[GRASS5] g51 v.build accelerated

[Andrea Aime]

Radim Blazek wrote:
> 
> v.build accelerated now:
> 
> grass50  grass51
> 270s     9s     (with attributes)
> 124s     6s     (without attributes)
> 
> How boring. Somebody should check, seems to be too good.
> 

Mmm, I haven't looked at the new code, but the old
version uses a hand made realloc that allocates a new
array and then copies the old array into the new 
element by element, thus making
lots of works each time an array has to be enlarged
(according to the few comments available realloc was
buggy on Solaris at the time v.build was written) ...
maybe your new implementation uses the standard libc 
realloc, which is much faster than this... just a guess
(maybe I am completely wrong)
ciao
Andrea Aime