rc_string_base.h (__rc_string_base<>::_Rep): Avoid the anonymous struct…

rc_string_base.h (__rc_string_base<>::_Rep): Avoid the anonymous struct extension, adjust everywhere.

2005-11-18  Paolo Carlini  <pcarlini@suse.de>

	* include/ext/rc_string_base.h (__rc_string_base<>::_Rep): Avoid the
	anonymous struct extension, adjust everywhere.

	* include/ext/rc_string_base.h (__rc_string_base<>::_S_empty_rep()):
	Just use a static member.
	(__rc_string_base<>::__rc_string_base(), _S_construct): Adjust.

	* include/ext/rc_string_base.h (__rc_string_base<>::_Rep): Use anonymous
	union together with _CharT to fix alignment issues, rebind to _Rep and
	rename _Raw_alloc to _Rep_alloc_type.
	(__rc_string_base<>::_Rep::_S_create, _M_destroy): Adjust consistently.

	* include/ext/vstring_util.h (__is_null_p): Move inside struct
	__vstring_utility as static _S_is_null_pointer.
	* include/ext/sso_string.h
	(__sso_string_base<>::_M_construct(std::forward_iterator_tag): Adjust.
	* include/ext/rc_string_base.h
	(__rc_string_base<>::_S_construct(std::forward_iterator_tag): Likewise.

	Implement Option 3 of DR 431 for ext/vstring - both available bases.
	* include/bits/cpp_type_traits.h (struct __is_empty): Add.
	* include/ext/vstring.h (__versa_string<>::swap): Delegate to
	this->_M_swap.
	* include/ext/vstring.tcc (__versa_string<>::swap): Remove.
	* include/ext/vstring_util.h (struct __vstring_utility<>): Add struct
	_Alloc_hider<>, augmented of allocator swapping facility, specialized
	to nop for empty allocators.
	* include/ext/rc_string_base.h (__rc_string_base<>::_M_swap): Use it.
	(__rc_string_base<>::_M_is_leaked, _M_set_sharable): Change to private.
	* include/ext/sso_string_base.h	(__sso_string_base<>::_M_swap):
	Likewise.
	(__sso_string_base<>::_M_is_leaked, _M_set_sharable): Remove, unused.	

	* include/ext/rc_string_base.h (__rc_string_base<>::_M_data(_CharT*):
	Return void.
	* include/ext/sso_string_base.h (__sso_string_base<>::_M_data(_CharT*):
	Likewise.

From-SVN: r107176

libstdc++-v3/ChangeLog

+2005-11-18  Paolo Carlini  <pcarlini@suse.de>
+
+	* include/ext/rc_string_base.h (__rc_string_base<>::_Rep): Avoid the
+	anonymous struct extension, adjust everywhere.
+
+	* include/ext/rc_string_base.h (__rc_string_base<>::_S_empty_rep()):
+	Just use a static member.
+	(__rc_string_base<>::__rc_string_base(), _S_construct): Adjust.
+
+	* include/ext/rc_string_base.h (__rc_string_base<>::_Rep): Use anonymous
+	union together with _CharT to fix alignment issues, rebind to _Rep and
+	rename _Raw_alloc to _Rep_alloc_type.
+	(__rc_string_base<>::_Rep::_S_create, _M_destroy): Adjust consistently.
+
+	* include/ext/vstring_util.h (__is_null_p): Move inside struct
+	__vstring_utility as static _S_is_null_pointer.
+	* include/ext/sso_string.h
+	(__sso_string_base<>::_M_construct(std::forward_iterator_tag): Adjust.
+	* include/ext/rc_string_base.h
+	(__rc_string_base<>::_S_construct(std::forward_iterator_tag): Likewise.
+
+	Implement Option 3 of DR 431 for ext/vstring - both available bases.
+	* include/bits/cpp_type_traits.h (struct __is_empty): Add.
+	* include/ext/vstring.h (__versa_string<>::swap): Delegate to
+	this->_M_swap.
+	* include/ext/vstring.tcc (__versa_string<>::swap): Remove.
+	* include/ext/vstring_util.h (struct __vstring_utility<>): Add struct
+	_Alloc_hider<>, augmented of allocator swapping facility, specialized
+	to nop for empty allocators.
+	* include/ext/rc_string_base.h (__rc_string_base<>::_M_swap): Use it.
+	(__rc_string_base<>::_M_is_leaked, _M_set_sharable): Change to private.
+	* include/ext/sso_string_base.h	(__sso_string_base<>::_M_swap):
+	Likewise.
+	(__sso_string_base<>::_M_is_leaked, _M_set_sharable): Remove, unused.	
+
+	* include/ext/rc_string_base.h (__rc_string_base<>::_M_data(_CharT*):
+	Return void.
+	* include/ext/sso_string_base.h (__sso_string_base<>::_M_data(_CharT*):
+	Likewise.
+
 2005-11-17  Geoffrey Keating  <geoffk@apple.com>
 
 	* config/os/bsd/darwin/ppc-extra.ver: New.

