Package com.github.luben.zstd
Class ZstdCompressCtx
- java.lang.Object
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- com.github.luben.zstd.ZstdCompressCtx
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
public class ZstdCompressCtx extends java.lang.Object
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Constructor Summary
Constructors Constructor Description ZstdCompressCtx()
Create a context for faster compress operations One such context is required for each thread - put this in a ThreadLocal.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
close()
byte[]
compress(byte[] src)
int
compress(byte[] dst, byte[] src)
java.nio.ByteBuffer
compress(java.nio.ByteBuffer srcBuf)
Compresses the data in buffer 'srcBuf'int
compress(java.nio.ByteBuffer dstBuf, java.nio.ByteBuffer srcBuf)
Compresses the data in buffer 'srcBuf'int
compressByteArray(byte[] dstBuff, int dstOffset, int dstSize, byte[] srcBuff, int srcOffset, int srcSize)
Compresses byte array 'srcBuff' into byte array 'dstBuff' reusing this ZstdCompressCtx.int
compressDirectByteBuffer(java.nio.ByteBuffer dstBuff, int dstOffset, int dstSize, java.nio.ByteBuffer srcBuff, int srcOffset, int srcSize)
Compresses buffer 'srcBuff' into buffer 'dstBuff' reusing this ZstdCompressCtx.boolean
compressDirectByteBufferStream(java.nio.ByteBuffer dst, java.nio.ByteBuffer src, EndDirective endOp)
Compress as much of thesrc
ByteBuffer
into thedst
ByteBuffer
as possible.ZstdFrameProgression
getFrameProgression()
Tells how much data has been ingested (read from input), consumed (input actually compressed) and produced (output) for current frame.ZstdCompressCtx
loadDict(byte[] dict)
Load compression dictionary to be used for subsequently compressed frames.ZstdCompressCtx
loadDict(ZstdDictCompress dict)
Load compression dictionary to be used for subsequently compressed frames.void
reset()
Clear all state and parameters from the compression context.ZstdCompressCtx
setChainLog(int chainLog)
ZstdCompressCtx
setChecksum(boolean checksumFlag)
Enable or disable compression checksumsZstdCompressCtx
setContentSize(boolean contentSizeFlag)
Enable or disable content sizeZstdCompressCtx
setDictID(boolean dictIDFlag)
Enable or disable dictIDZstdCompressCtx
setHashLog(int hashLog)
ZstdCompressCtx
setJobSize(int jobSize)
ZstdCompressCtx
setLevel(int level)
Set compression levelZstdCompressCtx
setLong(int windowLog)
Enable or disable LongDistanceMatching and set the window sizeZstdCompressCtx
setMagicless(boolean magiclessFlag)
Enable or disable magicless framesZstdCompressCtx
setMinMatch(int minMatch)
ZstdCompressCtx
setOverlapLog(int overlapLog)
void
setPledgedSrcSize(long srcSize)
Promise to compress a certain number of source bytes.ZstdCompressCtx
setSearchLog(int searchLog)
ZstdCompressCtx
setStrategy(int strategy)
ZstdCompressCtx
setTargetLength(int targetLength)
ZstdCompressCtx
setWindowLog(int windowLog)
ZstdCompressCtx
setWorkers(int workers)
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Method Detail
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setLevel
public ZstdCompressCtx setLevel(int level)
Set compression level- Parameters:
level
- compression level, default:Zstd.defaultCompressionLevel()
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setMagicless
public ZstdCompressCtx setMagicless(boolean magiclessFlag)
Enable or disable magicless frames- Parameters:
magiclessFlag
- A 32-bits magic number is written at start of frame, default: false
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setChecksum
public ZstdCompressCtx setChecksum(boolean checksumFlag)
Enable or disable compression checksums- Parameters:
checksumFlag
- A 32-bits checksum of content is written at end of frame, default: false
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setWorkers
public ZstdCompressCtx setWorkers(int workers)
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setOverlapLog
public ZstdCompressCtx setOverlapLog(int overlapLog)
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setJobSize
public ZstdCompressCtx setJobSize(int jobSize)
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setTargetLength
public ZstdCompressCtx setTargetLength(int targetLength)
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setMinMatch
public ZstdCompressCtx setMinMatch(int minMatch)
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setSearchLog
public ZstdCompressCtx setSearchLog(int searchLog)
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setChainLog
public ZstdCompressCtx setChainLog(int chainLog)
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setHashLog
public ZstdCompressCtx setHashLog(int hashLog)
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setWindowLog
public ZstdCompressCtx setWindowLog(int windowLog)
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setStrategy
public ZstdCompressCtx setStrategy(int strategy)
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setContentSize
public ZstdCompressCtx setContentSize(boolean contentSizeFlag)
Enable or disable content size- Parameters:
contentSizeFlag
- Content size will be written into frame header _whenever known_, default: true
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setDictID
public ZstdCompressCtx setDictID(boolean dictIDFlag)
Enable or disable dictID- Parameters:
dictIDFlag
- When applicable, dictionary's ID is written into frame header, default: true
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setLong
public ZstdCompressCtx setLong(int windowLog)
Enable or disable LongDistanceMatching and set the window size- Parameters:
windowLog
- Maximum allowed back-reference distance, expressed as power of 2. This will set a memory budget for streaming decompression, with larger values requiring more memory and typically compressing more. Must be clamped between 10 and 32/64 but values greater than 27 may not be decompressable in all context as they require more memory. 0 disables LDM.
