#!/usr/bin/perl

use URI::Escape;

($url, $value) = split(/=/, $ENV{QUERY_STRING});
$value = uri_unescape($value);

print "Content-Type: text/plain\r\n\r\n";
print '6'._compute_ch_new('info:'.$value);

sub _compute_ch_new {
  my $url = shift;

  my $ch = _compute_ch($url);
  $ch = (($ch % 0x0d) & 7) | (($ch / 7) << 2);

  return _compute_ch(pack("V20", map {my $t = $ch; _wsub($t, $_*9); $t} 0..19));
}

sub _compute_ch {
  my $url = shift;

  my @url = map {ord $_} split '', $url;
  my ($a, $b, $c, $k) = (0x9e3779b9, 0x9e3779b9, 0xe6359a60, 0);
  my $len = scalar @url;

  while ($len >= 12) {
    _wadd($a, $url[$k+0] | ($url[$k+1] << 8) | ($url[$k+2] << 16) | ($url[$k+3] << 24));
    _wadd($b, $url[$k+4] | ($url[$k+5] << 8) | ($url[$k+6] << 16) | ($url[$k+7] << 24));
    _wadd($c, $url[$k+8] | ($url[$k+9] << 8) | ($url[$k+10] << 16) | ($url[$k+11] << 24));

    _mix($a, $b, $c);

    $k += 12;
    $len -= 12;
  }

  _wadd($c, scalar @url);

  _wadd($c, $url[$k+10] << 24) if $len > 10;
  _wadd($c, $url[$k+9] << 16) if $len > 9;
  _wadd($c, $url[$k+8] << 8) if $len > 8;
  _wadd($b, $url[$k+7] << 24) if $len > 7;
  _wadd($b, $url[$k+6] << 16) if $len > 6;
  _wadd($b, $url[$k+5] << 8) if $len > 5;
  _wadd($b, $url[$k+4]) if $len > 4;
  _wadd($a, $url[$k+3] << 24) if $len > 3;
  _wadd($a, $url[$k+2] << 16) if $len > 2;
  _wadd($a, $url[$k+1] << 8) if $len > 1;
  _wadd($a, $url[$k]) if $len > 0;

  _mix($a, $b, $c);

  return $c; # integer is positive always
}

sub _mix {
  my ($a, $b, $c) = @_;

  _wsub($a, $b); _wsub($a, $c); $a ^= $c >> 13;
  _wsub($b, $c); _wsub($b, $a); $b ^= ($a << 8) % 4294967296;
  _wsub($c, $a); _wsub($c, $b); $c ^= $b >>13;
  _wsub($a, $b); _wsub($a, $c); $a ^= $c >> 12;
  _wsub($b, $c); _wsub($b, $a); $b ^= ($a << 16) % 4294967296;
  _wsub($c, $a); _wsub($c, $b); $c ^= $b >> 5;
  _wsub($a, $b); _wsub($a, $c); $a ^= $c >> 3;
  _wsub($b, $c); _wsub($b, $a); $b ^= ($a << 10) % 4294967296;
  _wsub($c, $a); _wsub($c, $b); $c ^= $b >> 15;

  @_[0 .. $#_] = ($a, $b, $c);
}

sub _wadd { $_[0] = int(($_[0] + $_[1]) % 4294967296);}
sub _wsub { $_[0] = int(($_[0] - $_[1]) % 4294967296);}