Shows the floating point representation of a hexadecimal string.

h2f.rb

# coding: utf-8
# ex.) $ ruby h2f.rb 0000803f -> 1.0
#      $ ruby h2f.rb c3f54840 -> 3.140000
#      $ ruby h2f.rb 182d4454fb210940 -> 3.141592653589793
#      $ ruby h2f.rb 400921fb54442d18 -b -> 3.141592653589793

require 'getoptlong'

$cmd_opts = GetoptLong.new(
  [ '-b', GetoptLong::NO_ARGUMENT ],
)

$opt_big = false

$cmd_opts.each do |opt, arg|
  case opt
  when '-b'; $opt_big = true
  end
end

if $0 == __FILE__
  values = ARGV.select {|arg| /\H/.match(arg) == nil } # == !arg[/\H/]
  values.each do |value|
    hex_str = value
    if $opt_big
      re = hex_str.scan(/(\h\h)/)
      hex_str = ""
      re.reverse.each do |byte|
        hex_str += byte[0]
      end
    end
    print "#{value}\t"
    case value.length
    when 8
      printf "%.6f\n", [hex_str].pack('H8').unpack('F')[0]
    when 16
      puts [hex_str].pack('H16').unpack('D')
    else
      print "Unknown\n"
    end
  end
end