#! perl -slw
use strict;
use Time::HiRes qw[ time ];

our $N //= 100;

open INDEX, '<:raw', "$ARGV[ 0 ].idx" or die $!;
my $len = -s( INDEX );
sysread INDEX, my( $idx ), $len;
close INDEX;

my $start = time;
open DAT, '<', $ARGV[ 0 ] or die $!;
for( 1 .. $N ) {
    my $toRead = int rand( length( $idx ) / 4 );
    my $offset = unpack 'N', substr $idx, $toRead * 4, 4;
    seek DAT, $offset, 0;
    my $line = <DAT>;
#    print $line;
}
close DAT;

printf "Ave. %.6f seconds/record\n", ( time() -$start ) / $N;