On 10/06/2011 18:35, Robert Ramey wrote:
Mathias Gaunard wrote:
On 10/06/2011 01:14, Robert Ramey wrote:
I think you'd find it interesting to see how the serialization library does it.
../boost/archive/iterators/base64_from_binary ../boost/archive/iterators/binary_from_base64
The code of these is much more complicated than it needs to be; there is too much coupling between the algorithm and the iterator adaptor.
well, it's implemented in terms of iterator adaptor. I see that as a feature. This gives maximal efficiency and total compile time flexibility and leverages on working/tested/reviewed code - which to me is what boost is about.
Yes, it's a feature, but unfortunately the base64 logic is intertwined with the iterator logic, and concerns are not as well separated as they could be. From a glimpse at the code, I am also not really convinced that it's got maximal efficiency either, it could probably be faster by computing at compile-time the optimal bit twiddling logic and reducing the redundant branches.
I can't see how another implementation which doesn't use the already made stuff can be faster or more efficient or add less code to the code base.
I have an implementation of a generic system that can generate, from a model of a very simple and explicit Converter concept, an iterator adaptor, an eager algorithm, a codecvt facet or a boost.iostreams filter. The idea is basically that I put inside a concept the notion of a conversion step, and then I built an iterator adaptor that can work for any model of that concept. A possible implementation of a base64 encoder Converter, along with a codecvt demo (hardly the best backend) is available at <http://svn.boost.org/svn/boost/sandbox/SOC/2009/unicode/libs/unicode/example/base64.cpp> It's not generic (in the sense that it doesn't allow N to M bit conversion like transform_width, it just does base64 -- after all it's only meant to be an example) but that's something that would also be fairly easy to do. Now I am not suggesting that Boost should definitely use this, I'm just presenting alternatives.