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* upstream/dev: (305 commits)
  added test for ZSTD_estimateCStreamSize()
  changed variable name, for clarity
  fixed ZSTD_estimateCStreamSize()
  shortened ZSTD_createCStream_Advanced()
  fixed symbols test
  added ZSTD_estimateDStreamSize()
  changed name frameParams into frameHeader
  regroup memory usage function declarations
  separated ZSTD_estimateCStreamSize() from ZSTD_estimateCCtxSize()
  bumped version number
  added ZSTD_estimateCDictSize() and ZSTD_estimateDDictSize()
  Updated ZSTD_freeCCtx()
  updated ZSTD_estimateCCtxSize()
  Updated ZSTD_sizeof_CCtx()
  merged CCtx and CStream as a single same object
  cli : -d and -t do not stop after a failed decompression
  added dev branch CircleCI badge
  added dev branch Appveyor badge
  keep dev branch status only
  creates a binary archive without the `programs` directory
  ...
This commit is contained in:
Nick Terrell
2017-05-10 16:49:58 -07:00
parent f35ef5c8e9 ba41b26405
commit 5f2c7213c7
149 changed files with 22690 additions and 2821 deletions
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@@ -1,10 +1,10 @@
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>zstd 1.1.4 Manual</title>
<title>zstd 1.3.0 Manual</title>
</head>
<body>
<h1>zstd 1.1.4 Manual</h1>
<h1>zstd 1.3.0 Manual</h1>
<hr>
<a name="Contents"></a><h2>Contents</h2>
<ol>
@@ -19,8 +19,8 @@
<li><a href="#Chapter9">Streaming decompression - HowTo</a></li>
<li><a href="#Chapter10">START OF ADVANCED AND EXPERIMENTAL FUNCTIONS</a></li>
<li><a href="#Chapter11">Advanced types</a></li>
<li><a href="#Chapter12">Compressed size functions</a></li>
<li><a href="#Chapter13">Decompressed size functions</a></li>
<li><a href="#Chapter12">Frame size functions</a></li>
<li><a href="#Chapter13">Context memory usage</a></li>
<li><a href="#Chapter14">Advanced compression functions</a></li>
<li><a href="#Chapter15">Advanced decompression functions</a></li>
<li><a href="#Chapter16">Advanced streaming functions</a></li>
@@ -55,48 +55,48 @@
<a name="Chapter3"></a><h2>Simple API</h2><pre></pre>
<pre><b>size_t ZSTD_compress( void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
int compressionLevel);
</b><p> Compresses `src` content as a single zstd compressed frame into already allocated `dst`.
Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
@return : compressed size written into `dst` (<= `dstCapacity),
or an error code if it fails (which can be tested using ZSTD_isError()).
const void* src, size_t srcSize,
int compressionLevel);
</b><p> Compresses `src` content as a single zstd compressed frame into already allocated `dst`.
Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
@return : compressed size written into `dst` (<= `dstCapacity),
or an error code if it fails (which can be tested using ZSTD_isError()).
</p></pre><BR>
<pre><b>size_t ZSTD_decompress( void* dst, size_t dstCapacity,
const void* src, size_t compressedSize);
</b><p> `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames.
`dstCapacity` is an upper bound of originalSize.
If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.
@return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
or an errorCode if it fails (which can be tested using ZSTD_isError()).
const void* src, size_t compressedSize);
</b><p> `compressedSize` : must be the _exact_ size of some number of compressed and/or skippable frames.
`dstCapacity` is an upper bound of originalSize.
If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.
@return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
or an errorCode if it fails (which can be tested using ZSTD_isError()).
</p></pre><BR>
<pre><b>unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);
</b><p> NOTE: This function is planned to be obsolete, in favour of ZSTD_getFrameContentSize.
ZSTD_getFrameContentSize functions the same way, returning the decompressed size of a single
frame, but distinguishes empty frames from frames with an unknown size, or errors.
