Various fixes for <codecvt> facets

commit 3118704bc37cd771b9fc5bf83230f38a16a7c5c3
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Mar 14 17:47:12 2017 +0000

    PR libstdc++/80041 fix codecvt_utf16<wchar_t> to use UTF-16 not UTF-8
    
    	PR libstdc++/80041
    	* src/c++11/codecvt.cc (__codecvt_utf16_base<wchar_t>::do_out)
    	(__codecvt_utf16_base<wchar_t>::do_in): Convert char arguments to
    	char16_t to work with UTF-16 instead of UTF-8.
    	* testsuite/22_locale/codecvt/codecvt_utf16/80041.cc: New test.

diff --git a/libstdc++-v3/src/c++11/codecvt.cc b/libstdc++-v3/src/c++11/codecvt.cc
index 9c91725..ef38267 100644
--- a/libstdc++-v3/src/c++11/codecvt.cc
+++ b/libstdc++-v3/src/c++11/codecvt.cc
@@ -1217,7 +1217,10 @@  do_out(state_type&, const intern_type* __from, const intern_type* __from_end,
        extern_type* __to, extern_type* __to_end,
        extern_type*& __to_next) const
 {
-  range<char> to{ __to, __to_end };
+  range<char16_t> to{
+    reinterpret_cast<char16_t*>(__to),
+    reinterpret_cast<char16_t*>(__to_end)
+  };
 #if __SIZEOF_WCHAR_T__ == 2
   range<const char16_t> from{
     reinterpret_cast<const char16_t*>(__from),
@@ -1234,7 +1237,7 @@  do_out(state_type&, const intern_type* __from, const intern_type* __from_end,
   return codecvt_base::error;
 #endif
   __from_next = reinterpret_cast<const wchar_t*>(from.next);
-  __to_next = to.next;
+  __to_next = reinterpret_cast<char*>(to.next);
   return res;
 }
 
@@ -1254,7 +1257,10 @@  do_in(state_type&, const extern_type* __from, const extern_type* __from_end,
       intern_type* __to, intern_type* __to_end,
       intern_type*& __to_next) const
 {
-  range<const char> from{ __from, __from_end };
+  range<const char16_t> from{
+    reinterpret_cast<const char16_t*>(__from),
+    reinterpret_cast<const char16_t*>(__from_end)
+  };
 #if __SIZEOF_WCHAR_T__ == 2
   range<char16_t> to{
     reinterpret_cast<char16_t*>(__to),
@@ -1270,7 +1276,7 @@  do_in(state_type&, const extern_type* __from, const extern_type* __from_end,
 #else
   return codecvt_base::error;
 #endif
-  __from_next = from.next;
+  __from_next = reinterpret_cast<const char*>(from.next);
   __to_next = reinterpret_cast<wchar_t*>(to.next);
   return res;
 }
diff --git a/libstdc++-v3/testsuite/22_locale/codecvt/codecvt_utf16/80041.cc b/libstdc++-v3/testsuite/22_locale/codecvt/codecvt_utf16/80041.cc
new file mode 100644
index 0000000..a78b194
--- /dev/null
+++ b/libstdc++-v3/testsuite/22_locale/codecvt/codecvt_utf16/80041.cc
@@ -0,0 +1,87 @@ 
+// Copyright (C) 2017 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 <codecvt>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+#ifdef _GLIBCXX_USE_WCHAR_T
+  std::codecvt_utf16<wchar_t> conv;
+  const wchar_t wc = 0x6557;
+  char bytes[2] = {0};
+  const wchar_t* wcnext;
+  std::mbstate_t st{};
+  char* next = nullptr;
+  auto res = conv.out(st, &wc, &wc+ 1, wcnext, bytes, std::end(bytes), next);
+  VERIFY( res == std::codecvt_base::ok );
+  VERIFY( wcnext == &wc + 1 );
+  VERIFY( next == std::end(bytes) );
+  VERIFY( bytes[0] == 0x65 );
+  VERIFY( bytes[1] == 0x57 );
+  VERIFY( conv.length(st, bytes, next, 1) == (next - bytes) );
+
+  wchar_t w;
+  wchar_t* wnext;
+  const char* cnext;
+  st = {};
+  res = conv.in(st, bytes, next, cnext, &w, &w + 1, wnext);
+  VERIFY( res == std::codecvt_base::ok );
+  VERIFY( wnext == &w + 1 );
+  VERIFY( cnext == next );
+  VERIFY( w == wc );
+#endif
+}
+
+void
+test02()
+{
+#ifdef _GLIBCXX_USE_WCHAR_T
+  std::codecvt_utf16<wchar_t, 0x10FFFF, std::little_endian> conv;
+  wchar_t wc = 0x6557;
+  char bytes[2] = {0};
+  const wchar_t* wcnext;
+  std::mbstate_t st{};
+  char* next = nullptr;
+  auto res = conv.out(st, &wc, &wc+ 1, wcnext, bytes, std::end(bytes), next);
+  VERIFY( res == std::codecvt_base::ok );
+  VERIFY( wcnext == &wc + 1 );
+  VERIFY( next == std::end(bytes) );
+  VERIFY( bytes[0] == 0x57 );
+  VERIFY( bytes[1] == 0x65 );
+  VERIFY( conv.length(st, bytes, next, 1) == (next - bytes) );
+
+  wchar_t w;
+  wchar_t* wnext;
+  const char* cnext;
+  st = {};
+  res = conv.in(st, bytes, next, cnext, &w, &w + 1, wnext);
+  VERIFY( res == std::codecvt_base::ok );
+  VERIFY( wnext == &w + 1 );
+  VERIFY( cnext == next );
+  VERIFY( w == wc );
+#endif
+}
+
+int main()
+{
+  test01();
+  test02();
+}