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Yann Collet 2020-12-02 00:15:07 -08:00
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@ -1,10 +1,10 @@
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>zstd 1.4.5 Manual</title>
<title>zstd 1.4.6 Manual</title>
</head>
<body>
<h1>zstd 1.4.5 Manual</h1>
<h1>zstd 1.4.6 Manual</h1>
<hr>
<a name="Contents"></a><h2>Contents</h2>
<ol>
@ -27,16 +27,10 @@
<li><a href="#Chapter17">Advanced compression functions</a></li>
<li><a href="#Chapter18">Advanced decompression functions</a></li>
<li><a href="#Chapter19">Advanced streaming functions</a></li>
<li><a href="#Chapter20">! ZSTD_initCStream_usingDict() :</a></li>
<li><a href="#Chapter21">! ZSTD_initCStream_advanced() :</a></li>
<li><a href="#Chapter22">! ZSTD_initCStream_usingCDict() :</a></li>
<li><a href="#Chapter23">! ZSTD_initCStream_usingCDict_advanced() :</a></li>
<li><a href="#Chapter24">This function is deprecated, and is equivalent to:</a></li>
<li><a href="#Chapter25">This function is deprecated, and is equivalent to:</a></li>
<li><a href="#Chapter26">Buffer-less and synchronous inner streaming functions</a></li>
<li><a href="#Chapter27">Buffer-less streaming compression (synchronous mode)</a></li>
<li><a href="#Chapter28">Buffer-less streaming decompression (synchronous mode)</a></li>
<li><a href="#Chapter29">Block level API</a></li>
<li><a href="#Chapter20">Buffer-less and synchronous inner streaming functions</a></li>
<li><a href="#Chapter21">Buffer-less streaming compression (synchronous mode)</a></li>
<li><a href="#Chapter22">Buffer-less streaming decompression (synchronous mode)</a></li>
<li><a href="#Chapter23">Block level API</a></li>
</ol>
<hr>
<a name="Chapter1"></a><h2>Introduction</h2><pre>
@ -72,8 +66,14 @@
<a name="Chapter2"></a><h2>Version</h2><pre></pre>
<pre><b>unsigned ZSTD_versionNumber(void); </b>/**< to check runtime library version */<b>
</b></pre><BR>
<pre><b>unsigned ZSTD_versionNumber(void);
</b><p> Return runtime library version, the value is (MAJOR*100*100 + MINOR*100 + RELEASE).
</p></pre><BR>
<pre><b>const char* ZSTD_versionString(void);
</b><p> Return runtime library version, like "1.4.5". Requires v1.3.0+.
</p></pre><BR>
<a name="Chapter3"></a><h2>Simple API</h2><pre></pre>
<pre><b>size_t ZSTD_compress( void* dst, size_t dstCapacity,
@ -277,7 +277,9 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
* for large inputs, by finding large matches at long distance.
* It increases memory usage and window size.
* Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB
* except when expressly set to a different value. */
* except when expressly set to a different value.
* Note: will be enabled by default if ZSTD_c_windowLog >= 128 MB and
* compression strategy >= ZSTD_btopt (== compression level 16+) */
ZSTD_c_ldmHashLog=161, </b>/* Size of the table for long distance matching, as a power of 2.<b>
* Larger values increase memory usage and compression ratio,
* but decrease compression speed.
@ -308,16 +310,20 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
ZSTD_c_dictIDFlag=202, </b>/* When applicable, dictionary's ID is written into frame header (default:1) */<b>
</b>/* multi-threading parameters */<b>
</b>/* These parameters are only useful if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD).<b>
* They return an error otherwise. */
</b>/* These parameters are only active if multi-threading is enabled (compiled with build macro ZSTD_MULTITHREAD).<b>
* Otherwise, trying to set any other value than default (0) will be a no-op and return an error.
* In a situation where it's unknown if the linked library supports multi-threading or not,
* setting ZSTD_c_nbWorkers to any value >= 1 and consulting the return value provides a quick way to check this property.
*/
ZSTD_c_nbWorkers=400, </b>/* Select how many threads will be spawned to compress in parallel.<b>
* When nbWorkers >= 1, triggers asynchronous mode when used with ZSTD_compressStream*() :
* When nbWorkers >= 1, triggers asynchronous mode when invoking ZSTD_compressStream*() :
* ZSTD_compressStream*() consumes input and flush output if possible, but immediately gives back control to caller,
* while compression work is performed in parallel, within worker threads.
