File	Doc	Category	Size	Date	Package
BitSet.java	API Doc	Java SE 5 API	36179	Fri Aug 26 14:57:22 BST 2005	java.util

BitSet

• java.lang.Object

Fields Summary
private static final int	ADDRESS_BITS_PER_UNIT
private static final int	BITS_PER_UNIT
private static final int	BIT_INDEX_MASK
private static final long	WORD_MASK
private long[]	bits The bits in this BitSet. The ith bit is stored in bits[i/64] at bit position i % 64 (where bit position 0 refers to the least significant bit and 63 refers to the most significant bit). INVARIANT: The words in bits[] above unitsInUse-1 are zero.
private transient int	unitsInUse The number of units in the logical size of this BitSet. INVARIANT: unitsInUse is nonnegative. INVARIANT: bits[unitsInUse-1] is nonzero unless unitsInUse is zero.
private static final long	serialVersionUID
private static final byte[]	trailingZeroTable

Constructors Summary
public BitSet() Creates a new bit set. All bits are initially false. this(BITS_PER_UNIT);
public BitSet(int nbits) Creates a bit set whose initial size is large enough to explicitly represent bits with indices in the range 0 through nbits-1. All bits are initially false. param nbits the initial size of the bit set. exception NegativeArraySizeException if the specified initial size is negative. // nbits can't be negative; size 0 is OK if (nbits < 0) throw new NegativeArraySizeException("nbits < 0: " + nbits); bits = new long[(unitIndex(nbits-1) + 1)];

Methods Summary
public void	and(java.util.BitSet set) Performs a logical AND of this target bit set with the argument bit set. This bit set is modified so that each bit in it has the value true if and only if it both initially had the value true and the corresponding bit in the bit set argument also had the value true. param set a bit set. if (this == set) return; // Perform logical AND on bits in common int oldUnitsInUse = unitsInUse; unitsInUse = Math.min(unitsInUse, set.unitsInUse); int i; for(i=0; i<unitsInUse; i++) bits[i] &= set.bits[i]; // Clear out units no longer used for( ; i < oldUnitsInUse; i++) bits[i] = 0; // Recalculate units in use if necessary if (unitsInUse > 0 && bits[unitsInUse - 1] == 0) recalculateUnitsInUse();
public void	andNot(java.util.BitSet set) Clears all of the bits in this BitSet whose corresponding bit is set in the specified BitSet. param set the BitSet with which to mask this BitSet. since JDK1.2 int unitsInCommon = Math.min(unitsInUse, set.unitsInUse); // Perform logical (a & !b) on bits in common for (int i=0; i<unitsInCommon; i++) { bits[i] &= ~set.bits[i]; } recalculateUnitsInUse();
private static long	bit(int bitIndex) Given a bit index, return a unit that masks that bit in its unit. return 1L << (bitIndex & BIT_INDEX_MASK);
private static int	bitCount(long val) Returns the number of bits set in val. For a derivation of this algorithm, see "Algorithms and data structures with applications to graphics and geometry", by Jurg Nievergelt and Klaus Hinrichs, Prentice Hall, 1993. val -= (val & 0xaaaaaaaaaaaaaaaaL) >>> 1; val = (val & 0x3333333333333333L) + ((val >>> 2) & 0x3333333333333333L); val = (val + (val >>> 4)) & 0x0f0f0f0f0f0f0f0fL; val += val >>> 8; val += val >>> 16; return ((int)(val) + (int)(val >>> 32)) & 0xff;
private static int	bitLen(int w) bitLen(val) is the number of bits in val. // Binary search - decision tree (5 tests, rarely 6) return (w < 1<<15 ? (w < 1<<7 ? (w < 1<<3 ? (w < 1<<1 ? (w < 1<<0 ? (w<0 ? 32 : 0) : 1) : (w < 1<<2 ? 2 : 3)) : (w < 1<<5 ? (w < 1<<4 ? 4 : 5) : (w < 1<<6 ? 6 : 7))) : (w < 1<<11 ? (w < 1<<9 ? (w < 1<<8 ? 8 : 9) : (w < 1<<10 ? 10 : 11)) : (w < 1<<13 ? (w < 1<<12 ? 12 : 13) : (w < 1<<14 ? 14 : 15)))) : (w < 1<<23 ? (w < 1<<19 ? (w < 1<<17 ? (w < 1<<16 ? 16 : 17) : (w < 1<<18 ? 18 : 19)) : (w < 1<<21 ? (w < 1<<20 ? 20 : 21) : (w < 1<<22 ? 22 : 23))) : (w < 1<<27 ? (w < 1<<25 ? (w < 1<<24 ? 24 : 25) : (w < 1<<26 ? 26 : 27)) : (w < 1<<29 ? (w < 1<<28 ? 28 : 29) : (w < 1<<30 ? 30 : 31)))));
private static long	bitsLeftOf(int x) Returns a long that has all the bits that are more significant than or equal to the specified index set to 1. All other bits are 0. return WORD_MASK << x;
