[Boost-users] [statechart] Using fast_pool_allocator along with state_machine

From: Babi Seal (sseal73_at_[hidden])
Date: 2008-04-17 14:29:41

Hi,

I would like to avoid fragmentation and perhaps reduce the time spent entering and leaving state in my state machine by leveraging the fast_pool_allocator. 

 My very limited understanding of allocators comes from Scott Meyer's  Effective STL and his references to articles on the Web. From reading the implementation of state_machine, I am not clear what the template-arguments for the UserAllocator should be if  I  wish to use the fast_pool_allocator  as the UserAllocator parameter for state-machine. If I specified boost::fast_pool_allocator<int> does the library take care of somehow doing a rebind and allocating the right amount of memory for the states ? 

>From reading the changeset documentation (Point 2, Breaking Change of 14 August 2005) I see that  

" this considerably simplifies memory management customization. A user now only    needs to pass his own allocator to state_machine<> and    no longer has to separately overload operator
    new/delete for his state classes"

Any guidance would be really appreciated ?

Thanks

#ifndef __STATE_H_INCL__
#define __STATE_H_INCL__

#include <boost/statechart/state_machine.hpp>
#include <boost/statechart/state.hpp>
#include <boost/statechart/transition.hpp>
#include <boost/pool/pool_alloc.hpp>

namespace sc = boost::statechart;

// We need to forward-declare the initial state because it can
// only be defined at a point where the state machine is
// defined.
struct Enabled;
struct Machine : sc::state_machine< Machine, 
                     Enabled, 
                     boost::fast_pool_allocator< int > > /* ??? is this right ? */
{
    Machine();
    ~Machine() {
        terminate();
    }
   int ContextAssociatedwithStateMachine;
};

#endif

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