* while compression is performed in parallel, within worker thread(s).
* (note : a strong exception to this rule is when first invocation of ZSTD_compressStream2() sets ZSTD_e_end :
* in which case, ZSTD_compressStream2() delegates to ZSTD_compress2(), which is always a blocking call).
* More workers improve speed, but also increase memory usage.
* Default value is `0`, aka "single-threaded mode" : no worker is spawned, compression is performed inside Caller's thread, all invocations are blocking */
* Default value is `0`, aka "single-threaded mode" : no worker is spawned,
* compression is performed inside Caller's thread, and all invocations are blocking */
ZSTD_c_jobSize=401, </b>/* Size of a compression job. This value is enforced only when nbWorkers >= 1.<b>
* Each compression job is completed in parallel, so this value can indirectly impact the nb of active threads.
* 0 means default, which is dynamically determined based on compression parameters.
@ -346,6 +352,11 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
* ZSTD_c_literalCompressionMode
* ZSTD_c_targetCBlockSize
* ZSTD_c_srcSizeHint
* ZSTD_c_enableDedicatedDictSearch
* ZSTD_c_stableInBuffer
* ZSTD_c_stableOutBuffer
* ZSTD_c_blockDelimiters
* ZSTD_c_validateSequences
* Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
* note : never ever use experimentalParam? names directly;
* also, the enums values themselves are unstable and can still change.
@ -356,7 +367,12 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
ZSTD_c_experimentalParam4=1001,
ZSTD_c_experimentalParam5=1002,
ZSTD_c_experimentalParam6=1003,
ZSTD_c_experimentalParam7=1004
ZSTD_c_experimentalParam7=1004,
ZSTD_c_experimentalParam8=1005,
ZSTD_c_experimentalParam9=1006,
ZSTD_c_experimentalParam10=1007,
ZSTD_c_experimentalParam11=1008,
ZSTD_c_experimentalParam12=1009
} ZSTD_cParameter;
</b></pre><BR>
<pre><b>typedef struct {
@ -456,11 +472,13 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
* At the time of this writing, they include :
* ZSTD_d_format
* ZSTD_d_stableOutBuffer
* ZSTD_d_forceIgnoreChecksum
* Because they are not stable, it's necessary to define ZSTD_STATIC_LINKING_ONLY to access them.
* note : never ever use experimentalParam? names directly
*/
ZSTD_d_experimentalParam1=1000,
ZSTD_d_experimentalParam2=1001
ZSTD_d_experimentalParam2=1001,
ZSTD_d_experimentalParam3=1002
} ZSTD_dParameter;
</b></pre><BR>
@ -591,8 +609,9 @@ size_t ZSTD_freeCStream(ZSTD_CStream* zcs);
- Compression parameters cannot be changed once compression is started (save a list of exceptions in multi-threading mode)
- output->pos must be <= dstCapacity, input->pos must be <= srcSize
- output->pos and input->pos will be updated. They are guaranteed to remain below their respective limit.
- endOp must be a valid directive
- When nbWorkers==0 (default), function is blocking : it completes its job before returning to caller.
- When nbWorkers>=1, function is non-blocking : it just acquires a copy of input, and distributes jobs to internal worker threads, flush whatever is available,
- When nbWorkers>=1, function is non-blocking : it copies a portion of input, distributes jobs to internal worker threads, flush to output whatever is available,
and then immediately returns, just indicating that there is some data remaining to be flushed.
The function nonetheless guarantees forward progress : it will return only after it reads or write at least 1+ byte.
- Exception : if the first call requests a ZSTD_e_end directive and provides enough dstCapacity, the function delegates to ZSTD_compress2() which is always blocking.
@ -895,21 +914,40 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
<BR></pre>
<pre><b>typedef struct {
unsigned int matchPos; </b>/* Match pos in dst */<b>
</b>/* If seqDef.offset > 3, then this is seqDef.offset - 3<b>
* If seqDef.offset < 3, then this is the corresponding repeat offset
* But if seqDef.offset < 3 and litLength == 0, this is the
* repeat offset before the corresponding repeat offset
* And if seqDef.offset == 3 and litLength == 0, this is the
* most recent repeat offset - 1
*/
unsigned int offset;
unsigned int litLength; </b>/* Literal length */<b>
unsigned int matchLength; </b>/* Match length */<b>
</b>/* 0 when seq not rep and seqDef.offset otherwise<b>
* when litLength == 0 this will be <= 4, otherwise <= 3 like normal
*/
unsigned int rep;
unsigned int offset; </b>/* The offset of the match. (NOT the same as the offset code)<b>
* If offset == 0 and matchLength == 0, this sequence represents the last
* literals in the block of litLength size.