private static long	bitsRightOf(int x) Returns a long that has all bits that are less significant than the specified index set to 1. All other bits are 0. return (x==0 ? 0 : WORD_MASK >>> (64-x));
public int	cardinality() Returns the number of bits set to true in this BitSet. return the number of bits set to true in this BitSet. since 1.4 int sum = 0; for (int i=0; i<unitsInUse; i++) sum += bitCount(bits[i]); return sum;
public void	clear(int bitIndex) Sets the bit specified by the index to false. param bitIndex the index of the bit to be cleared. exception IndexOutOfBoundsException if the specified index is negative. since JDK1.0 if (bitIndex < 0) throw new IndexOutOfBoundsException("bitIndex < 0: " + bitIndex); int unitIndex = unitIndex(bitIndex); if (unitIndex >= unitsInUse) return; bits[unitIndex] &= ~bit(bitIndex); if (bits[unitsInUse-1] == 0) recalculateUnitsInUse();
public void	clear(int fromIndex, int toIndex) Sets the bits from the specified fromIndex(inclusive) to the specified toIndex(exclusive) to false. param fromIndex index of the first bit to be cleared. param toIndex index after the last bit to be cleared. exception IndexOutOfBoundsException if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex. since 1.4 if (fromIndex < 0) throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex); if (toIndex < 0) throw new IndexOutOfBoundsException("toIndex < 0: " + toIndex); if (fromIndex > toIndex) throw new IndexOutOfBoundsException("fromIndex: " + fromIndex + " > toIndex: " + toIndex); int startUnitIndex = unitIndex(fromIndex); if (startUnitIndex >= unitsInUse) return; int endUnitIndex = unitIndex(toIndex); long bitMask = 0; if (startUnitIndex == endUnitIndex) { // Case 1: One word bitMask = (1L << (toIndex & BIT_INDEX_MASK)) - (1L << (fromIndex & BIT_INDEX_MASK)); bits[startUnitIndex] &= ~bitMask; if (bits[unitsInUse-1] == 0) recalculateUnitsInUse(); return; } // Case 2: Multiple words // Handle first word bitMask = bitsLeftOf(fromIndex & BIT_INDEX_MASK); bits[startUnitIndex] &= ~bitMask; // Handle intermediate words, if any if (endUnitIndex - startUnitIndex > 1) { for(int i=startUnitIndex+1; i<endUnitIndex; i++) { if (i < unitsInUse) bits[i] = 0; } } // Handle last word if (endUnitIndex < unitsInUse) { bitMask = bitsRightOf(toIndex & BIT_INDEX_MASK); bits[endUnitIndex] &= ~bitMask; } if (bits[unitsInUse-1] == 0) recalculateUnitsInUse();
public void	clear() Sets all of the bits in this BitSet to false. since 1.4 while (unitsInUse > 0) bits[--unitsInUse] = 0;
public java.lang.Object	clone() Cloning this BitSet produces a new BitSet that is equal to it. The clone of the bit set is another bit set that has exactly the same bits set to true as this bit set and the same current size. Overrides the clone method of Object. return a clone of this bit set. see java.util.BitSet#size() BitSet result = null; try { result = (BitSet) super.clone(); } catch (CloneNotSupportedException e) { throw new InternalError(); } result.bits = new long[bits.length]; System.arraycopy(bits, 0, result.bits, 0, unitsInUse); return result;
private void	ensureCapacity(int unitsRequired) Ensures that the BitSet can hold enough units. param unitsRequired the minimum acceptable number of units. if (bits.length < unitsRequired) { // Allocate larger of doubled size or required size int request = Math.max(2 * bits.length, unitsRequired); long newBits[] = new long[request]; System.arraycopy(bits, 0, newBits, 0, unitsInUse); bits = newBits; }
public boolean	equals(java.lang.Object obj) Compares this object against the specified object. The result is true if and only if the argument is not null and is a Bitset object that has exactly the same set of bits set to true as this bit set. That is, for every nonnegative int index k, ((BitSet)obj).get(k) == this.get(k) must be true. The current sizes of the two bit sets are not compared. Overrides the equals method of Object. param obj the object to compare with. return true if the objects are the same; false otherwise. see java.util.BitSet#size() if (!(obj instanceof BitSet)) return false; if (this == obj) return true; BitSet set = (BitSet) obj; int minUnitsInUse = Math.min(unitsInUse, set.unitsInUse); // Check units in use by both BitSets for (int i = 0; i < minUnitsInUse; i++) if (bits[i] != set.bits[i]) return false; // Check any units in use by only one BitSet (must be 0 in other) if (unitsInUse > minUnitsInUse) { for (int i = minUnitsInUse; i<unitsInUse; i++) if (bits[i] != 0) return false; } else { for (int i = minUnitsInUse; i<set.unitsInUse; i++) if (set.bits[i] != 0) return false; } return true;
