re PR libstdc++/22515 (operator>>(istream, string/CharT*) can be faster)

2005-07-24  Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/22515
	* include/bits/basic_string.h: Declare the specialization
	operator>>(basic_istream<char>&, basic_string<char>&).
	* include/std/std_istream.h: Declate the specialization
	operator>>(basic_istream<char>&, char*).
	* include/std/std_streambuf.h (basic_streambuf): Add friend
	declarations for the above.
	* src/istream.cc: Define the above.
	* testsuite/27_io/basic_istream/extractors_character/char/4.cc: New.
	* testsuite/27_io/basic_istream/extractors_character/wchar_t/4.cc:
	Likewise.
	* testsuite/performance/27_io/ifstream_extract_chars.cc: Likewise.

From-SVN: r102353

libstdc++-v3/ChangeLog

+2005-07-24  Paolo Carlini  <pcarlini@suse.de>
+
+	PR libstdc++/22515
+	* include/bits/basic_string.h: Declare the specialization
+	operator>>(basic_istream<char>&, basic_string<char>&).
+	* include/std/std_istream.h: Declate the specialization
+	operator>>(basic_istream<char>&, char*).
+	* include/std/std_streambuf.h (basic_streambuf): Add friend
+	declarations for the above.
+	* src/istream.cc: Define the above.
+	* testsuite/27_io/basic_istream/extractors_character/char/4.cc: New.
+	* testsuite/27_io/basic_istream/extractors_character/wchar_t/4.cc:
+	Likewise.
+	* testsuite/performance/27_io/ifstream_extract_chars.cc: Likewise.
+
 2005-07-20  Paolo Carlini  <pcarlini@suse.de>
 
 	* include/bits/streambuf.tcc (xsgetn, xsputn): Use streamsize

libstdc++-v3/include/bits/basic_string.h

@@ -2373,6 +2373,10 @@ namespace std
     operator>>(basic_istream<_CharT, _Traits>& __is,
 	       basic_string<_CharT, _Traits, _Alloc>& __str);
 
+  template<>
+    basic_istream<char>&
+    operator>>(basic_istream<char>& __is, basic_string<char>& __str);
+
   /**
    *  @brief  Write string to a stream.
    *  @param os  Output stream.

libstdc++-v3/include/std/std_istream.h

 // Input streams -*- C++ -*-
 
-// Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003, 2004
+// Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003, 2004, 2005
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -723,7 +723,12 @@ namespace std
   template<typename _CharT, typename _Traits>
     basic_istream<_CharT, _Traits>&
     operator>>(basic_istream<_CharT, _Traits>& __in, _CharT* __s);
-  
+
+  // Explicit specialization declaration, defined in src/istream.cc.
+  template<>
+    basic_istream<char>&
+    operator>>(basic_istream<char>& __in, char* __s);
+
   template<class _Traits>
     basic_istream<char, _Traits>&
     operator>>(basic_istream<char, _Traits>& __in, unsigned char* __s)

libstdc++-v3/include/std/std_streambuf.h

 // Stream buffer classes -*- C++ -*-
 
-// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
+// Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -153,7 +153,16 @@ namespace std
       friend streamsize
       __copy_streambufs<>(__streambuf_type* __sbin,
 			  __streambuf_type* __sbout);
-
+      
+      template<typename _CharT2, typename _Traits2>
+        friend basic_istream<_CharT2, _Traits2>&
+        operator>>(basic_istream<_CharT2, _Traits2>&, _CharT2*);
+      
+      template<typename _CharT2, typename _Traits2, typename _Alloc>
+        friend basic_istream<_CharT2, _Traits2>&
+        operator>>(basic_istream<_CharT2, _Traits2>&,
+		   basic_string<_CharT2, _Traits2, _Alloc>&);
+      
       template<typename _CharT2, typename _Traits2, typename _Alloc>
         friend basic_istream<_CharT2, _Traits2>&
         getline(basic_istream<_CharT2, _Traits2>&,

