PR libstdc++/59568 fix error handling for std::complex stream extraction

	PR libstdc++/59568
	* include/std/complex (operator>>): Implement proposed resolution to
	LWG 2714. Use putback if and only if a character has been successfully
	extracted but isn't a delimiter. Use ctype::widen and traits::eq when
	testing if extracted characters match delimiters.
	* testsuite/26_numerics/complex/dr2714.cc: New test.

From-SVN: r255608

libstdc++-v3/ChangeLog

+2017-12-13  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/59568
+	* include/std/complex (operator>>): Implement proposed resolution to
+	LWG 2714. Use putback if and only if a character has been successfully
+	extracted but isn't a delimiter. Use ctype::widen and traits::eq when
+	testing if extracted characters match delimiters.
+	* testsuite/26_numerics/complex/dr2714.cc: New test.
+
 2017-12-12  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/83395

libstdc++-v3/include/std/complex

@@ -492,31 +492,52 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     basic_istream<_CharT, _Traits>&
     operator>>(basic_istream<_CharT, _Traits>& __is, complex<_Tp>& __x)
     {
-      _Tp __re_x, __im_x;
+      bool __fail = true;
       _CharT __ch;
-      __is >> __ch;
-      if (__ch == '(')
+      if (__is >> __ch)
 	{
-	  __is >> __re_x >> __ch;
-	  if (__ch == ',')
+	  if (_Traits::eq(__ch, __is.widen('(')))
 	    {
-	      __is >> __im_x >> __ch;
-	      if (__ch == ')')
-		__x = complex<_Tp>(__re_x, __im_x);
+	      _Tp __u;
+	      if (__is >> __u >> __ch)
+		{
+		  const _CharT __rparen = __is.widen(')');
+		  if (_Traits::eq(__ch, __rparen))
+		    {
+		      __x = __u;
+		      __fail = false;
+		    }
+		  else if (_Traits::eq(__ch, __is.widen(',')))
+		    {
+		      _Tp __v;
+		      if (__is >> __v >> __ch)
+			{
+			  if (_Traits::eq(__ch, __rparen))
+			    {
+			      __x = complex<_Tp>(__u, __v);
+			      __fail = false;
+			    }
 			  else
-		__is.setstate(ios_base::failbit);
+			    __is.putback(__ch);
+			}
 		    }
-	  else if (__ch == ')')
-	    __x = __re_x;
 		  else
-	    __is.setstate(ios_base::failbit);
+		    __is.putback(__ch);
+		}
 	    }
 	  else
 	    {
 	      __is.putback(__ch);
-	  __is >> __re_x;
-	  __x = __re_x;
+	      _Tp __u;
+	      if (__is >> __u)
+		{
+		  __x = __u;
+		  __fail = false;
+		}
 	    }
+	}
+      if (__fail)
+	__is.setstate(ios_base::failbit);
       return __is;
     }
 

libstdc++-v3/testsuite/26_numerics/complex/dr2714.cc

+// 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-options "-std=gnu++98" }
+
+#include <complex>
+#include <sstream>
+#include <complex>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  std::istringstream in(" 1 (2) ( 2.0 , 0.5 ) ");
+  std::complex<double> c1, c2, c3;
+  in >> c1 >> c2 >> c3;
+  VERIFY( in.good() );
+  VERIFY( c1.real() == 1 && c1.imag() == 0 );
+  VERIFY( c2.real() == 2 && c2.imag() == 0 );
+  VERIFY( c3.real() == 2 && c3.imag() == 0.5 );
+}
+
+void
+test02()
+{
+  std::wistringstream in(L" ( 2.0 , 0.5 ) ");
+  std::complex<double> c;
+  in >> c;
+  VERIFY( in.good() );
+  VERIFY( c.real() == 2.0 && c.imag() == 0.5 );
+}
+
+void
+test03()
+{
+  std::istringstream in;
+  std::complex<double> c(-1, -1);
+  const std::complex<double> c0 = c;
+
+  in.str("a");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+
+  in.str(" ( ) ");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == ')' );
+
+  in.str("(,");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == ',' );
+
+  in.str("(b)");
+  in >> c;
+  VERIFY( in.fail() );
+
+  in.clear();
+  VERIFY( in.get() == 'b' );
+  in.str("( c)");
+
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == 'c' );
+
+  in.str("(99d");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == 'd' );
+
+  in.str("(99 e");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == 'e' );
+
+  in.str("(99, f");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == 'f' );
+
+  in.str("(99, 88g");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == 'g' );
+
+  in.str("(99, 88 h");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == 'h' );
+
+  in.str("(99, )");
+  in >> c;
+  VERIFY( in.fail() );
+  in.clear();
+  VERIFY( in.get() == ')' );
+
+  VERIFY( c == c0 );
+}
+
+void
+test04()
+{
+  // PR libstdc++/59568
+  std::istringstream in;
+  std::complex<double> c;
+
+  in.str("");
+  in >> c;
+  VERIFY( in.fail() );
+  VERIFY( in.eof() );
+  in.clear();
+
+  in.str(" ");
+  in >> c;
+  VERIFY( in.fail() );
+  VERIFY( in.eof() );
+  in.clear();
+
+  in.str("(99");
+  in >> c;
+  VERIFY( in.fail() );
+  VERIFY( in.eof() );
+  in.clear();
+
+  in.str("(99,");
+  in >> c;
+  VERIFY( in.fail() );
+  VERIFY( in.eof() );
+  in.clear();
+
+  in.str("(99,99");
+  in >> c;
+  VERIFY( in.fail() );
+  VERIFY( in.eof() );
+  in.clear();
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+  test04();
+}