[QUIZ] IP to Country (#139) - early submission, please forward after deadline

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From: "Adam Shelly" <adam.shelly@gmail.com>
Date: September 15, 2007 3:27:43 AM CDT
To: submission@rubyquiz.com
Subject: Re: [QUIZ] IP to Country (#139) - early submission, please forward after deadline

This week's Ruby Quiz is to write a simple utility. Your program should accept
an IP address as a command-line argument and print out the two letter code for
the country that IP is assigned in. You can find a database for the matching

Hi James,
I'm going to be offline for the next few days, so please accept my
early submission to forward after the deadline.
Thanks,
-Adam.

-------------------------------

Here's my quickly created version that works off the unmodified file
without any initialization.

--- IpToCountry.rb --

#Use this function to find the first and last record of the file.
#I ran this once and hardcoded the values in order to improve execution time
#It was run against file dated Fri Sep 14 12:08:01 2007 UTC.
#It should be run again if the database changes

def find_valid_data filename
  start = 0
  dbfile = File.new(filename)
  s = dbfile.gets
  while s[0] == ?# or s[0]==?\n
    start+= s.size
    s = dbfile.gets
  end
  dbfile.seek(-128, File::SEEK_END)
  s = dbfile.read(128).chomp;
  last = s.rindex("\n");
  dbfile.close
  return [start-1,File.size(filename) - last]
end

def addr_to_i addr
  radix = 256**4
  addr.split('.').inject(0){|sum,part| sum + part.to_i * (radix /=256)}
end

def bsearch_file value, min, max
  return "Not Found" if max<=min
  point = (max-min)/2 + min
  DBFile.seek(point-1, File::SEEK_SET)
  DBFile.gets #get partial line
  line = DBFile.gets
  rec = line.split('"')
  range = (rec[1].to_i .. rec[3].to_i)
  #puts "searching #{point}: range = (#{range})"
  return rec[9] if range.include? value
  if value < range.first
    #p "lower"
    return bsearch_file(value, min, point-2)
  else
    #p "higher"
    return bsearch_file(value,point+line.size,max)
  end
end

DBFilename = "IpToCountry.csv"
#
# datarange = find_valid_data DBFilename
#
datarange = [6604,5788762]

DBFile = File.new(DBFilename)

addr_n = addr_to_i(ARGV[0]||"123.45.67.89")
puts bsearch_file(addr_n, *datarange)

ยทยทยท

Begin forwarded message:

On 9/14/07, Ruby Quiz <james@grayproductions.net> wrote: