From: Jason Roelofs <jameskilton@...>
Date: 2009-06-12T22:31:33+09:00
Subject: Re: wrapping a C struct[] constant

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On Fri, Jun 12, 2009 at 7:42 AM, Eero Saynatkari <ruby-ml@kittensoft.org>wrote:

> Martin DeMello wrote:
> > I have some C code with a struct definition
> >
> > struct flag_str {
> >   unsigned int val;
> >   const char *str;
> > };
> >
> > and an inline array
> >
> > struct flag_str extent_flags[] = {
> >   { FIEMAP_EXTENT_LAST,    "last" },
> >   { FIEMAP_EXTENT_UNKNOWN,  "unkown" },
> >   { FIEMAP_EXTENT_DELALLOC,  "delalloc" },
> >   { FIEMAP_EXTENT_NO_BYPASS,  "no_bypass" },
> >   { FIEMAP_EXTENT_SECONDARY,  "secondary" },
> >   { FIEMAP_EXTENT_NET,    "net" },
> >   { FIEMAP_EXTENT_DATA_COMPRESSED, "data_compressed" },
> >   { FIEMAP_EXTENT_DATA_ENCRYPTED, "data_encrypted" },
> >   { FIEMAP_EXTENT_NOT_ALIGNED,  "not_aligned" },
> >   { FIEMAP_EXTENT_DATA_INLINE,  "data_inline" },
> >   { FIEMAP_EXTENT_DATA_TAIL,  "data_tail" },
> >   { FIEMAP_EXTENT_UNWRITTEN,  "unwritten" },
> >   { FIEMAP_EXTENT_MERGED,    "merged" },
> >   { 0,        NULL },
> > };
> >
> > What's the simplest way to expose that array as a ruby constant (other
> > than just copy/pasting the data, of course :))?
>
> How/where are you *using* it?
>
> FFI is generally a good solution, although it
> would probably be best to actually define the
> Array on the Ruby side and pass it in as needed.
>
>
> Eero
> --
> Magic is insufficiently advanced technology.
> --
> Posted via http://www.ruby-forum.com/.
>
>
Even using FFI, you'll need to define the wrapping between C constant to
Ruby constant, and using Ruby's API, you'll be define_const-ing every one of
those, then putting them into an array. Just define them in the Ruby
yourself, there isn't a faster way to do it.

Jason

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