On 25/08/01 12:52 -0400, Ken Williams wrote:
> Hiya,
>
> Brian keeps encouraging me to get on the Inline train, so here I am. =)
Welcome.
> I'm wondering whether there's a better way to embed C data structures
> inside Perl data structures. I don't need to access them from Perl
> (I'm using Inline wrappers for that), so I don't think Inline::Struct
> is the ticket. So far I have this hacky method:
Ken,
I'm afraid I couldn't figure out exactly where you were coming from. My
guess is that you are looking for a more memory efficient way to store a
lot of numbers. I cooked up a little example of how you might want to
implement your own array of doubles. It uses tie, which makes things a
lot cleaner. It also avoids malloc which is generally a bad idea to mix
in with Perl API calls. (Just use a new SV for your struct buffer and
inherit all the ease of use that SV's provide) Here's what I came up
with. (It's oversimplified for general use, but you'll get the idea)
--8<--
package main;
tie @foo, "Double::Array";
$foo[5] = 10.5;
print $foo[5], "\n";
print $foo[6], "\n";
#####################################################
package Double::Array;
use Inline C;
__DATA__
__C__
SV* TIEARRAY(char* class) {
SV* obj_ref = newSViv(0);
SV* obj = newSVrv(obj_ref, class);
SvUPGRADE(obj, SVt_PV);
return obj_ref;
}
double STORE(SV* self, int index, double value) {
SV* obj = SvRV(self);
double* array_ptr = (double*)SvGROW(obj, (index + 1) * sizeof(double));
return *(array_ptr + index) = value;
}
double FETCH(SV* self, int index) {
SV* obj = SvRV(self);
double* array_ptr = (double*)SvPVX(obj);
if (index >= SvLEN(obj) / sizeof(double))
croak("Double::Array index [%d] exceeds bounds", index);
return *(array_ptr + index);
}
--8<--
BTW, It's generally better to send a working example to the mailing
list, than just parts of code. Let me know if this helps.
Cheers, Brian