libstdc++-v3/src/istream.cc

@@ -185,6 +185,157 @@ namespace std
 
   template<>
     basic_istream<char>&
+    operator>>(basic_istream<char>& __in, char* __s)
+    {
+      typedef basic_istream<char>       	__istream_type;
+      typedef __istream_type::int_type		__int_type;
+      typedef __istream_type::char_type		__char_type;
+      typedef __istream_type::traits_type	__traits_type;
+      typedef __istream_type::__streambuf_type  __streambuf_type;
+      typedef __istream_type::__ctype_type	__ctype_type;
+
+      streamsize __extracted = 0;
+      ios_base::iostate __err = ios_base::iostate(ios_base::goodbit);
+      __istream_type::sentry __cerb(__in, false);
+      if (__cerb)
+	{
+	  try
+	    {
+	      // Figure out how many characters to extract.
+	      streamsize __num = __in.width();
+	      if (__num <= 0)
+		__num = numeric_limits<streamsize>::max();
+
+	      const __ctype_type& __ct = use_facet<__ctype_type>(__in.getloc());
+
+	      const __int_type __eof = __traits_type::eof();
+	      __streambuf_type* __sb = __in.rdbuf();
+	      __int_type __c = __sb->sgetc();
+
+	      while (__extracted < __num - 1
+		     && !__traits_type::eq_int_type(__c, __eof)
+		     && !__ct.is(ctype_base::space,
+				 __traits_type::to_char_type(__c)))
+		{
+		  streamsize __size = std::min(streamsize(__sb->egptr()
+							  - __sb->gptr()),
+					       streamsize(__num - __extracted
+							  - 1));
+		  if (__size > 1)
+		    {
+		      __size = (__ct.scan_is(ctype_base::space,
+					     __sb->gptr() + 1,
+					     __sb->gptr() + __size)
+				- __sb->gptr());
+		      __traits_type::copy(__s, __sb->gptr(), __size);
+		      __s += __size;
+		      __sb->gbump(__size);
+		      __extracted += __size;
+		      __c = __sb->sgetc();
+		    }
+		  else
+		    {
+		      *__s++ = __traits_type::to_char_type(__c);
+		      ++__extracted;
+		      __c = __sb->snextc();
+		    }
+		}
+
+	      if (__traits_type::eq_int_type(__c, __eof))
+		__err |= ios_base::eofbit;
+
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 68.  Extractors for char* should store null at end
+	      *__s = __char_type();
+	      __in.width(0);
+	    }
+	  catch(...)
+	    { __in._M_setstate(ios_base::badbit); }
+	}
+      if (!__extracted)
+	__err |= ios_base::failbit;
+      if (__err)
+	__in.setstate(__err);
+      return __in;
+    }
+
+  template<>
+    basic_istream<char>&
+    operator>>(basic_istream<char>& __in, basic_string<char>& __str)
+    {
+      typedef basic_istream<char>       	__istream_type;
+      typedef __istream_type::int_type		__int_type;
+      typedef __istream_type::char_type		__char_type;
+      typedef __istream_type::traits_type	__traits_type;
+      typedef __istream_type::__streambuf_type  __streambuf_type;
+      typedef __istream_type::__ctype_type	__ctype_type;
+      typedef basic_string<char>        	__string_type;
+      typedef __string_type::size_type		__size_type;
+
+      __size_type __extracted = 0;
+      ios_base::iostate __err = ios_base::iostate(ios_base::goodbit);
+      __istream_type::sentry __cerb(__in, false);
+      if (__cerb)
+	{
+	  try
+	    {
+	      __str.erase();
+	      const streamsize __w = __in.width();
+	      const __size_type __n = __w > 0 ? static_cast<__size_type>(__w)
+		                              : __str.max_size();
+	      const __ctype_type& __ct = use_facet<__ctype_type>(__in.getloc());
+	      const __int_type __eof = __traits_type::eof();
+	      __streambuf_type* __sb = __in.rdbuf();
+	      __int_type __c = __sb->sgetc();
+
+	      while (__extracted < __n
+		     && !__traits_type::eq_int_type(__c, __eof)
+		     && !__ct.is(ctype_base::space,
+				 __traits_type::to_char_type(__c)))
+		{
+		  streamsize __size = std::min(streamsize(__sb->egptr()
+							  - __sb->gptr()),
+					       streamsize(__n - __extracted));
+		  if (__size > 1)
+		    {
+		      __size = (__ct.scan_is(ctype_base::space,
+					     __sb->gptr() + 1,
+					     __sb->gptr() + __size)
+				- __sb->gptr());
+		      __str.append(__sb->gptr(), __size);
+		      __sb->gbump(__size);
+		      __extracted += __size;
+		      __c = __sb->sgetc();
+		    }
+		  else
+		    {
+		      __str += __traits_type::to_char_type(__c);
+		      ++__extracted;
+		      __c = __sb->snextc();
+		    }		  
+		}
+
+	      if (__traits_type::eq_int_type(__c, __eof))
+		__err |= ios_base::eofbit;
+	      __in.width(0);
+	    }
+	  catch(...)
+	    {
+	      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+	      // 91. Description of operator>> and getline() for string<>
+	      // might cause endless loop
+	      __in._M_setstate(ios_base::badbit);
+	    }
+	}
+      if (!__extracted)
+	__err |= ios_base::failbit;
+      if (__err)
+	__in.setstate(__err);
+      return __in;
+    }
+
+  template<>
+    basic_istream<char>&
     getline(basic_istream<char>& __in, basic_string<char>& __str,
 	    char __delim)
     {

