On Sep 24, 2009, at 10:02 AM, Thorsten Ottosen wrote:
Howard Hinnant skrev:
On Sep 19, 2009, at 4:18 AM, Thorsten Ottosen wrote:
Ion Gaztañaga skrev:
Thorsten Ottosen escribió:
Suggestion: Using std::map as an example as I am not familiar with [interprocess][multi_index]. Also using C++0X notation (to be emulated in C++03). Add to the container: template <class Key, class T, class Compare, class Allocator> class map { public: ... typedef /details/ node_ptr; node_ptr remove(const_iterator p); pair<iterator, bool> insert(node_ptr&& nd); iterator insert(const_iterator p, node_ptr&& nd); ... }; map::node_ptr is a move-only smart pointer which holds an Allocator* and a map::node* (or equivalent smart pointer as interprocess may need?). node_ptr roughly looks like: template <class Key, class T, class Allocator> class node_ptr { node_ptr(const node_ptr&); node_ptr& operator=(const node_ptr&); public: typedef pair<Key, T> value_type; node_ptr(); ~node_ptr(); node_ptr(node_ptr&& n); node_ptr& operator=(node_ptr&& n); void reset(); value_type& operator*() const; value_type* operator->() const; };
I'm fine with this interface, and it seems less complicated compared to Joaquin's modify_key().
It doesn't quite address my first issue though, namely that I need to construct the mapped value in the node, and then compute the key from this mapped value (after some modification).
I think if the node_ptr class had
a) a forwarding (Key,Value) constructor
b) an emplacing constructor that constructed the pair with (Key,...)
then I could do exactly what I needed :-)
With what allocator would the node_ptr allocate the node? -Howard