int ZSTD_maxCLevel(void);/*!< maximum compression level available */ +
int ZSTD_maxCLevel(void); /*!< maximum compression level available */ size_t ZSTD_compressBound(size_t srcSize); /*!< maximum compressed size in worst case scenario */ unsigned ZSTD_isError(size_t code); /*!< tells if a `size_t` function result is an error code */ const char* ZSTD_getErrorName(size_t code); /*!< provides readable string from an error code */ -
When compressing many times, - it is recommended to allocate a context just once, and re-use it for each successive compression operation. - This will make workload friendlier for system's memory. - Use one context per thread for parallel execution in multi-threaded environments. -
typedef struct ZSTD_CCtx_s ZSTD_CCtx; -ZSTD_CCtx* ZSTD_createCCtx(void); -size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx); -
size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel);Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()).
typedef struct ZSTD_DCtx_s ZSTD_DCtx; +Decompression context
typedef struct ZSTD_DCtx_s ZSTD_DCtx; ZSTD_DCtx* ZSTD_createDCtx(void); size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx); -
size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()).
typedef struct ZSTD_CStream_s ZSTD_CStream; -ZSTD_CStream* ZSTD_createCStream(void); -size_t ZSTD_freeCStream(ZSTD_CStream* zcs); -size_t ZSTD_initCStream(ZSTD_CStream* zcs, int compressionLevel); -size_t ZSTD_compressStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output, ZSTD_inBuffer* input); -size_t ZSTD_flushStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); -size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output); -
size_t ZSTD_CStreamInSize(void); /**< recommended size for input buffer */
size_t ZSTD_CStreamOutSize(void); /**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block in all circumstances. */ @@ -261,12 +245,6 @@ size_t ZSTD_endStream(ZSTD_CStream* zcs, ZSTD_outBuffer* output);-
typedef struct ZSTD_DStream_s ZSTD_DStream; -ZSTD_DStream* ZSTD_createDStream(void); -size_t ZSTD_freeDStream(ZSTD_DStream* zds); -size_t ZSTD_initDStream(ZSTD_DStream* zds); -size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input); -
size_t ZSTD_DStreamInSize(void); /*!< recommended size for input buffer */
size_t ZSTD_DStreamOutSize(void); /*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */
@@ -303,10 +281,10 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
ZSTD_frameParameters fParams;
} ZSTD_parameters;
typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size); +Custom memory allocation functions
typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size); typedef void (*ZSTD_freeFunction) (void* opaque, void* address); typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; void* opaque; } ZSTD_customMem; -
size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams);
@@ -331,14 +309,14 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
Gives the amount of memory used by a given ZSTD_sizeof_CDict
ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long srcSize, size_t dictSize); -same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of a `ZSTD_compressionParameters`. - All fields of `ZSTD_frameParameters` are set to default (0) +
ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); +@return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize. + `estimatedSrcSize` value is optional, select 0 if not known
-ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long srcSize, size_t dictSize); -@return ZSTD_compressionParameters structure for a selected compression level and srcSize. - `srcSize` value is optional, select 0 if not known +
ZSTD_parameters ZSTD_getParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize); +same as ZSTD_getCParams(), but @return a full `ZSTD_parameters` object instead of sub-component `ZSTD_compressionParameters`. + All fields of `ZSTD_frameParameters` are set to default (0)
size_t ZSTD_checkCParams(ZSTD_compressionParameters params); @@ -409,22 +387,23 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; vAdvanced streaming functions
-Advanced Streaming compression functions
ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); +Advanced Streaming compression functions
ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem); +size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize); /**< pledgedSrcSize must be correct */ size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); /**< pledgedSrcSize is optional and can be zero == unknown */ size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); /**< note : cdict will just be referenced, and must outlive compression session */ size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); /**< re-use compression parameters from previous init; skip dictionary loading stage; zcs must be init at least once before */ size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs); -
-Advanced Streaming decompression functions
typedef enum { ZSTDdsp_maxWindowSize } ZSTD_DStreamParameter_e; +
+Advanced Streaming decompression functions
typedef enum { ZSTDdsp_maxWindowSize } ZSTD_DStreamParameter_e; ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem); size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue); size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); /**< note : ddict will just be referenced, and must outlive decompression session */ size_t ZSTD_resetDStream(ZSTD_DStream* zds); /**< re-use decompression parameters from previous init; saves dictionary loading */ size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); -
+
Buffer-less and synchronous inner streaming functions
This is an advanced API, giving full control over buffer management, for users which need direct control over memory. But it's also a complex one, with many restrictions (documented below). @@ -461,13 +440,13 @@ size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds); You can then reuse `ZSTD_CCtx` (ZSTD_compressBegin()) to compress some new frame.-Buffer-less streaming compression functions
size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel); +Buffer-less streaming compression functions
size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel); size_t ZSTD_compressBegin_usingDict(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, int compressionLevel); size_t ZSTD_compressBegin_advanced(ZSTD_CCtx* cctx, const void* dict, size_t dictSize, ZSTD_parameters params, unsigned long long pledgedSrcSize); size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); -
+
A ZSTD_DCtx object is required to track streaming operations.
Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
@@ -511,7 +490,7 @@ size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const vo
Note : it's possible to know if next input to present is a header or a block, using ZSTD_nextInputType().
This information is not required to properly decode a frame.
- == Special case : skippable frames ==
+ == Special case : skippable frames ==
Skippable frames allow integration of user-defined data into a flow of concatenated frames.
Skippable frames will be ignored (skipped) by a decompressor. The format of skippable frames is as follows :
@@ -530,7 +509,7 @@ size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const vo
unsigned checksumFlag;
} ZSTD_frameParams;
size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t srcSize);/**< doesn't consume input, see details below */ +
size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t srcSize); /**< doesn't consume input, see details below */
size_t ZSTD_decompressBegin(ZSTD_DCtx* dctx);
size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
void ZSTD_copyDCtx(ZSTD_DCtx* dctx, const ZSTD_DCtx* preparedDCtx);
@@ -538,7 +517,7 @@ size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx);
size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
-
Block functions produce and decode raw zstd blocks, without frame metadata.
Frame metadata cost is typically ~18 bytes, which can be non-negligible for very small blocks (< 100 bytes).
@@ -563,10 +542,10 @@ ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
Use ZSTD_insertBlock() in such a case.
-size_t ZSTD_getBlockSizeMax(ZSTD_CCtx* cctx); +Raw zstd block functions
size_t ZSTD_getBlockSizeMax(ZSTD_CCtx* cctx); size_t ZSTD_compressBlock (ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize); size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize); /**< insert block into `dctx` history. Useful for uncompressed blocks */ -