]> git.ipfire.org Git - thirdparty/gcc.git/blobdiff - libstdc++-v3/include/bits/forward_list.tcc
PR libstdc++/90105 make forward_list::sort stable
[thirdparty/gcc.git] / libstdc++-v3 / include / bits / forward_list.tcc
index 7cc630f06d929f13728fd56877b27b5f410b4ca5..088111e3330e5409738d02e2b8946c6b084aeb1d 100644 (file)
@@ -1,6 +1,6 @@
 // <forward_list.tcc> -*- C++ -*-
 
-// Copyright (C) 2008-2016 Free Software Foundation, Inc.
+// Copyright (C) 2008-2019 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
@@ -32,6 +32,7 @@
 
 namespace std _GLIBCXX_VISIBILITY(default)
 {
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
   template<typename _Tp, typename _Alloc>
@@ -40,12 +41,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     : _M_impl(std::move(__a))
     {
       if (__lst._M_get_Node_allocator() == _M_get_Node_allocator())
-       {
-         this->_M_impl._M_head._M_next = __lst._M_impl._M_head._M_next;
-         __lst._M_impl._M_head._M_next = 0;
-       }
-      else
-       this->_M_impl._M_head._M_next = 0;
+       this->_M_impl._M_head = std::move(__lst._M_impl._M_head);
     }
 
   template<typename _Tp, typename _Alloc>
@@ -54,12 +50,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       _Fwd_list_base<_Tp, _Alloc>::
       _M_insert_after(const_iterator __pos, _Args&&... __args)
       {
-        _Fwd_list_node_base* __to
+       _Fwd_list_node_base* __to
          = const_cast<_Fwd_list_node_base*>(__pos._M_node);
        _Node* __thing = _M_create_node(std::forward<_Args>(__args)...);
-        __thing->_M_next = __to->_M_next;
-        __to->_M_next = __thing;
-        return __to->_M_next;
+       __thing->_M_next = __to->_M_next;
+       __to->_M_next = __thing;
+       return __to->_M_next;
       }
 
   template<typename _Tp, typename _Alloc>
@@ -69,8 +65,8 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     {
       _Node* __curr = static_cast<_Node*>(__pos->_M_next);
       __pos->_M_next = __curr->_M_next;
-      _Tp_alloc_type __a(_M_get_Node_allocator());
-      allocator_traits<_Tp_alloc_type>::destroy(__a, __curr->_M_valptr());
+      _Node_alloc_traits::destroy(_M_get_Node_allocator(),
+                                 __curr->_M_valptr());
       __curr->~_Node();
       _M_put_node(__curr);
       return __pos->_M_next;
@@ -79,19 +75,19 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
   template<typename _Tp, typename _Alloc>
     _Fwd_list_node_base*
     _Fwd_list_base<_Tp, _Alloc>::
-    _M_erase_after(_Fwd_list_node_base* __pos, 
-                   _Fwd_list_node_base* __last)
+    _M_erase_after(_Fwd_list_node_base* __pos,
+                  _Fwd_list_node_base* __last)
     {
       _Node* __curr = static_cast<_Node*>(__pos->_M_next);
       while (__curr != __last)
-        {
-          _Node* __temp = __curr;
-          __curr = static_cast<_Node*>(__curr->_M_next);
-         _Tp_alloc_type __a(_M_get_Node_allocator());
-         allocator_traits<_Tp_alloc_type>::destroy(__a, __temp->_M_valptr());
+       {
+         _Node* __temp = __curr;
+         __curr = static_cast<_Node*>(__curr->_M_next);
+         _Node_alloc_traits::destroy(_M_get_Node_allocator(),
+                                     __temp->_M_valptr());
          __temp->~_Node();
-          _M_put_node(__temp);
-        }
+         _M_put_node(__temp);
+       }
       __pos->_M_next = __last;
       return __last;
     }
@@ -103,12 +99,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       forward_list<_Tp, _Alloc>::
       _M_range_initialize(_InputIterator __first, _InputIterator __last)
       {
-        _Node_base* __to = &this->_M_impl._M_head;
-        for (; __first != __last; ++__first)
-          {
-            __to->_M_next = this->_M_create_node(*__first);
-            __to = __to->_M_next;
-          }
+       _Node_base* __to = &this->_M_impl._M_head;
+       for (; __first != __last; ++__first)
+         {
+           __to->_M_next = this->_M_create_node(*__first);
+           __to = __to->_M_next;
+         }
       }
 
