Package it.unimi.dsi.sux4j.bits

Class RankSelect

  • All Implemented Interfaces:
    Rank, Select, SelectZero, java.io.Serializable
    public class RankSelect
extends java.lang.Object
implements Rank, Select, SelectZero, java.io.Serializable
    A serialisation-oriented container for associated rank/select(zero) structures.

    Since structures in Sux4J serialise all contained data, including, if necessary, the underlying bit vector, serialising separately a rank and a select structure might result in storing the underlying bit vector twice. This class provide a simple solution by allowing one-shot serialisation of all structures related to a bit vector. For convenience, it provides also delegate methods, albeit the suggested usage is deserialisation and extraction of non-null structures.

    See Also:
    Serialized Form

    • Constructor Summary

      Constructors 
      Constructor Description
      RankSelect​(Rank rank, Select select)
      Creates a new rank/select container without zero selection using the given structures.
      RankSelect​(Rank rank, Select select, SelectZero selectZero)
      Creates a new rank/select container using the given structures.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      it.unimi.dsi.bits.BitVector bitVector()
      Returns the bit vector indexed by this structure.
      long count()
      Returns the number of ones in the bit vector indexed by this class.
      long numBits()
      Returns the overall number of bits allocated by this structure.
      long rank​(long pos)
      Returns the number of ones preceding the specified position.
      long rank​(long from, long to)
      Returns the number of ones in the specified interval.
      long rankZero​(long pos)
      Returns the number of zeroes preceding the specified position.
      long rankZero​(long from, long to)
      Returns the number of zeroes in the specified interval.
      long select​(long rank)
      Returns the position of the bit of given rank.
      long selectZero​(long rank)
      Returns the position of the bit of given zero rank.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • rank

        public final Rank rank
        A rank structure, or null.

      • select

        public final Select select
        A select structure, or null.

      • selectZero

        public final SelectZero selectZero
        A zero-select structure, or null.

    • Constructor Detail

      • RankSelect

        public RankSelect​(Rank rank,
                  Select select,
                  SelectZero selectZero)
        Creates a new rank/select container using the given structures.
        Parameters:
        rank - a rank structure, or null.
        select - a select structure, or null.
        selectZero - a zero-select structure, or null.

      • RankSelect

        public RankSelect​(Rank rank,
                  Select select)
        Creates a new rank/select container without zero selection using the given structures.
        Parameters:
        rank - a rank structure, or null.
        select - a select structure, or null.

    • Method Detail

      • count

        public long count()
        Description copied from interface: Rank
        Returns the number of ones in the bit vector indexed by this class.
        Specified by:
        count in interface Rank
        Returns:
        number of ones in the bit vector indexed by this class.

      • numBits

        public long numBits()
        Description copied from interface: Rank
        Returns the overall number of bits allocated by this structure.
        Specified by:
        numBits in interface Rank
        Specified by:
        numBits in interface Select
        Specified by:
        numBits in interface SelectZero
        Returns:
        the overall number of bits allocated by this structure (not including the bits of the indexed vector).

      • rank

        public long rank​(long from,
                 long to)
        Description copied from interface: Rank
        Returns the number of ones in the specified interval.
        Specified by:
        rank in interface Rank
        Parameters:
        from - a position in the bit vector between 0 (inclusive) and the length of the bit vector (inclusive).
        to - a position in the bit vector between 0 (inclusive) and the length of the bit vector (inclusive); must be greater than or equal to from.
        Returns:
        the number of ones between from (inclusive) and to (exclusive); if the parameters are out of bounds, behavior is undefined.

      • rank

        public long rank​(long pos)
        Description copied from interface: Rank
        Returns the number of ones preceding the specified position.
        Specified by:
        rank in interface Rank
        Parameters:
        pos - a position in the bit vector between 0 (inclusive) and the length of the bit vector (inclusive).
        Returns:
        the number of ones preceding position pos; if pos is out of bounds, behavior is undefined.

      • rankZero

        public long rankZero​(long from,
                     long to)
        Description copied from interface: Rank
        Returns the number of zeroes in the specified interval.
        Specified by:
        rankZero in interface Rank
        Parameters:
        from - a position in the bit vector between 0 (inclusive) and the length of the bit vector (inclusive).
        to - a position in the bit vector between 0 (inclusive) and the length of the bit vector (inclusive); must be greater than or equal to from.
        Returns:
        the number of zeros between from (inclusive) and to (exclusive); if the parameters are out of bounds, behavior is undefined (might throw an exception).

      • rankZero

        public long rankZero​(long pos)
        Description copied from interface: Rank
        Returns the number of zeroes preceding the specified position.
        Specified by:
        rankZero in interface Rank
        Parameters:
        pos - a position in the bit vector between 0 (inclusive) and the length of the bit vector (inclusive).
        Returns:
        the number of zeroes preceding pos; if pos is out of bounds, behavior is undefined.

      • select

        public long select​(long rank)
        Description copied from interface: Select
        Returns the position of the bit of given rank. Equivalently, returns the greatest position that is preceded by the specified number of ones.
        Specified by:
        select in interface Select
        Parameters:
        rank - a rank.
        Returns:
        the position of the bit of given rank; if no such bit exists, behavior is undefined .

      • selectZero

        public long selectZero​(long rank)
        Description copied from interface: SelectZero
        Returns the position of the bit of given zero rank. Equivalently, returns the greatest position that is preceded by the specified number of zeroes.
        Specified by:
        selectZero in interface SelectZero
        Parameters:
        rank - a zero rank.
        Returns:
        the position of the bit of given zero rank; if no such bit exists, behavior is undefined .

      • bitVector

        public it.unimi.dsi.bits.BitVector bitVector()
        Description copied from interface: Rank
        Returns the bit vector indexed by this structure.

        Note that you must not modify the returned vector.

        Specified by:
        bitVector in interface Rank
        Specified by:
        bitVector in interface Select
        Specified by:
        bitVector in interface SelectZero
        Returns:
        the bit vector indexed by this structure.