#! perl -slw
use strict;
use Time::HiRes qw[ time ];
use constant {
    XMAX => 4587,
    YMAX => 2889,
    REC_SIZE => 7 * 4,
};

my( $year, $day, $xRange, $yRange ) = @ARGV;
my( $xStart, $xEnd ) = split ':', $xRange
$xEnd += $xStart;
my( $yStart, $yEnd ) = split ':', $yRange;
$yEnd += $yStart;

my $start = time;

open BIN, '<:perlio', "tmp/$year.$day.bin" or die $!;
binmode BIN;

my $xLen = ( $xEnd - $xStart + 1 ) * REC_SIZE;

for my $y ( $yStart .. $yEnd ) {
    my $pos = ( $y * XMAX * REC_SIZE ) + $xStart * REC_SIZE;

    seek BIN, $pos, 0;
    my $read = sysread( BIN, my $rec, $xLen ) or die $!;

    my @recs = unpack '(A28)*', $rec;

    for my $x ( $xStart .. $xEnd ) {
        my( $a, $b, $c, $d, $e, $f, $g ) = unpack 'N7', $recs[ $x - $xStart ];

        printf "%4d.%03d : %10u %10u %10u %10u %10u %10u %10u\n",
            $year, $day, $a, $b, $c, $d, $e, $f, $g//0;
    }
}
close BIN;

printf STDERR "[@ARGV] Took %.3f seconds\n", time() - $start;