#!/usr/bin/perl

use strict;
use warnings;

use Math::BigInt;

# solution: 990644297
my $buffer = "/etc/test2.sh";
my $crc = Math::BigInt->new('0');

&determineCrc32($buffer, $crc);

print $crc . "\n";

sub determineCrc32()
{
	my $buffer = $_[0];
	my $crc = $_[1];
	my $i = 0;
	my $val = 0;
	my $k = 0;
	
	for( $i = 0; $i < int(length($buffer) / 4); $i = $i + 1 )
    {
		$val =
			sprintf("%02X", ord(substr($buffer, ($i*4) + 0, 1))) .
			sprintf("%02X", ord(substr($buffer, ($i*4) + 1, 1))) .
			sprintf("%02X", ord(substr($buffer, ($i*4) + 2, 1))) .
			sprintf("%02X", ord(substr($buffer, ($i*4) + 3, 1)));
		
		$crc->badd(hex($val));
		$crc->bmod('0x100000000');
	}

	$val = "";
	$k = 0;
	for( 1 .. int(length($buffer) % 4) )
    {	
		$val .= sprintf("%02X", ord(substr($buffer, ($i*4) + $k, 1)));
		$k++;
	}

    # pad other bytes of 32bit with "00"
	for( 1 .. (4 - int(length($buffer) % 4)) )
    {
		$val .= "00";
	}

	$crc->badd(hex($val));
	$crc->bmod('0x100000000');
}