Re: Extending Moose with Inline C?

Thanks for all the replies,

Apparently this will take longer time - as it seems it is not the
highest priority right now - but I do find it interesting so I'll try
to continue it.

On Fri, Jan 9, 2009 at 6:58 PM, Stevan Little
<[email protected]> wrote:
> Zbigniew,
>
> Well, if you are creating the objects with C, this might be tricky, but can
> be worked around. If you are writing/reading data from C-based accessors,
> this is still a little tricky but easily worked around. If you just need to
> call methods which are not accessors or constructors, but are written in C,
> then this will be no problem at all.

For now I have the following:

package Net::Packet::EraApi;
use base 'Class::Accessor';
__PACKAGE__->mk_accessors(qw( OpRef MsgType Operation DataSize data ) );

use warnings;
use strict;
use ERAAPI2Inline;

.
.
.
sub decode_headers {
    my ( $class, $packet ) = @_;
    my %frame;
    my $f_ref = \%frame;
    ERAAPI2Inline::Framedecode( $packet, $f_ref );  # this is the Inline builder
    return bless $f_ref, $class;
}

So I create the object with 'ecode_headers' and in it I add entries to
it's data hash with an Inline C function.  The measurements of the
overheads need to wait - but this is what I was asked to do.


The C Inline function in ERAAPI2Inline is:

void* Framedecode(SV* packet, SV* hash_ref) {
    HV* hash;
    void* pkt;
    STRLEN pktlen;
    struct era_hdr* era_hdr;

    hash = (HV*) SvRV( hash_ref );
    pkt = SvPV(packet, pktlen);
    era_hdr = pkt;

    hv_store(hash, "OpRef",     5, newSViv(htonl(era_hdr->opref)), 0);
    hv_store(hash, "MsgType",   7, newSViv(era_hdr->msgtype), 0);
    hv_store(hash, "Operation", 9, newSViv((era_hdr->operation)), 0);
    hv_store(hash, "DataSize",  8, newSViv((era_hdr->datasize)), 0);
    if(pktlen >= era_hdr_len + era_hdr->datasize )
        hv_store(hash, "data",  4, newSVpv(pkt+era_hdr_len,
pktlen-era_hdr_len), 0);
    else
        hv_store(hash, "data",  4, &PL_sv_undef, 0);
    return;
}


Apparently with Class::Accessor this works.

I was also thinking about the Marco Fontani's and Chris Prather's
proposals of doing:

Net::Packet::EraAp->new(%{ ERAAPI2Inline::Framedecode( $packet ) } );

(with a small change to the C function) - this looks like simple
workaround and I'll need to check it.  I think this would trigger the
type checkers in Moose and probably that would mean too much overhead
though.


Cheers,
Zbigniew
http://brudnopis.blogspot.com/
http://perlalchemy.blogspot.com/