Re: [Jack-Devel] Alignment (again)

OK... after further thought, I retract my proposal.

On Thu, Aug 4, 2011 at 7:57 AM, Gabriel Beddingfield <[hidden]> wrote:
> But now that I think of it... the problem with jack_ringbuffer is actually
> pretty fundamental.
>
> Suppose you allocate a ringbuffer of size N (where N is a power of 2). The
> storage space is (N-1).  So even if you start with an aligned pointer...
> when you wrap around it will no longer be aligned. :-/

When using the read/write vectors... the programmer must never EVER:

  - Assume that the read/write vector jack_ringbuffer_data_t::buf
    is aligned.

  - Directly cast jack_ringbuffer_data_t::buf to anything with
    a size > 1 byte.

I.e. the read/write vectors are only suitable for memcopying the data
to a properly aligned float* buffer.  Therefore, I'll instead submit a
documentation patch... to warn about this.

-gabriel

p.s. I made this programming error while playing around with
read/write vectors in trying to create a test case for memory ordering
issues.  (No flames or continued discussions, I was just having some
fun.)

1312466019.8260_0.ltw:2,a <CAPbw_hxLLcU=Pz-nu48pGuYt31TRDyrGBfe_62XJ_VAf+DmjQg at mail dot gmail dot com>