   // Called by forward_list(n,v,a).
@@ -119,10 +115,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     {
       _Node_base* __to = &this->_M_impl._M_head;
       for (; __n; --__n)
-        {
-          __to->_M_next = this->_M_create_node(__value);
-          __to = __to->_M_next;
-        }
+       {
+         __to->_M_next = this->_M_create_node(__value);
+         __to = __to->_M_next;
+       }
     }
 
   template<typename _Tp, typename _Alloc>
@@ -132,10 +128,10 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     {
       _Node_base* __to = &this->_M_impl._M_head;
       for (; __n; --__n)
-        {
-          __to->_M_next = this->_M_create_node();
-          __to = __to->_M_next;
-        }
+       {
+         __to->_M_next = this->_M_create_node();
+         __to = __to->_M_next;
+       }
     }
 
   template<typename _Tp, typename _Alloc>
@@ -144,21 +140,21 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
     operator=(const forward_list& __list)
     {
       if (std::__addressof(__list) != this)
-        {
+       {
          if (_Node_alloc_traits::_S_propagate_on_copy_assign())
            {
-              auto& __this_alloc = this->_M_get_Node_allocator();
-              auto& __that_alloc = __list._M_get_Node_allocator();
-              if (!_Node_alloc_traits::_S_always_equal()
-                 && __this_alloc != __that_alloc)
-               {
+             auto& __this_alloc = this->_M_get_Node_allocator();
+             auto& __that_alloc = __list._M_get_Node_allocator();
+             if (!_Node_alloc_traits::_S_always_equal()
+                 && __this_alloc != __that_alloc)
+               {
                  // replacement allocator cannot free existing storage
                  clear();
                }
              std::__alloc_on_copy(__this_alloc, __that_alloc);
-            }
+           }
          assign(__list.cbegin(), __list.cend());
-        }
+       }
       return *this;
     }
 
@@ -189,12 +185,12 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
       size_type __len = 0;
       while (__k._M_next() != end() && __len < __sz)
-        {
-          ++__k;
-          ++__len;
-        }
+       {
+         ++__k;
+         ++__len;
+       }
       if (__len == __sz)
-        erase_after(__k, end());
+       erase_after(__k, end());
       else
        _M_default_insert_after(__k, __sz - __len);
     }
@@ -208,14 +204,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
 
       size_type __len = 0;
       while (__k._M_next() != end() && __len < __sz)
-        {
-          ++__k;
-          ++__len;
-        }
+       {
+         ++__k;
+         ++__len;
+       }
       if (__len == __sz)
-        erase_after(__k, end());
+       erase_after(__k, end());
       else
-        insert_after(__k, __sz - __len, __val);
+       insert_after(__k, __sz - __len, __val);
     }
 
   template<typename _Tp, typename _Alloc>
@@ -232,7 +228,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
        __end = __end->_M_next;
 
       if (__b != __end)
-       return iterator(__tmp->_M_transfer_after(__b, __end));      
+       return iterator(__tmp->_M_transfer_after(__b, __end));
       else
        return iterator(__tmp);
     }
@@ -282,114 +278,136 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
          return iterator(const_cast<_Node_base*>(__pos._M_node));
       }
 
