string_view()
   const std::experimental::string_view str00{};
   VERIFY( str00.length() == 0 );
-  VERIFY( str00.data() != nullptr );
+  VERIFY( str00.data() == nullptr );
 
   // basic_string_view(const char*)
   const char str_lit01[] = "rodeo beach, marin";
@@ -54,11 +54,6 @@ test01()
   VERIFY( str05.length() == len_lit01 );
   VERIFY( str05.data() == str_lit01 );
 
-  //  basic_string_view(const char* s, std::size_t l)
-  std::experimental::string_view str06{nullptr, len_lit01};
-  VERIFY( str06.length() == 0 );
-  VERIFY( str06.data() != nullptr );
-
   // basic_string_view(basic_string& s)
   std::string istr07(10, 'z');
   std::experimental::string_view str07{istr07};
diff --git a/libstdc++-v3/testsuite/experimental/string_view/cons/wchar_t/1.cc b/libstdc++-v3/testsuite/experimental/string_view/cons/wchar_t/1.cc
index 12db72f..9ba9b84 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/cons/wchar_t/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/cons/wchar_t/1.cc
@@ -33,7 +33,7 @@ test01()
   // basic_string_view()
   const std::experimental::wstring_view str00{};
   VERIFY( str00.length() == 0 );
-  VERIFY( str00.data() != nullptr );
+  VERIFY( str00.data() == nullptr );
 
   // basic_string_view(const char*)
   const wchar_t str_lit01[] = L"rodeo beach, marin";
@@ -54,11 +54,6 @@ test01()
   VERIFY( str05.length() == len_lit01 );
   VERIFY( str05.data() == str_lit01 );
 
-  //  basic_string_view(const wchar_t* s, std::size_t l)
-  std::experimental::wstring_view str06{nullptr, len_lit01};
-  VERIFY( str06.length() == 0 );
-  VERIFY( str06.data() != nullptr );
-
   // basic_string_view(basic_string& s)
   std::wstring istr07(10, L'z');
   std::experimental::wstring_view str07{istr07};
diff --git a/libstdc++-v3/testsuite/experimental/string_view/operations/copy/char/1.cc b/libstdc++-v3/testsuite/experimental/string_view/operations/copy/char/1.cc
index 25b2af1..d0f3e8d 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/operations/copy/char/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/operations/copy/char/1.cc
@@ -1,6 +1,6 @@
 // { dg-options "-std=gnu++1y" }
 
-// Copyright (C) 2013 Free Software Foundation, Inc.
+// Copyright (C) 2013-2014 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
@@ -20,7 +20,6 @@
 // basic_string_view::copy
 
 #include <experimental/string_view>
-#include <stdexcept>
 #include <testsuite_hooks.h>
 
 bool
diff --git a/libstdc++-v3/testsuite/experimental/string_view/operations/copy/wchar_t/1.cc b/libstdc++-v3/testsuite/experimental/string_view/operations/copy/wchar_t/1.cc
index 0348e1f..bf3f14b 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/operations/copy/wchar_t/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/operations/copy/wchar_t/1.cc
@@ -1,6 +1,6 @@
 // { dg-options "-std=gnu++1y" }
 
-// Copyright (C) 2013 Free Software Foundation, Inc.
+// Copyright (C) 2013-2014 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
@@ -20,7 +20,6 @@
 // basic_string_view::copy
 
 #include <experimental/string_view>
-#include <stdexcept>
 #include <testsuite_hooks.h>
 
 bool
diff --git a/libstdc++-v3/testsuite/experimental/string_view/operations/data/char/1.cc b/libstdc++-v3/testsuite/experimental/string_view/operations/data/char/1.cc
index be75de9..a344926 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/operations/data/char/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/operations/data/char/1.cc
@@ -1,6 +1,6 @@
 // { dg-options "-std=gnu++1y" }
 
-// Copyright (C) 2013 Free Software Foundation, Inc.
+// Copyright (C) 2013-2014 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
@@ -29,10 +29,9 @@ test01()
 
   std::experimental::string_view empty;
 
-  // data() for size == 0 is non-NULL.
   VERIFY( empty.size() == 0 );
   const std::experimental::string_view::value_type* p = empty.data();
-  VERIFY( p );
+  VERIFY( p == nullptr );
 
   return 0;
 }
diff --git a/libstdc++-v3/testsuite/experimental/string_view/operations/data/wchar_t/1.cc b/libstdc++-v3/testsuite/experimental/string_view/operations/data/wchar_t/1.cc
index 5e00b00..41d2d14 100644
--- a/libstdc++-v3/testsuite/experimental/string_view/operations/data/wchar_t/1.cc
+++ b/libstdc++-v3/testsuite/experimental/string_view/operations/data/wchar_t/1.cc
@@ -1,6 +1,6 @@
 // { dg-options "-std=gnu++1y" }
 
-// Copyright (C) 2013 Free Software Foundation, Inc.
+// Copyright (C) 2013-2014 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
@@ -29,10 +29,9 @@ test01()
 
   std::experimental::wstring_view empty;
 
-  // data() for size == 0 is non-NULL.
   VERIFY( empty.size() == 0 );
   const std::experimental::wstring_view::value_type* p = empty.data();
-  VERIFY( p );
+  VERIFY( p == nullptr );
 
   return 0;
 }
diff --git a/libstdc++-v3/testsuite/experimental/string_view/operations/to_string/1.cc b/libstdc++-v3/testsuite/experimental/string_view/operations/to_string/1.cc
new file mode 100644
index 0000000..c0a5734
--- /dev/null
+++ b/libstdc++-v3/testsuite/experimental/string_view/operations/to_string/1.cc
@@ -0,0 +1,53 @@
+// { dg-options "-std=gnu++1y" }
+
+// Copyright (C) 2014 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/>.
+
+// basic_string_view::to_string
+
+#include <experimental/string_view>
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_allocator.h>
+
+bool
+test01()
+{
+  bool test [[gnu::unused]] = true;
+
+  const char str_lit[] = "123456789A";
+  const std::experimental::string_view sv(str_lit);
+  char buffer[4] = { 0 };
+
+  auto s1 = sv.to_string();
+  VERIFY( s1 == str_lit );
+  using test_alloc = __gnu_test::tracker_allocator<char>;
+  auto s2 = sv.to_string( test_alloc{} );
+  static_assert( std::is_same<decltype(s2)::allocator_type, test_alloc>::value,
+                 "to_string() uses custom allocator" );
+  VERIFY( std::equal(s1.begin(), s1.end(), s2.begin(), s2.end()) );
+  auto s3 = static_cast<std::string>(sv);
+  VERIFY( s3 == s1 );
+
+  return test;
+}
+
+int
+main()
+{
+  test01();
+}