PR libstdc++/84087 add default arguments to basic_string members (LWG 2268)

This change was a DR against C++11 and so should have been implemented
years ago.

	PR libstdc++/84087 LWG DR 2268 basic_string default arguments
	* include/bits/basic_string.h [_GLIBCXX_USE_CXX11_ABI=1]
	(append(const basic_string&, size_type, size_type)
	(assign(const basic_string&, size_type, size_type)
	(insert(size_type, const basic_string&, size_type, size_type)
	(replace(size_type,size_type,const basic_string&,size_type,size_type)
	(compare(size_type,size_type,constbasic_string&,size_type,size_type)):
	Add default arguments (LWG 2268).
	[_GLIBCXX_USE_CXX11_ABI=0]
	(append(const basic_string&, size_type, size_type)
	(assign(const basic_string&, size_type, size_type)
	(insert(size_type, const basic_string&, size_type, size_type)
	(replace(size_type,size_type,const basic_string&,size_type,size_type)
	(compare(size_type,size_type,constbasic_string&,size_type,size_type)):
	Likewise.
	* testsuite/21_strings/basic_string/dr2268.cc: New test.

From-SVN: r259895

3 files changed, 72 insertions, 10 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 4176044..3b12844 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,22 @@
 2018-05-03  Jonathan Wakely  <jwakely@redhat.com>
 
+	PR libstdc++/84087 LWG DR 2268 basic_string default arguments
+	* include/bits/basic_string.h [_GLIBCXX_USE_CXX11_ABI=1]
+	(append(const basic_string&, size_type, size_type)
+	(assign(const basic_string&, size_type, size_type)
+	(insert(size_type, const basic_string&, size_type, size_type)
+	(replace(size_type,size_type,const basic_string&,size_type,size_type)
+	(compare(size_type,size_type,constbasic_string&,size_type,size_type)):
+	Add default arguments (LWG 2268).
+	[_GLIBCXX_USE_CXX11_ABI=0]
+	(append(const basic_string&, size_type, size_type)
+	(assign(const basic_string&, size_type, size_type)
+	(insert(size_type, const basic_string&, size_type, size_type)
+	(replace(size_type,size_type,const basic_string&,size_type,size_type)
+	(compare(size_type,size_type,constbasic_string&,size_type,size_type)):
+	Likewise.
+	* testsuite/21_strings/basic_string/dr2268.cc: New test.
+
 	PR libstdc++/84535
 	* include/std/thread (thread::__not_same): New SFINAE helper.
 	(thread::thread(_Callable&&, _Args&&...)): Add SFINAE constraint that
diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h
index 3e8310e..5bffa1c 100644
--- a/libstdc++-v3/include/bits/basic_string.h
+++ b/libstdc++-v3/include/bits/basic_string.h
@@ -1216,7 +1216,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
        *  remainder of @a __str is appended.
        */
       basic_string&
-      append(const basic_string& __str, size_type __pos, size_type __n)
+      append(const basic_string& __str, size_type __pos, size_type __n = npos)
       { return _M_append(__str._M_data()
 			 + __str._M_check(__pos, "basic_string::append"),
 			 __str._M_limit(__pos, __n)); }
@@ -1381,7 +1381,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
        *  __str, the remainder of @a __str is used.
        */
       basic_string&
-      assign(const basic_string& __str, size_type __pos, size_type __n)
+      assign(const basic_string& __str, size_type __pos, size_type __n = npos)
       { return _M_replace(size_type(0), this->size(), __str._M_data()
 			  + __str._M_check(__pos, "basic_string::assign"),
 			  __str._M_limit(__pos, __n)); }
@@ -1633,7 +1633,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       */
       basic_string&
       insert(size_type __pos1, const basic_string& __str,
-	     size_type __pos2, size_type __n)
+	     size_type __pos2, size_type __n = npos)
       { return this->replace(__pos1, size_type(0), __str._M_data()
 			     + __str._M_check(__pos2, "basic_string::insert"),
 			     __str._M_limit(__pos2, __n)); }
@@ -1881,7 +1881,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       */
       basic_string&
       replace(size_type __pos1, size_type __n1, const basic_string& __str,
-	      size_type __pos2, size_type __n2)
+	      size_type __pos2, size_type __n2 = npos)
       { return this->replace(__pos1, __n1, __str._M_data()
 			     + __str._M_check(__pos2, "basic_string::replace"),
 			     __str._M_limit(__pos2, __n2)); }
@@ -2941,7 +2941,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       */
       int
       compare(size_type __pos1, size_type __n1, const basic_string& __str,
-	      size_type __pos2, size_type __n2) const;
+	      size_type __pos2, size_type __n2 = npos) const;
 
