binary 02packages search

#!/usr/bin/env perl
use 5.010;
use strict;
use warnings;
use autodie;
use XDG;
use Tie::File;

tie my @index, 'Tie::File', "02packages.details.txt";

my $blank = 0;
$blank++ until $index[$blank] !~ /^\w/;

sub first { my ($f) = split / /, $_[0]; return $f }

sub search {
  my ($array, $key) = @_;
  my ($lo, $hi) = ($blank, $#{$array});

  while (1) {
    if ($hi == $lo) {
      my ($val) = first($array->[$hi]);
      return $val eq $key ? $array->[$hi] : undef;
    }

    my $mid = int(($lo + $hi)/2);
    my $rec = $array->[$mid];
#    say "HI : " . first($array->[$hi]);
#    say "MID: " . first($rec);
#    say "LOW: " . first($array->[$lo]);

    if (lc first( $rec ) lt lc $key) { $lo = $mid+1 }
    else                    { $hi = $mid   }
  }
}

while (<>) {
  chomp;
  my $val = search(\@index, $_);
  say( (defined $val) ? "found $val" : 'not found');
}