public void	flip(int bitIndex) Sets the bit at the specified index to the complement of its current value. param bitIndex the index of the bit to flip. exception IndexOutOfBoundsException if the specified index is negative. since 1.4 if (bitIndex < 0) throw new IndexOutOfBoundsException("bitIndex < 0: " + bitIndex); int unitIndex = unitIndex(bitIndex); int unitsRequired = unitIndex+1; if (unitsInUse < unitsRequired) { ensureCapacity(unitsRequired); bits[unitIndex] ^= bit(bitIndex); unitsInUse = unitsRequired; } else { bits[unitIndex] ^= bit(bitIndex); if (bits[unitsInUse-1] == 0) recalculateUnitsInUse(); }
public void	flip(int fromIndex, int toIndex) Sets each bit from the specified fromIndex(inclusive) to the specified toIndex(exclusive) to the complement of its current value. param fromIndex index of the first bit to flip. param toIndex index after the last bit to flip. exception IndexOutOfBoundsException if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex. since 1.4 if (fromIndex < 0) throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex); if (toIndex < 0) throw new IndexOutOfBoundsException("toIndex < 0: " + toIndex); if (fromIndex > toIndex) throw new IndexOutOfBoundsException("fromIndex: " + fromIndex + " > toIndex: " + toIndex); // Increase capacity if necessary int endUnitIndex = unitIndex(toIndex); int unitsRequired = endUnitIndex + 1; if (unitsInUse < unitsRequired) { ensureCapacity(unitsRequired); unitsInUse = unitsRequired; } int startUnitIndex = unitIndex(fromIndex); long bitMask = 0; if (startUnitIndex == endUnitIndex) { // Case 1: One word bitMask = (1L << (toIndex & BIT_INDEX_MASK)) - (1L << (fromIndex & BIT_INDEX_MASK)); bits[startUnitIndex] ^= bitMask; if (bits[unitsInUse-1] == 0) recalculateUnitsInUse(); return; } // Case 2: Multiple words // Handle first word bitMask = bitsLeftOf(fromIndex & BIT_INDEX_MASK); bits[startUnitIndex] ^= bitMask; // Handle intermediate words, if any if (endUnitIndex - startUnitIndex > 1) { for(int i=startUnitIndex+1; i<endUnitIndex; i++) bits[i] ^= WORD_MASK; } // Handle last word bitMask = bitsRightOf(toIndex & BIT_INDEX_MASK); bits[endUnitIndex] ^= bitMask; // Check to see if we reduced size if (bits[unitsInUse-1] == 0) recalculateUnitsInUse();
public boolean	get(int bitIndex) Returns the value of the bit with the specified index. The value is true if the bit with the index bitIndex is currently set in this BitSet; otherwise, the result is false. param bitIndex the bit index. return the value of the bit with the specified index. exception IndexOutOfBoundsException if the specified index is negative. if (bitIndex < 0) throw new IndexOutOfBoundsException("bitIndex < 0: " + bitIndex); boolean result = false; int unitIndex = unitIndex(bitIndex); if (unitIndex < unitsInUse) result = ((bits[unitIndex] & bit(bitIndex)) != 0); return result;
public java.util.BitSet	get(int fromIndex, int toIndex) Returns a new BitSet composed of bits from this BitSet from fromIndex(inclusive) to toIndex(exclusive). param fromIndex index of the first bit to include. param toIndex index after the last bit to include. return a new BitSet from a range of this BitSet. exception IndexOutOfBoundsException if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex. since 1.4 if (fromIndex < 0) throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex); if (toIndex < 0) throw new IndexOutOfBoundsException("toIndex < 0: " + toIndex); if (fromIndex > toIndex) throw new IndexOutOfBoundsException("fromIndex: " + fromIndex + " > toIndex: " + toIndex); // If no set bits in range return empty bitset if (length() <= fromIndex || fromIndex == toIndex) return new BitSet(0); // An optimization if (length() < toIndex) toIndex = length(); BitSet result = new BitSet(toIndex - fromIndex); int startBitIndex = fromIndex & BIT_INDEX_MASK; int endBitIndex = toIndex & BIT_INDEX_MASK; int targetWords = (toIndex - fromIndex + 63)/64; int sourceWords = unitIndex(toIndex) - unitIndex(fromIndex) + 1; int inverseIndex = 64 - startBitIndex; int targetIndex = 0; int sourceIndex = unitIndex(fromIndex); // Process all words but the last word while (targetIndex < targetWords - 1) result.bits[targetIndex++] = (bits[sourceIndex++] >>> startBitIndex) | ((inverseIndex==64) ? 0 : bits[sourceIndex] << inverseIndex); // Process the last word result.bits[targetIndex] = (sourceWords == targetWords ? (bits[sourceIndex] & bitsRightOf(endBitIndex)) >>> startBitIndex : (bits[sourceIndex++] >>> startBitIndex) | ((inverseIndex==64) ? 0 : (getBits(sourceIndex) & bitsRightOf(endBitIndex)) << inverseIndex)); // Set unitsInUse correctly result.unitsInUse = targetWords; result.recalculateUnitsInUse(); return result;
private long	getBits(int j) Returns the unit of this bitset at index j as if this bitset had an infinite amount of storage. return (j < unitsInUse) ? bits[j] : 0;
public int	hashCode() Returns a hash code value for this bit set. The has code depends only on which bits have been set within this BitSet. The algorithm used to compute it may be described as follows. Suppose the bits in the BitSet were to be stored in an array of long integers called, say, bits, in such a manner that bit k is set in the BitSet (for nonnegative values of k) if and only if the expression ((k>>6) < bits.length) && ((bits[k>>6] & (1L << (bit & 0x3F))) != 0) is true. Then the following definition of the hashCode method would be a correct implementation of the actual algorithm: public int hashCode() { long h = 1234; for (int i = bits.length; --i >= 0; ) { h ^= bits[i] * (i + 1); } return (int)((h >> 32) ^ h); } Note that the hash code values change if the set of bits is altered. Overrides the hashCode method of Object. return a hash code value for this bit set. long h = 1234; for (int i = bits.length; --i >= 0; ) h ^= bits[i] * (i + 1); return (int)((h >> 32) ^ h);
public boolean	intersects(java.util.BitSet set) Returns true if the specified BitSet has any bits set to true that are also set to true in this BitSet. param set BitSet to intersect with return boolean indicating whether this BitSet intersects the specified BitSet. since 1.4 for(int i = Math.min(unitsInUse, set.unitsInUse)-1; i>=0; i--) if ((bits[i] & set.bits[i]) != 0) return true; return false;
public boolean	isEmpty() Returns true if this BitSet contains no bits that are set to true. return boolean indicating whether this BitSet is empty. since 1.4 return (unitsInUse == 0);
public int	length() Returns the "logical size" of this BitSet: the index of the highest set bit in the BitSet plus one. Returns zero if the BitSet contains no set bits. return the logical size of this BitSet. since 1.2 if (unitsInUse == 0) return 0; long highestUnit = bits[unitsInUse - 1]; int highPart = (int)(highestUnit >>> 32); return 64 * (unitsInUse - 1) + (highPart == 0 ? bitLen((int)highestUnit) : 32 + bitLen((int)highPart));
public int	nextClearBit(int fromIndex) Returns the index of the first bit that is set to false that occurs on or after the specified starting index. param fromIndex the index to start checking from (inclusive). return the index of the next clear bit. throws IndexOutOfBoundsException if the specified index is negative. since 1.4 if (fromIndex < 0) throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex); int u = unitIndex(fromIndex); if (u >= unitsInUse) return fromIndex; int testIndex = (fromIndex & BIT_INDEX_MASK); long unit = bits[u] >> testIndex; if (unit == (WORD_MASK >> testIndex)) testIndex = 0; while((unit==WORD_MASK) && (u < unitsInUse-1)) unit = bits[++u]; if (unit == WORD_MASK) return length(); if (unit == 0) return u * BITS_PER_UNIT + testIndex; testIndex += trailingZeroCnt(~unit); return ((u * BITS_PER_UNIT) + testIndex);