</b><p> NOTE: This function is planned to be obsolete, in favour of ZSTD_getFrameContentSize.
ZSTD_getFrameContentSize functions the same way, returning the decompressed size of a single
frame, but distinguishes empty frames from frames with an unknown size, or errors.
Additionally, ZSTD_findDecompressedSize can be used instead. It can handle multiple
concatenated frames in one buffer, and so is more general.
As a result however, it requires more computation and entire frames to be passed to it,
as opposed to ZSTD_getFrameContentSize which requires only a single frame's header.
Additionally, ZSTD_findDecompressedSize can be used instead. It can handle multiple
concatenated frames in one buffer, and so is more general.
As a result however, it requires more computation and entire frames to be passed to it,
as opposed to ZSTD_getFrameContentSize which requires only a single frame's header.
'src' is the start of a zstd compressed frame.
@return : content size to be decompressed, as a 64-bits value _if known_, 0 otherwise.
note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
When `return==0`, data to decompress could be any size.
In which case, it's necessary to use streaming mode to decompress data.
Optionally, application can still use ZSTD_decompress() while relying on implied limits.
(For example, data may be necessarily cut into blocks <= 16 KB).
note 2 : decompressed size is always present when compression is done with ZSTD_compress()
note 3 : decompressed size can be very large (64-bits value),
potentially larger than what local system can handle as a single memory segment.
In which case, it's necessary to use streaming mode to decompress data.
note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.
Always ensure result fits within application's authorized limits.
Each application can set its own limits.
note 5 : when `return==0`, if precise failure cause is needed, use ZSTD_getFrameParams() to know more.
'src' is the start of a zstd compressed frame.
@return : content size to be decompressed, as a 64-bits value _if known_, 0 otherwise.
note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
When `return==0`, data to decompress could be any size.
In which case, it's necessary to use streaming mode to decompress data.
Optionally, application can still use ZSTD_decompress() while relying on implied limits.
(For example, data may be necessarily cut into blocks <= 16 KB).
note 2 : decompressed size is always present when compression is done with ZSTD_compress()
note 3 : decompressed size can be very large (64-bits value),
potentially larger than what local system can handle as a single memory segment.
In which case, it's necessary to use streaming mode to decompress data.
note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.
Always ensure result fits within application's authorized limits.
Each application can set its own limits.
note 5 : when `return==0`, if precise failure cause is needed, use ZSTD_getFrameParams() to know more.
</p></pre><BR>
<h3>Helper functions</h3><pre></pre><b><pre>int ZSTD_maxCLevel(void); </b>/*!< maximum compression level available */<b>
@@ -106,42 +106,46 @@ const char* ZSTD_getErrorName(size_t code); </b>/*!< provides readable strin
</pre></b><BR>
<a name="Chapter4"></a><h2>Explicit memory management</h2><pre></pre>
<h3>Compression context</h3><pre> 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.
<h3>Compression context</h3><pre> 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.
</pre><b><pre>typedef struct ZSTD_CCtx_s ZSTD_CCtx;
ZSTD_CCtx* ZSTD_createCCtx(void);
size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx);
</pre></b><BR>
<pre><b>size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel);
</b><p> Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()).
</b><p> Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()).
</p></pre><BR>
<h3>Decompression context</h3><pre></pre><b><pre>typedef struct ZSTD_DCtx_s ZSTD_DCtx;
<h3>Decompression context</h3><pre> When decompressing 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.
</pre><b><pre>typedef struct ZSTD_DCtx_s ZSTD_DCtx;
ZSTD_DCtx* ZSTD_createDCtx(void);
size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
</pre></b><BR>
<pre><b>size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
</b><p> Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()).
</b><p> Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()).
</p></pre><BR>
<a name="Chapter5"></a><h2>Simple dictionary API</h2><pre></pre>
<pre><b>size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize,
int compressionLevel);
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize,
int compressionLevel);
</b><p> Compression using a predefined Dictionary (see dictBuilder/zdict.h).
