BitSet

This class implements a vector of bits that grows as needed. Each component of the bit set has a {@code bool} value. The bits of a {@code BitSet} are indexed by nonnegative integers. Individual indexed bits can be examined, set, or cleared. One {@code BitSet} may be used to modify the contents of another {@code BitSet} through logical AND, logical inclusive OR, and logical exclusive OR operations.

By default, all bits in the set initially have the value {@code false}.

Every bit set has a current size, which is the number of bits of space currently in use by the bit set. Note that the size is related to the implementation of a bit set, so it may change with implementation. The length of a bit set relates to logical length of a bit set and is defined independently of implementation.

Unless otherwise noted, passing a null parameter to any of the methods in a {@code BitSet} will result in a {@code NullPointerException}.

A {@code BitSet} is not safe for multithreaded use without external synchronization.

@author Arthur van Hoff @author Michael McCloskey @author Martin Buchholz

Constructors

this this(): Creates a new bit set. All bits are initially {@code false}.
this this(size_t nbits): Creates a bit set whose initial size is large enough to explicitly represent bits with indices in the range {@code 0} through {@code nbits-1}. All bits are initially {@code false}.

Members

Functions

and void and(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 {@code true} if and only if it both initially had the value {@code true} and the corresponding bit in the bit set argument also had the value {@code true}.
andNot void andNot(BitSet set): Clears all of the bits in this {@code BitSet} whose corresponding bit is set in the specified {@code BitSet}.
cardinality size_t cardinality(): Returns the number of bits set to {@code true} in this {@code BitSet}.
clear void clear(size_t bitIndex): Sets the bit specified by the index to {@code false}.
clear void clear(size_t fromIndex, size_t toIndex): Sets the bits from the specified {@code fromIndex} (inclusive) to the specified {@code toIndex} (exclusive) to {@code false}.
clear void clear(): Sets all of the bits in this BitSet to {@code false}.
equals bool equals(Object obj): Compares this object against the specified object. The result is {@code true} if and only if the argument is not {@code null} and is a {@code Bitset} object that has exactly the same set of bits set to {@code true} as this bit set. That is, for every nonnegative {@code int} index {@code k}, <pre>((BitSet)obj).get(k) == this.get(k)</pre> must be true. The current sizes of the two bit sets are not compared.
flip void flip(size_t bitIndex): Sets the bit at the specified index to the complement of its current value.
get bool get(size_t bitIndex): Returns the value of the bit with the specified index. The value is {@code true} if the bit with the index {@code bitIndex} is currently set in this {@code BitSet}; otherwise, the result is {@code false}.
get BitSet get(size_t fromIndex, size_t toIndex): Returns a new {@code BitSet} composed of bits from this {@code BitSet} from {@code fromIndex} (inclusive) to {@code toIndex} (exclusive).
intersects bool intersects(BitSet set): Returns true if the specified {@code BitSet} has any bits set to {@code true} that are also set to {@code true} in this {@code BitSet}.
isEmpty bool isEmpty(): Returns true if this {@code BitSet} contains no bits that are set to {@code true}.
length size_t length(): Returns the "logical size" of this {@code BitSet}: the index of the highest set bit in the {@code BitSet} plus one. Returns zero if the {@code BitSet} contains no set bits.
nextClearBit size_t nextClearBit(int fromIndex): Returns the index of the first bit that is set to {@code false} that occurs on or after the specified starting index.
nextSetBit size_t nextSetBit(size_t fromIndex): Returns the index of the first bit that is set to {@code true} that occurs on or after the specified starting index. If no such bit exists then {@code -1} is returned.
or void or(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 {@code true} if and only if it either already had the value {@code true} or the corresponding bit in the bit set argument has the value {@code true}.
previousClearBit size_t previousClearBit(size_t fromIndex): Returns the index of the nearest bit that is set to {@code false} that occurs on or before the specified starting index. If no such bit exists, or if {@code -1} is given as the starting index, then {@code -1} is returned.
previousSetBit size_t previousSetBit(size_t fromIndex): Returns the index of the nearest bit that is set to {@code true} that occurs on or before the specified starting index. If no such bit exists, or if {@code -1} is given as the starting index, then {@code -1} is returned.
set void set(size_t bitIndex): Sets the bit at the specified index to {@code true}.
set void set(int bitIndex, bool value): Sets the bit at the specified index to the specified value.
set void set(int fromIndex, int toIndex): Sets the bits from the specified {@code fromIndex} (inclusive) to the specified {@code toIndex} (exclusive) to {@code true}.
set void set(int fromIndex, int toIndex, bool value): Sets the bits from the specified {@code fromIndex} (inclusive) to the specified {@code toIndex} (exclusive) to the specified value.
size size_t size(): Returns the number of bits of space actually in use by this {@code BitSet} to represent bit values. The maximum element in the set is the size - 1st element.
toHash size_t toHash(): Returns the hash code value for this bit set. The hash code depends only on which bits are set within this {@code BitSet}.
toLongArray long[] toLongArray(): * Returns a new long array containing all the bits in this bit set. * * More precisely, if * {@code long[] longs = s.toLongArray();} * then {@code longs.length == (s.length()+63)/64} and * {@code s.get(n) == ((longs[n/64] & (1L<<(n%64))) != 0)} * for all {@code n < 64 * longs.length}. * * @return a long array containing a little-endian representation * of all the bits in this bit set
xor void xor(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 {@code true} if and only if one of the following statements holds: <ul> <li>The bit initially has the value {@code true}, and the corresponding bit in the argument has the value {@code false}. <li>The bit initially has the value {@code false}, and the corresponding bit in the argument has the value {@code true}. </ul>

BitSet

Constructors

Members

Functions

Meta

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