*/
unsigned int litLength; </b>/* Literal length of the sequence. */<b>
unsigned int matchLength; </b>/* Match length of the sequence. */<b>
</b>/* Note: Users of this API may provide a sequence with matchLength == litLength == offset == 0.<b>
* In this case, we will treat the sequence as a marker for a block boundary.
*/
unsigned int rep; </b>/* Represents which repeat offset is represented by the field 'offset'.<b>
* Ranges from [0, 3].
*
* Repeat offsets are essentially previous offsets from previous sequences sorted in
* recency order. For more detail, see doc/zstd_compression_format.md
*
* If rep == 0, then 'offset' does not contain a repeat offset.
* If rep > 0:
* If litLength != 0:
* rep == 1 --> offset == repeat_offset_1
* rep == 2 --> offset == repeat_offset_2
* rep == 3 --> offset == repeat_offset_3
* If litLength == 0:
* rep == 1 --> offset == repeat_offset_2
* rep == 2 --> offset == repeat_offset_3
* rep == 3 --> offset == repeat_offset_1 - 1
*
* Note: This field is optional. ZSTD_generateSequences() will calculate the value of
* 'rep', but repeat offsets do not necessarily need to be calculated from an external
* sequence provider's perspective. For example, ZSTD_compressSequences() does not
* use this 'rep' field at all (as of now).
*/
} ZSTD_Sequence;
</b></pre><BR>
<pre><b>typedef struct {
@ -951,6 +989,12 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
* Decoder cannot recognise automatically this format, requiring this instruction. */
} ZSTD_format_e;
</b></pre><BR>
<pre><b>typedef enum {
</b>/* Note: this enum controls ZSTD_d_forceIgnoreChecksum */<b>
ZSTD_d_validateChecksum = 0,
ZSTD_d_ignoreChecksum = 1
} ZSTD_forceIgnoreChecksum_e;
</b></pre><BR>
<pre><b>typedef enum {
</b>/* Note: this enum and the behavior it controls are effectively internal<b>
* implementation details of the compressor. They are expected to continue
@ -1045,12 +1089,69 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
or an error code (if srcSize is too small)
</p></pre><BR>
<pre><b>size_t ZSTD_getSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs,
size_t outSeqsSize, const void* src, size_t srcSize);
</b><p> Extract sequences from the sequence store
<pre><b>typedef enum {
ZSTD_sf_noBlockDelimiters = 0, </b>/* Representation of ZSTD_Sequence has no block delimiters, sequences only */<b>
ZSTD_sf_explicitBlockDelimiters = 1 </b>/* Representation of ZSTD_Sequence contains explicit block delimiters */<b>
} ZSTD_sequenceFormat_e;
</b></pre><BR>
<pre><b></b><p> Generate sequences using ZSTD_compress2, given a source buffer.
Each block will end with a dummy sequence
with offset == 0, matchLength == 0, and litLength == length of last literals.
litLength may be == 0, and if so, then the sequence of (of: 0 ml: 0 ll: 0)
simply acts as a block delimiter.
zc can be used to insert custom compression params.
This function invokes ZSTD_compress2
@return : number of sequences extracted
The output of this function can be fed into ZSTD_compressSequences() with CCtx
setting of ZSTD_c_blockDelimiters as ZSTD_sf_explicitBlockDelimiters
@return : number of sequences generated
</p></pre><BR>
<pre><b>size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, size_t seqsSize);
</b><p> Given an array of ZSTD_Sequence, remove all sequences that represent block delimiters/last literals
by merging them into into the literals of the next sequence.
As such, the final generated result has no explicit representation of block boundaries,
and the final last literals segment is not represented in the sequences.
The output of this function can be fed into ZSTD_compressSequences() with CCtx
setting of ZSTD_c_blockDelimiters as ZSTD_sf_noBlockDelimiters
@return : number of sequences left after merging
</p></pre><BR>
<pre><b>size_t ZSTD_compressSequences(ZSTD_CCtx* const cctx, void* dst, size_t dstSize,
const ZSTD_Sequence* inSeqs, size_t inSeqsSize,
const void* src, size_t srcSize);
</b><p> Compress an array of ZSTD_Sequence, generated from the original source buffer, into dst.
