#!/usr/bin/env ruby

cmd = ['dd']
countarg = nil

def decr(mult)
  return {
    'c'  => ['c',  1],
    'w'  => ['c',  2],
    'b'  => ['c',  512],
    'kB' => ['w',  500],
    'K'  => ['w',  512],
    'MB' => ['kB', 1000],
    'M'  => ['K',  1024],
    'GB' => ['MB', 1000],
    'G'  => ['M',  1024],
    'TB' => ['GB', 1000],
    'T'  => ['G',  1024],
    'PB' => ['TB', 1000],
    'P'  => ['T',  1024],
    'EB' => ['PB', 1000],
    'E'  => ['P',  1024],
    'ZB' => ['EB', 1000],
    'Z'  => ['E',  1024],
    'YB' => ['ZB', 1000],
    'Y'  => ['Z',  1024],
  }[mult]
end

def parsecount(countarg)
  if countarg =~ /^(\d+)(c|w|b|kB|K|[MGTPEZY]B?)$/
    if $1 == '1' then
      unit, num = decr($2)
      count = "count=1#{unit}"
      seeks = (0...num).map do |i|
        "seek=#{i}#{unit}"
      end
    else
      count = "count=1#{$2}"
      seeks = (0...($1.to_i)).map do |i|
        "seek=#{i}#{$2}"
      end
    end
    return count, seeks
  else
    puts "BAD COUNT"
    exit 1
  end
end

ARGV.each do |arg|
  if arg =~ /count=(.*)/ then
    countarg=$1
  else
    cmd << arg
  end
end

if countarg.nil? then
  run = cmd.join(' ')
  puts "*** " + run
  system(run)
else
  count, seeks = parsecount(countarg)
  seeks.each do |seek|
    run = (cmd + [seek, count]).join(' ')
    puts "*** " + run
    system(run)
  end
end