Note : This function loads the dictionary, resulting in significant startup delay.
Note : When `dict == NULL || dictSize < 8` no dictionary is used.
</p></pre><BR>
<pre><b>size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize);
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize);
</b><p> Decompression using a predefined Dictionary (see dictBuilder/zdict.h).
Dictionary must be identical to the one used during compression.
Note : This function loads the dictionary, resulting in significant startup delay.
@@ -162,12 +166,13 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
</p></pre><BR>
<pre><b>size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const ZSTD_CDict* cdict);
</b><p> Compression using a digested Dictionary.
Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
Note that compression level is decided during dictionary creation.
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const ZSTD_CDict* cdict);
</b><p> Compression using a digested Dictionary.
Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
Note that compression level is decided during dictionary creation.
Frame parameters are hardcoded (dictID=yes, contentSize=yes, checksum=no)
</p></pre><BR>
<pre><b>ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize);
@@ -180,9 +185,9 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
</p></pre><BR>
<pre><b>size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const ZSTD_DDict* ddict);
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const ZSTD_DDict* ddict);
</b><p> Decompression using a digested Dictionary.
Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times.
</p></pre><BR>
@@ -239,6 +244,16 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
<BR></pre>
<pre><b>typedef ZSTD_CCtx ZSTD_CStream; </b>/**< CCtx and CStream are effectively same object */<b>
</b></pre><BR>
<h3>ZSTD_CStream management functions</h3><pre></pre><b><pre>ZSTD_CStream* ZSTD_createCStream(void);
size_t ZSTD_freeCStream(ZSTD_CStream* zcs);
</pre></b><BR>
<h3>Streaming compression functions</h3><pre></pre><b><pre>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);
</pre></b><BR>
<pre><b>size_t ZSTD_CStreamInSize(void); </b>/**< recommended size for input buffer */<b>
</b></pre><BR>
<pre><b>size_t ZSTD_CStreamOutSize(void); </b>/**< recommended size for output buffer. Guarantee to successfully flush at least one complete compressed block in all circumstances. */<b>
@@ -264,6 +279,12 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
<BR></pre>
<h3>ZSTD_DStream management functions</h3><pre></pre><b><pre>ZSTD_DStream* ZSTD_createDStream(void);
size_t ZSTD_freeDStream(ZSTD_DStream* zds);
</pre></b><BR>
<h3>Streaming decompression functions</h3><pre></pre><b><pre>size_t ZSTD_initDStream(ZSTD_DStream* zds);
size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input);
</pre></b><BR>
<pre><b>size_t ZSTD_DStreamInSize(void); </b>/*!< recommended size for input buffer */<b>
</b></pre><BR>
<pre><b>size_t ZSTD_DStreamOutSize(void); </b>/*!< recommended size for output buffer. Guarantee to successfully flush at least one complete block in all circumstances. */<b>
@@ -300,70 +321,101 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
ZSTD_frameParameters fParams;
} ZSTD_parameters;
</b></pre><BR>
<pre><b>typedef struct {
unsigned long long frameContentSize;
unsigned windowSize;
unsigned dictID;
unsigned checksumFlag;
} ZSTD_frameHeader;
</b></pre><BR>
<h3>Custom memory allocation functions</h3><pre></pre><b><pre>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;
</pre></b><BR>
<a name="Chapter12"></a><h2>Compressed size functions</h2><pre></pre>
<a name="Chapter12"></a><h2>Frame size functions</h2><pre></pre>
<pre><b>size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize);
</b><p> `src` should point to the start of a ZSTD encoded frame or skippable frame
`srcSize` must be at least as large as the frame
@return : the compressed size of the frame pointed to by `src`, suitable to pass to
`ZSTD_decompress` or similar, or an error code if given invalid input.