+#if __cplusplus > 201703L
+# define _GLIBCXX20_ONLY(__expr) __expr
+#else
+# define _GLIBCXX20_ONLY(__expr)
+#endif
+
   template<typename _Tp, typename _Alloc>
-    void
+    auto
     forward_list<_Tp, _Alloc>::
-    remove(const _Tp& __val)
+    remove(const _Tp& __val) -> __remove_return_type
     {
+      size_type __removed __attribute__((__unused__)) = 0;
       _Node_base* __curr = &this->_M_impl._M_head;
       _Node_base* __extra = nullptr;
 
       while (_Node* __tmp = static_cast<_Node*>(__curr->_M_next))
-        {
-          if (*__tmp->_M_valptr() == __val)
+       {
+         if (*__tmp->_M_valptr() == __val)
            {
              if (__tmp->_M_valptr() != std::__addressof(__val))
                {
                  this->_M_erase_after(__curr);
+                 _GLIBCXX20_ONLY( __removed++ );
                  continue;
                }
              else
                __extra = __curr;
            }
          __curr = __curr->_M_next;
-        }
+       }
 
       if (__extra)
-       this->_M_erase_after(__extra);
+       {
+         this->_M_erase_after(__extra);
+         _GLIBCXX20_ONLY( __removed++ );
+       }
+      return _GLIBCXX20_ONLY( __removed );
     }
 
   template<typename _Tp, typename _Alloc>
     template<typename _Pred>
-      void
+      auto
       forward_list<_Tp, _Alloc>::
-      remove_if(_Pred __pred)
+      remove_if(_Pred __pred) -> __remove_return_type
       {
+       size_type __removed __attribute__((__unused__)) = 0;
        _Node_base* __curr = &this->_M_impl._M_head;
-        while (_Node* __tmp = static_cast<_Node*>(__curr->_M_next))
-          {
-            if (__pred(*__tmp->_M_valptr()))
-              this->_M_erase_after(__curr);
-            else
-              __curr = __curr->_M_next;
-          }
+       while (_Node* __tmp = static_cast<_Node*>(__curr->_M_next))
+         {
+           if (__pred(*__tmp->_M_valptr()))
+             {
+               this->_M_erase_after(__curr);
+               _GLIBCXX20_ONLY( __removed++ );
+             }
+           else
+             __curr = __curr->_M_next;
+         }
+       return _GLIBCXX20_ONLY( __removed );
       }
 
   template<typename _Tp, typename _Alloc>
     template<typename _BinPred>
-      void
+      auto
       forward_list<_Tp, _Alloc>::
-      unique(_BinPred __binary_pred)
+      unique(_BinPred __binary_pred) -> __remove_return_type
       {
-        iterator __first = begin();
-        iterator __last = end();
-        if (__first == __last)
-          return;
-        iterator __next = __first;
-        while (++__next != __last)
-        {
-          if (__binary_pred(*__first, *__next))
-            erase_after(__first);
-          else
-            __first = __next;
-          __next = __first;
-        }
+       iterator __first = begin();
+       iterator __last = end();
+       if (__first == __last)
+         return _GLIBCXX20_ONLY(0);
+       size_type __removed __attribute__((__unused__)) = 0;
+       iterator __next = __first;
+       while (++__next != __last)
+       {
+         if (__binary_pred(*__first, *__next))
+           {
+             erase_after(__first);
+             _GLIBCXX20_ONLY( __removed++ );
+           }
+         else
+           __first = __next;
+         __next = __first;
+       }
+        return _GLIBCXX20_ONLY( __removed );
       }
 
