Re: Improve insert/emplace robustness to self insertion

[Jonathan Wakely]

On 28/06/16 21:59 +0200, François Dumont wrote:

@@ -303,16 +301,20 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
      emplace(const_iterator __position, _Args&&... __args)
      {
        const size_type __n = __position - begin();

It looks like this should use __position - cbegin(), to avoid an
implicit conversion from iterator to const_iterator, and ...

-       if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage
-           && __position == end())
-         {
-           _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
-                                    std::forward<_Args>(__args)...);
-           ++this->_M_impl._M_finish;
-         }
+       if (this->_M_impl._M_finish != this->_M_impl._M_end_of_storage)
+         if (__position == end())

This could be __position == cend(), and ...

+           {
+             _Alloc_traits::construct(this->_M_impl, this->_M_impl._M_finish,
+                                      std::forward<_Args>(__args)...);
+             ++this->_M_impl._M_finish;
+           }
+         else
+           _M_insert_aux(begin() + (__position - cbegin()),

This could use __n, and ...

+                         std::forward<_Args>(__args)...);
        else
-         _M_insert_aux(begin() + (__position - cbegin()),
-                       std::forward<_Args>(__args)...);
+         _M_realloc_insert_aux(begin() + (__position - cbegin()),

This could also use __n.

+                               std::forward<_Args>(__args)...);
+
        return iterator(this->_M_impl._M_start + __n);
      }