[Boost-users] boost::multi_index help

Subject: [Boost-users] boost::multi_index help
From: Axel (axel.azerty_at_[hidden])
Date: 2008-09-18 04:32:30

I'm trying to use multi_index to store objects pointers. These objects 
have mainly 3 fields :
- string name
- int id
- int block_id

name & id are unique among all instances, but block_id can be the same 
for many instances. I want to distribute the object instances among a 
few blocks, so many instances can have block_id 0, many others block_id 
1, and so on. (there are 6 blocks for the moment)

here is my struct :

/* tags */
struct name_{} ;
struct id_{} ;
struct block_id_{} ;

typedef hashed_unique<
    tag<name_>,
    boost::multi_index::mem_fun<Foo, string, &Foo::getName>
    > NameIndex ;

typedef ordered_unique<
    tag<id_>,
    boost::multi_index::mem_fun<Foo, int, &Foo::getId>
    > IdIndex ;

typedef ordered_non_unique<
    tag<block_id_>,
    boost::multi_index::mem_fun<Foo, int, &Foo::getBlockId>
    > BlockIndex ;

typedef multi_index_container<Foo*, indexed_by<NameIndex, IdIndex, 
BlockIndex> > FooList ;

The name & id indexes work well but I dont manage to get the Foo* 
pointers for a given block_id. I m using :
foo_list_.get<block_id_>().find(1)  to grab the wanted list. My problem 
is that in the result I have not only Foo instances from the block 1. 
This is what I get when I try to query for a given block_id :

For block 5 : only objects with block_id == 5
For block 4 : objects with block_id == 4 and 5
For block 3 : objects with block_id == 3, 4 and 5
For block 2 : objects with block_id == 2, 3, 4 and 5
and so on.

I d like to get only the objects with block_id = 4 when I query the 
multi_index object on its block_id index.
I now wonder if what I want to do can be done with multi_index.

Thanks in advance for your help