Re^2: accessing mpz_t * of Math::BigInt::GMP from XS

aha -- if i change your code from:

derivation($o);
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to:

derivation($o->{value});
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then i get:

A Math::BigInt::GMP object
Not a Math::BigInt object
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So i think i can actually get access to the Math::BigInt::GMP at least.

But i think i'm still stuck on how to deal with the #defines so that my module will be reasonably portable without requiring that the person building it know exactly what #defines were used when their instance of Math::BigInt::GMP was built.

Any suggestions? Thanks for pointing me part of the way forward, at least! It's very helpful :)

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Re^3: accessing mpz_t * of Math::BigInt::GMP from XS by syphilis (Archbishop) on Mar 18, 2011 at 22:55 UTC
Yes, I eventually got around to passing $obj->{value}, but there's probably still something I'm missing. The following works for me - but it avoids a lot of the pre-processor stuff that Math::BigInt::GMP's GMP.xs contains, and I therefore wonder about its portability use Math::BigInt lib => 'GMP'; use Inline C => Config => LIBS => '-lgmp', USING => 'ParseRegExp', BUILD_NOISY => 1; use Inline C => <<'EOC'; #include <gmp.h> mpz_t * mpz_from_sv_nofail (SV sv) { MAGIC mg; if (!sv_derived_from(sv, "Math::BigInt::GMP")) croak("not of type Math::BigInt::GMP"); mg = SvMAGIC(SvRV(sv)); return (mpz_t )mg->mg_ptr; } mpz_t mpz_from_sv (SV sv) { mpz_t mpz; if (!(mpz = mpz_from_sv_nofail(sv))) croak("failed to fetch mpz pointer"); return mpz; } void my_mul(SV * bi_rop, SV * bi_op, SV * si) { mpz_t t1, t2; t1 = mpz_from_sv(bi_rop); t2 = mpz_from_sv(bi_op); mpz_mul_si(t1, t2, SvIV(si) * 10); } EOC my $rop = Math::BigInt->new(0); my $op = Math::BigInt->new(123456); my $x = -110; my_mul($rop->{value}, $op->{value}, $x); print $rop, "\n"; __END__ Outputs: -13580160 [download] I also wonder: 1) How is the change of sign being effected by my_mul() - given that it should be working only with 'value'; (Update: Setting $op to -123456 and multiplying by -110 still results in an output of -13580160. So 'sign' is not being dealt with correctly ... which is what I expected. ) 2) Why do I have to multiply the 3rd arg of my_mul() by 10 in order to have it produce the correct value in the Math::BigInt::GMP object. I'm sure there's a very good (and likely very simple) explanation for both. Cheers, Rob	[reply] [d/l]
Re^4: accessing mpz_t * of Math::BigInt::GMP from XS by syphilis (Archbishop) on Mar 19, 2011 at 04:34 UTC
Eventually got it down to the following (which works correctly for me, afaik): use Math::BigInt lib => 'GMP'; use Inline C => Config => LIBS => '-lgmp', USING => 'ParseRegExp', BUILD_NOISY => 1; use Inline C => <<'EOC'; #include <gmp.h> mpz_t * mpz_from_sv_nofail (SV sv) { MAGIC mg; if (!sv_derived_from(sv, "Math::BigInt::GMP")) croak("not of type Math::BigInt::GMP"); mg = SvMAGIC(SvRV(sv)); return (mpz_t )mg->mg_ptr; } void _my_mul(SV bi_rop, SV * bi_op, SV * si, SV * rop_sign, SV * op_ +sign) { mpz_t t1, t2; sv_setpv(rop_sign, SvPV_nolen(op_sign)); t1 = mpz_from_sv_nofail(bi_rop); t2 = mpz_from_sv_nofail(bi_op); mpz_abs(t2, t2); mpz_mul_si(t1, t2, abs(SvIV(si))); if(SvIV(si) < 0) { if(strEQ(SvPV_nolen(op_sign), "-")) sv_setpv(rop_sign, "+"); else sv_setpv(rop_sign, "-"); } } EOC my $rop = Math::BigInt->new(0); my $op = Math::BigInt->new(-123456); my $x = 1103; my_mul($rop, $op, $x); print $rop, "\n"; my_mul($op, $op, 5); print $op, "\n"; sub my_mul { _my_mul($_[0]->{value}, $_[1]->{value}, $_[2], $_[0]->{sign}, $_[1]- +>{sign}); } [download] Cheers, Rob	[reply] [d/l]