[linux-audio-dev] [ot] [rant] gcc, you let me down one time too many

[Jussi Laako]

On Wed, 2005-06-08 at 14:08 +0200, Alfons Adriaensen wrote:

> >      typedef list<Foo> Foos;
> > 
> Valid point, there are occasions where you can do this sort of thing.
> But when we are talking about large data sets and heavy use, it could
> lead to some nasty surprises. For small data sets, it doesn't matter
> much.

Using C++ and/or templates doesn't necessarily make anything any slower,
but improves readability.

For example, if you would like to multiply some dataset with window...

With libDSP you can do:

	typedef float sample_t;
	clDSPVector<sample_t> vData;
	clDSPVector<sample_t> vWindow;

	vWindow.WinHamming(1024);

	...

	vData.Set(pSrcBuf, 1024);
	vData *= vWindow;

This would perform the multiply using handwritten asm SIMD routines.
And you can still access the individual samples by using vData[n]
without significant performance penalty compared to a simple float
array. And I say "significant" here just because it also performs bounds
checking. It could be made even equally fast by changing the operator[]
implementation.

I think the above is much clearer and faster to use than calling equal C
functions (which also exist). And you can easily change it to use
doubles instead of floats just by changing the typedef.


-- 
Jussi Laako <jussi.laako at pp.inet.fi>