#!perl
use Config;
use File::Basename qw(&basename &dirname);
use Cwd;

$origdir = cwd;
chdir dirname($0);
$file = basename($0, '.PL');
$file .= $^O eq 'VMS' ? '.com' : '.pl';

open OUT,">$file" or die "Can't create $file: $!";

print "Extracting $file (with variable substitutions)\n";

print OUT <<"!GROK!THIS!";
$Config{startperl} -w
!GROK!THIS!

# In the following, perl variables are not expanded during extraction.

print OUT <<'!NO!SUBS!';
# file: name_trans.pl
# Figure 3.6: Translating IP addresses into hostnames

use Socket;
my $ADDR_PAT = /^\d+\.\d+\.\d+\.\d+$/;

while (<>) {
  chomp;
  die "$_: Not a valid address" unless /$ADDR_PAT/o;
  my $name = gethostbyaddr(inet_aton($_),AF_INET);
  $name ||= '?';
  print "$_ => $name\n";
}
!NO!SUBS!
close OUT or die "Can't close $file: $!";
chmod 0755, $file or die "Can't reset permissions for $file: $!\n";
exec("$Config{'eunicefix'} $file") if $Config{'eunicefix'} ne ':';
chdir $origdir;