28 lines
902 B
Java
28 lines
902 B
Java
|
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
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|