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Re^4: elsif chain vs. dispatch

by almut (Canon)
on Apr 27, 2009 at 20:59 UTC ( #760433=note: print w/replies, xml ) Need Help??

in reply to Re^3: elsif chain vs. dispatch
in thread elsif chain vs. dispatch

I recall that perls from 5.8.3 or so have code in place to watch out for this sort of degenerate case

I think it's the HV_MAX_LENGTH_BEFORE_SPLIT, currently set to 14.

/* hv.c */ #define HV_MAX_LENGTH_BEFORE_SPLIT 14 ... Perl_hv_common( ... ) { ... while ((counter = HeNEXT(counter))) n_links++; if (n_links > HV_MAX_LENGTH_BEFORE_SPLIT) { /* Use only the old HvKEYS(hv) > HvMAX(hv) condition t +o limit bucket splits on a rehashed hash, as we're not goin +g to split it again, and if someone is lucky (evil) enou +gh to get all the keys in one list they could exhaust our + memory as we repeatedly double the number of buckets on ev +ery entry. Linear search feels a less worse thing to do +. */ hsplit(hv); } ... }

(the comment seems to be a left-over from an ealier implementation, though...)

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[GotToBTru]: $aohoaoh->[0] is a hash reference, so $aohoaoh->[0]->{ key1} would work
[1nickt]: If 1nickt is the some guy, that's not what he said.
[GotToBTru]: thepkd might not know about last hour of cb
[1nickt]: my $x = $aohoaoh->[0]->{' foo'}->[0]->{'bar' }; should work
[thepkd]: its not $aohoaoh->[0]. its $aohoaoh[0]->{'foo '}. Tried it. Its working. Thnaks
[thepkd]: Hey 1nickt sorry man. What
[GotToBTru]: a ref too far ;)

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