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Utility classes and methods developed for Brooklyn but not dependendent on Brooklyn or much else
package brooklyn.util.math;
public class BitUtils {
/** reverses the bits in a byte, i.e. 128 = 0b1000000 = bit list {0,0,0,0,0,0,0,1},
* reversed yields 1 = 0b00000001 = bit list {1,0,0,0,0,0,0,0} */
public static byte reverseBitSignificance(byte b) {
int result = 0;
for (int i=0; i<8; i++) {
result <<= 1;
if ((b&1)==1) result++;
b >>= 1;
}
return (byte)result;
}
/** as {@link #reverseBitSignificance(byte)} but accepting int for convenience */
public static byte reverseBitSignificanceInByte(int b) {
return reverseBitSignificance((byte)b);
}
/** returns an array of bytes where the bits in each byte have been reversed;
* note however the order of the arguments is not reversed;
* useful e.g. in working with IP address CIDR's */
public static byte[] reverseBitSignificance(byte ...bytes) {
byte[] result = new byte[bytes.length];
for (int i=0; i