_mp_alloc vs ALLOC

bodrato at mail.dm.unipi.it bodrato at mail.dm.unipi.it
Thu May 31 13:49:42 CEST 2012


I'm looking inside the mpq directory, to perform something similar to
Torbjorn's change "mpz: Use MPZ_REALLOC return value when possible",
that's why I revive an old question...

Il Ven, 24 Febbraio 2012 12:32 pm, Torbjorn Granlund ha scritto:
> bodrato at mail.dm.unipi.it writes:

>   I always used the MPZ_REALLOC macro, to enlarge (if needed) the memory
>   area available for an integer. This macro gives a (possibly new) pointer
>   with the requested size available... but it also copies the content.
>   Sometimes I know in advance that the content can be discarded. Is there

> I use this trick for that:
>   rp = realloc (rp, 1);
>   rp = realloc (rp, newsize);
> I suspect there is a lot to win from using such a trick, at least of the
> I am not sure how to deal with this in GMP.  We could add a flag field
> in MPZ_REALLOC, or have special functions+macros.

Most of the uses of MPZ_REALLOC in mpq don't need the data relocation at
all, because the next step usually consists in overwriting them.

Do you mind if I define a new macro MPZ_NEWALLOC?
Currently it should be the same as MPZ_REALLOC, but it can be changed in
the future...


PS: I'm also removing LIMBS from gmp-impl.h, an alias for PTR.


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