Class BytesRefHash

BytesRefHash is a special purpose hash-map like data-structure optimized for BytesRef instances. BytesRefHash maintains mappings of byte arrays to ids (Map<BytesRef,int>) storing the hashed bytes efficiently in continuous storage. The mapping to the id is encapsulated inside BytesRefHash and is guaranteed to be increased for each added BytesRef.

Note: The maximum capacity BytesRef instance passed to Add(BytesRef) must not be longer than BYTE_BLOCK_SIZE-2. The internal storage is limited to 2GB total byte storage.

This is a Lucene.NET INTERNAL API, use at your own risk

Inheritance

System.Object

BytesRefHash

Namespace: Lucene.Net.Util

Assembly: Lucene.Net.dll

Syntax

public sealed class BytesRefHash : IDisposable

Constructors

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BytesRefHash()

Creates a new BytesRefHash with a ByteBlockPool using a ByteBlockPool.DirectAllocator.

Declaration

public BytesRefHash()

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BytesRefHash(ByteBlockPool)

Creates a new BytesRefHash

Declaration

public BytesRefHash(ByteBlockPool pool)

Parameters

Type	Name	Description
ByteBlockPool	pool

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BytesRefHash(ByteBlockPool, Int32, BytesRefHash.BytesStartArray)

Creates a new BytesRefHash

Declaration

public BytesRefHash(ByteBlockPool pool, int capacity, BytesRefHash.BytesStartArray bytesStartArray)

Parameters

Type	Name	Description
ByteBlockPool	pool
System.Int32	capacity
BytesRefHash.BytesStartArray	bytesStartArray

Fields

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DEFAULT_CAPACITY

Declaration

public const int DEFAULT_CAPACITY = null

Field Value

Type	Description
System.Int32

Properties

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Count

Returns the number of BytesRef values in this BytesRefHash.

NOTE: This was size() in Lucene.

Declaration

public int Count { get; }

Property Value

Type	Description
System.Int32	The number of BytesRef values in this BytesRefHash.

Methods

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Add(BytesRef)

Adds a new BytesRef

Declaration

public int Add(BytesRef bytes)

Parameters

Type	Name	Description
BytesRef	bytes	The bytes to hash

Returns

Type	Description
System.Int32	The id the given bytes are hashed if there was no mapping for the given bytes, otherwise `(-(id)-1)`. this guarantees that the return value will always be >= 0 if the given bytes haven't been hashed before.

Exceptions

Type	Condition
BytesRefHash.MaxBytesLengthExceededException	if the given bytes are > 2 + BYTE_BLOCK_SIZE

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AddByPoolOffset(Int32)

Adds a "arbitrary" int offset instead of a BytesRef term. This is used in the indexer to hold the hash for term vectors, because they do not redundantly store the byte[] term directly and instead reference the byte[] term already stored by the postings BytesRefHash. See Lucene.Net.Index.TermsHashPerField.Add(System.Int32).

Declaration

public int AddByPoolOffset(int offset)

Parameters

Type	Name	Description
System.Int32	offset

Returns

Type	Description
System.Int32

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ByteStart(Int32)

Returns the bytesStart offset into the internally used ByteBlockPool for the given bytesID

Declaration

public int ByteStart(int bytesID)

Parameters

Type	Name	Description
System.Int32	bytesID	The id to look up

Returns

Type	Description
System.Int32	The bytesStart offset into the internally used ByteBlockPool for the given id

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Clear()

Declaration

public void Clear()

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Clear(Boolean)

Clears the BytesRef which maps to the given BytesRef

Declaration

public void Clear(bool resetPool)

Parameters

Type	Name	Description
System.Boolean	resetPool

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Compact()

Returns the ids array in arbitrary order. Valid ids start at offset of 0 and end at a limit of Count - 1

Note: this is a destructive operation. Clear() must be called in order to reuse this BytesRefHash instance.

Declaration

public int[] Compact()

Returns

Type	Description
System.Int32[]

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Dispose()

Closes the BytesRefHash and releases all internally used memory

Declaration

public void Dispose()

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Find(BytesRef)

Returns the id of the given BytesRef.

Declaration

public int Find(BytesRef bytes)

Parameters

Type	Name	Description
BytesRef	bytes	The bytes to look for

Returns

Type	Description
System.Int32	The id of the given bytes, or `-1` if there is no mapping for the given bytes.

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Get(Int32, BytesRef)

Populates and returns a BytesRef with the bytes for the given bytesID.

Note: the given bytesID must be a positive integer less than the current size (Count)

Declaration

public BytesRef Get(int bytesID, BytesRef ref)

Parameters

Type	Name	Description
System.Int32	bytesID	The id
BytesRef	ref	The BytesRef to populate

Returns

Type	Description
BytesRef	The given BytesRef instance populated with the bytes for the given bytesID

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Reinit()

Reinitializes the BytesRefHash after a previous Clear() call. If Clear() has not been called previously this method has no effect.

Declaration

public void Reinit()

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Sort(IComparer<BytesRef>)

Returns the values array sorted by the referenced byte values.

Note: this is a destructive operation. Clear() must be called in order to reuse this BytesRefHash instance.

Declaration

public int[] Sort(IComparer<BytesRef> comp)

Parameters

Type	Name	Description
IComparer<BytesRef>	comp	The IComparer<BytesRef> used for sorting

Returns

Type	Description
System.Int32[]