[vlc-devel] [RFC 0/3] Improving vlc_array_t

Denis Charmet typx at dinauz.org
Sun Jul 22 18:16:18 CEST 2018


Hi,

On 2018-07-19 17:57, Romain Vimont wrote:
> There are 3 arrays API in vlc_arrays.h:
>  1. TAB_* macros
>  2. ARRAY_* macros
>  3. vlc_array_t + functions
> 
> When we want a dynamic array of pointers, the vlc_array_t seems more
> appropriate. Moreover, the macro versions abort() on allocation 
> failure.

In my opinion, an array of void* pointers feels generic to the point of 
waste.
I completely get that handling insertion, deletion, lookup for every 
structure is a PITA but I think that arrays of void* are more nefarious 
than useful.

Vectors are awesome but as far as I know they handle more cases than 
the vlc_array_t: they allocate the size of the object, call its 
destructor on deletion and ensure type safety. To be fair, I would 
personally prefer if the array allocated the whole size of each element, 
like calloc does but I agree that it probably won't be enough since we 
have no way in C to enforce the C++ rule of 3 
(constructor/destructor/copy) to make it safer.

In that regard, I prefer the TAB_ macros for their flexibility and type 
preserving even with their drawbacks and would love to see them improved 
rather than relying on arrays of void* pointers.

In any case I agree that the playlist should be flat and ordered. I 
lack the algorithmic theoretical knowledge to propose a better structure 
than an array or a linked chain. But maybe if you elaborate on what the 
playlist elements will actually hold we could come up with a proposition 
that will satisfy everybody.

Regards,
-- 
Denis Charmet - TypX
Le mauvais esprit est un art de vivre


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