If a dictionary is included, then the cctx should reference the dict. (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.)
The entire source is compressed into a single frame.
The compression behavior changes based on cctx params. In particular:
If ZSTD_c_blockDelimiters == ZSTD_sf_noBlockDelimiters, the array of ZSTD_Sequence is expected to contain
no block delimiters (defined in ZSTD_Sequence). Block boundaries are roughly determined based on
the block size derived from the cctx, and sequences may be split. This is the default setting.
If ZSTD_c_blockDelimiters == ZSTD_sf_explicitBlockDelimiters, the array of ZSTD_Sequence is expected to contain
block delimiters (defined in ZSTD_Sequence). Behavior is undefined if no block delimiters are provided.
If ZSTD_c_validateSequences == 0, this function will blindly accept the sequences provided. Invalid sequences cause undefined
behavior. If ZSTD_c_validateSequences == 1, then if sequence is invalid (see doc/zstd_compression_format.md for
specifics regarding offset/matchlength requirements) then the function will bail out and return an error.
In addition to the two adjustable experimental params, there are other important cctx params.
- ZSTD_c_minMatch MUST be set as less than or equal to the smallest match generated by the match finder. It has a minimum value of ZSTD_MINMATCH_MIN.
- ZSTD_c_compressionLevel accordingly adjusts the strength of the entropy coder, as it would in typical compression.
- ZSTD_c_windowLog affects offset validation: this function will return an error at higher debug levels if a provided offset
is larger than what the spec allows for a given window log and dictionary (if present). See: doc/zstd_compression_format.md
Note: Repcodes are, as of now, always re-calculated within this function, so ZSTD_Sequence::rep is unused.
Note 2: Once we integrate ability to ingest repcodes, the explicit block delims mode must respect those repcodes exactly,
and cannot emit an RLE block that disagrees with the repcode history
@return : final compressed size or a ZSTD error.
</p></pre><BR>
@ -1141,7 +1242,11 @@ ZSTD_CStream* ZSTD_initStaticCStream(void* workspace, size_t workspaceSize);
<pre><b>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;
static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; </b>/**< this constant defers to stdlib's functions */<b>
static
#ifdef __GNUC__
__attribute__((__unused__))
#endif
ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; </b>/**< this constant defers to stdlib's functions */<b>
</b><p> These prototypes make it possible to pass your own allocation/free functions.
ZSTD_customMem is provided at creation time, using ZSTD_create*_advanced() variants listed below.
All allocation/free operations will be completed using these custom variants instead of regular <stdlib.h> ones.
@ -1270,8 +1375,10 @@ size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params);
<pre><b>size_t ZSTD_CCtxParams_setParameter(ZSTD_CCtx_params* params, ZSTD_cParameter param, int value);
</b><p> Similar to ZSTD_CCtx_setParameter.
Set one compression parameter, selected by enum ZSTD_cParameter.
Parameters must be applied to a ZSTD_CCtx using ZSTD_CCtx_setParametersUsingCCtxParams().
@result : 0, or an error code (which can be tested with ZSTD_isError()).
Parameters must be applied to a ZSTD_CCtx using
ZSTD_CCtx_setParametersUsingCCtxParams().
@result : a code representing success or failure (which can be tested with
ZSTD_isError()).
</p></pre><BR>
@ -1348,6 +1455,13 @@ size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params);
</p></pre><BR>
<pre><b>size_t ZSTD_DCtx_getParameter(ZSTD_DCtx* dctx, ZSTD_dParameter param, int* value);
</b><p> Get the requested decompression parameter value, selected by enum ZSTD_dParameter,
and store it into int* value.
@return : 0, or an error code (which can be tested with ZSTD_isError()).
</p></pre><BR>
<pre><b>size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format);
</b><p> Instruct the decoder context about what kind of data to decode next.
This instruction is mandatory to decode data without a fully-formed header,
@ -1371,24 +1485,29 @@ size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params);
redundant functions will be deprecated, and then at some point removed.
<BR></pre>
<h3>Advanced Streaming compression functions</h3><pre></pre><b><pre></b>/**! ZSTD_initCStream_srcSize() :<b>
* This function is deprecated, and equivalent to:
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
* ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any)
* ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
* ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
*
* pledgedSrcSize must be correct. If it is not known at init time, use
* ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs,
* "0" also disables frame content size field. It may be enabled in the future.