@return : the compressed size of the frame pointed to by `src`,
suitable to pass to `ZSTD_decompress` or similar,
or an error code if given invalid input.
</p></pre><BR>
<a name="Chapter13"></a><h2>Decompressed size functions</h2><pre></pre>
<pre><b>unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
</b><p> `src` should point to the start of a ZSTD encoded frame
`srcSize` must be at least as large as the frame header. A value greater than or equal
to `ZSTD_frameHeaderSize_max` is guaranteed to be large enough in all cases.
@return : decompressed size of the frame pointed to be `src` if known, otherwise
- ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
- ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small)
<pre><b>#define ZSTD_CONTENTSIZE_UNKNOWN (0ULL - 1)
#define ZSTD_CONTENTSIZE_ERROR (0ULL - 2)
unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize);
</b><p> `src` should point to the start of a ZSTD encoded frame.
`srcSize` must be at least as large as the frame header.
A value >= `ZSTD_frameHeaderSize_max` is guaranteed to be large enough.
@return : - decompressed size of the frame pointed to be `src` if known
- ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
- ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small)
</p></pre><BR>
<pre><b>unsigned long long ZSTD_findDecompressedSize(const void* src, size_t srcSize);
</b><p> `src` should point the start of a series of ZSTD encoded and/or skippable frames
`srcSize` must be the _exact_ size of this series
</b><p> `src` should point the start of a series of ZSTD encoded and/or skippable frames
`srcSize` must be the _exact_ size of this series
(i.e. there should be a frame boundary exactly `srcSize` bytes after `src`)
@return : the decompressed size of all data in the contained frames, as a 64-bit value _if known_
- if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN
- if an error occurred: ZSTD_CONTENTSIZE_ERROR
@return : - decompressed size of all data in all successive frames
- if the decompressed size cannot be determined: ZSTD_CONTENTSIZE_UNKNOWN
- if an error occurred: ZSTD_CONTENTSIZE_ERROR
note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
In which case, it's necessary to use streaming mode to decompress data.
Optionally, application can still use ZSTD_decompress() while relying on implied limits.
(For example, data may be necessarily cut into blocks <= 16 KB).
note 2 : decompressed size is always present when compression is done with ZSTD_compress()
note 3 : decompressed size can be very large (64-bits value),
potentially larger than what local system can handle as a single memory segment.
In which case, it's necessary to use streaming mode to decompress data.
note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.
Always ensure result fits within application's authorized limits.
Each application can set its own limits.
note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to
read each contained frame header. This is efficient as most of the data is skipped,
however it does mean that all frame data must be present and valid.
note 1 : decompressed size is an optional field, that may not be present, especially in streaming mode.
When `return==ZSTD_CONTENTSIZE_UNKNOWN`, data to decompress could be any size.
In which case, it's necessary to use streaming mode to decompress data.
Optionally, application can still use ZSTD_decompress() while relying on implied limits.
(For example, data may be necessarily cut into blocks <= 16 KB).
note 2 : decompressed size is always present when compression is done with ZSTD_compress()
note 3 : decompressed size can be very large (64-bits value),
potentially larger than what local system can handle as a single memory segment.
In which case, it's necessary to use streaming mode to decompress data.
note 4 : If source is untrusted, decompressed size could be wrong or intentionally modified.
Always ensure result fits within application's authorized limits.
Each application can set its own limits.
note 5 : ZSTD_findDecompressedSize handles multiple frames, and so it must traverse the input to
read each contained frame header. This is efficient as most of the data is skipped,
however it does mean that all frame data must be present and valid.
</p></pre><BR>
<a name="Chapter13"></a><h2>Context memory usage</h2><pre></pre>
<pre><b>size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);
size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx);
size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);
size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);
size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict);
size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
</b><p> These functions give the current memory usage of selected object.
Object memory usage can evolve if it's re-used multiple times.
