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import java.util.BitSet;

//Generates a crc32 checksum for a given string or byte array

public class crc32 {

public static void main(String[] args) {

System.out.println(Integer.toHexString(crc32("Hello World")));

}

public static int crc32(String str) {

return crc32(str.getBytes());

}

public static int crc32(byte[] data) {

BitSet bitSet = BitSet.valueOf(data);

int crc32 = 0xFFFFFFFF; //initial value

for(int i=0;i<data.length*8;i++) {

if(((crc32>>>31)&1) != (bitSet.get(i)?1:0))

crc32 = (crc32 << 1) ^ 0x04C11DB7; //xoring with polynomial

else

crc32 = (crc32 << 1);

}

crc32 = Integer.reverse(crc32); //result reflect

return crc32 ^ 0xFFFFFFFF; //final xor value

}

}