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Re^2: slurped scalar map

by 0xbeef (Hermit)
on Jun 20, 2006 at 15:13 UTC ( #556429=note: print w/replies, xml ) Need Help??

in reply to Re: slurped scalar map
in thread slurped scalar map

Thanks, this is spot on for my requirement. ++



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Re^3: slurped scalar map
by ikegami (Patriarch) on Jun 20, 2006 at 16:35 UTC

    I should have mentioned that substr makes a copy when $rec1->() is called. That's unavoidable. You can't extract a string from another without making the new string. However, the copy is only done when $rec1->() is executed.

    If that's a problem, you could extract small chunks at a time. For example, only 100 (by default) chars are duplicated at any given time.

    sub new_callback_accessor { my $start = $_[0]; my $end = $_[1]; my $data_ref = \$_[2]; # Avoid making a copy. return sub { my ($callback, $blk_size) = @_; local *_; $blk_size = 100 unless defined $blk_size; $blk_size = $end-$start unless $blk_size; my $ofs = $start; my $len = $end-$start; while ($len) { $blk_size = $len if $blk_size > $len; $_ = substr($$data_ref, $ofs, $blk_size); $callback->(); $ofs += $len; $len -= $blk_size; } }; } { my $data = ...; my $start1 = ...; # Calculate start from map. my $end1 = ...; # Calculate end from map. my $rec1 = new_callback_accessor($start1, $end1, $data); $rec1->(sub { print }); print("\n"); }


Re^3: slurped scalar map
by BrowserUk (Patriarch) on Jun 20, 2006 at 18:23 UTC

    Be warned. This method uses more space than simply copying the records to an array,

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