</p></pre><BR>
<pre><b>size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams);
size_t ZSTD_estimateDCtxSize(void);
</b><p> These functions make it possible to estimate memory usage
of a future target object, before its allocation,
given a set of parameters, which vary depending on target object.
The objective is to guide decision before allocation.
</p></pre><BR>
<pre><b>size_t ZSTD_estimateCStreamSize(ZSTD_compressionParameters cParams);
size_t ZSTD_estimateDStreamSize(ZSTD_frameHeader fHeader);
</b><p> Note : if streaming is init with function ZSTD_init?Stream_usingDict(),
an internal ?Dict will be created, which size is not estimated.
In this case, get additional size by using ZSTD_estimate?DictSize
</p></pre><BR>
<pre><b>size_t ZSTD_estimateCDictSize(ZSTD_compressionParameters cParams, size_t dictSize);
size_t ZSTD_estimateDDictSize(size_t dictSize);
</b><p> Note : if dictionary is created "byReference", reduce estimation by dictSize
</p></pre><BR>
<a name="Chapter14"></a><h2>Advanced compression functions</h2><pre></pre>
<pre><b>size_t ZSTD_estimateCCtxSize(ZSTD_compressionParameters cParams);
</b><p> Gives the amount of memory allocated for a ZSTD_CCtx given a set of compression parameters.
`frameContentSize` is an optional parameter, provide `0` if unknown
</p></pre><BR>
<pre><b>ZSTD_CCtx* ZSTD_createCCtx_advanced(ZSTD_customMem customMem);
</b><p> Create a ZSTD compression context using external alloc and free functions
</p></pre><BR>
<pre><b>size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);
</b><p> Gives the amount of memory used by a given ZSTD_CCtx
</p></pre><BR>
<pre><b>typedef enum {
ZSTD_p_forceWindow, </b>/* Force back-references to remain < windowSize, even when referencing Dictionary content (default:0) */<b>
ZSTD_p_forceRawDict </b>/* Force loading dictionary in "content-only" mode (no header analysis) */<b>
@@ -381,14 +433,10 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
</p></pre><BR>
<pre><b>ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, unsigned byReference,
ZSTD_parameters params, ZSTD_customMem customMem);
ZSTD_compressionParameters cParams, ZSTD_customMem customMem);
</b><p> Create a ZSTD_CDict using external alloc and free, and customized compression parameters
</p></pre><BR>
<pre><b>size_t ZSTD_sizeof_CDict(const ZSTD_CDict* cdict);
</b><p> Gives the amount of memory used by a given ZSTD_sizeof_CDict
</p></pre><BR>
<pre><b>ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize);
</b><p> @return ZSTD_compressionParameters structure for a selected compression level and estimated srcSize.
`estimatedSrcSize` value is optional, select 0 if not known
@@ -408,12 +456,19 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
both values are optional, select `0` if unknown.
</p></pre><BR>
<pre><b>size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize,
ZSTD_parameters params);
</b><p> Same as ZSTD_compress_usingDict(), with fine-tune control of each compression parameter
<pre><b>size_t ZSTD_compress_advanced (ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict,size_t dictSize,
ZSTD_parameters params);
</b><p> Same as ZSTD_compress_usingDict(), with fine-tune control over each compression parameter
</p></pre><BR>
<pre><b>size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const ZSTD_CDict* cdict, ZSTD_frameParameters fParams);
</b><p> Same as ZSTD_compress_usingCDict(), with fine-tune control over frame parameters
</p></pre><BR>
<a name="Chapter15"></a><h2>Advanced decompression functions</h2><pre></pre>
@@ -425,26 +480,19 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
Note 3 : Skippable Frame Identifiers are considered valid.
