faster implementations of Rails' number_to_currency with hard coded formatting options

gistfile1.rb

def fast_number_to_currency number
  fix = number.fix
  frac = number.frac.abs
  "#{fix.to_i.to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1'")}#{('%.2f' % frac)[1..-1]}"
end

def faster_number_to_currency1 number
  integer = (number * 100).to_i
  sign = integer.positive? ? '' : '-'
  positive = integer.abs

  return '0.00' if positive.zero?

  fix = positive / 100
  frac1 = positive / 10 % 10
  frac2 = positive % 10

  string = ""
  j = 0
  while fix > 0 do
    if j == 3
      string.concat "'"
      j = 0
    end
    j += 1
    digit = (fix % 10) + 48
    string.concat digit
    fix = fix / 10
  end

  return "#{sign}#{string.reverse}.".concat(frac1+48).concat(frac2+48)
end