Re: [Chicken-users] set-file-position! only works with fixnums

[Kon Lovett]

On Oct 1, 2009, at 12:27 AM, John Cowan wrote:

> Thomas Bushnell BSG scripsit:
>
> > I think this is a mistake, but "fixing" it is harder than it seems.
> >
> > Really, this is totally non-schemey.
> >
> > The criterion should be an exact integer, just as it is for arrays.
> > Instead of allowing inexact integers to be file positions, how about
> > extending the hierarchy to handle these cases directly?
>
> Well, in order for that to work you have to persuade Felix to  
> incorporate
> bignums in the core, and they can't be GMP bignums either because of
> the licensing -- that would make Chicken as a whole GPL, and that's  
> not
> gonna happen.  Making all that happen is what is harder than it seems.

Possible is adding a int64_t heap type. But involves hitting every  
piece of code that any extension of the core number system would.

> Indexing arrays with fixnums is no problem, because Chicken won't let
> them be bigger than 2^24 elements anyhow, and fixnums go up to 2^32  
> - 1.
> The sizes of files isn't under Chicken's control, but 2^53 is plenty
> big enough for a long time to come.

Changed posixunix to use fseeko, ftello and treat lseek as taking &  
returning an off_t. It will use the 'long' forms when  
_POSIX_V6_ILP32_OFF32 is defined. (Only tested with MacOS 10.5)

Changed posixwin to use _fseeki64, _ftelli64 and _lseeki64.

Note: 'file-position' now ONLY returns integer flonums!

There is a test for flonum offsets.

> --
> It was impossible to inveigle           John Cowan <address@hidden>
> Georg Wilhelm Friedrich Hegel           http://www.ccil.org/~cowan
> Into offering the slightest apology
> For his Phenomenology.                      --W. H. Auden, from  
> "People" (1953)

Best Wishes,
Kon