[Boost-users] [1.33][ptr_container] bug in erase() in associative containers?

From: Malte Clasen (news_at_[hidden])
Date: 2005-08-23 16:00:21

Hi,

the erase() method (defined in associative_ptr_container.hpp, line 104) 
seems a bit strange:

         size_type erase( const key_type& x ) // nothrow
         {
             BOOST_ASSERT( !this->empty() );
             iterator i = find( x );                     // nothrow
             if( i == this->end() )                      // nothrow
                 return 0;                               // nothrow
             this->remove( i );                          // nothrow
             return this->c_private().erase( i.base() ); // nothrow
         }

http://cvs.sourceforge.net/viewcvs.py/boost/boost/boost/ptr_container/detail/associative_ptr_container.hpp?rev=1.4&view=markup

My compiler (vc++7.1) complained about the unknown find() when I called 
erase() on ptr_map. "find" is not declared neither in this class nor in 
its base class. The closest valid call I could think of would be

        this->c_private().find( x )

. But there seems to be a nicer solution:

         size_type erase( const key_type& x ) // nothrow
         {
             BOOST_ASSERT( !this->empty() );
             return this->c_private().erase( x ); // nothrow
         }

This compiles fine and does just what I want it to do, even nothrow is 
guaranteed (I checked the vc++ reference for std::map). Now I wonder why 
erase() is implemented differently in Boost 1.33. Is there anything I 
overlooked?

Btw, is there a rationale for the declaration of insert()?

        std::pair<iterator,bool> insert( key_type& k, value_type x );

http://cvs.sourceforge.net/viewcvs.py/boost/boost/boost/ptr_container/ptr_map_adapter.hpp?rev=1.12&view=auto

Passing key_type by non-const reference caused some unaesthetic 
constructs in my code because return values (temporaries) cannot be used 
directly.

Malte