I think all you mention has already been said in the other answers. If I switch to

sysread

and compare buk with ike1 (reading one line at the time) and ike2 (reading two lines at the time), your method wins a bit but leaves all three methods withing the noise level. Also note how *all* numbers go up!

With these rates, I wonder if I would still use your substr ref method or the unpack approach, as I find the latter way easier to read and maintain. If however performance is vital, maybe XS code would squeeze out even more (with pre-bound variables).

         Rate ike1  buk ike2
ike1 384977/s   --  -2%  -3%
buk  392677/s   2%   --  -1%
ike2 394907/s   3%   1%   --

[download]

Note that if you keep local $/ = \122; in ike1, it has a *huge* influence on performance, even if you'd say that it should not be used:

         Rate ike1  buk ike2
ike1 275687/s   -- -27% -30%
buk  378299/s  37%   --  -4%
ike2 392677/s  42%   4%   --

[download]
use strict;
use warnings;

use Benchmark qw(cmpthese);

my $data = do { local $/; <DATA> } x 400;
my @data;
my $rec  = chr (0) x 512;

{   # 1. BrowserUk
    my @type3l = split m/:/, "02:10:33:15:19:10:3:18:6:4";
    my $n      = 0;
    my @type3o = map { $n += $_; $n - $_; } @type3l;
    my @type3  = map \substr ($rec, $type3o[$_], $type3l[$_]), 0 .. $#
+type3o;
    my @typeOl = split m/:/, "02:98:11:9";
    $n = 0;
    my @typeOo = map { $n += $_; $n - $_; } @typeOl;
    my @typeO  = map \substr ($rec, $typeOo[$_], $typeOl[$_]), 0 .. $#
+typeOo;


    sub buk
    {
        open my $fh, "<", \$data;
        while (sysread $fh, $rec, 122, 0) {
            @data = map $$_, @type3;
            sysread $fh, $rec, 122, 0;
            @data = map $$_, @typeO;
            }
        } # buk
    }

sub ike2
{
    open my $fh, "<", \$data;
    while (sysread $fh, $rec, 244, 0) {
        @data = unpack
            "A2 A10 A33 A15 A19 A10 A3 A18 A6 A4 x2" .
            "A2 A98 A11 A9 x2",
                $rec;
        }
    } # ike2

sub ike1
{
    # local $/ = \122;
    open my $fh, "<", \$data;
    while (sysread $fh, $rec, 122, 0) {
        @data = unpack "A2 A10 A33 A15 A19 A10 A3 A18 A6 A4 x2", $rec;
        sysread $fh, $rec, 122, 0;
        @data = unpack "A2 A98 A11 A9 x2", $rec;
        }
    } # ike1

cmpthese (-2, {
    ike1 => \&ike1,
    ike2 => \&ike2,
    buk  => \&buk,
    });

__END__
03002068454210482                            000000004204.572011-04-14
+ 19:53:41INTERNET  C  750467375
0214833                                                               
+                              G02042954
03002068703214833                            000000002558.662011-04-15
+ 08:17:19INTERNET  C  761212737
0211561                                                               
+                              05601207284
03002068802911561                            000000001463.702011-04-15
+ 08:40:52INTERNET  C  719807216
029911                                                                
+                              00100275296

[download]

Enjoy, Have FUN! H.Merijn

In reply to Re^6: Working with fixed length files by Tux
in thread Working with fixed length files by vendion

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.