+#undef _GLIBCXX20_ONLY
+
   template<typename _Tp, typename _Alloc>
     template<typename _Comp>
       void
       forward_list<_Tp, _Alloc>::
       merge(forward_list&& __list, _Comp __comp)
       {
-        _Node_base* __node = &this->_M_impl._M_head;
-        while (__node->_M_next && __list._M_impl._M_head._M_next)
-          {
-            if (__comp(*static_cast<_Node*>
-                       (__list._M_impl._M_head._M_next)->_M_valptr(),
-                       *static_cast<_Node*>
-                       (__node->_M_next)->_M_valptr()))
-              __node->_M_transfer_after(&__list._M_impl._M_head,
-                                        __list._M_impl._M_head._M_next);
-            __node = __node->_M_next;
-          }
-        if (__list._M_impl._M_head._M_next)
-          {
-            __node->_M_next = __list._M_impl._M_head._M_next;
-            __list._M_impl._M_head._M_next = 0;
-          }
+       _Node_base* __node = &this->_M_impl._M_head;
+       while (__node->_M_next && __list._M_impl._M_head._M_next)
+         {
+           if (__comp(*static_cast<_Node*>
+                      (__list._M_impl._M_head._M_next)->_M_valptr(),
+                      *static_cast<_Node*>
+                      (__node->_M_next)->_M_valptr()))
+             __node->_M_transfer_after(&__list._M_impl._M_head,
+                                       __list._M_impl._M_head._M_next);
+           __node = __node->_M_next;
+         }
+
+       if (__list._M_impl._M_head._M_next)
+         *__node = std::move(__list._M_impl._M_head);
       }
 
   template<typename _Tp, typename _Alloc>
     bool
     operator==(const forward_list<_Tp, _Alloc>& __lx,
-               const forward_list<_Tp, _Alloc>& __ly)
+              const forward_list<_Tp, _Alloc>& __ly)
     {
       //  We don't have size() so we need to walk through both lists
       //  making sure both iterators are valid.
       auto __ix = __lx.cbegin();
       auto __iy = __ly.cbegin();
       while (__ix != __lx.cend() && __iy != __ly.cend())
-        {
-          if (*__ix != *__iy)
-            return false;
-          ++__ix;
-          ++__iy;
-        }
+       {
+         if (!(*__ix == *__iy))
+           return false;
+         ++__ix;
+         ++__iy;
+       }
       if (__ix == __lx.cend() && __iy == __ly.cend())
-        return true;
+       return true;
       else
-        return false;
+       return false;
     }
 