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
*/
size_t
<h3>Advanced Streaming compression functions</h3><pre></pre><b><pre></pre></b><BR>
<pre><b>size_t
ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
int compressionLevel,
unsigned long long pledgedSrcSize);
</pre></b><BR>
<a name="Chapter20"></a><h2>! ZSTD_initCStream_usingDict() :</h2><pre> This function is deprecated, and is equivalent to:
int compressionLevel,
unsigned long long pledgedSrcSize);
</b><p> This function is deprecated, and equivalent to:
ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any)
ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
pledgedSrcSize must be correct. If it is not known at init time, use
ZSTD_CONTENTSIZE_UNKNOWN. Note that, for compatibility with older programs,
"0" also disables frame content size field. It may be enabled in the future.
Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
</p></pre><BR>
<pre><b>size_t
ZSTD_initCStream_usingDict(ZSTD_CStream* zcs,
const void* dict, size_t dictSize,
int compressionLevel);
</b><p> This function is deprecated, and is equivalent to:
ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
@ -1399,9 +1518,14 @@ ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy.
Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
<BR></pre>
</p></pre><BR>
<a name="Chapter21"></a><h2>! ZSTD_initCStream_advanced() :</h2><pre> This function is deprecated, and is approximately equivalent to:
<pre><b>size_t
ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
const void* dict, size_t dictSize,
ZSTD_parameters params,
unsigned long long pledgedSrcSize);
</b><p> This function is deprecated, and is approximately equivalent to:
ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
// Pseudocode: Set each zstd parameter and leave the rest as-is.
for ((param, value) : params) {
@ -1415,18 +1539,24 @@ ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
If srcSize is not known at init time, use value ZSTD_CONTENTSIZE_UNKNOWN.
Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
<BR></pre>
</p></pre><BR>
<a name="Chapter22"></a><h2>! ZSTD_initCStream_usingCDict() :</h2><pre> This function is deprecated, and equivalent to:
<pre><b>size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict);
</b><p> This function is deprecated, and equivalent to:
ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
ZSTD_CCtx_refCDict(zcs, cdict);
note : cdict will just be referenced, and must outlive compression session
Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
<BR></pre>
</p></pre><BR>
<a name="Chapter23"></a><h2>! ZSTD_initCStream_usingCDict_advanced() :</h2><pre> This function is DEPRECATED, and is approximately equivalent to:
<pre><b>size_t
ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs,
const ZSTD_CDict* cdict,
ZSTD_frameParameters fParams,
unsigned long long pledgedSrcSize);
</b><p> This function is DEPRECATED, and is approximately equivalent to:
ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
// Pseudocode: Set each zstd frame parameter and leave the rest as-is.
for ((fParam, value) : fParams) {
@ -1440,7 +1570,7 @@ ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
value ZSTD_CONTENTSIZE_UNKNOWN.
Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
<BR></pre>
</p></pre><BR>
<pre><b>size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize);
</b><p> This function is deprecated, and is equivalent to:
@ -1483,42 +1613,44 @@ ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
</p></pre><BR>
<h3>Advanced Streaming decompression functions</h3><pre></pre><b><pre></b>/**<b>
* This function is deprecated, and is equivalent to:
*
* ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
* ZSTD_DCtx_loadDictionary(zds, dict, dictSize);
*
* note: no dictionary will be used if dict == NULL or dictSize < 8
* Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
*/
size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize);
</pre></b><BR>
<a name="Chapter24"></a><h2>This function is deprecated, and is equivalent to:</h2><pre>
<h3>Advanced Streaming decompression functions</h3><pre></pre><b><pre></pre></b><BR>
<pre><b>size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize);
</b><p>
ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
ZSTD_DCtx_loadDictionary(zds, dict, dictSize);
note: no dictionary will be used if dict == NULL or dictSize < 8
Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
</p></pre><BR>
<pre><b>size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict);
</b><p>
ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
ZSTD_DCtx_refDDict(zds, ddict);
note : ddict is referenced, it must outlive decompression session
Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
<BR></pre>
</p></pre><BR>
<a name="Chapter25"></a><h2>This function is deprecated, and is equivalent to:</h2><pre>
<pre><b>size_t ZSTD_resetDStream(ZSTD_DStream* zds);
</b><p>
ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
re-use decompression parameters from previous init; saves dictionary loading
Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
<BR></pre>
</p></pre><BR>
<a name="Chapter26"></a><h2>Buffer-less and synchronous inner streaming functions</h2><pre>
<a name="Chapter20"></a><h2>Buffer-less and synchronous inner streaming functions</h2><pre>
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 several restrictions, documented below.