       /**
        *  @brief  Compare to a C string.
@@ -4135,7 +4135,7 @@ _GLIBCXX_END_NAMESPACE_CXX11
        *  remainder of @a __str is appended.
        */
       basic_string&
-      append(const basic_string& __str, size_type __pos, size_type __n);
+      append(const basic_string& __str, size_type __pos, size_type __n = npos);
 
       /**
        *  @brief  Append a C substring.
@@ -4280,7 +4280,7 @@ _GLIBCXX_END_NAMESPACE_CXX11
        *  __str, the remainder of @a __str is used.
        */
       basic_string&
-      assign(const basic_string& __str, size_type __pos, size_type __n)
+      assign(const basic_string& __str, size_type __pos, size_type __n = npos)
       { return this->assign(__str._M_data()
 			    + __str._M_check(__pos, "basic_string::assign"),
 			    __str._M_limit(__pos, __n)); }
@@ -4468,7 +4468,7 @@ _GLIBCXX_END_NAMESPACE_CXX11
       */
       basic_string&
       insert(size_type __pos1, const basic_string& __str,
-	     size_type __pos2, size_type __n)
+	     size_type __pos2, size_type __n = npos)
       { return this->insert(__pos1, __str._M_data()
 			    + __str._M_check(__pos2, "basic_string::insert"),
 			    __str._M_limit(__pos2, __n)); }
@@ -4703,7 +4703,7 @@ _GLIBCXX_END_NAMESPACE_CXX11
       */
       basic_string&
       replace(size_type __pos1, size_type __n1, const basic_string& __str,
-	      size_type __pos2, size_type __n2)
+	      size_type __pos2, size_type __n2 = npos)
       { return this->replace(__pos1, __n1, __str._M_data()
 			     + __str._M_check(__pos2, "basic_string::replace"),
 			     __str._M_limit(__pos2, __n2)); }
@@ -5779,7 +5779,7 @@ _GLIBCXX_END_NAMESPACE_CXX11
       */
       int
       compare(size_type __pos1, size_type __n1, const basic_string& __str,
-	      size_type __pos2, size_type __n2) const;
+	      size_type __pos2, size_type __n2 = npos) const;
 
       /**
        *  @brief  Compare to a C string.
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/dr2268.cc b/libstdc++-v3/testsuite/21_strings/basic_string/dr2268.cc
new file mode 100644
index 0000000..3ad6860
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/dr2268.cc
@@ -0,0 +1,45 @@
+// Copyright (C) 2018 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 <string>
+#include <testsuite_hooks.h>
+
+void
+test01()
+{
+  // PR libstdc++/84087
+
+  std::string s0 = "string";
+  std::string s;
+  s.append(s0, 2);
+  VERIFY( s == "ring" );
+  s.assign(s0, 3);
+  VERIFY( s == "ing" );
+  s.insert(2, s0, 4);
+  VERIFY( s == "inngg" );
+  s.replace(2, 3, s0, 2);
+  VERIFY( s == "inring" );
+  VERIFY( s.compare(2, 4, s0, 2) == 0 );
+}
+
+int
+main()
+{
+  test01();
+}