[PD] Store data in memory more efficiently than in arrays

[Christof Ressi]

> I read
> once in IRC that one value in a Pd-array requires not 4 bytes, but 8
> bytes on 64-bit systems.
Yes. Pd's graphical arrays (and Pd's data structure arrays in general) 
are implemented as a linear array of "words" (t_word). A "word" can hold 
one of several possible types. It is implemented as a C union, so the 
overall size is always that of the largest member. In our case, the 
largest member is a pointer (e.g. t_symbol *), which is 4 bytes on a 
32-bit system and 8 bytes on a 64-bit systems.

This means that even if you would add a "byte" type, the overall size of 
"t_word" would stay the same.

However, you can always implement your own byte array object as an 
external. But as you noted, this is not necessary except you're on a 
very tight memory and/or CPU budget.

Christof

On 12.01.2022 14:20, Roman Haefeli wrote:
> Hi
>
> Sometimes I stored byte data (lists of bytes) in arrays. IIRC, I read
> once in IRC that one value in a Pd-array requires not 4 bytes, but 8
> bytes on 64-bit systems. Since storing plain bytes seems not such an
> uncommon use case for me, I wonder if it can be done more efficiently.
> Not that I ever hit a memory limit, I'm just curious. With the new
> (amazing!) [file] object, dealing with byte lists has become even more
> appealing, so the desire to store them in memory increases.
>
>
> Roman
>
>
>
> _______________________________________________
> Pd-list at lists.iem.at mailing list
> UNSUBSCRIBE and account-management -> https://lists.puredata.info/listinfo/pd-list