Thanks Edwin and Oliver, I wasn't aware of these libraries. I'll definitely have a look. Thanks again everybody for your help on this! ph.
2012/3/18 Török Edwin <edwin+ml-oc...@etorok.net> > On 03/16/2012 04:49 PM, Jérémie Dimino wrote: > > Le Fri, 16 Mar 2012 14:03:38 +0100, > > Philippe Veber <philippe.ve...@gmail.com> a écrit : > > > >> Say that you'd like to search a regexp on a file with lines so long > >> that you'd rather not load them entirely at once. If you can bound > >> the size of a match by k << length of a line, then you know that you > >> can only keep a small portion of the line in memory to search the > >> regexp. Typically you'd like to access substrings of size k from left > >> to right. I guess such a thing should involve buffered inputs and > >> avoid copying strings as much as possible. My question is as follows: > >> has anybody written a library to access these substrings gracefully > >> and with decent performance? Cheers, > > > > You can use a non-backtracking regexp library to find offsets of the > > substrings, then seek in the file to extract them. You can use for > > example the libre library from Jérôme Vouillon [1]. It only accept > > strings as input but it would be really easy to make it work on input > > channels (just replace "s.[pos]" by "input_char ic"). > > > > [1] http://sourceforge.net/projects/libre/ > > https://github.com/avsm/ocaml-re.git > > > > A nice library for regular expression matching is LibTRE (BSD licensed), > and it has a way to parse arbitrary data with callbacks: > http://laurikari.net/tre/documentation/reguexec/ > > According to the paper it is also good at finding substring matches > with its tagged NFA: > http://laurikari.net/ville/regex-submatch.pdf > > If you don't use back-references (!tre_have_backrefs) then it guarantees > linear-time matching. > > I couldn't find an OCaml wrapper for it, but should be simple enough to > write one. > > Best regards, > --Edwin > > -- > 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
