generates N data sets like: [[1,2],[3,4] .. [M-1,M]] and calculates intersection. accepts two integer arguments N, M defaults is 3 and 100

intersect_geoip_CSVs.rb

#!/usr/bin/env ruby
require 'csv'
require 'ipaddr'

# Formating:
ff = ->() {
  f = ->(a) {a.take(2).map(&IPAddr.method(:new)).map(&:to_i) rescue a.take(2).map(&:to_i) }
  f[CSV.parse(self.peek).first]
}

Enumerator.send(:define_method, :foo, ff)
data = ARGV
  .map(&File.method(:open))
  .map(&:each_line)


# Intersection
result = []
loop do
  max = nil
  begin 
    max = data.map(&:foo).map(&:first).max
    data.each do |e|
      e.next while e.foo.last < max
    end
  end while max != data.map(&:foo).map(&:first).max
 
  result << [data.map(&:foo).map(&:first).max,
             data.map(&:foo).map(&:last).min]
 
  data.each do |e|
    e.next while e.foo.last == result.last.last
  end
end

puts result.map(&:to_csv).join

ranges_intersection.rb

#!/usr/bin/env ruby
n = (ARGV.first||3).to_i
m = (ARGV.last||100).to_i

print = ->(a,c=?.){0.upto(m){|i| putc a.map{|r| Range.new(r.first,r.last).include?(i)}.any? ? c : ' ' }; puts}
data  = n.times.map{rand(m/2).step(m,rand(19)+1).each_slice(2)}
data.each &print
cursor = []
result = []
loop do
  max = data.map(&:peek).map(&:first).max

  data.each do |e|
    e.next while e.peek.last <= max
  end
  cursor << [max,max]
  result << [data.map(&:peek).map(&:first).max,
             data.map(&:peek).map(&:last).min]

  data.each do |e|
    e.next while e.peek.last == result.last.last
  end
end

print[[[0,m]],?=]
pring[cursor, ?^] 
print[result, ?x]

result.sh

$ ./ranges_intersection.rb 3 60
              .......     .......     .......     .......    
    ...................                 ...................  
     ................              ................          
=============================================================
              xxxxxxx                   xxxxx                

$ ./ranges_intersection.rb 3 60
................              ................              .
           .....   .....   .....   .....   .....   .....   . 
                           .................               . 
=============================================================
                              xx   xxxxx                     

$ ./ranges_intersection.rb 2 50
                    ....  ....  ....  ....  ....  .
        .................               .          
===================================================
                    xxxx