#!/usr/local/bin/perl

#   Copyright(C)1999,2001 by Daniel B. Sedory
#
#    This PROGRAM creates a list of Formatted IP Addresses (one per line)
#  with evenly spaced groups of 3 digits each by inserting leading zeros
#  where necessary.  For example:
#
#        1.23.4.56   will end up as   001.023.004.056
#
#    The OUTPUT FILE will be named:   ipf.txt
#  ( INPUT files will NOT be changed )
#
#  One Reason for doing this: So you can SORT data rows in a database
#  by IP numbers with the numbers in the correct order; rather than
#  having 1.x.x.x, 11.x.x.x, 100.x.x.x all ending up together!
#
#     Note: The entire file is read into memory, so don't use this
#  program on a 'monster-sized' DNS server file of some kind.


print "\n    This program makes NO changes to the INPUT file.  The INPUT\n";
print " file must contain only a listing of IP Numbers (one per line!)\n";
print "    It will ADD leading ZEROs to IPs such as 1.23.4.56   then\n";
print " save the Formatted IP numbers (001.023.004.056) to an OUTPUT\n";
print " file called:   ipf.txt\n\n";
print " What is the file you wish to read? "; 

$inpfilename = <STDIN>;
chop($inpfilename);

open (FILE, "$inpfilename") || die("Could not open the file $inpfilename");
@lines = <FILE>;
close(FILE);

open(PIPF, ">ipf.txt");

foreach $line (@lines)		   # Examine one line at a time.
   {
     @words = split(/\./, $line);  # Split line into an array of 4 words
				   # using the "dots" as separators.

     $words[3] =~ s/\n//;	   # Remove "newline char" from last.
     foreach $word (@words)
        {			   # Add leading zeros if necessary.
          $strlen = length($word);
          if ($strlen == 1) {$word = "00" . $word;}
          elsif ($strlen == 2) {$word = "0" . $word;}

        }		      # Put the line back together with "dots" :
			      # Yes, the double-meaning was intended :-)

#  $line = $words[0]. "." . $words[1]. "." . $words[2]. "." . $words[3];
#
#  Some time after using the statement above, I changed the way to RE-
#  CREATE the line from its various parts... I just wanted you to see
#  the sad bit of humor above rather than erase it.  Here's a better
#  way to do it using the JOIN function:

     $line = join (".", @words);
                                          
     print PIPF "$line\n";     # Write the new line and get another one
   }

close(PIPF);

exit;

#   Copyright(C)1999,2001 by Daniel B. Sedory