Patchwork [libstdc++-v3,C++14] Implement N3654 - Quoted Strings

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Submitter Ed Smith-Rowland
Date June 5, 2013, 7:18 p.m.
Message ID <51AF8F13.80807@verizon.net>
Download mbox | patch
Permalink /patch/249168/
State New
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Comments

Ed Smith-Rowland - June 5, 2013, 7:18 p.m.
Greetings,
This patch implements quoted string manipulators for C++14.

27.7.6 - Quoted manipulators        [quoted.manip].

The idea is to allow round trip insert and extract of strings with spaces.

   std::stringstream ss;
   std::string original = "thing1  thing1";
   std::string round_trip;
   ss << std::quoted(original);
   ss >> std::quoted(round_trip);
   assert( original == round_trip );

Builds and tests clean on x86-64-linux.

Ed Smith-Rowland
2013-06-05  Ed Smith-Rowland  <3dw4rd@verizon.net>

	Implement N3654 - Quoted Strings Library Proposal
	* include/std/iomanip: Add quoted(String, Char delim, Char escape)
	manipulators and supporting machinery in c++1y mode.
	* testsuite/27_io/manipulators/standard/char/quoted.cc: New.
	* testsuite/27_io/manipulators/standard/wchar_t/quoted.cc: New.
Jonathan Wakely - June 5, 2013, 8:01 p.m.
On 5 June 2013 20:18, Ed Smith-Rowland wrote:
> Greetings,
> This patch implements quoted string manipulators for C++14.
>
> 27.7.6 - Quoted manipulators        [quoted.manip].
>
> The idea is to allow round trip insert and extract of strings with spaces.
>
>   std::stringstream ss;
>   std::string original = "thing1  thing1";
>   std::string round_trip;
>   ss << std::quoted(original);
>   ss >> std::quoted(round_trip);
>   assert( original == round_trip );
>
> Builds and tests clean on x86-64-linux.

As I suggested for your literals patch, couldn't the test for:
#if __cplusplus > 201103L
go inside the existing one?

i.e.

#if __cplusplus >= 201103L
[...]
#if __cplusplus > 201103L
[...]
#endif
#endif


_Quoted_string appears to do two copies of the string, one for the
constructor argument and one for the member variable, do they
definitely get elided?

The members of _Quoted_string should be named _M_xxx not __xxx, to
follow the coding style guidelines.

What is __delim2 for?

What if the first extraction in the operator>> fails, is doing
__is.unget() the right thing to do?

You could simplify the quoted() overloads by using auto return type
deduction, is it an intentional choice not to use that?

Patch

Index: include/std/iomanip
===================================================================
--- include/std/iomanip	(revision 199583)
+++ include/std/iomanip	(working copy)
@@ -336,6 +336,160 @@ 
 
