Re: [Boost-users] String Pools: Reusing Memory

Subject: Re: [Boost-users] String Pools: Reusing Memory
From: joaquin_at_[hidden]
Date: 2010-02-02 09:01:57

Bilokon, Paul escribió:
> Dear all,
>  
> First, may I blaspheme by invoking Java. In Java, a pool of strings, 
> initially empty,
> is maintained privately by the class String. This is essentially a 
> case of the Flyweight
> design pattern (http://en.wikipedia.org/wiki/Flyweight_pattern) where 
> memory usage
> is minimised by sharing as much data as possible with other similar 
> objects. Thus if
> we have two different instances of a string "foo" we shall reuse a 
> single area of
> memory. In Java there is a concept of string internisation:
>  
> http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html#intern%28%29
>  
> My question is, what is the best way to implement this in C++? Is the 
> answer to this
> a combination of std::string and boost::fast_pool_allocator, as 
> discussed here:
>  
> http://www.gamedev.net/community/forums/topic.asp?topic_id=534428
>  
> Or are there better ways? Perhaps there is something like 
> an intern_string? What
> would be the best practice where memory usage is an issue?

Boost provides an interpretation of the Flyweight pattern:

http://www.boost.org/libs/flyweight

You can then use boost::flyweight<std::string> directly or a light wrapper
around it as your intern string type.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo