######## Quelle: http://www.miscel.dk/MiscEl/CRCcalculations.html#CRC8 #####

use strict; 
use warnings;

use 5.010;

## CRC8 bit
sub Crc8 {
  my $Buffer = shift;
  my $Poly = shift;
  my $Init = shift;
  
  my @Buffer = split //,$Buffer;
  my $Result = $Init;
  for my $i (1..length($Buffer)) {
    $Result = $Result ^ ord($Buffer[$i-1]);
    for my $j (0..7) {  
        $Result = 
          ($Result & 0x80) 
          ? ($Result << 1) ^ $Poly
          : $Result << 1;
      }
   }
   $Result = $Result & 0xFF;
   return $Result;
}


### CRC8 byte, normal

my @CrcTable = (); 
sub GenerateTableCrc8 {
  my $Poly = shift;
  for my $i (0..255) { 
    $CrcTable[$i]= Crc8(chr($i),$Poly,0);
  }
}

sub Crc8Byte {
  my $Buffer = shift;
  my $Initial = shift;
  my $Result = $Initial;
  
  my @Buffer = split //,$Buffer;
  for my $i(1..length($Buffer)){
    $Result = ($Result << 8) ^ $CrcTable[ (ord($Buffer[$i-1]) ^ ($Result)) & 0xFF ];
  }
  $Result = $Result & 0xFF;
  return $Result;
}