Class ByteBlockPool

Class that Posting and PostingVector use to write byte streams into shared fixed-size byte[] arrays. The idea is to allocate slices of increasing lengths. For example, the first slice is 5 bytes, the next slice is 14, etc. We start by writing our bytes into the first 5 bytes. When we hit the end of the slice, we allocate the next slice and then write the address of the new slice into the last 4 bytes of the previous slice (the "forwarding address").

Each slice is filled with 0's initially, and we mark the end with a non-zero byte. This way the methods that are writing into the slice don't need to record its length and instead allocate a new slice once they hit a non-zero byte.

This is a Lucene.NET INTERNAL API, use at your own risk
Inheritance
System.Object
ByteBlockPool
Namespace: Lucene.Net.Util
Assembly: Lucene.Net.dll
Syntax
public sealed class ByteBlockPool : object

Constructors

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ByteBlockPool(ByteBlockPool.Allocator)

Declaration
public ByteBlockPool(ByteBlockPool.Allocator allocator)
Parameters
Type Name Description
ByteBlockPool.Allocator allocator

Fields

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BYTE_BLOCK_MASK

Declaration
public static readonly int BYTE_BLOCK_MASK
Field Value
Type Description
System.Int32
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BYTE_BLOCK_SHIFT

Declaration
public static readonly int BYTE_BLOCK_SHIFT
Field Value
Type Description
System.Int32
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BYTE_BLOCK_SIZE

Declaration
public static readonly int BYTE_BLOCK_SIZE
Field Value
Type Description
System.Int32
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FIRST_LEVEL_SIZE

The first level size for new slices

Declaration
public static readonly int FIRST_LEVEL_SIZE
Field Value
Type Description
System.Int32
See Also
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LEVEL_SIZE_ARRAY

An array holding the level sizes for byte slices.

Declaration
public static readonly int[] LEVEL_SIZE_ARRAY
Field Value
Type Description
System.Int32[]
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NEXT_LEVEL_ARRAY

An array holding the offset into the LEVEL_SIZE_ARRAY to quickly navigate to the next slice level.

Declaration
public static readonly int[] NEXT_LEVEL_ARRAY
Field Value
Type Description
System.Int32[]

Properties

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Buffer

Current head buffer

Declaration
public byte[] Buffer { get; set; }
Property Value
Type Description
System.Byte[]
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Buffers

Array of buffers currently used in the pool. Buffers are allocated if needed don't modify this outside of this class.

Declaration
public byte[][] Buffers { get; set; }
Property Value
Type Description
System.Byte[][]
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ByteOffset

Current head offset

Declaration
public int ByteOffset { get; set; }
Property Value
Type Description
System.Int32
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ByteUpto

Where we are in head buffer

Declaration
public int ByteUpto { get; set; }
Property Value
Type Description
System.Int32

Methods

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AllocSlice(Byte[], Int32)

Creates a new byte slice with the given starting size and returns the slices offset in the pool.

Declaration
public int AllocSlice(byte[] slice, int upto)
Parameters
Type Name Description
System.Byte[] slice
System.Int32 upto
Returns
Type Description
System.Int32
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Append(BytesRef)

Appends the bytes in the provided BytesRef at the current position.

Declaration
public void Append(BytesRef bytes)
Parameters
Type Name Description
BytesRef bytes
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NewSlice(Int32)

Allocates a new slice with the given size.

Declaration
public int NewSlice(int size)
Parameters
Type Name Description
System.Int32 size
Returns
Type Description
System.Int32
See Also
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NextBuffer()

Advances the pool to its next buffer. This method should be called once after the constructor to initialize the pool. In contrast to the constructor a Reset() call will advance the pool to its first buffer immediately.

Declaration
public void NextBuffer()
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ReadBytes(Int64, Byte[], Int32, Int32)

Reads bytes bytes out of the pool starting at the given offset with the given length into the given byte array at offset off.

Note: this method allows to copy across block boundaries.

Declaration
public void ReadBytes(long offset, byte[] bytes, int off, int length)
Parameters
Type Name Description
System.Int64 offset
System.Byte[] bytes
System.Int32 off
System.Int32 length
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Reset()

Resets the pool to its initial state reusing the first buffer and fills all buffers with 0 bytes before they reused or passed to RecycleByteBlocks(Byte[][], Int32, Int32). Calling NextBuffer() is not needed after reset.

Declaration
public void Reset()
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Reset(Boolean, Boolean)

Expert: Resets the pool to its initial state reusing the first buffer. Calling NextBuffer() is not needed after reset.

Declaration
public void Reset(bool zeroFillBuffers, bool reuseFirst)
Parameters
Type Name Description
System.Boolean zeroFillBuffers

if true the buffers are filled with 0. this should be set to true if this pool is used with slices.

System.Boolean reuseFirst

if true the first buffer will be reused and calling NextBuffer() is not needed after reset if the block pool was used before ie. NextBuffer() was called before.

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SetBytesRef(BytesRef, Int32)

Declaration
public void SetBytesRef(BytesRef term, int textStart)
Parameters
Type Name Description
BytesRef term
System.Int32 textStart