package org.xbib.io.compress.xz.check;
public class CRC64 extends Check {
private static final long poly = 0xC96C5795D7870F42L;
private static final long crcTable[] = new long[256];
private long crc = -1;
static {
for (int b = 0; b < crcTable.length; ++b) {
long r = b;
for (int i = 0; i < 8; ++i) {
if ((r & 1) == 1) {
r = (r >>> 1) ^ poly;
} else {
r >>>= 1;
}
}
crcTable[b] = r;
}
}
public CRC64() {
size = 8;
name = "CRC64";
}
public void update(byte[] buf, int off, int len) {
int end = off + len;
while (off < end) {
crc = crcTable[(buf[off++] ^ (int) crc) & 0xFF] ^ (crc >>> 8);
}
}
public byte[] finish() {
long value = ~crc;
crc = -1;
byte[] buf = new byte[8];
for (int i = 0; i < buf.length; ++i) {
buf[i] = (byte) (value >> (i * 8));
}
return buf;
}
}