#!/usr/local/bin/perl
#
# program name : gacf (graphic access counter for first Web page)
#
# function     : count the number of guest, rewrite "index.html" 
#                and send a dummy gif file.
#
# note         : this counter is made for mesh home page (first page), 
#                where CGI is available, but SSI is not.
#
# programmer   : makoto takenaka : takesoft@mxs.meshnet.or.jp
#
# copyright    : (C) 1996 by Takesoft
#
# version(date): version  1. 0(June 22, 1996)
#                version  1. 1(June 26, 1996)
#                   mail address is changed and commented.
#
#(1) set constants.
#
   $html_file0     = "./index_.html";     # prototype html file
   $html_file      = "./index.html";      # output html file with guest number
   $count_file     = "./count.txt";       # guest number file
   $gif_dir        = "./image/";          # directory of digit gif files
   $dummy_gif_file = "./image/trans.gif"; # dummy gif file
#
#(2) Increment $count.
#
         open(COUNT_FILE, "+< $count_file")
            || &error_mail("gacf: Unable to open $count_file");
         flock(COUNT_FILE, 2);
         $count = <COUNT_FILE>;
         $count++;
         seek(COUNT_FILE, 0, 0);
         print COUNT_FILE $count;
         flock(COUNT_FILE, 8);
         close(COUNT_FILE);
#
#(3) Copy $html_file0 to $html_file, but insert guest number.
#
   open(HTML_FILE, ">$html_file")
      ||&error_mail("gacf: Unable to open $html_file. ");
   flock(HTML_FILE, 2);
   open(HTML_FILE0, "$html_file0")
      ||&error_mail("gacf: Unable to open $html_file0.");

#
   while(<HTML_FILE0>)
      {
#
#  If this line contains "INSERT_COUNTER", send guest number.
#
      if ( $_ =~ /INSERT_COUNTER/ )
         {
#
#(4) insert counter image tags.
#
         $nd = length($count);
#
         for ($digit = $nd; $digit > 0; $digit--)
            {
            $d = substr($count, (-1)*($digit), 1);
#
#           if($d < 0 || $d > 9)
#              {&error_mail("(4) wrong number d, d = $d")}
#
            $gif_file = "$gif_dir$d.gif";

            print HTML_FILE "<IMG SRC=\"$gif_file\" BORDER=0 ALT=\"$d\">";
            }
         }
      else
         {
         print HTML_FILE $_;
         }
      }
#
   flock(HTML_FILE, 8);
   close(HTML_FILE);
   close(HTML_FILE0);
#
#(5) send dummy gif file to browser.
#
   print "Content-type: image/gif\n\n";
#
   open(GIF_FILE, "$dummy_gif_file")
      ||&error_mail("gacf: Unable to open $dummy_gif_file");
#
   while(read(GIF_FILE, $buf, 16384))
      {
      print $buf;
      }
   close(GIF_FILE);
#
sub error_mail
   {
   local($message) = @_;
#
#(sub routine) Send error mail.
#
#   If you want to use error mail, change mail address to yours
#   and uncomment(remove #) next four lines. But at some provider
#   such as rimnet mailing from cgi is not allowed. In such case
#   write error message on some file having access mask of 606.
#
#  open(MAIL, "|mail user_id\@xxx.yyyyyyy.or.jp");
#  print MAIL "Error Message from gacf.cgi of home page: \n";
#  print MAIL "$message\n";
#  close(MAIL);
#
#  stop this perl program.
#
   die;
   }