Prefer normal streaming API for an easier experience.
<BR></pre>
<a name="Chapter27"></a><h2>Buffer-less streaming compression (synchronous mode)</h2><pre>
<a name="Chapter21"></a><h2>Buffer-less streaming compression (synchronous mode)</h2><pre>
A ZSTD_CCtx object is required to track streaming operations.
Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource.
ZSTD_CCtx object can be re-used multiple times within successive compression operations.
@ -1554,7 +1686,7 @@ size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
size_t ZSTD_compressBegin_usingCDict_advanced(ZSTD_CCtx* const cctx, const ZSTD_CDict* const cdict, ZSTD_frameParameters const fParams, unsigned long long const pledgedSrcSize); </b>/* compression parameters are already set within cdict. pledgedSrcSize must be correct. If srcSize is not known, use macro ZSTD_CONTENTSIZE_UNKNOWN */<b>
size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); </b>/**< note: if pledgedSrcSize is not known, use ZSTD_CONTENTSIZE_UNKNOWN */<b>
</pre></b><BR>
<a name="Chapter28"></a><h2>Buffer-less streaming decompression (synchronous mode)</h2><pre>
<a name="Chapter22"></a><h2>Buffer-less streaming decompression (synchronous mode)</h2><pre>
A ZSTD_DCtx object is required to track streaming operations.
Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
A ZSTD_DCtx object can be re-used multiple times.
@ -1650,7 +1782,7 @@ size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long
<pre><b>typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
</b></pre><BR>
<a name="Chapter29"></a><h2>Block level API</h2><pre></pre>
<a name="Chapter23"></a><h2>Block level API</h2><pre></pre>
<pre><b></b><p> Frame metadata cost is typically ~12 bytes, which can be non-negligible for very small blocks (< 100 bytes).
But users will have to take in charge needed metadata to regenerate data, such as compressed and content sizes.

66
lib/zstd.h
View File

@ -339,7 +339,7 @@ typedef enum {
* for large inputs, by finding large matches at long distance.
* It increases memory usage and window size.
* Note: enabling this parameter increases default ZSTD_c_windowLog to 128 MB
* except when expressly set to a different value.
* except when expressly set to a different value.
* Note: will be enabled by default if ZSTD_c_windowLog >= 128 MB and
* compression strategy >= ZSTD_btopt (== compression level 16+) */
ZSTD_c_ldmHashLog=161, /* Size of the table for long distance matching, as a power of 2.
@ -1135,13 +1135,13 @@ typedef struct {
/* Note: Users of this API may provide a sequence with matchLength == litLength == offset == 0.
* In this case, we will treat the sequence as a marker for a block boundary.
*/
unsigned int rep; /* Represents which repeat offset is represented by the field 'offset'.
* Ranges from [0, 3].
*
*
* Repeat offsets are essentially previous offsets from previous sequences sorted in
* recency order. For more detail, see doc/zstd_compression_format.md
*
*
* If rep == 0, then 'offset' does not contain a repeat offset.
* If rep > 0:
* If litLength != 0:
@ -1152,7 +1152,7 @@ typedef struct {
* rep == 1 --> offset == repeat_offset_2
* rep == 2 --> offset == repeat_offset_3
* rep == 3 --> offset == repeat_offset_1 - 1
*
*
* Note: This field is optional. ZSTD_generateSequences() will calculate the value of
* 'rep', but repeat offsets do not necessarily need to be calculated from an external
* sequence provider's perspective. For example, ZSTD_compressSequences() does not
@ -1309,15 +1309,15 @@ typedef enum {
/*! ZSTD_generateSequences() :
* Generate sequences using ZSTD_compress2, given a source buffer.
*
*
* Each block will end with a dummy sequence
* with offset == 0, matchLength == 0, and litLength == length of last literals.
* litLength may be == 0, and if so, then the sequence of (of: 0 ml: 0 ll: 0)
* simply acts as a block delimiter.
*
*
* zc can be used to insert custom compression params.