   template<typename _Tp, class _Alloc>
@@ -398,102 +416,102 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
       forward_list<_Tp, _Alloc>::
       sort(_Comp __comp)
       {
-        // If `next' is 0, return immediately.
-        _Node* __list = static_cast<_Node*>(this->_M_impl._M_head._M_next);
-        if (!__list)
-          return;
-
-        unsigned long __insize = 1;
-
-        while (1)
-          {
-            _Node* __p = __list;
-            __list = 0;
-            _Node* __tail = 0;
-
-            // Count number of merges we do in this pass.
-            unsigned long __nmerges = 0;
-
-            while (__p)
-              {
-                ++__nmerges;
-                // There exists a merge to be done.
-                // Step `insize' places along from p.
-                _Node* __q = __p;
-                unsigned long __psize = 0;
-                for (unsigned long __i = 0; __i < __insize; ++__i)
-                  {
-                    ++__psize;
-                    __q = static_cast<_Node*>(__q->_M_next);
-                    if (!__q)
-                      break;
-                  }
-
-                // If q hasn't fallen off end, we have two lists to merge.
-                unsigned long __qsize = __insize;
-
-                // Now we have two lists; merge them.
-                while (__psize > 0 || (__qsize > 0 && __q))
-                  {
-                    // Decide whether next node of merge comes from p or q.
-                    _Node* __e;
-                    if (__psize == 0)
-                      {
-                        // p is empty; e must come from q.
-                        __e = __q;
-                        __q = static_cast<_Node*>(__q->_M_next);
-                        --__qsize;
-                      }
-                    else if (__qsize == 0 || !__q)
-                      {
-                        // q is empty; e must come from p.
-                        __e = __p;
-                        __p = static_cast<_Node*>(__p->_M_next);
-                        --__psize;
-                      }
-                    else if (__comp(*__p->_M_valptr(), *__q->_M_valptr()))
-                      {
-                        // First node of p is lower; e must come from p.
-                        __e = __p;
-                        __p = static_cast<_Node*>(__p->_M_next);
-                        --__psize;
-                      }
-                    else
-                      {
-                        // First node of q is lower; e must come from q.
-                        __e = __q;
-                        __q = static_cast<_Node*>(__q->_M_next);
-                        --__qsize;
-                      }
-
-                    // Add the next node to the merged list.
-                    if (__tail)
-                      __tail->_M_next = __e;
-                    else
-                      __list = __e;
-                    __tail = __e;
-                  }
-
-                // Now p has stepped `insize' places along, and q has too.
-                __p = __q;
-              }
-            __tail->_M_next = 0;
-
-            // If we have done only one merge, we're finished.
-            // Allow for nmerges == 0, the empty list case.
-            if (__nmerges <= 1)
-              {
-                this->_M_impl._M_head._M_next = __list;
-                return;
-              }
-
-            // Otherwise repeat, merging lists twice the size.
-            __insize *= 2;
-          }
+       // If `next' is nullptr, return immediately.
+       _Node* __list = static_cast<_Node*>(this->_M_impl._M_head._M_next);
+       if (!__list)
+         return;
+
+       unsigned long __insize = 1;
+
+       while (1)
+         {
+           _Node* __p = __list;
+           __list = nullptr;
+           _Node* __tail = nullptr;
+
+           // Count number of merges we do in this pass.
+           unsigned long __nmerges = 0;
+
+           while (__p)
+             {
+               ++__nmerges;
+               // There exists a merge to be done.
+               // Step `insize' places along from p.
+               _Node* __q = __p;
+               unsigned long __psize = 0;
+               for (unsigned long __i = 0; __i < __insize; ++__i)
+                 {
+                   ++__psize;
+                   __q = static_cast<_Node*>(__q->_M_next);
+                   if (!__q)
+                     break;
+                 }
+
+               // If q hasn't fallen off end, we have two lists to merge.
+               unsigned long __qsize = __insize;
+
+               // Now we have two lists; merge them.
+               while (__psize > 0 || (__qsize > 0 && __q))
+                 {
+                   // Decide whether next node of merge comes from p or q.
+                   _Node* __e;
+                   if (__psize == 0)
+                     {
+                       // p is empty; e must come from q.
+                       __e = __q;
+                       __q = static_cast<_Node*>(__q->_M_next);
+                       --__qsize;
+                     }
+                   else if (__qsize == 0 || !__q)
+                     {
+                       // q is empty; e must come from p.
+                       __e = __p;
+                       __p = static_cast<_Node*>(__p->_M_next);
+                       --__psize;
+                     }
+                   else if (!__comp(*__q->_M_valptr(), *__p->_M_valptr()))
+                     {
+                       // First node of q is not lower; e must come from p.
+                       __e = __p;
+                       __p = static_cast<_Node*>(__p->_M_next);
+                       --__psize;
+                     }
+                   else
+                     {
+                       // First node of q is lower; e must come from q.
+                       __e = __q;
+                       __q = static_cast<_Node*>(__q->_M_next);
+                       --__qsize;
+                     }
+
+                   // Add the next node to the merged list.
+                   if (__tail)
+                     __tail->_M_next = __e;
+                   else
+                     __list = __e;
+                   __tail = __e;
+                 }
+
+               // Now p has stepped `insize' places along, and q has too.
+               __p = __q;
+             }
+           __tail->_M_next = nullptr;
+
+           // If we have done only one merge, we're finished.
+           // Allow for nmerges == 0, the empty list case.
+           if (__nmerges <= 1)
+             {
+               this->_M_impl._M_head._M_next = __list;
+               return;
+             }
+
+           // Otherwise repeat, merging lists twice the size.
+           __insize *= 2;
+         }
       }
+
 _GLIBCXX_END_NAMESPACE_CONTAINER
+_GLIBCXX_END_NAMESPACE_VERSION
 } // namespace std
 
 #endif /* _FORWARD_LIST_TCC */
-