Package com.github.luben.zstd
Class ZstdCompressCtx
java.lang.Object
com.github.luben.zstd.AutoCloseBase
com.github.luben.zstd.ZstdCompressCtx
- All Implemented Interfaces:
Closeable
,AutoCloseable
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Field Summary
Fields -
Constructor Summary
ConstructorsConstructorDescriptionCreate a context for faster compress operations One such context is required for each thread - put this in a ThreadLocal. -
Method Summary
Modifier and TypeMethodDescriptionbyte[]
compress
(byte[] src) int
compress
(byte[] dst, byte[] src) compress
(ByteBuffer srcBuf) Compresses the data in buffer 'srcBuf'int
compress
(ByteBuffer dstBuf, 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.private long
compressByteArray0
(byte[] dst, int dstOffset, int dstSize, byte[] src, int srcOffset, int srcSize) int
compressDirectByteBuffer
(ByteBuffer dstBuff, int dstOffset, int dstSize, ByteBuffer srcBuff, int srcOffset, int srcSize) Compresses buffer 'srcBuff' into buffer 'dstBuff' reusing this ZstdCompressCtx.private long
compressDirectByteBuffer0
(ByteBuffer dst, int dstOffset, int dstSize, ByteBuffer src, int srcOffset, int srcSize) boolean
compressDirectByteBufferStream
(ByteBuffer dst, ByteBuffer src, EndDirective endOp) private long
compressDirectByteBufferStream0
(ByteBuffer dst, int dstOffset, int dstSize, ByteBuffer src, int srcSize, int srcOffset, int endOp) 4 pieces of information are packed into the return value of this method, which must be treated as an unsigned long.(package private) void
doClose()
private void
private void
free()
private void
init()
private long
loadCDict0
(byte[] dict) private long
loadDict
(byte[] dict) Load compression dictionary to be used for subsequently compressed frames.loadDict
(ZstdDictCompress dict) Load compression dictionary to be used for subsequently compressed frames.void
reset()
Clear all state and parameters from the compression context.private long
reset0()
setChecksum
(boolean checksumFlag) Enable or disable compression checksumsprivate void
setChecksum0
(boolean checksumFlag) setContentSize
(boolean contentSizeFlag) Enable or disable content sizeprivate void
setContentSize0
(boolean contentSizeFlag) setDictID
(boolean dictIDFlag) Enable or disable dictIDprivate void
setDictID0
(boolean dictIDFlag) setLevel
(int level) Set compression levelprivate void
setLevel0
(int level) setLong
(int windowLog) Enable or disable LongDistanceMatching and set the window sizevoid
setPledgedSrcSize
(long srcSize) Promise to compress a certain number of source bytes.private long
setPledgedSrcSize0
(long srcSize) setWorkers
(int workers) Methods inherited from class com.github.luben.zstd.AutoCloseBase
acquireSharedLock, close, releaseSharedLock, storeFence
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Field Details
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nativePtr
private long nativePtr -
compression_dict
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Constructor Details
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ZstdCompressCtx
public 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 Details
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init
private void init() -
free
private void free() -
doClose
void doClose()- Specified by:
doClose
in classAutoCloseBase
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setLevel
Set compression level- Parameters:
level
- compression level, default:Zstd.defaultCompressionLevel()
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setLevel0
private void setLevel0(int level) -
setChecksum
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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setChecksum0
private void setChecksum0(boolean checksumFlag) -
setWorkers
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setContentSize
Enable or disable content size- Parameters:
contentSizeFlag
- Content size will be written into frame header _whenever known_, default: true
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setContentSize0
private void setContentSize0(boolean contentSizeFlag) -
setDictID
Enable or disable dictID- Parameters:
dictIDFlag
- When applicable, dictionary's ID is written into frame header, default: true
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setDictID0
private void setDictID0(boolean dictIDFlag) -
setLong
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 then 27 may not be decompressable in all context as they require more memory. 0 disables LDM.
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loadDict
Load compression dictionary to be used for subsequently compressed frames.- Parameters:
dict
- the dictionary or `null` to remove loaded dictionary
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loadCDictFast0
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loadDict
Load compression dictionary to be used for subsequently compressed frames.- Parameters:
dict
- the dictionary or `null` to remove loaded dictionary
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loadCDict0
private long loadCDict0(byte[] dict) -
ensureOpen
private void ensureOpen() -
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. -
reset0
private long reset0() -
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 than the pledged size will result in an error. -
setPledgedSrcSize0
private long setPledgedSrcSize0(long srcSize) -
compressDirectByteBufferStream
- 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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compressDirectByteBufferStream0
private long compressDirectByteBufferStream0(ByteBuffer dst, int dstOffset, int dstSize, ByteBuffer src, int srcSize, int srcOffset, int endOp) 4 pieces of information are packed into the return value of this method, which must be treated as an unsigned long. The highest bit is set if all data has been flushed from internal buffers. The next 31 bits are the new position of the destination buffer. The next bit is set if an error occurred. If an error occurred, the lowest 31 bits encode a zstd error code. Otherwise, the lowest 31 bits are the new position of the source buffer. -
compressDirectByteBuffer
public int compressDirectByteBuffer(ByteBuffer dstBuff, int dstOffset, int dstSize, 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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compressDirectByteBuffer0
private long compressDirectByteBuffer0(ByteBuffer dst, int dstOffset, int dstSize, ByteBuffer src, int srcOffset, int srcSize) -
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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compressByteArray0
private long compressByteArray0(byte[] dst, int dstOffset, int dstSize, byte[] src, int srcOffset, int srcSize) -
compress
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
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) -
compress
public byte[] compress(byte[] src)
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