OK,
I read perlguts. I read perlapi. I read Inline::C. I read
Inline::C-Cookbook.
I had the most trouble with passing the input data properly. Eventually
everything works.
I offer the following up for inclusion in C-Cookbook to save someone else the
pain of doing this again. There is really very little in the
Cookbook about AV*
structures and NV*'s.
I am unclear if the newRV_noinc() macros should be newRV_inc() macros. I used
the noinc macros because the Hash of Lists examples used them. Does anyone
know for sure?
Scott
#!/usr/bin/perl -w
use strict;
my $n = 21;
my @angles = map {$_ * 3.1415926/($n-1)} (0..$n);
my ($cosine, $sine) = trig_wrap($n, \@angles);
for (0..$n-1) {
print $_," ", $angles[$_]," ", $$cosine[$_], " ", $$sine[$_], "\n";
}
use Inline C => <<'END_OF_C_CODE';
/* this typically would be in a library */
void trig(int n, double * angles, double ** cosines, double ** sines)
{
int i;
*sines = (double *) malloc(n*sizeof(double));
*cosines = (double *) malloc(n*sizeof(double));
for (i=0; i<n; i++) {
(*cosines)[i] = cos(angles[i]);
(*sines)[i] = sin(angles[i]);
}
}
void trig_wrap(int n, SV* array_ref)
{
Inline_Stack_Vars;
double *cosine, *sine, *angles;
AV *pcos, *psin, *av_ptr;
SV** sv_ptr;
int i;
/* copy values from array_ref into C array */
angles = (double *) malloc(n*sizeof(double));
av_ptr = (AV*) SvRV(array_ref);
for (i=0; i<n; i++) {
sv_ptr = av_fetch(av_ptr,i,0);
angles[i] = SvNV(*sv_ptr);
}
trig(n, angles, &cosine, &sine);
/* copy values from C arrays into perl arrays */
pcos = newAV();
psin = newAV();
for (i=0; i<n; i++) {
av_push(pcos, newSVnv(cosine[i]));
av_push(psin, newSVnv(sine[i] ));
}
/* get rid of C arrays */
free(angles);
free(sine);
free(cosine);
/* return references to perl arrays */
Inline_Stack_Reset;
Inline_Stack_Push(newRV_noinc((SV*) pcos));
Inline_Stack_Push(newRV_noinc((SV*) psin));
Inline_Stack_Done;
}
END_OF_C_CODE
--
____________________________________________________________
Scott Prahl http://omlc.ogi.edu/
Oregon Medical Laser Center (503) 216-2197
9205 SW Barnes Rd (503) 216-2109 (secretary)
Portland OR 97225 (503) 216-2422 (fax)
