#! /usr/bin/perl 

## encodes quality bits
 

@bits=();

print "Enter Quality Bit (0-31, 'q' to quit):  ";
chomp( $bit = <STDIN> );
while ($bit ne "q") {
  if ( ($bit =~ /\d{1,2}/ ) && ($bit >= 0) && ($bit <= 31) ) {
    @bits = ($bit,@bits);
    print "Enter Quality Bit (0-31, 'q' to quit):  ";
    chomp( $bit = <STDIN> );
  } else {
    print "Oops...Enter Quality Bit (0-31, 'q' to quit):  ";
    chomp( $bit = <STDIN> );
  }
}

%seen = ();
@uniq = ();
foreach $item ( @bits ) {
  unless ($seen{$item}) {
    $seen{$item} = 1;
    push (@uniq,$item);
  }
}

  $i = 0;
  while ( $i <= 31 ) {
    $qual{$i} = 0;
    $i++;
  }
  foreach $bit ( @bits ) {
    $qual{$bit} = 1;
  }
  $i = 31;
  print "\n";
  while ( $i >= 0 ) {
    print "$qual{$i}";
    $i--;
  }
  print "\n\n";
  
  $j = 0;
  $k = 1;
  @bit_value = ();
  while ( $k <= 8 ) {
    $total = (1*$qual{$j}) + (2*$qual{$j+1}) + (4*$qual{$j+2}) + (8*$qual{$j+3});
    if ( $total > 9 ) {
      $total = "a" if ( $total == 10 );
      $total = "b" if ( $total == 11 ); 
      $total = "c" if ( $total == 12 ); 
      $total = "d" if ( $total == 13 ); 
      $total = "e" if ( $total == 14 ); 
      $total = "f" if ( $total == 15 ); 
    }
    @bit_value = ($total, @bit_value);
    $j = $j + 4;
    $k++;
  }

print "Quality expression is ";
$n = 0;
while ( $n <= 7) {
  print "$bit_value[$n]";
  $quality = $quality.$bit_value[$n];
  $n++;
}
print "\n$quality: \n";
system ("decode $quality" );