#!/usr/local/bin/perl
# Counter
##############################

use NDBM_File ;
use Fcntl ;
use Fcntl ':flock';

open (CONFIG,"config.txt");
while (<CONFIG>) { chop $_ if ($_ =~ /\n/); @line=split(/=/,$_,2); $config{"$line[0]"}=$line[1]; }
close (CONFIG);

$minLen = 1;
$isHigh = 1;
$isInverse = 1;
$lockWait = 5;
$counterFile = $ENV{QUERY_STRING};
$counterFile =~ s/\//_/g;
&initialize;

# hit accesses are logged to the cntdb database by host, address, port key
# and the last access time in secs from 1970 is stored per source address
# only accept a new hit from an identical source if more than a day has passed
# the total number of hits is stored under key "totalhits"
$dbfname = "$config{'data_dir'}/counter/$counterFile";
# print "dbfname = $dbfname\n";
# obtain lock
$lck = "$dbfname.lck";
$i = 0;
until (sysopen(FH, $lck, O_RDWR|O_CREAT) && flock(FH, LOCK_EX|LOCK_NB) || $i++ > $lockWait)
  { sleep(1); }
if ( $i > $lockWait )
  {
  print "Content-type: text/plain\n\nCan't lock file $lck\n";
  exit(1);
  }
chmod 0666, "$dbfname.dir", "$dbfname.pag", "$dbfname.lck";
# open database
tie(%h, 'NDBM_File', "$dbfname", O_RDWR|O_CREAT, 0666);
$totalReads = $h{"totalhits"};
#print "totalReads = $totalReads\n";
if ($totalReads == "")
  {
  $totalReads = 0;
  }
$key = "$hostname,$host,$port";
# print "key = $key\n";
$oldlv = $h{$key}; # previous time value, blank if no hit before
# if no prior hit or last hit more than 24 hours ago update hit count and time
if ( "$oldlv" == "" || ($oldlv + 86400 < time) )
  {
  $totalReads++;
  $h{"totalhits"} = $totalReads; # increment hit count
  $h{$key} = time; # update hit source time to now
  }
untie %h ;
# release lock
close FH or die "can't close lockfile: $!";

# print counter image
&generateBitmap;
&writeBitmap;
exit(0);

sub writeBitmap {
   print ("Content-type: image/x-xbitmap\n\n");
   if ($isHigh) {
      printf ("#define count_width %d\n#define count_height 16\n", 
              $len*8);
   }
   else {
      printf ("#define count_width %d\n#define count_height 10\n", 
              $len*8);
   }
   printf STDOUT "static char count_bits[] = {\n";
   for($i = 0; $i < ($#bytes + 1); $i++) {
      print("0x$bytes[$i]");
      if ($i != $#bytes) {
         print(",");
         if (($i+1) % 7 == 0) {
            print("\n");
         }
      }
   }
   print("};\n");
}

sub generateBitmap {
   $count = $totalReads;
   @bytes = ();
   $len = length($count) > $minLen ? length($count) : $minLen;
   $formattedCount = sprintf("%0${len}d",$count);
   if ($isHigh) {
      for ($i = 0; $i < $len*3; $i++ ) {
         if ($isInverse) {
            push(@bytes,"ff");       # add three blank rows to each digit
         }
         else {
            push(@bytes,"00");
         }
      }
   }
   for ($y=0; $y < 10; $y++) {
       for ($x=0; $x < $len; $x++) {
           $digit = substr($formattedCount,$x,1);
           if ($isInverse) {             # $inv = 1 for inverted text
               $byte = substr(@invdigits[$digit],$y*3,2);
           } 
           else {
               $byte = substr(@digits[$digit],$y*3,2);
           }
           push(@bytes,$byte);
       }
   }
   if ($isHigh) {
      for ($i = 0; $i < $len*3; $i++ ) {
         if ($isInverse) {
            push(@bytes,"ff");       # add three blank rows to each digit
         }
         else {
            push(@bytes,"00");
         }
      }
   }
}

sub initialize {
   $hostname = $ENV{REMOTE_HOST};
   $host     = $ENV{REMOTE_ADDR};
   $port     = $ENV{SERVER_PORT};

   # bitmap for each digit
   #  Each digit is 8 pixels wide, 10 high
   #  @invdigits are white on black, @digits black on white
   @invdigits = ("c3 99 99 99 99 99 99 99 99 c3",  # 0
                 "cf c7 cf cf cf cf cf cf cf c7",  # 1
                 "c3 99 9f 9f cf e7 f3 f9 f9 81",  # 2
                 "c3 99 9f 9f c7 9f 9f 9f 99 c3",  # 3
                 "cf cf c7 c7 cb cb cd 81 cf 87",  # 4
                 "81 f9 f9 f9 c1 9f 9f 9f 99 c3",  # 5
                 "c7 f3 f9 f9 c1 99 99 99 99 c3",  # 6
                 "81 99 9f 9f cf cf e7 e7 f3 f3",  # 7
                 "c3 99 99 99 c3 99 99 99 99 c3",  # 8
                 "c3 99 99 99 99 83 9f 9f cf e3"); # 9
   
      @digits = ("3c 66 66 66 66 66 66 66 66 3c",  # 0
                 "30 38 30 30 30 30 30 30 30 30",  # 1
                 "3c 66 60 60 30 18 0c 06 06 7e",  # 2
                 "3c 66 60 60 38 60 60 60 66 3c",  # 3
                 "30 30 38 38 34 34 32 7e 30 78",  # 4
                 "7e 06 06 06 3e 60 60 60 66 3c",  # 5
                 "38 0c 06 06 3e 66 66 66 66 3c",  # 6
                 "7e 66 60 60 30 30 18 18 0c 0c",  # 7
                 "3c 66 66 66 3c 66 66 66 66 3c",  # 8
                 "3c 66 66 66 66 7c 60 60 30 1c"); # 9
}