Re^2: Problem on perl callbacks from XS

Yes, indeed. This should be the approach. However, (there's always one :), I want the serialization function to handle a big data structure, which can contain these blessed objects rather deep inside it.

Since the main purpose of all this mess is to speed up things, I thought I'd want to pass a reference to this "big structure" and then the XS function would do the heavy work.

Doing as you say, and I've tried that before, probably means that I must move all the data structure traversal outside of XS. Example:

my $big_struct = [
   {a=>1}, {b=>2},
   [1, 2, 3, 4, 5],
   ['blah', 'blah', ['bluh', $blessed_object]],
   {d=>3, e=>[1,2,3]}
];
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If I want to correctly handle $blessed_object from XS, I must call its toString() (assume for now it has one) with call_sv().
Doing this from Perl code, means I must shift all the structure traversal from XS to Perl... losing a share of the speed gain...

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Re^3: Problem on perl callbacks from XS by tachyon-II (Chaplain) on May 25, 2008 at 15:35 UTC
Here is an example. It's done in Inline but is just straight vanilla XS. The stack pointer behaves itself over the separate calls. package Serialize; use Data::Dump; sub new { bless {foo=>'bar'}, shift } sub toString { return Data::Dump::dump($_[0]) } my $obj = new Serialize; my $str = "some string"; print serialize($obj), $/; print serialize($str), $/; use Inline Config => FORCE_BUILD => 1, CLEAN_AFTER_BUILD => 0; use Inline C => <<'END_OF_C_CODE'; void serialize(SV* sv_data) { int count; dXSARGS; sp = mark; printf("\nEntry SP is %d\n", sp); if (sv_isobject(sv_data)) { // this is an object so presume a toString method PUSHMARK(sp); XPUSHs(sv_data); // whack it back on the stack PUTBACK; count = perl_call_pv("toString", G_SCALAR); if ( count != 1 ) croak("Expected 1 value got %d\n", count); XPUSHs(sv_2mortal(newSVsv(POPs))); } else { // just return SV with something appended for this example sv_catpv(sv_data, " - serialized\0"); XPUSHs(sv_2mortal(newSVsv(sv_data))); } PUTBACK; printf("Exit SP is %d\n", sp); XSRETURN(1); } END_OF_C_CODE __DATA__ bless({ foo => "bar" }, "Serialize") some string - serialized Entry SP is 32203548 Exit SP is 32203552 Entry SP is 32203548 Exit SP is 32203552 [download]	[reply] [d/l]

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Re^3: Problem on perl callbacks from XS
by tachyon-II (Chaplain) on May 25, 2008 at 15:35 UTC

Here is an example. It's done in Inline but is just straight vanilla XS. The stack pointer behaves itself over the separate calls.

package Serialize;
use Data::Dump;

sub new { bless {foo=>'bar'}, shift }
sub toString { return Data::Dump::dump($_[0]) } 
my $obj = new Serialize;
my $str = "some string";
print serialize($obj), $/;
print serialize($str), $/;

use Inline Config => FORCE_BUILD => 1, CLEAN_AFTER_BUILD => 0;
use Inline C => <<'END_OF_C_CODE';

void serialize(SV* sv_data) {
    int count;
    dXSARGS;
    sp = mark;
    printf("\nEntry SP is %d\n", sp);
    if (sv_isobject(sv_data)) {
        // this is an object so presume a toString method
        PUSHMARK(sp);
        XPUSHs(sv_data);  // whack it back on the stack
        PUTBACK;
        count = perl_call_pv("toString", G_SCALAR);
        if ( count != 1 ) 
            croak("Expected 1 value got %d\n", count);
        XPUSHs(sv_2mortal(newSVsv(POPs)));
    }
    else {
        // just return SV with something appended for this example
        sv_catpv(sv_data, " - serialized\0");
        XPUSHs(sv_2mortal(newSVsv(sv_data)));  
    }
    PUTBACK;
    printf("Exit  SP is %d\n", sp);
    XSRETURN(1);
}
END_OF_C_CODE

__DATA__
bless({ foo => "bar" }, "Serialize")
some string - serialized

Entry SP is 32203548
Exit  SP is 32203552

Entry SP is 32203548
Exit  SP is 32203552
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