Re: [boost] Re: [ptr_container] ptr_map throws in []

From: Felipe Magno de Almeida (felipe.almeida_at_[hidden])
Date: 2005-03-17 17:05:34

Ive modified the ptr_map_adapter in the operator[]
to be:
const_reference operator[]( const key_type& key ) const
{
     //return lookup( key );
     iterator i = find( key );
     if( i != end() )
         return *i;
     else {
         i = const_cast<ptr_map_adapter_base*>(this)
             ->insert(begin(), key, 
CloneAllocator::allocate_clone(value_type()));
         return *i;
     }
}
and the non-const just dont have the const_cast, but this way I think 
value_type is default-constructed and then copy-constructed isnt? well, 
this isnt very efficient, but to my needs it is already better.

Thorsten Ottosen wrote:
> Hi Felipe,
> 
> "Felipe Magno de Almeida" <felipe.almeida_at_[hidden]> wrote in message 
> news:4239C1B1.3050507_at_ic.unicamp.br...
> | Hi.
> |
> | I dont see why ptr_map throws in operator[], I think it should have the
> | same behavior of std::map and return a default constructed object in
> | case it doesnt find the key.
> | Anyway, it is just a opinion
> 
> Hm..yeah...I guess you can use
> 
> map.at( "foo" );
> 
> if you want the exception to be thrown. I think you're right
> it should call insert a heap-allocated object.
> 
> I will change this for the post-review. In the meantime, you can make
> a new function in ptr_map_adapter using lookup()
> as a template to get the behavior you need.
> .
> | Im using ptr_map in production code and
> 
> I'm glad to hear that.
> 
> -Thorsten 
> 
> 
> 
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-- 
    Felipe Magno de Almeida
    UIN: 2113442
     email: felipe.almeida at ic unicamp br, felipe.m.almeida at gmail 
com, felipe at synergy com
I am a C, modern C++, MFC, ODBC, Windows Services, MAPI developer
from synergy, and Computer Science student from State
University of Campinas(UNICAMP).
To know more about:
Unicamp: http://www.ic.unicamp.br
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current work: http://www.mintercept.com