LogUtil.java

public class LogUtil {
    static int log2 (int number) {
        int logCount = 0;
        if(65536 <= number) { logCount += 16; number >>= 16; }
        if(256 <= number) { logCount += 8; number >>= 8; }
        if(16 <= number) { logCount += 4;  number >>= 4; }
        if(4 <= number) { logCount += 2; number >>= 2; }
        return logCount  + (2 <= number  ?  1 : 0);
    }
}