Re: [boost] Random Access to Files (RAF) - any interest ?

From: Slava, Alex (raf.devel_at_[hidden])
Date: 2006-05-20 00:28:32

On 5/18/06, Beman Dawes <bdawes_at_[hidden]> wrote:
> * It isn't possible for a regular file implementation to efficiently support
> non-constant iterators, because there is no way to tell when a buffer has
> been written into, and thus must be rewritten to disk. An update() function
> is needed. It can be a no-op on memory-mapped implementations.
>

We probably should, something like fflush() in C library. And it may
not necessarily be no-op for MMF, because there are syncronization
routines for this facility, so it might make sense to use them.

> * Note that a regular file implementation of an STL iterator based interface
> may be more efficient than fread/fwrite, because unnecessary copying of data
> is eliminated. I'm really curious to see timings on this.

Highly unlikely, but we will perform the test and post the results.

>
> * Your design uses a class template for the record type, so is limited to
> files containing a single type. Real files often contain a mix of types. By
> use of member templates, it is easy to support files containing a mixture of
> types. If that isn't clear, I can post an example of an experimental
> interface that does so.

This seems to be a burning question, and could significantly affect
implementation.. Could you please post an example ASAP ?

>
> That should be enough to start discussion!
>
> --Beman
>

-- 
Svyatoslav Trukhanov,
Oleksii Ursulenko