[PD] reading arrays from an external

[oscar pablo di liscia]

Very clear, many thanks.

Oscar Pablo Di Liscia

2015-09-21 11:41 GMT-03:00 IOhannes m zmoelnig <zmoelnig at iem.at>:

> On 2015-09-21 16:24, oscar pablo di liscia wrote:
> > Many thanks.
> > So that, if a table is not used in a dsp process, and we
> > don't use the garray_usedindsp() function,  it is safe to change
> > its contents providing the fact that this change is properly
> > done using the access methods available?
>
>
> really there is only a single access method (to the data) available:
> garray_getfloatwords() returns a pointer to an array of words which you
> can dereference to read or write the actual values.
>
>
> it's always safe to *immediately* use the data returned by
> garray_getfloatwords().
>
> however, if you want - for performance reasons - to cache the returned
> pointer, then you need some wy of invalidating it (e.g. because the
> table the pointer referred to has moved to some other place).
> that's the use case of garray_usedindsp().
>
> it builds on the assumption that only DSP objects would use this kind of
> optimization.
> as a result, you *can* only use this optimization in DSP perform
> routines. all other table access has to be done through
> garray_getfloatwords() immediately before dereferencing the pointer.
>
>
>
> if you must change the size of a table, use garray_resize_long();
> after that you must call garray_usedindsp() again to get the new data
> pointer.
>
> hopefully this makes it a bit clearer.
>
> fgmasdr
> IOhannes
>
>
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