* This function invokes ZSTD_compress2
*
*
* The output of this function can be fed into ZSTD_compressSequences() with CCtx
* setting of ZSTD_c_blockDelimiters as ZSTD_sf_explicitBlockDelimiters
* @return : number of sequences generated
@ -1329,10 +1329,10 @@ ZSTDLIB_API size_t ZSTD_generateSequences(ZSTD_CCtx* zc, ZSTD_Sequence* outSeqs,
/*! ZSTD_mergeBlockDelimiters() :
* Given an array of ZSTD_Sequence, remove all sequences that represent block delimiters/last literals
* by merging them into into the literals of the next sequence.
*
*
* As such, the final generated result has no explicit representation of block boundaries,
* and the final last literals segment is not represented in the sequences.
*
*
* The output of this function can be fed into ZSTD_compressSequences() with CCtx
* setting of ZSTD_c_blockDelimiters as ZSTD_sf_noBlockDelimiters
* @return : number of sequences left after merging
@ -1342,26 +1342,26 @@ ZSTDLIB_API size_t ZSTD_mergeBlockDelimiters(ZSTD_Sequence* sequences, size_t se
/*! ZSTD_compressSequences() :
* Compress an array of ZSTD_Sequence, generated from the original source buffer, into dst.
* If a dictionary is included, then the cctx should reference the dict. (see: ZSTD_CCtx_refCDict(), ZSTD_CCtx_loadDictionary(), etc.)
* The entire source is compressed into a single frame.
*
* The entire source is compressed into a single frame.
*
* The compression behavior changes based on cctx params. In particular:
* If ZSTD_c_blockDelimiters == ZSTD_sf_noBlockDelimiters, the array of ZSTD_Sequence is expected to contain
* no block delimiters (defined in ZSTD_Sequence). Block boundaries are roughly determined based on
* the block size derived from the cctx, and sequences may be split. This is the default setting.
*
*
* If ZSTD_c_blockDelimiters == ZSTD_sf_explicitBlockDelimiters, the array of ZSTD_Sequence is expected to contain
* block delimiters (defined in ZSTD_Sequence). Behavior is undefined if no block delimiters are provided.
*
*
* If ZSTD_c_validateSequences == 0, this function will blindly accept the sequences provided. Invalid sequences cause undefined
* behavior. If ZSTD_c_validateSequences == 1, then if sequence is invalid (see doc/zstd_compression_format.md for
* specifics regarding offset/matchlength requirements) then the function will bail out and return an error.
*
*
* In addition to the two adjustable experimental params, there are other important cctx params.
* - ZSTD_c_minMatch MUST be set as less than or equal to the smallest match generated by the match finder. It has a minimum value of ZSTD_MINMATCH_MIN.
* - ZSTD_c_compressionLevel accordingly adjusts the strength of the entropy coder, as it would in typical compression.
* - ZSTD_c_windowLog affects offset validation: this function will return an error at higher debug levels if a provided offset
* is larger than what the spec allows for a given window log and dictionary (if present). See: doc/zstd_compression_format.md
*
*
* Note: Repcodes are, as of now, always re-calculated within this function, so ZSTD_Sequence::rep is unused.
* Note 2: Once we integrate ability to ingest repcodes, the explicit block delims mode must respect those repcodes exactly,
* and cannot emit an RLE block that disagrees with the repcode history
@ -1513,7 +1513,7 @@ ZSTDLIB_API ZSTD_threadPool* ZSTD_createThreadPool(size_t numThreads);
ZSTDLIB_API void ZSTD_freeThreadPool (ZSTD_threadPool* pool);
ZSTDLIB_API size_t ZSTD_CCtx_refThreadPool(ZSTD_CCtx* cctx, ZSTD_threadPool* pool);
/**
/*
* This API is temporary and is expected to change or disappear in the future!
*/
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_advanced2(
@ -1771,9 +1771,9 @@ ZSTDLIB_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* pre
/* ZSTD_c_blockDelimiters
* Default is 0 == ZSTD_sf_noBlockDelimiters.
*
*
* For use with sequence compression API: ZSTD_compressSequences().
*
*
* Designates whether or not the given array of ZSTD_Sequence contains block delimiters
* and last literals, which are defined as sequences with offset == 0 and matchLength == 0.
* See the definition of ZSTD_Sequence for more specifics.
@ -1782,18 +1782,18 @@ ZSTDLIB_API size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* pre
/* ZSTD_c_validateSequences
* Default is 0 == disabled. Set to 1 to enable sequence validation.
*
*
* For use with sequence compression API: ZSTD_compressSequences().
