Partition dump MBR

pd.pl6

#!/usr/bin/env perl6

# Reference:
# https://wiki.osdev.org/Partition_Table

my %ids = 0x00 => "Empty", 0x0b => "W95 FAT32", 0x0c => "W95 FAT32 (LBA)",
        0x82 => "Linux swap", 0x83 => "Linux", 0x93 => "Amoeba";

sub MAIN($filename) {
        say "Disk: $filename";
        say "NB: addesses given in (decimal) blocks of 512 bytes each";
        say "Part  Boot    Start      End     Size   Id Type";
        my $fh = IO::Handle.new(:path($filename.IO.path)).open;
        $fh.seek(0x01BE);

        my $entry;
        sub eat() { return $entry.shift; }
        for 1..4 { 
                $entry = $fh.read(16);
                my $boo = eat;
                $boo = $boo == 0x80 ?? "*" !! " ";
                for 1..3 { eat; }
                my $sid = eat;
                for 1..3 { eat; }
                my $start = $entry.read-uint32(0, LittleEndian);
                last if $start == 0;
                my $size = $entry.read-uint32(4, LittleEndian);
                my $end = $start + $size -1 ;
                my $name = %ids{$sid} || "Unknown";
                printf "%d %8.8s %8d %8d %8d 0x%.2X %s\n", $_, $boo, $start,$end, $size,  $sid, $name;

        }
        $fh.close;
}