Daryle Walker wrote:
This is something I've been working on for the past few months. It's in the Sandbox and I just uploaded it to the new Vault as "big_radix_whole.tar.bz2" under the "Math - Numerics" directory, i.e. <http://www.boost-consulting.com/vault/index.php?action=downloadfile&filenam e=big_radix_whole.tar.bz2&directory=Math%20-%20Numerics&>.
Very cool!
The only documentation right now is the Doxygen comments.
But most importantly the code reads nice. It would probably read even better without those comments ;-).
Many of the operations are repeated, each with optimized algorithms for the different sizes of the parameters. Since the traditional method of multiplication is actually a fused-add/multiply, member functions for such fused actions were added. There are many variants for shifting-up where additions/subtractions start since it's faster than doing a separate shifting operation first. And it saves memory, which was an important goal in all the algorithms, along with the strong exception guarantee.
Did you consider using expression templates to - eliminate temporaries in expressions - detect temporaries to use in-place operations instead of copying ones, IOW exploiting destructibility of values - decorate the allocator for stack-based allocation during evaluation - replacing widening conversion operations with views ? The last point of the above list can probably be implemented with a "hollow base", CRTP and deduce-from-base instead of ET (similar to polymorphism of parsers in Spirit). The ET approach could also be used to implement interesting syntactic properties. I once wrote a Wiki page about it: http://tinyurl.com/qtyhh The information in the above section of my post is probably not too properly explained - please ask specific questions in case you are interested in something that seems mysterious.
... What other routines should be added?
Logarithm
Should there be Serialization?
Yes. Especially for Base64 encoding.
Could Spirit and/or Regex be used for the I/O routines?
Given these two alternatives I'd prefer Spirit for header-only code: // schematic, untested code typedef big_radix_whole<Rx,Al> value_type; value_type result; uint_parser< value_type, 10 > dec_ap; uint_parser< value_type, 16 > hex_ap; uint_parser< value_type, 8 > oct_ap; uint_parser< value_type, 2 > bin_ap; if (! parse(first,last, // or some char* instead // this expression could be statically initialized // for optimization "0x" >> hex_ap [ var(result) = arg1 ] | "0b" >> bin_ap [ var(result) = arg1 ] | "0" >> oct_ap [ var(result) = arg1 ] | dec_ap [ var(result) = arg1 ] ).full) throw some_error; But it might be faster to just hand-code the whole thing (in particular to avoid copying), I figure. Regards, Tobias