Re: [boost] [serialization] fast array serialization (10x speedup)

From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-11-22 15:23:01

David Abrahams wrote:

> 3. An archive can normally only apply an array optimization to a
>   particular subset of types.  This subset varies by archive type and
>   can usually be captured by a type trait such as is_POD or
>   is_fundamental.

In the situations that I've needed it, the subset of types that could be 
written in a single operation could not be described by a type trait. A type 
trait can't tell you whether the in-memory representation and the on-disk 
representation of a type are the same. I just enumerated the types, guarding 
the overloads with an appropriate #ifdef on endianness.

I don't understand how an archive could handle an array of arbitrary PODs.

>   We'd like to encapsulate that choice in a base
>   class template that allows us to avoid writing complex dispatching
>   logic in each array-optimized archive.

I usually just add the equivalent of a save_sequence( A&, X*, unsigned ) 
overload for every X that is supported by A.