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

@@ -364,6 +364,26 @@ namespace std
 	};
     };
 
+  //
+  // A stripped-down version of std::tr1::is_empty
+  //
+  template<typename _Tp>
+    struct __is_empty
+    { 
+    private:
+      template<typename>
+        struct __first { };
+      template<typename _Up>
+        struct __second
+        : public _Up { };
+           
+    public:
+      enum
+	{
+	  __value = sizeof(__first<_Tp>) == sizeof(__second<_Tp>)
+	};
+    };
+
 } // namespace std
 
 #endif //_CPP_TYPE_TRAITS_H

libstdc++-v3/include/ext/sso_string_base.h

@@ -47,8 +47,8 @@ namespace __gnu_cxx
       typedef typename _Traits::char_type		    value_type;
       typedef _Alloc					    allocator_type;
 
-      typedef typename __vstring_utility<_CharT, _Traits, _Alloc>::
-        _CharT_alloc_type                                   _CharT_alloc_type;
+      typedef __vstring_utility<_CharT, _Traits, _Alloc>    _Util_Base;
+      typedef typename _Util_Base::_CharT_alloc_type        _CharT_alloc_type;
       typedef typename _CharT_alloc_type::size_type	    size_type;
       
     private:
@@ -66,18 +66,9 @@ namespace __gnu_cxx
       enum { _S_max_size = (((static_cast<size_type>(-1)
 			      / sizeof(_CharT)) - 1) / 4) };
 
-      // Use empty-base optimization: http://www.cantrip.org/emptyopt.html
-      struct _Alloc_hider : _Alloc
-      {
-	_Alloc_hider(const _Alloc& __a, _CharT* __ptr)
-	: _Alloc(__a), _M_p(__ptr) { }
-
-	_CharT* _M_p; // The actual data.
-      };
-
       // Data Members (private):
-      _Alloc_hider	        _M_dataplus;
-      size_type                 _M_string_length;
+      typename _Util_Base::template _Alloc_hider<_Alloc>    _M_dataplus;
+      size_type                                             _M_string_length;
 
       enum { _S_local_capacity = 15 };
       
@@ -87,9 +78,9 @@ namespace __gnu_cxx
 	size_type               _M_allocated_capacity;
       };
 
-      _CharT*
+      void
       _M_data(_CharT* __p)
-      { return (_M_dataplus._M_p = __p); }
+      { _M_dataplus._M_p = __p; }
 
       void
       _M_length(size_type __length)
@@ -118,7 +109,7 @@ namespace __gnu_cxx
       _M_destroy(size_type) throw();
 
       // _M_construct_aux is used to implement the 21.3.1 para 15 which
-      // requires special behaviour if _InIter is an integral type
+      // requires special behaviour if _InIterator is an integral type
       template<class _InIterator>
         void
         _M_construct_aux(_InIterator __beg, _InIterator __end, __false_type)
@@ -181,28 +172,19 @@ namespace __gnu_cxx
       _M_is_shared() const
       { return false; }
 
-      bool
-      _M_is_leaked() const
-      { return false; }
-
       void
-      _M_set_sharable() { }
+      _M_set_leaked() { }
 
       void
-      _M_set_leaked() { }
+      _M_leak() { }
 
       void
       _M_set_length(size_type __n)
       {
 	_M_length(__n);
-	// grrr. (per 21.3.4)
-	// You cannot leave those LWG people alone for a second.
 	traits_type::assign(_M_data()[__n], _CharT());
       }
 
-      void
-      _M_leak() { }
-
       __sso_string_base()
       : _M_dataplus(_Alloc(), _M_local_data)
       { _M_set_length(0); }
@@ -248,6 +230,9 @@ namespace __gnu_cxx
     __sso_string_base<_CharT, _Traits, _Alloc>::
     _M_swap(__sso_string_base& __rcs)
     {
+      // NB: Implement Option 3 of DR 431 (see N1599).
+      _M_dataplus._M_alloc_swap(__rcs._M_dataplus);
+
       if (_M_is_local())
 	if (__rcs._M_is_local())
 	  {
@@ -325,9 +310,6 @@ namespace __gnu_cxx
       // The below implements an exponential growth policy, necessary to
       // meet amortized linear time requirements of the library: see
       // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.
-      // It's active for allocations requiring an amount of memory above
-      // system pagesize. This is consistent with the requirements of the
-      // standard: http://gcc.gnu.org/ml/libstdc++/2001-07/msg00130.html
       if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)
 	__capacity = 2 * __old_capacity;
 
