Steven Ross wrote:
algorithm_sorting.tar.gz is now in the boost vault, and is formatted for submission. I'd appreciate it if people could test it on their compiler and give me some feedback.
Seems to be here: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=algorithm_sorting.tar.gz&directory=& Some first impressions follow. I will try to find time to look at it more carefully at some point but I can't promise. You seem to have quite a lot of code that's duplicated for the functor and non-function versions. Can't this be eliminated by using e.g. std::less as a default for the compare template parameter? (Isn't this what std::sort does?) I suggest that you get rid of the tab characters in the source. I personally find your lines rather long, but that's a matter of taste. It would be good if it were possible to automatically detect whether a floating point type is one for which the cast-to-integer trick works. It would be great if C++ defined some macro or similar that defined whether float and double were IEEE 754 or not. (Hmm, is there some sort of type_traits thing to do this?). Maybe it's possible to get a "good guess" answer by checking whether the bit pattern is as expected for some known constant; would someone like to suggest a good way to check this at compile time? You could then fall back to std::sort if it fails. I think you can use things like typename RandomAccessIter::value_type instead of passing *first in order to determine data_type. I'm not sure how useful your functor-versions are since they still seem to depend on the "integer-ness" or "float-ness" of the sorted type. Apart from sorting backwards, what use cases are there? Using functors would be more useful if it let you sort types that are neither integers nor floats; for example, fixed-point types or pointers-to-integers or structs containing a key field to be sorted on. I think that the key here is that you make assumptions about the return type of operator>> or the right_shift functor which are not true in those cases. It may be that you just need to rename that functor and document what it needs to do. I think it's really "get N bits from key". I would have thought that the floating-point algorithm would just be an instance of the generic algorithm with custom functors, with a bit of specialisation to cope with the reverse-order-for-negatives thing. One of the things that your string sort does is to not compare known-equal initial substrings. Does anyone know if there is a variant of a conventional sort (e.g. quicksort) that does this? Some more documentation of the performance benefit would be useful. How about some graphs? Cheers, Phil.