* Designates whether or not we validate sequences provided to ZSTD_compressSequences()
* during function execution.
*
*
* Without validation, providing a sequence that does not conform to the zstd spec will cause
* undefined behavior, and may produce a corrupted block.
*
*
* With validation enabled, a if sequence is invalid (see doc/zstd_compression_format.md for
* specifics regarding offset/matchlength requirements) then the function will bail out and
* return an error.
*
*
*/
#define ZSTD_c_validateSequences ZSTD_c_experimentalParam12
@ -2010,7 +2010,8 @@ ZSTDLIB_API size_t ZSTD_decompressStream_simpleArgs (
********************************************************************/
/*===== Advanced Streaming compression functions =====*/
/**! ZSTD_initCStream_srcSize() :
/*! ZSTD_initCStream_srcSize() :
* This function is deprecated, and equivalent to:
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
* ZSTD_CCtx_refCDict(zcs, NULL); // clear the dictionary (if any)
@ -2027,7 +2028,7 @@ ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
int compressionLevel,
unsigned long long pledgedSrcSize);
/**! ZSTD_initCStream_usingDict() :
/*! ZSTD_initCStream_usingDict() :
* This function is deprecated, and is equivalent to:
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
* ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
@ -2044,7 +2045,7 @@ ZSTD_initCStream_usingDict(ZSTD_CStream* zcs,
const void* dict, size_t dictSize,
int compressionLevel);
/**! ZSTD_initCStream_advanced() :
/*! ZSTD_initCStream_advanced() :
* This function is deprecated, and is approximately equivalent to:
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
* // Pseudocode: Set each zstd parameter and leave the rest as-is.
@ -2065,7 +2066,7 @@ ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
ZSTD_parameters params,
unsigned long long pledgedSrcSize);
/**! ZSTD_initCStream_usingCDict() :
/*! ZSTD_initCStream_usingCDict() :
* This function is deprecated, and equivalent to:
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
* ZSTD_CCtx_refCDict(zcs, cdict);
@ -2075,7 +2076,7 @@ ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
*/
ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict);
/**! ZSTD_initCStream_usingCDict_advanced() :
/*! ZSTD_initCStream_usingCDict_advanced() :
* This function is DEPRECATED, and is approximately equivalent to:
* ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
* // Pseudocode: Set each zstd frame parameter and leave the rest as-is.
@ -2148,7 +2149,8 @@ ZSTDLIB_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx);
/*===== Advanced Streaming decompression functions =====*/
/**
/*!
* This function is deprecated, and is equivalent to:
*
* ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
@ -2159,7 +2161,7 @@ ZSTDLIB_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx);
*/
ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize);
/**
/*!
* This function is deprecated, and is equivalent to:
*
* ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
@ -2170,7 +2172,7 @@ ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dic
*/
ZSTDLIB_API size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict);
/**
/*!
* This function is deprecated, and is equivalent to:
*
* ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
@ -2232,7 +2234,7 @@ ZSTDLIB_API size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t dstC
ZSTDLIB_API size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
/*-
/**
Buffer-less streaming decompression (synchronous mode)
A ZSTD_DCtx object is required to track streaming operations.

8
tests/Makefile
View File

@ -149,12 +149,12 @@ fullbench-dll: $(PRGDIR)/datagen.c $(PRGDIR)/util.c $(PRGDIR)/benchfn.c $(PRGDIR
# $(CC) $(FLAGS) $(filter %.c,$^) -o $@$(EXT) -DZSTD_DLL_IMPORT=1 $(ZSTDDIR)/dll/libzstd.dll
$(CC) $(FLAGS) $(filter %.c,$^) -o $@$(EXT)
fuzzer : LDFLAGS += $(MULTITHREAD_LD)
fuzzer : $(ZSTDMT_OBJECTS)
fuzzer : LDFLAGS += $(MULTITHREAD_LD)
fuzzer : $(ZSTDMT_OBJECTS)
fuzzer fuzzer32 : $(ZDICT_FILES) $(PRGDIR)/util.c $(PRGDIR)/timefn.c $(PRGDIR)/datagen.c fuzzer.c
fuzzer32: CFLAGS += -m32
fuzzer32: $(ZSTD_FILES)
fuzzer32 : CFLAGS += -m32
fuzzer32 : $(ZSTD_FILES)
$(LINK.c) $^ -o $@$(EXT)
# note : broken : requires symbols unavailable from dynamic library