@@ -373,7 +355,6 @@ namespace __gnu_cxx
       _M_construct(_InIterator __beg, _InIterator __end,
 		   std::input_iterator_tag)
       {
-	// Avoid reallocation for common case.
 	size_type __len = 0;
 	size_type __capacity = size_type(_S_local_capacity);
 
@@ -418,7 +399,7 @@ namespace __gnu_cxx
 		   std::forward_iterator_tag)
       {
 	// NB: Not required, but considered best practice.
-	if (__builtin_expect(__is_null_p(__beg) && __beg != __end, 0))
+	if (__builtin_expect(_S_is_null_pointer(__beg) && __beg != __end, 0))
 	  std::__throw_logic_error(__N("__sso_string_base::"
 				       "_M_construct NULL not valid"));
 

libstdc++-v3/include/ext/vstring.h

@@ -1214,7 +1214,8 @@ namespace __gnu_cxx
        *  time.
       */
       void
-      swap(__versa_string& __s);
+      swap(__versa_string& __s)
+      { this->_M_swap(__s); }
 
       // String operations:
       /**

libstdc++-v3/include/ext/vstring.tcc

@@ -222,30 +222,6 @@ namespace __gnu_cxx
 	   template <typename, typename, typename> class _Base>
     void
     __versa_string<_CharT, _Traits, _Alloc, _Base>::
-    swap(__versa_string& __s)
-    {
-      if (this->_M_is_leaked())
-	this->_M_set_sharable();
-      if (__s._M_is_leaked())
-	__s._M_set_sharable();
-      if (this->get_allocator() == __s.get_allocator())
-	this->_M_swap(__s);
-      // The code below can usually be optimized away.
-      else
-	{
-	  const __versa_string __tmp1(_M_ibegin(), _M_iend(),
-				      __s.get_allocator());
-	  const __versa_string __tmp2(__s._M_ibegin(), __s._M_iend(),
-				      this->get_allocator());
-	  *this = __tmp2;
-	  __s = __tmp1;
-	}
-    }
-
-  template<typename _CharT, typename _Traits, typename _Alloc,
-	   template <typename, typename, typename> class _Base>
-    void
-    __versa_string<_CharT, _Traits, _Alloc, _Base>::
     resize(size_type __n, _CharT __c)
     {
       const size_type __size = this->size();

libstdc++-v3/include/ext/vstring_util.h

-// Versatile string utilities -*- C++ -*-
+// Versatile string utility -*- C++ -*-
 
 // Copyright (C) 2005 Free Software Foundation, Inc.
 //
@@ -47,16 +47,6 @@
 
 namespace __gnu_cxx
 {
-  template<typename _Type>
-    inline bool
-    __is_null_p(_Type* __ptr)
-    { return __ptr == 0; }
-
-  template<typename _Type>
-    inline bool
-    __is_null_p(_Type)
-    { return false; }
-
   template<typename _CharT, typename _Traits, typename _Alloc>
     struct __vstring_utility
     {
@@ -92,6 +82,53 @@ namespace __gnu_cxx
 				       __rc_string_base> >
         __const_rc_iterator;
 
+      // NB:  When the allocator is empty, deriving from it saves space 
+      // (http://www.cantrip.org/emptyopt.html).  We do that anyway for
+      // consistency.
+      template<typename _Alloc1, bool = std::__is_empty<_Alloc1>::__value>
+        struct _Alloc_hider
+	: public _Alloc1
+	{
+	  _Alloc_hider(const _Alloc1& __a, _CharT* __ptr)
+	  : _Alloc1(__a), _M_p(__ptr) { }
+
+	  void
+	  _M_alloc_swap(_Alloc_hider& __ah)
+	  {
+	    // Implement Option 3 of DR 431 (see N1599).
+	    // Precondition: swappable allocators.
+	    _Alloc1& __this = static_cast<_Alloc1&>(*this);
+	    _Alloc1& __that = static_cast<_Alloc1&>(__ah);
+	    if (__this != __that)
+	      swap(__this, __that);
+	  }
+
+	  _CharT*  _M_p; // The actual data.
+	};
+
+      template<typename _Alloc1>
+        struct _Alloc_hider<_Alloc1, true>
+	: public _Alloc1
+	{
+	  _Alloc_hider(const _Alloc1& __a, _CharT* __ptr)
+	  : _Alloc1(__a), _M_p(__ptr) { }
+
+	  void _M_alloc_swap(_Alloc_hider&) { }
+
+	  _CharT*  _M_p; // The actual data.
+	};
+
+      // For use in _M_construct (_S_construct) forward_iterator_tag.
+      template<typename _Type>
+        static bool
+        _S_is_null_pointer(_Type* __ptr)
+        { return __ptr == 0; }
+
+      template<typename _Type>
+        static bool
+        _S_is_null_pointer(_Type)
+        { return false; }
+
       // When __n = 1 way faster than the general multichar
       // traits_type::copy/move/assign.
       static void