public int	nextSetBit(int fromIndex) Returns the index of the first bit that is set to true that occurs on or after the specified starting index. If no such bit exists then -1 is returned. To iterate over the true bits in a BitSet, use the following loop: for(int i=bs.nextSetBit(0); i>=0; i=bs.nextSetBit(i+1)) { // operate on index i here } param fromIndex the index to start checking from (inclusive). return the index of the next set bit. throws IndexOutOfBoundsException if the specified index is negative. since 1.4 if (fromIndex < 0) throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex); int u = unitIndex(fromIndex); if (u >= unitsInUse) return -1; int testIndex = (fromIndex & BIT_INDEX_MASK); long unit = bits[u] >> testIndex; if (unit == 0) testIndex = 0; while((unit==0) && (u < unitsInUse-1)) unit = bits[++u]; if (unit == 0) return -1; testIndex += trailingZeroCnt(unit); return ((u * BITS_PER_UNIT) + testIndex);
public void	or(java.util.BitSet set) Performs a logical OR of this bit set with the bit set argument. This bit set is modified so that a bit in it has the value true if and only if it either already had the value true or the corresponding bit in the bit set argument has the value true. param set a bit set. if (this == set) return; ensureCapacity(set.unitsInUse); // Perform logical OR on bits in common int unitsInCommon = Math.min(unitsInUse, set.unitsInUse); int i; for(i=0; i<unitsInCommon; i++) bits[i] |= set.bits[i]; // Copy any remaining bits for(; i<set.unitsInUse; i++) bits[i] = set.bits[i]; if (unitsInUse < set.unitsInUse) unitsInUse = set.unitsInUse;
private void	readObject(java.io.ObjectInputStream in) This override of readObject makes sure unitsInUse is set properly when deserializing a bitset in.defaultReadObject(); // Assume maximum length then find real length // because recalculateUnitsInUse assumes maintenance // or reduction in logical size unitsInUse = bits.length; recalculateUnitsInUse();
private void	recalculateUnitsInUse() Set the field unitsInUse with the logical size in units of the bit set. WARNING:This function assumes that the number of units actually in use is less than or equal to the current value of unitsInUse! // Traverse the bitset until a used unit is found int i; for (i = unitsInUse-1; i >= 0; i--) if(bits[i] != 0) break; unitsInUse = i+1; // The new logical size
public void	set(int bitIndex) Sets the bit at the specified index to true. param bitIndex a bit index. exception IndexOutOfBoundsException if the specified index is negative. since JDK1.0 if (bitIndex < 0) throw new IndexOutOfBoundsException("bitIndex < 0: " + bitIndex); int unitIndex = unitIndex(bitIndex); int unitsRequired = unitIndex + 1; if (unitsInUse < unitsRequired) { ensureCapacity(unitsRequired); bits[unitIndex] |= bit(bitIndex); unitsInUse = unitsRequired; } else { bits[unitIndex] |= bit(bitIndex); }
public void	set(int bitIndex, boolean value) Sets the bit at the specified index to the specified value. param bitIndex a bit index. param value a boolean value to set. exception IndexOutOfBoundsException if the specified index is negative. since 1.4 if (value) set(bitIndex); else clear(bitIndex);
public void	set(int fromIndex, int toIndex) Sets the bits from the specified fromIndex(inclusive) to the specified toIndex(exclusive) to true. param fromIndex index of the first bit to be set. param toIndex index after the last bit to be set. exception IndexOutOfBoundsException if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex. since 1.4 if (fromIndex < 0) throw new IndexOutOfBoundsException("fromIndex < 0: " + fromIndex); if (toIndex < 0) throw new IndexOutOfBoundsException("toIndex < 0: " + toIndex); if (fromIndex > toIndex) throw new IndexOutOfBoundsException("fromIndex: " + fromIndex + " > toIndex: " + toIndex); // Increase capacity if necessary int endUnitIndex = unitIndex(toIndex); int unitsRequired = endUnitIndex + 1; if (unitsInUse < unitsRequired) { ensureCapacity(unitsRequired); unitsInUse = unitsRequired; } int startUnitIndex = unitIndex(fromIndex); long bitMask = 0; if (startUnitIndex == endUnitIndex) { // Case 1: One word bitMask = (1L << (toIndex & BIT_INDEX_MASK)) - (1L << (fromIndex & BIT_INDEX_MASK)); bits[startUnitIndex] |= bitMask; return; } // Case 2: Multiple words // Handle first word bitMask = bitsLeftOf(fromIndex & BIT_INDEX_MASK); bits[startUnitIndex] |= bitMask; // Handle intermediate words, if any if (endUnitIndex - startUnitIndex > 1) { for(int i=startUnitIndex+1; i<endUnitIndex; i++) bits[i] |= WORD_MASK; } // Handle last word bitMask = bitsRightOf(toIndex & BIT_INDEX_MASK); bits[endUnitIndex] |= bitMask;
