cpf_andre_vs_james.rb

module CpfJames
  module_function

  def protect(string)
    string.split(' ').map { |s| valid?(s) ? mask(s) : s  }.join(' ')
  end

  def valid?(s)
    !!s.match(/\d{3}.\d{3}.\d{3}-\d{2}/)
  end

  def mask(s)
    md = s.match(/(\d\d)\d.(\d{3}).(\d{3})-(\d{2})/)
    "#{md[1]}X.#{md[2]}.#{md[3]}-#{md[4]}"
  end
end

module CpfAndre
  module_function

  def protect(string)
    string.split('').inject('') { |acc, char| mask_protected_chars(char, acc) }
  end

  def mask_protected_chars(char, acc)
    should_mask?(char, acc.size) ? acc + 'X' : acc + char
  end

  def should_mask?(char, char_index)
    is_a_digit = char.match?(/\d/)
    in_the_first_6_digits = char_index <= 7
    value_lesser_than_index = char.to_i <= char_index
    is_a_digit && in_the_first_6_digits && value_lesser_than_index
  end
end

module CpfAndreProc
  module_function
  def protect(text)
    tmp_string = ''
    text.split('').each do |i|
      if i.match?(/\d/) && tmp_string.size <= 7 && i.to_i <= tmp_string.size
        tmp_string += 'X'
      else
        tmp_string += i
      end
    end
    tmp_string
  end
end





USE_CASE = "120.979.700-71 BRASIL 254"
EXPECTED = "12X.979.700-71 BRASIL 254"

puts "CpfJames: #{CpfJames.protect(USE_CASE)}"
puts "CpfAndre: #{CpfAndre.protect(USE_CASE)}"
puts "CpfAndreProc: #{CpfAndreProc.protect(USE_CASE)}"

raise 'James' if CpfJames.protect(USE_CASE) != EXPECTED
raise 'Andre' if CpfAndre.protect(USE_CASE) != EXPECTED
raise 'AndreProc' if CpfAndreProc.protect(USE_CASE) != EXPECTED






require 'benchmark'

n = 1_000_000 #_000
Benchmark.bm do |x|
  x.report("#{n} runs, James:") { n.times { CpfJames.protect USE_CASE } }
  x.report("#{n} runs, Andre:") { n.times { CpfAndre.protect USE_CASE } }
  x.report("#{n} runs, CpfAndreProc:") { n.times { CpfAndreProc.protect USE_CASE } }
end

output.txt

ruby cpf_andre_vs_james.rb 
CpfJames: 12X.979.700-71 BRASIL 254
CpfAndre: 12X.979.700-71 BRASIL 254
CpfAndreProc: 12X.979.700-71 BRASIL 254


       user     system      total        real
1000000 runs, James:  9.072773   0.074202   9.146975 (  9.393672)
1000000 runs, Andre: 17.585979   0.075285  17.661264 ( 17.816493)
1000000 runs, CpfAndreProc: 12.549021   0.045396  12.594417 ( 12.672436)