libstdc++-v3/testsuite/27_io/basic_istream/extractors_character/char/4.cc

+// 2005-07-22  Paolo Carlini  <pcarlini@suse.de>
+
+// Copyright (C) 2005 Free Software Foundation
+//
+// 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 2, 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 COPYING.  If not, write to the Free
+// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+// USA.
+
+// 27.6.1.2.3 basic_istream::operator>>
+
+#include <istream>
+#include <string>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+using namespace std;
+
+string prepare(string::size_type len, unsigned nchunks)
+{
+  string ret;
+  for (unsigned i = 0; i < nchunks; ++i)
+    {
+      for (string::size_type j = 0; j < len; ++j)
+	ret.push_back('a' + rand() % 26);
+      len *= 2;
+      ret.push_back(' ');
+    }
+  return ret;
+}
+
+void check(istream& stream, const string& str, unsigned nchunks)
+{
+  bool test __attribute__((unused)) = true;
+
+  char* chunk = new char[str.size()];
+  memset(chunk, 'X', str.size());
+
+  string::size_type index = 0, index_new = 0;
+  unsigned n = 0;
+
+  while (stream >> chunk)
+    {
+      index_new = str.find(' ', index);
+      VERIFY( !str.compare(index, index_new - index, chunk) );
+      index = index_new + 1;
+      ++n;
+      memset(chunk, 'X', str.size());
+    }
+  VERIFY( stream.eof() );
+  VERIFY( n == nchunks );
+
+  delete[] chunk;
+}
+
+// istream& operator>>(istream&, charT*)
+void test01()
+{
+  const char filename[] = "inserters_extractors-4.txt";
+
+  const unsigned nchunks = 10;
+  const string data = prepare(666, nchunks);
+
+  ofstream ofstrm;
+  ofstrm.open(filename);
+  ofstrm.write(data.data(), data.size());
+  ofstrm.close();
+
+  ifstream ifstrm;
+  ifstrm.open(filename);
+  check(ifstrm, data, nchunks);
+  ifstrm.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}

