[Speex-dev] [patch] Mac Universal Binaries

[Peter Grayson]

On 5/3/07, Jean-Marc Valin <jean-marc.valin at usherbrooke.ca> wrote:
> I don't quite see the major difference between doing things at configure
> time or at compile time, bug anyway...

Sorry, I was not clear. The thing that is unique about the Mac build
process is that it shares the same configuration for both x86 and ppc
builds. It also uses a single compiler invocation for both where
__BIG_ENDIAN__ is defined ppc and __LITTLE_ENDIAN__ for x86.

> My suspicion is that I don't want to break things because MacOS X has
> strange requirements.

I suspect your suspicion to be quite valid. Agreed.

>
> > The extra thing we could do is set a preprocessor variable at
> > configure-time that we could use at compile-time to determine whether
> > the endianess was resolved at configure-time or should be resolved at
> > compile-time. For example:
> >
> > #if defined(COMPILE_TIME_ENDIANESS) && defined(__BIG_ENDIAN__) ||
> > !defined(COMPILE_TIME_ENDIANESS) && defined(WORDS_BIGENDIAN)
> > /* do big endian thing */
> > #else
> > /* do little endian thing */
> > #endif
> >
> > This seems excessively complicated, so I preferred not to do it.
>
> Actually, all we need is to do is have that once in the main include:
> #if defined(WORDS_BIGENDIAN) || defined(__BIG_ENDIAN__)
> #define SPEEX_BIGENDIAN
> #endif
>
> and then we just use SPEEX_BIGENDIAN everywhere else.

This technique would work for in all cases except when building the
universal binary on a ppc machine. In that case, both WORDS_BIGENDIAN
and __LITTLE_ENDIAN__ will be defined at compile time (for the x86
part of the build). Maybe if we amended the expression to this:

#if !defined(__LITTLE_ENDIAN__) && ( defined(WORDS_BIGENDIAN) ||
defined(__BIG_ENDIAN__) )
...

I think that would cover all the bases.

I have attached a patch that makes this change. There is a little code
duplication because wavio.h and misc.h both need this trick, but they
don't appear to share any headers besides speex_types.h. I wasn't sure
if speex_types.h was a good place for this or not.

Pete
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