A while back I wrote a Base64 encoder, and have been using it to play with the primitive enhancements in 1.3. After a bit of fiddling I was able to get it from around an order of magnitude slower than apache commons-codec down to about 5x slower.
Taking Rich's exclamation that "clojure was meant to replace java, not ruby" to heart, I fired up the profiler. It turns out that calls to aset-byte were killing me. The aset-byte macro expanded into clojure.core$aset_byte.invoke(Object, Object, Object), an autoboxing nightmare. By replacing those calls with plain aset (which goes to one of the primitive RT.aset methods), it's now *faster* than commons-codec: user=> (time (dotimes [_ 10000] (Base64/encodeBase64 rand- bytes-4096))) "Elapsed time: 413.225 msecs" nil user=> (time (dotimes [_ 10000] (encode rand-bytes-4096))) "Elapsed time: 182.8 msecs" nil A few other things I ran into: - bit-shifting requires int or long if you want to avoid reflection, so bytes from the array had to be explicitly converted. - But you can't convert a byte to a long (missing overload on longCast), you have to use int - the let bindings are smart, but if the value is the result of some expression (e.g., case) then it needs to be wrapped in a cast if you want a primitive instead of an Object binding. http://github.com/ataggart/codec/blob/master/src/codec/base64.clj -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