libstdc++-v3/testsuite/27_io/basic_istream/extractors_character/wchar_t/4.cc

+// 2005-07-22  Paolo Carlini  <pcarlini@suse.de>
+
+// Copyright (C) 2005 Free Software Foundation
+//
+// 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 2, 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 COPYING.  If not, write to the Free
+// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+// USA.
+
+// 27.6.1.2.3 basic_istream::operator>>
+
+#include <istream>
+#include <string>
+#include <fstream>
+#include <testsuite_hooks.h>
+
+using namespace std;
+
+wstring prepare(wstring::size_type len, unsigned nchunks)
+{
+  wstring ret;
+  for (unsigned i = 0; i < nchunks; ++i)
+    {
+      for (wstring::size_type j = 0; j < len; ++j)
+	ret.push_back(L'a' + rand() % 26);
+      len *= 2;
+      ret.push_back(L' ');
+    }
+  return ret;
+}
+
+void check(wistream& stream, const wstring& str, unsigned nchunks)
+{
+  bool test __attribute__((unused)) = true;
+
+  wchar_t* chunk = new wchar_t[str.size()];
+  wmemset(chunk, L'X', str.size());
+
+  wstring::size_type index = 0, index_new = 0;
+  unsigned n = 0;
+
+  while (stream >> chunk)
+    {
+      index_new = str.find(' ', index);
+      VERIFY( !str.compare(index, index_new - index, chunk) );
+      index = index_new + 1;
+      ++n;
+      wmemset(chunk, L'X', str.size());
+    }
+  VERIFY( stream.eof() );
+  VERIFY( n == nchunks );
+
+  delete[] chunk;
+}
+
+// istream& operator>>(istream&, charT*)
+void test01()
+{
+  const char filename[] = "inserters_extractors-4.txt";
+
+  const unsigned nchunks = 10;
+  const wstring data = prepare(666, nchunks);
+
+  wofstream ofstrm;
+  ofstrm.open(filename);
+  ofstrm.write(data.data(), data.size());
+  ofstrm.close();
+
+  wifstream ifstrm;
+  ifstrm.open(filename);
+  check(ifstrm, data, nchunks);
+  ifstrm.close();
+}
+
+int main()
+{
+  test01();
+  return 0;
+}

libstdc++-v3/testsuite/performance/27_io/ifstream_extract_chars.cc

+// Copyright (C) 2005 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 2, 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 COPYING.  If not, write to the Free
+// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+// USA.
+
+// As a special exception, you may use this file as part of a free software
+// library without restriction.  Specifically, if other files instantiate
+// templates or use macros or inline functions from this file, or you compile
+// this file and link it with other files to produce an executable, this
+// file does not by itself cause the resulting executable to be covered by
+// the GNU General Public License.  This exception does not however
+// invalidate any other reasons why the executable file might be covered by
+// the GNU General Public License.
+
+#include <cstdio>
+#include <fstream>
+#include <string>
+#include <testsuite_performance.h>
+
+// libstdc++/22515
+int main() 
+{
+  using namespace std;
+  using namespace __gnu_test;
+
+  time_counter time;
+  resource_counter resource;
+
+  const char filename[] = "tmp_perf_chars.txt";
+  const unsigned lines = 200000;
+  const unsigned line_length = 200;
+
+  char* line = new char[line_length + 2];
+
+  // Construct data.
+  {
+    memset(line, 'x', line_length);
+    line[line_length] = '\n';
+    line[line_length + 1] = '\0';
+    
+    ofstream out(filename);
+    for (unsigned i = 0; i < lines; ++i)
+      out << line;
+  }
+  
+  // operator>>(basic_istream<char>& __in, basic_string<char>& __str)
+  {
+    start_counters(time, resource);
+    for (int iter = 0; iter < 25; ++iter)
+      {
+	ifstream file(filename);
+	string string_line;
+	
+	while (file >> string_line);
+      }
+    stop_counters(time, resource);
+    report_performance(__FILE__, "string&", time, resource);
+    clear_counters(time, resource);
+  }
+  
+  // operator>>(basic_istream<char>& __in, char* __s)
+  {
+    start_counters(time, resource);
+    for (int iter = 0; iter < 25; ++iter)
+      {
+	ifstream file(filename);
+	
+	while (file >> line);
+      }
+    stop_counters(time, resource);
+    report_performance(__FILE__, "char*", time, resource);
+    clear_counters(time, resource);
+  }
+
+  delete[] line;
+  unlink(filename);
+  return 0;
+}