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loadDict
public ZstdCompressCtx loadDict(ZstdDictCompress dict)
Load compression dictionary to be used for subsequently compressed frames.- Parameters:
dict
- the dictionary or `null` to remove loaded dictionary
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loadDict
public ZstdCompressCtx loadDict(byte[] dict)
Load compression dictionary to be used for subsequently compressed frames.- Parameters:
dict
- the dictionary or `null` to remove loaded dictionary
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getFrameProgression
public ZstdFrameProgression getFrameProgression()
Tells how much data has been ingested (read from input), consumed (input actually compressed) and produced (output) for current frame.
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reset
public void reset()
Clear all state and parameters from the compression context. This leaves the object in a state identical to a newly created compression context.
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setPledgedSrcSize
public void setPledgedSrcSize(long srcSize)
Promise to compress a certain number of source bytes. Knowing the number of bytes to compress up front helps to choose proper compression settings and size internal buffers. Additionally, the pledged size is stored in the header of the output stream, allowing decompressors to know how much uncompressed data to expect. Attempting to compress more or less than the pledged size will result in an error.
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compressDirectByteBufferStream
public boolean compressDirectByteBufferStream(java.nio.ByteBuffer dst, java.nio.ByteBuffer src, EndDirective endOp)
Compress as much of thesrc
ByteBuffer
into thedst
ByteBuffer
as possible.- Parameters:
dst
- destination of compressed datasrc
- buffer to compressendOp
- directive for handling the end of the stream- Returns:
- true if all state has been flushed from internal buffers
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compressDirectByteBuffer
public int compressDirectByteBuffer(java.nio.ByteBuffer dstBuff, int dstOffset, int dstSize, java.nio.ByteBuffer srcBuff, int srcOffset, int srcSize)
Compresses buffer 'srcBuff' into buffer 'dstBuff' reusing this ZstdCompressCtx. Destination buffer should be sized to handle worst cases situations (input data not compressible). Worst case size evaluation is provided by function ZSTD_compressBound(). This is a low-level function that does not take into account or affect the `limit` or `position` of source or destination buffers.- Parameters:
dstBuff
- the destination buffer - must be directdstOffset
- the start offset of 'dstBuff'dstSize
- the size of 'dstBuff' (after 'dstOffset')srcBuff
- the source buffer - must be directsrcOffset
- the start offset of 'srcBuff'srcSize
- the length of 'srcBuff' (after 'srcOffset')- Returns:
- the number of bytes written into buffer 'dstBuff'.
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compressByteArray
public int compressByteArray(byte[] dstBuff, int dstOffset, int dstSize, byte[] srcBuff, int srcOffset, int srcSize)
Compresses byte array 'srcBuff' into byte array 'dstBuff' reusing this ZstdCompressCtx. Destination buffer should be sized to handle worst cases situations (input data not compressible). Worst case size evaluation is provided by function ZSTD_compressBound().- Parameters:
dstBuff
- the destination buffer (byte array)dstOffset
- the start offset of 'dstBuff'dstSize
- the size of 'dstBuff' (after 'dstOffset')srcBuff
- the source buffer (byte array)srcOffset
- the start offset of 'srcBuff'srcSize
- the length of 'srcBuff' (after 'srcOffset')- Returns:
- the number of bytes written into buffer 'dstBuff'.
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compress
public int compress(java.nio.ByteBuffer dstBuf, java.nio.ByteBuffer srcBuf)
Compresses the data in buffer 'srcBuf'- Parameters:
dstBuf
- the destination buffer - must be direct. It is assumed that the `position()` of this buffer marks the offset at which the compressed data are to be written, and that the `limit()` of this buffer is the maximum compressed data size to allow.When this method returns successfully, its `position()` will be set to its current `position()` plus the compressed size of the data.
srcBuf
- the source buffer - must be direct. It is assumed that the `position()` of this buffer marks the beginning of the uncompressed data to be compressed, and that the `limit()` of this buffer marks its end.When this method returns successfully, its `position()` will be set to the initial `limit()`.
- Returns:
- the size of the compressed data
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compress
public java.nio.ByteBuffer compress(java.nio.ByteBuffer srcBuf) throws ZstdException
Compresses the data in buffer 'srcBuf'- Parameters:
srcBuf
- the source buffer - must be direct. It is assumed that the `position()` of the buffer marks the beginning of the uncompressed data to be compressed, and that the `limit()` of this buffer marks its end.When this method returns successfully, its `position()` will be set to its initial `limit()`.
- Returns:
- A newly allocated direct ByteBuffer containing the compressed data.
- Throws:
ZstdException
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compress
public int compress(byte[] dst, byte[] src)
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compress
public byte[] compress(byte[] src)
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close
public void close()
- Specified by:
close
in interfacejava.lang.AutoCloseable
- Specified by:
close
in interfacejava.io.Closeable
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