EwahCompressedBitArray Class

[Missing <summary> documentation for "T:VelocityDBExtensions.CompressedBitArray.EwahCompressedBitArray"]

Inheritance Hierarchy

SystemObject
VelocityDbOptimizedPersistable
VelocityDBExtensions.CompressedBitArrayEwahCompressedBitArray

Namespace: VelocityDBExtensions.CompressedBitArray
Assembly: VelocityDBExtensions (in VelocityDBExtensions.dll) Version: 11.1.0.0 (11.1.0)

Syntax

C++

Copy

[SerializableAttribute]
public sealed class EwahCompressedBitArray : OptimizedPersistable, 
	ICloneable, IEnumerable<int>, IEnumerable

<SerializableAttribute>
Public NotInheritable Class EwahCompressedBitArray
	Inherits OptimizedPersistable
	Implements ICloneable, IEnumerable(Of Integer), 
	IEnumerable

[SerializableAttribute]
public ref class EwahCompressedBitArray sealed : public OptimizedPersistable, 
	ICloneable, IEnumerable<int>, IEnumerable

[<SealedAttribute>]
[<SerializableAttribute>]
type EwahCompressedBitArray =  
    class
        inherit OptimizedPersistable
        interface ICloneable
        interface IEnumerable<int>
        interface IEnumerable
    end

The EwahCompressedBitArray type exposes the following members.

Constructors

	Name	Description
	EwahCompressedBitArray	Creates an empty bitmap (no bit set to true).
	EwahCompressedBitArray(Int32)	Sets explicitly the buffer size (in 64-bit words). The initial memory usage will be "buffersize * 64". For large poorly compressible bitmaps, using large values may improve performance.

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Properties

	Name	Description
	SizeInBits	The size in bits of the uncompressed bitmap represented by this compressed bitmap. Initially, the SizeInBits is zero. It is extended automatically when you set bits to true.
	SizeInBytes	Report the compressed size of the bitmap (equivalent to memory usage, after accounting for some overhead).

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Methods

	Name	Description
	Add(Int64)	Adding words directly to the bitmap (for expert use). This is normally how you add data to the array. So you add bits in streams of 8*8 bits.
	Add(Int64, Int32)	Adding words directly to the bitmap (for expert use).
	AddStreamOfEmptyWords	For experts: You want to add many zeroes or ones? This is the method you use.
	And	Returns a new compressed bitmap containing the bitwise AND values of the current bitmap with some other bitmap. The running time is proportional to the sum of the compressed sizes (as reported by SizeInBytes).
	AndNot	Returns a new compressed bitmap containing the bitwise AND NOT values of the current bitmap with some other bitmap. The running time is proportional to the sum of the compressed sizes (as reported by SizeInBytes).
	bitCount	Counts the number of set (1) bits.
	BitmapOf
	Clone	(Overrides OptimizedPersistableClone.)
	Equals	Check to see whether the two compressed bitmaps contain the same data (effectively check whether the cardinality of a XOR is == 0. (Overrides OptimizedPersistableEquals(Object).)
	GetCardinality	reports the number of bits set to true. Running time is proportional to compressed size (as reported by SizeInBytes).
	GetEnumerator	Iterator over the set bits (this is what most people will want to use to browse the content). The location of the set bits is returned, in increasing order.
	GetHashCode	Returns a customized hash code (based on Karp-Rabin). Naturally, if the bitmaps are equal, they will hash to the same value. (Overrides OptimizedPersistableGetHashCode.)
	GetObjectData
	GetPositions	get the locations of the true values as one vector. (may use more memory than GetEnumerator()
	Intersects	Return true if the two EwahCompressedBitArray have both at least one true bit in the same Position. Equivalently, you could call "And" and check whether there is a set bit, but intersects will run faster if you don't need the result of the "and" operation.
	Not	Negate (bitwise) the current bitmap. To get a negated copy, do ((EwahCompressedBitArray) mybitmap.Clone()).not(); The running time is proportional to the compressed size (as reported by SizeInBytes).
	Or	Returns a new compressed bitmap containing the bitwise OR values of the current bitmap with some other bitmap. The running time is proportional to the sum of the compressed sizes (as reported by SizeInBytes).
	Set	set the bit at Position i to true, the bits must be set in increasing order. For example, Set(15) and then Set(7) will fail. You must do Set(7) and then Set(15).
	SetSizeInBits	Change the reported size in bits of the uncompressed bitmap represented by this compressed bitmap. It is not possible to reduce the SizeInBits, but it can be extended. The new bits are set to false or true depending on the value of defaultvalue.
	Shrink	Sets the internal buffer to the minimum possible size required to contain the current bitarray. This method is useful when dealing with static bitmasks, if it is called after the final bit has been set, some memory can be free-ed. Please note, the next bit set after a call to shrink will cause the memory usage of the bit-array to double.
	ToDebugString	A more detailed string describing the bitmap (useful for debugging).
	ToString	A string describing the bitmap (Overrides OptimizedPersistableToString.)
	Xor	Returns a new compressed bitmap containing the bitwise XOR values of the current bitmap with some other bitmap. The running time is proportional to the sum of the compressed sizes (as reported by SizeInBytes).

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Fields

	Name	Description
	WordInBits	the number of bits in a long

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Extension Methods

	Name	Description
	ToStringDetails(SessionBase, Boolean)	Overloaded. Object details as a string (Defined by Utilities.)
	ToStringDetails(Schema, TypeVersion, Boolean)	Overloaded. Currently only used by Database Manager (Defined by Utilities.)

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Reference

VelocityDBExtensions.CompressedBitArray Namespace