module Benchmark::Compare

def compare(*reports)
  return if reports.size < 2
  iter = false
  sorted = reports.sort do |a,b|
    if a.respond_to? :ips
      iter = true
      b.ips <=> a.ips
    else
      a.runtime <=> b.runtime
    end
  end
  best = sorted.shift
  $stdout.puts "\nComparison:"
  if iter
    $stdout.printf "%20s: %10.1f i/s\n", best.label, best.ips
  else
    $stdout.puts "#{best.rjust(20)}: #{best.runtime}s"
  end
  sorted.each do |report|
    name = report.label
    if iter
      x = (best.ips.to_f / report.ips.to_f)
      $stdout.printf "%20s: %10.1f i/s - %.2fx slower\n", name, report.ips, x
    else
      x = "%.2f" % (report.ips.to_f / best.ips.to_f)
      $stdout.puts "#{name.rjust(20)}: #{report.runtime}s - #{x}x slower"
    end
  end
  $stdout.puts
end