The "mod" and the write barrier will significantly degrade performance vs C. Probably faster to replace "mod" with if-based wrap around but there's nothing you can do about the write barrier.
Cheers, Jon. > -----Original Message----- > From: David Allsopp [mailto:dra-n...@metastack.com] > Sent: 02 April 2012 16:05 > To: Hongbo Zhang; Caml List > Subject: RE: [Caml-list] How could I implement an efficient ring buffer? > > Hongbo Zhang wrote: > > Hi List, > > I want to implement sliding window algorithm (in place, no memory > > copy), I wonder whether I need to write c code. > > > > To make it clear and simple, > > In c, you can record the head pointer of the array, and do the > > modulo operations when get and set > > In ocaml, it seems you have an array a of type int array, you > > can not do things like this *(&a+5). > > Perhaps I'm missing something, but if you're planning on using arrays, what's > wrong with retrieving the item using the array index modulo the length of the > array? > > i.e. > > let a = [| ... or whatever ... |] in > a.(5 mod Array.length a) > > If accessing an array by index instead of by pointer worries you, then you're > looking at the wrong language ;o) > > > David > > > -- > Caml-list mailing list. Subscription management and archives: > https://sympa-roc.inria.fr/wws/info/caml-list > Beginner's list: http://groups.yahoo.com/group/ocaml_beginners > Bug reports: http://caml.inria.fr/bin/caml-bugs -- Caml-list mailing list. Subscription management and archives: https://sympa-roc.inria.fr/wws/info/caml-list Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
