Java Utililty Methods BitSet

int[] asArrayWith0s(int max, BitSet bits)
gets an array in which the i-th component has value i, if and only if i is contained in bits

final int[] array = new int[max + 1];
for (Integer t : members(bits))
 array[t] = t;
return array;

BitSet binaryStringToBitSet(String stringRepresentation)
Convert the string representation to a bit set

BitSet bitSet = new BitSet(stringRepresentation.length());
for (int i = 0; i < stringRepresentation.length(); i++) {
 if (stringRepresentation.charAt(i) == '1') {
 bitSet.set(i);
 } else if (stringRepresentation.charAt(i) != '0') {
 throw new IllegalArgumentException("bad format: " + stringRepresentation);
return bitSet;

BitSet binaryToGray(BitSet binary)
binary To Gray

if (binary.equals(ZERO)) {
 return (BitSet) ZERO.clone();
} else {
 BitSet gray = (BitSet) binary.clone();
 gray.xor(binary.get(1, binary.length()));
 return gray;

void bitsetCopy(BitSet src, int srcOffset, BitSet dest, int destOffset, int length)
bitset Copy

for (int i = 0; i < length; i++) {
 dest.set(destOffset + i, src.get(srcOffset + i));

boolean bitSetTest(BitSet bitSet, int index)
Check to see if the i-th bit is set.

if (bitSet == null)
 return false;
if (index < 0)
 return false;
return bitSet.get(index);

BitSet BitString2BitSet(String string)
Converts the given {0,1}-String to a BitSet .

char[] chStr = string.toCharArray();
BitSet bitset = new BitSet(chStr.length);
for (int i = 0; i < chStr.length; i++) {
 if (chStr[chStr.length - i - 1] == '1') {
 bitset.set(i);
return bitset;
...

BitSet boolToBitSet(boolean[] bits, int offset, int length)
Converts a boolean array into a BitSet

BitSet bitset = new BitSet(length - offset);
for (int i = offset; i < length; i++)
 bitset.set(i - offset, bits[i]);
return bitset;

BitSet byte2BitSet(BitSet bmap, byte[] b, int bitOffset)
Converts a binary representation of a Bitmap field into a Java BitSet

int len = b.length << 3;
for (int i = 0; i < len; i++)
 if (((b[i >> 3]) & (0x80 >> (i % 8))) > 0)
 bmap.set(bitOffset + i + 1);
return bmap;

BitSet byteArray2BitSet(byte[] bytes)
Returns a bitset containing the values in bytes.

BitSet bits = new BitSet();
for (int i = 0; i < bytes.length * 8; i++) {
 if ((bytes[bytes.length - i / 8 - 1] & (1 << (i % 8))) > 0) {
 bits.set(i);
return bits;

BitSet bytes2bitset(byte[] bytes, byte nbyte, BitSet bits)
bytesbitset

if (bytes == null) {
 return bits;
for (int i = 0; i < nbyte * 8; i++) {
 if ((bytes[nbyte - i / 8 - 1] & (1 << (i % 8))) > 0) {
 bits.set(i);
return bits;