Re: [Caml-list] Now it's faster (addendum to "Performance-question")

["Jean-Christophe Filliâtre" <Jean-Christophe.Filliatre@lri.fr>]

Vincent Hanquez wrote:
> the buffer library is actually pretty bad since it's actually just a
> simple string. each time the buffer need to grow, the string is
> reallocated and the previous one is copied to the new string.
> and you got the 16mb limit (max_string_length) on 32bit.

Just for fun, I wrote a ropes-based implementation of Buffer. The
interface is exactly the same. Differences between the two
implementations are the following:

 - Contrary to ocaml's standard library, a buffer size is not limited to
      [Sys.max_string_length], but to [max_int] (sizes are represented
      internally using native ocaml integers).

 - [contents] and [sub] raise [Invalid_argument] if the resulting string
      would be larger than [Sys.max_string_length] bytes.

 - The meaning of [create]'s argument is not exactly the same,
    though its value only affects performances, as for [Buffer];
    see below.

 - An additional function [print] is provided.

The code is here:

	http://www.lri.fr/~filliatr/ftp/ocaml/ds/rbuffer.mli
	http://www.lri.fr/~filliatr/ftp/ocaml/ds/rbuffer.ml

For general-purpose ropes, see

	http://www.lri.fr/~filliatr/software.en.html

-- 
Jean-Christophe