Stas Bekman wrote:
Philippe M. Chiasson wrote:
Stas Bekman wrote:
[EMAIL PROTECTED] wrote:
gozer 2004/09/09 15:16:38
+/* XXX: There is no XS accessible splice() */ +static void modperl_av_remove_entry(pTHX_ AV *av, I32 index) +{ + I32 i; + AV *tmpav = newAV(); + + /* stash the entries _before_ the item to delete */ + for (i=0; i<=index; i++) { + av_store(tmpav, i, SvREFCNT_inc(av_shift(av))); + } + + /* make size at the beginning of the array */ + av_unshift(av, index-1); + + /* add stashed entries back */ + for (i=0; i<index; i++) { + av_store(av, i, *av_fetch(tmpav, i, 0)); + } + + SvREFCNT_dec(tmpav);
shouldn't it just be sv_free'd? how do you know when the enclosing scope will force the free'ing when you can safely free it right here.
I was under the impression that SV *av = newAV(); [...] SvREFCNT_dec(av);
would achieve just that.
Yes, but with what price:
#if defined(__GNUC__) && !defined(__STRICT_ANSI__) && !defined(PERL_GCC_PEDANTIC)
# define SvREFCNT_dec(sv) \
({ \
SV *_sv = (SV*)(sv); \
if (_sv) { \
if (SvREFCNT(_sv)) { \
if (--(SvREFCNT(_sv)) == 0) \
Perl_sv_free2(aTHX_ _sv); \
} else { \
sv_free(_sv); \
} \
} \
})
#else
Are you saying you'd want to see: SV *av = newAV(); [...] av_undef(av);
SV *av = newAV(); ... sv_free(av).
won't that work just as well. I guess you get not much speed improvement here, but it's clear that this is a temp and you free it right there.
I read perlapi and basically got the idea that the only _clean_ way to destroy a SV * is by decreasing it's refcnt
sv_free Decrement an SV’s reference count, and if it drops to zero,
call "sv_clear" to invoke destructors and free up any memory
used by the body; finally, deallocate the SV’s head itself.
Normally called via a wrapper macro "SvREFCNT_dec". sv_clear
Clear an SV: call any destructors, free up any memory used by
the body, and free the body itself. The SV’s head is not freed,
although its type is set to all 1’s so that it won’t inadver-
tently be assumed to be live during global destruction etc.
This function should only be called when REFCNT is zero. Most
of the time you’ll want to call "sv_free()" (or its macro wrap-
per "SvREFCNT_dec") instead.So I thought calling either sv_clear/sv_free directly wasn't recommended.
I don't really care either way though.
-- -------------------------------------------------------------------------------- Philippe M. Chiasson m/gozer\@(apache|cpan|ectoplasm)\.org/ GPG KeyID : 88C3A5A5 http://gozer.ectoplasm.org/ F9BF E0C2 480E 7680 1AE5 3631 CB32 A107 88C3A5A5
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