PR libstdc++/64797

	* include/bits/locale_conv.h (wstring_convert::_M_conv): Handle
	incomplete multibyte sequences correctly.
	* include/std/codecvt (codecvt_utf8, codecvt_utf16,
	codecvt_utf8_utf16): Limit _Maxcode to maximum Unicode code point.
	* src/c++11/codecvt.cc (invalid_mb_sequence, incomplete_mb_character):
	Define constants.
	(is_high_surrogate, is_low_surrogate, surrogate_pair_to_code_point):
	Define convenience functions.
	(read_utf8_code_point): Return relevant constant to distinguish
	incomplete characters from invalid sequences.
	(read_utf16_code_point): Likewise. Check for invalid sequences.
	(ucs4_in, utf16_in): Use incomplete_mb_character constant.
	(utf16_out): Check for invalid sequences.
	(utf16_span): Fix condition.
	(ucs2_out): Use is_high_surrogate.
	(ucs2_in): Use incomplete_mb_character constant and fix condition.
	* testsuite/22_locale/codecvt/char16_t.cc: Fix whitespace.
	* testsuite/22_locale/conversions/buffer/1.cc: New.
	* testsuite/22_locale/conversions/string/2.cc: Use char16_t and
	char32_t instead of wchar_t.
	* testsuite/22_locale/conversions/string/3.cc: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@221189 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 5 insertions, 3 deletions

diff --git a/libstdc++-v3/include/bits/locale_conv.h b/libstdc++-v3/include/bits/locale_conv.h
index c8a44f42421..b53754d1541 100644
--- a/libstdc++-v3/include/bits/locale_conv.h
+++ b/libstdc++-v3/include/bits/locale_conv.h
@@ -198,18 +198,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  auto __outstr = __err ? _OutStr(__err->get_allocator()) : _OutStr();
 	  size_t __outchars = 0;
 	  auto __next = __first;
+	  const auto __maxlen = _M_cvt->max_length();
 
 	  codecvt_base::result __result;
 	  do
 	    {
-	      __outstr.resize(__outstr.size() + (__last - __next));
+	      __outstr.resize(__outstr.size() + (__last - __next) + __maxlen);
 	      auto __outnext = &__outstr.front() + __outchars;
 	      auto const __outlast = &__outstr.back() + 1;
 	      __result = ((*_M_cvt).*__memfn)(_M_state, __next, __last, __next,
 					    __outnext, __outlast, __outnext);
 	      __outchars = __outnext - &__outstr.front();
 	    }
-	  while (__result == codecvt_base::partial && __next != __last);
+	  while (__result == codecvt_base::partial && __next != __last
+		 && (__outstr.size() - __outchars) < __maxlen);
 
 	  __outstr.resize(__outchars);
 	  _M_count = __next - __first;
@@ -428,7 +430,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	      return _M_put(__next, __pending);
 
 	    if (!_M_put(__outbuf, __outnext - __outbuf))
-		return false;
+	      return false;
 	  }
 	while (__next != __last && __next != __start);