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import java.util.zip.Checksum;
public class ParityChecksum implements Checksum {
long checksum = 0;
public void update(int b) {
int numOneBits = 0;
for (int i = 1; i < 256; i *= 2) {
if ((b & i) != 0)
numOneBits++;
}
checksum = (checksum + numOneBits) % 2;
}
public void update(byte data[], int offset, int length) {
for (int i = offset; i < offset + length; i++) {
this.update(data[i]);
}
}
public long getValue() {
return checksum;
}
public void reset() {
checksum = 0;
}
}
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