</p></pre><BR>
<pre><b>size_t ZSTD_estimateDCtxSize(void);
</b><p> Gives the potential amount of memory allocated to create a ZSTD_DCtx
</p></pre><BR>
<pre><b>ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem);
</b><p> Create a ZSTD decompression context using external alloc and free functions
</p></pre><BR>
<pre><b>size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx);
</b><p> Gives the amount of memory used by a given ZSTD_DCtx
</p></pre><BR>
<pre><b>ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize);
</b><p> Create a digested dictionary, ready to start decompression operation without startup delay.
Dictionary content is simply referenced, and therefore stays in dictBuffer.
It is important that dictBuffer outlives DDict, it must remain read accessible throughout the lifetime of DDict
</p></pre><BR>
<pre><b>size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
</b><p> Gives the amount of memory used by a given ZSTD_DDict
<pre><b>ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize,
unsigned byReference, ZSTD_customMem customMem);
</b><p> Create a ZSTD_DDict using external alloc and free, optionally by reference
</p></pre><BR>
<pre><b>unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize);
@@ -468,27 +516,34 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
Note : this use case also happens when using a non-conformant dictionary.
- `srcSize` is too small, and as a result, the frame header could not be decoded (only possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`).
- This is not a Zstandard frame.
When identifying the exact failure cause, it's possible to used ZSTD_getFrameParams(), which will provide a more precise error code.
When identifying the exact failure cause, it's possible to use ZSTD_getFrameParams(), which will provide a more precise error code.
</p></pre><BR>
<a name="Chapter16"></a><h2>Advanced streaming functions</h2><pre></pre>
<h3>Advanced Streaming compression functions</h3><pre></pre><b><pre>ZSTD_CStream* ZSTD_createCStream_advanced(ZSTD_customMem customMem);
size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize); </b>/**< pledgedSrcSize must be correct, a size of 0 means unknown. for a frame size of 0 use initCStream_advanced */<b>
size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); </b>/**< note: a dict will not be used if dict == NULL or dictSize < 8 */<b>
size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); </b>/**< note: a dict will not be used if dict == NULL or dictSize < 8. This result in the creation of an internal CDict */<b>
size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
ZSTD_parameters params, unsigned long long pledgedSrcSize); </b>/**< pledgedSrcSize is optional and can be 0 (meaning unknown). note: if the contentSizeFlag is set, pledgedSrcSize == 0 means the source size is actually 0 */<b>
size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict); </b>/**< note : cdict will just be referenced, and must outlive compression session */<b>
size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize); </b>/**< re-use compression parameters from previous init; skip dictionary loading stage; zcs must be init at least once before. note: pledgedSrcSize must be correct, a size of 0 means unknown. for a frame size of 0 use initCStream_advanced */<b>
size_t ZSTD_sizeof_CStream(const ZSTD_CStream* zcs);
size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, unsigned long long pledgedSrcSize, ZSTD_frameParameters fParams); </b>/**< same as ZSTD_initCStream_usingCDict(), with control over frame parameters */<b>
</pre></b><BR>
<pre><b>size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize);
</b><p> start a new compression job, using same parameters from previous job.
This is typically useful to skip dictionary loading stage, since it will re-use it in-place..
Note that zcs must be init at least once before using ZSTD_resetCStream().
pledgedSrcSize==0 means "srcSize unknown".
If pledgedSrcSize > 0, its value must be correct, as it will be written in header, and controlled at the end.
@return : 0, or an error code (which can be tested using ZSTD_isError())
</p></pre><BR>
<h3>Advanced Streaming decompression functions</h3><pre></pre><b><pre>typedef enum { DStream_p_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); </b>/**< note: a dict will not be used if dict == NULL or dictSize < 8 */<b>
size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds, ZSTD_DStreamParameter_e paramType, unsigned paramValue);
size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize); </b>/**< note: a dict will not be used if dict == NULL or dictSize < 8 */<b>
size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); </b>/**< note : ddict will just be referenced, and must outlive decompression session */<b>
size_t ZSTD_resetDStream(ZSTD_DStream* zds); </b>/**< re-use decompression parameters from previous init; saves dictionary loading */<b>
size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);
</pre></b><BR>
<a name="Chapter17"></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.