public void	set(int fromIndex, int toIndex, boolean value) Sets the bits from the specified fromIndex(inclusive) to the specified toIndex(exclusive) to the specified value. param fromIndex index of the first bit to be set. param toIndex index after the last bit to be set param value value to set the selected bits to exception IndexOutOfBoundsException if fromIndex is negative, or toIndex is negative, or fromIndex is larger than toIndex. since 1.4 if (value) set(fromIndex, toIndex); else clear(fromIndex, toIndex);
public int	size() Returns the number of bits of space actually in use by this BitSet to represent bit values. The maximum element in the set is the size - 1st element. return the number of bits currently in this bit set. return bits.length << ADDRESS_BITS_PER_UNIT;
public java.lang.String	toString() Returns a string representation of this bit set. For every index for which this BitSet contains a bit in the set state, the decimal representation of that index is included in the result. Such indices are listed in order from lowest to highest, separated by ", " (a comma and a space) and surrounded by braces, resulting in the usual mathematical notation for a set of integers. Overrides the toString method of Object. Example: BitSet drPepper = new BitSet(); Now drPepper.toString() returns "{}". drPepper.set(2); Now drPepper.toString() returns "{2}". drPepper.set(4); drPepper.set(10); Now drPepper.toString() returns "{2, 4, 10}". return a string representation of this bit set. int numBits = unitsInUse << ADDRESS_BITS_PER_UNIT; StringBuffer buffer = new StringBuffer(8*numBits + 2); String separator = ""; buffer.append('{"); for (int i = 0 ; i < numBits; i++) { if (get(i)) { buffer.append(separator); separator = ", "; buffer.append(i); } } buffer.append('}"); return buffer.toString();
private static int	trailingZeroCnt(long val) // Loop unrolled for performance int byteVal = (int)val & 0xff; if (byteVal != 0) return trailingZeroTable[byteVal]; byteVal = (int)(val >>> 8) & 0xff; if (byteVal != 0) return trailingZeroTable[byteVal] + 8; byteVal = (int)(val >>> 16) & 0xff; if (byteVal != 0) return trailingZeroTable[byteVal] + 16; byteVal = (int)(val >>> 24) & 0xff; if (byteVal != 0) return trailingZeroTable[byteVal] + 24; byteVal = (int)(val >>> 32) & 0xff; if (byteVal != 0) return trailingZeroTable[byteVal] + 32; byteVal = (int)(val >>> 40) & 0xff; if (byteVal != 0) return trailingZeroTable[byteVal] + 40; byteVal = (int)(val >>> 48) & 0xff; if (byteVal != 0) return trailingZeroTable[byteVal] + 48; byteVal = (int)(val >>> 56) & 0xff; return trailingZeroTable[byteVal] + 56;
private static int	unitIndex(int bitIndex) Given a bit index return unit index containing it. return bitIndex >> ADDRESS_BITS_PER_UNIT;
public void	xor(java.util.BitSet set) Performs a logical XOR of this bit set with the bit set argument. This bit set is modified so that a bit in it has the value true if and only if one of the following statements holds: The bit initially has the value true, and the corresponding bit in the argument has the value false. The bit initially has the value false, and the corresponding bit in the argument has the value true. param set a bit set. int unitsInCommon; if (unitsInUse >= set.unitsInUse) { unitsInCommon = set.unitsInUse; } else { unitsInCommon = unitsInUse; int newUnitsInUse = set.unitsInUse; ensureCapacity(newUnitsInUse); unitsInUse = newUnitsInUse; } // Perform logical XOR on bits in common int i; for (i=0; i<unitsInCommon; i++) bits[i] ^= set.bits[i]; // Copy any remaining bits for ( ; i<set.unitsInUse; i++) bits[i] = set.bits[i]; recalculateUnitsInUse();