 #endif
 
+#if __cplusplus > 201103L
+
+  namespace __detail {
+
+    /**
+     * @brief Struct for delimited strings.
+     *        The left and right delimiters can be different.
+     */
+    template<typename _String, typename _CharT>
+      struct _Quoted_string
+      {
+	_Quoted_string(_String __str, _CharT __del, _CharT __esc)
+	: __string(__str), __delim{__del}, __escape{__esc}, __delim2{__del}
+	{ }
+
+	_Quoted_string(_String __str, _CharT __del, _CharT __esc,
+		       _CharT __del2)
+	: __string(__str), __delim{__del}, __escape{__esc}, __delim2{__del2}
+	{ }
+
+	_Quoted_string&
+	operator=(_Quoted_string&) = delete;
+
+	_String __string;
+	_CharT __delim;
+	_CharT __escape;
+	_CharT __delim2;
+      };
+
+    /**
+     * @brief Inserter for delimited strings.
+     *        The left and right delimiters can be different.
+     */
+    template<typename _CharT, typename _Traits>
+      std::basic_ostream<_CharT, _Traits>&
+      operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		 const _Quoted_string<const _CharT*, _CharT>& __str)
+      {
+	__os << __str.__delim;
+	for (const _CharT* __c = __str.__string; *__c; ++__c)
+	  {
+	    if (*__c == __str.__delim || *__c == __str.__escape)
+	      __os << __str.__escape;
+	    __os << *__c;
+	  }
+	__os << __str.__delim2;
+
+	return __os;
+      }
+
+    /**
+     * @brief Inserter for delimited strings.
+     *        The left and right delimiters can be different.
+     */
+    template<typename _CharT, typename _Traits, typename _String>
+      std::basic_ostream<_CharT, _Traits>&
+      operator<<(std::basic_ostream<_CharT, _Traits>& __os,
+		 const _Quoted_string<_String, _CharT>& __str)
+      {
+	__os << __str.__delim;
+	for (auto& __c : __str.__string)
+	  {
+	    if (__c == __str.__delim || __c == __str.__escape)
+	      __os << __str.__escape;
+	    __os << __c;
+	  }
+	__os << __str.__delim2;
+
+	return __os;
+      }
+
+    /**
+     * @brief Extractor for delimited strings.
+     *        The left and right delimiters can be different.
+     */
+    template<typename _CharT, typename _Traits, typename _Alloc>
+      std::basic_istream<_CharT, _Traits>&
+      operator>>(std::basic_istream<_CharT, _Traits>& __is,
+		 const _Quoted_string<basic_string<_CharT, _Traits, _Alloc>&,
+				      _CharT>& __str)
+      {
+	__str.__string.clear();
+
+	_CharT __c;
+	__is >> __c;
+	if (__c != __str.__delim)
+	  {
+	    __is.unget();
+	    __is >> __str.__string;
+	    return __is;
+	  }
+	std::ios_base::fmtflags __flags
+	  = __is.flags(__is.flags() & ~std::ios_base::skipws);
+	do
+	  {
+	    __is >> __c;
+	    if (!__is.good())
+	      break;
+	    if (__c == __str.__escape)
+	      {
+		__is >> __c;
+		if (!__is.good())
+		  break;
+	      }
+	    else if (__c == __str.__delim2)
+	      break;
+	    __str.__string += __c;
+	  }
+	while (true);
+	__is.setf(__flags);
+
+	return __is;
+      }
+
+  } // namespace __detail
+
+  /**
+   * @brief Manipulator for quoted strings.
+   * @param __str    String to quote.
+   * @param __delim  Character to quote string with.
+   * @param __escape Escape character to escape itself or quote character.
+   */
+  template<typename _CharT>
+    __detail::_Quoted_string<const _CharT*, _CharT>
+    inline quoted(const _CharT* __str,
+	   _CharT __delim = _CharT('"'), _CharT __escape = _CharT('\\'))
+    {
+      return __detail::_Quoted_string<const _CharT*, _CharT>(__str, __delim,
+							     __escape);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    __detail::_Quoted_string<
+		const basic_string<_CharT, _Traits, _Alloc>&, _CharT>
+    inline quoted(const basic_string<_CharT, _Traits, _Alloc>& __str,
+	   _CharT __delim = _CharT('"'), _CharT __escape = _CharT('\\'))
+    {
+      return __detail::_Quoted_string<
+			const basic_string<_CharT, _Traits, _Alloc>&, _CharT>(
+				__str, __delim, __escape);
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    __detail::_Quoted_string<basic_string<_CharT, _Traits, _Alloc>&, _CharT>
+    inline quoted(basic_string<_CharT, _Traits, _Alloc>& __str,
+	   _CharT __delim = _CharT('"'), _CharT __escape = _CharT('\\'))
+    {
+      return __detail::_Quoted_string<
+			basic_string<_CharT, _Traits, _Alloc>&, _CharT>(
+				__str, __delim, __escape);
+    }
+
+#endif
+
   // Inhibit implicit instantiations for required instantiations,
   // which are defined via explicit instantiations elsewhere.  
   // NB:  This syntax is a GNU extension.
Index: testsuite/27_io/manipulators/standard/char/quoted.cc
===================================================================
--- testsuite/27_io/manipulators/standard/char/quoted.cc	(revision 0)
+++ testsuite/27_io/manipulators/standard/char/quoted.cc	(working copy)
@@ -0,0 +1,75 @@ 
+// { dg-do run }
+// { dg-options "-std=gnu++1y" }
+
+// Copyright (C) 2013 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/>.
+
+// 27.7.6 - Quoted manipulators		[quoted.manip]
+
+#include <string>
+#include <sstream>
+#include <iomanip>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  bool test [[gnu::unused]] = true;
+  std::stringstream ss;
+  std::string original = "foolish me";
+  std::string round_trip;
+  ss << std::quoted(original);
+  ss >> std::quoted(round_trip);
+  VERIFY( original == round_trip );
+}
+
+void
+test02()
+{
+  //  Test skipws correctness.
+  bool test [[gnu::unused]] = true;
+  std::stringstream ss;
+  ss << std::quoted("Hello Goodbye") << ' ' << 1 << ' ' << 2;
+  std::string song;
+  int thing1, thing2;
+  ss >> std::quoted(song) >> thing1 >> thing2;
+  VERIFY( song == "Hello Goodbye" );
+  VERIFY( thing1 == 1 );
+  VERIFY( thing2 == 2 );
+}
+
+void
+test03()
+{
+  //  Test read of unquoted string.
+  bool test [[gnu::unused]] = true;
+  std::stringstream ss;
+  ss << "Alpha Omega";
+  std::string testit;
+  ss >> std::quoted(testit);
+  VERIFY( testit == "Alpha" );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+
+  return 0;
+}
Index: testsuite/27_io/manipulators/standard/wchar_t/quoted.cc
===================================================================
--- testsuite/27_io/manipulators/standard/wchar_t/quoted.cc	(revision 0)
+++ testsuite/27_io/manipulators/standard/wchar_t/quoted.cc	(working copy)
@@ -0,0 +1,76 @@ 
+// { dg-do run }
+// { dg-options "-std=gnu++1y" }
+
+// Copyright (C) 2013 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/>.
+
+// 27.7.6 - Quoted manipulators		[quoted.manip]
+
+#include <string>
+#include <sstream>
+#include <iomanip>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  //  Basic test from paper.
+  bool test [[gnu::unused]] = true;
+  std::wstringstream ss;
+  std::wstring original = L"foolish me";
+  std::wstring round_trip;
+  ss << std::quoted(original);
+  ss >> std::quoted(round_trip);
+  VERIFY( original == round_trip );
+}
+
+void
+test02()
+{
+  //  Test skipws correctness.
+  bool test [[gnu::unused]] = true;
+  std::wstringstream ss;
+  ss << std::quoted(L"Hello Goodbye") << L' ' << 1 << L' ' << 2;
+  std::wstring song;
+  int thing1, thing2;
+  ss >> std::quoted(song) >> thing1 >> thing2;
+  VERIFY( song == L"Hello Goodbye" );
+  VERIFY( thing1 == 1 );
+  VERIFY( thing2 == 2 );
+}
+
+void
+test03()
+{
+  //  Test read of unquoted string.
+  bool test [[gnu::unused]] = true;
+  std::wstringstream ss;
+  ss << L"Alpha Omega";
+  std::wstring testit;
+  ss >> std::quoted(testit);
+  VERIFY( testit == L"Alpha" );
+}
+
+int
+main()
+{
+  test01();
+  test02();
+  test03();
+
+  return 0;
+}