@@ -529,10 +584,9 @@ size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);
<h3>Buffer-less streaming compression functions</h3><pre></pre><b><pre>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); </b>/**< pledgedSrcSize is optional and can be 0 (meaning unknown). note: if the contentSizeFlag is set, pledgedSrcSize == 0 means the source size is actually 0 */<b>
size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict); </b>/**< note: fails if cdict==NULL */<b>
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=0 means null-size */<b>
size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize); </b>/**< note: if pledgedSrcSize can be 0, indicating unknown size. if it is non-zero, it must be accurate. for 0 size frames, use compressBegin_advanced */<b>
size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict, unsigned long long pledgedSrcSize); </b>/**< note: if pledgedSrcSize can be 0, indicating unknown size. if it is non-zero, it must be accurate. for 0 size frames, use compressBegin_advanced */<b>
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);
</pre></b><BR>
<a name="Chapter19"></a><h2>Buffer-less streaming decompression (synchronous mode)</h2><pre>
A ZSTD_DCtx object is required to track streaming operations.
@@ -592,14 +646,7 @@ size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const vo
It also returns Frame Size as fparamsPtr->frameContentSize.
<BR></pre>
<pre><b>typedef struct {
unsigned long long frameContentSize;
unsigned windowSize;
unsigned dictID;
unsigned checksumFlag;
} ZSTD_frameParams;
</b></pre><BR>
<h3>Buffer-less streaming decompression functions</h3><pre></pre><b><pre>size_t ZSTD_getFrameParams(ZSTD_frameParams* fparamsPtr, const void* src, size_t srcSize); </b>/**< doesn't consume input, see details below */<b>
<h3>Buffer-less streaming decompression functions</h3><pre></pre><b><pre>size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize); </b>/**< doesn't consume input, see details below */<b>
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);
@@ -617,19 +664,20 @@ ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
- Compressing and decompressing require a context structure
+ Use ZSTD_createCCtx() and ZSTD_createDCtx()
- It is necessary to init context before starting
+ compression : ZSTD_compressBegin()
+ decompression : ZSTD_decompressBegin()
+ variants _usingDict() are also allowed
+ copyCCtx() and copyDCtx() work too
- Block size is limited, it must be <= ZSTD_getBlockSizeMax()
+ If you need to compress more, cut data into multiple blocks
+ Consider using the regular ZSTD_compress() instead, as frame metadata costs become negligible when source size is large.
+ compression : any ZSTD_compressBegin*() variant, including with dictionary
+ decompression : any ZSTD_decompressBegin*() variant, including with dictionary
+ copyCCtx() and copyDCtx() can be used too
- Block size is limited, it must be <= ZSTD_getBlockSizeMax() <= ZSTD_BLOCKSIZE_ABSOLUTEMAX
+ If input is larger than a block size, it's necessary to split input data into multiple blocks
+ For inputs larger than a single block size, consider using the regular ZSTD_compress() instead.
Frame metadata is not that costly, and quickly becomes negligible as source size grows larger.
- When a block is considered not compressible enough, ZSTD_compressBlock() result will be zero.
In which case, nothing is produced into `dst`.
+ User must test for such outcome and deal directly with uncompressed data
+ ZSTD_decompressBlock() doesn't accept uncompressed data as input !!!
+ In case of multiple successive blocks, decoder must be informed of uncompressed block existence to follow proper history.
Use ZSTD_insertBlock() in such a case.
+ In case of multiple successive blocks, should some of them be uncompressed,
decoder must be informed of their existence in order to follow proper history.
Use ZSTD_insertBlock() for such a case.
<BR></pre>
<h3>Raw zstd block functions</h3><pre></pre><b><pre>size_t ZSTD_getBlockSizeMax(ZSTD_CCtx* cctx);