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added `manual` target in root Makefile 

`manual` target is added to `all` target
dev
Yann Collet 2017-02-22 01:10:43 -08:00
parent 508404514c
commit 7757577341
2 changed files with 148 additions and 55 deletions
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11
Makefile
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@ -26,8 +26,7 @@ endif
default: lib zstd-release
.PHONY: all
all: allmost
CPPFLAGS=-I../lib LDFLAGS=-L../lib $(MAKE) -C examples/ $@
all: | allmost examples manual
.PHONY: allmost
allmost:
@ -68,6 +67,14 @@ zlibwrapper:
test:
$(MAKE) -C $(TESTDIR) $@
.PHONY: examples
examples:
CPPFLAGS=-I../lib LDFLAGS=-L../lib $(MAKE) -C examples/ all
.PHONY: manual
manual:
$(MAKE) -C contrib/gen_html $@
.PHONY: clean
clean:
@$(MAKE) -C $(ZSTDDIR) $@ > $(VOID)

192
doc/zstd_manual.html
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@ -1,10 +1,10 @@
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>zstd 1.1.2 Manual</title>
<title>zstd 1.1.4 Manual</title>
</head>
<body>
<h1>zstd 1.1.2 Manual</h1>
<h1>zstd 1.1.4 Manual</h1>
<hr>
<a name="Contents"></a><h2>Contents</h2>
<ol>
@ -19,13 +19,15 @@
<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">Advanced compression functions</a></li>
<li><a href="#Chapter13">Advanced decompression functions</a></li>
<li><a href="#Chapter14">Advanced streaming functions</a></li>
<li><a href="#Chapter15">Buffer-less and synchronous inner streaming functions</a></li>
<li><a href="#Chapter16">Buffer-less streaming compression (synchronous mode)</a></li>
<li><a href="#Chapter17">Buffer-less streaming decompression (synchronous mode)</a></li>
<li><a href="#Chapter18">Block functions</a></li>
<li><a href="#Chapter12">Compressed size functions</a></li>
<li><a href="#Chapter13">Decompressed size functions</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>
<li><a href="#Chapter17">Buffer-less and synchronous inner streaming functions</a></li>
<li><a href="#Chapter18">Buffer-less streaming compression (synchronous mode)</a></li>
<li><a href="#Chapter19">Buffer-less streaming decompression (synchronous mode)</a></li>
<li><a href="#Chapter20">Block functions</a></li>
</ol>
<hr>
<a name="Chapter1"></a><h2>Introduction</h2><pre>
@ -63,7 +65,7 @@
<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 a single compressed frame.
</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`),
@ -71,7 +73,16 @@
</p></pre><BR>
<pre><b>unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);
</b><p> 'src' is the start of a zstd compressed frame.
</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.
'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.
@ -88,21 +99,29 @@
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><b>int ZSTD_maxCLevel(void); </b>/*!< maximum compression level available */<b>
<h3>Helper functions</h3><pre></pre><b><pre>int ZSTD_maxCLevel(void); </b>/*!< maximum compression level available */<b>
size_t ZSTD_compressBound(size_t srcSize); </b>/*!< maximum compressed size in worst case scenario */<b>
unsigned ZSTD_isError(size_t code); </b>/*!< tells if a `size_t` function result is an error code */<b>
const char* ZSTD_getErrorName(size_t code); </b>/*!< provides readable string from an error code */<b>
</b></pre><BR>
</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.
</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()).
</p></pre><BR>
<h3>Decompression context</h3><pre><b>typedef struct ZSTD_DCtx_s ZSTD_DCtx;
<h3>Decompression context</h3><pre></pre><b><pre>typedef struct ZSTD_DCtx_s ZSTD_DCtx;
ZSTD_DCtx* ZSTD_createDCtx(void);
size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
</b></pre><BR>
</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()).
</p></pre><BR>
@ -131,11 +150,11 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
<a name="Chapter6"></a><h2>Fast dictionary API</h2><pre></pre>
<pre><b>ZSTD_CDict* ZSTD_createCDict(const void* dict, size_t dictSize, int compressionLevel);
<pre><b>ZSTD_CDict* ZSTD_createCDict(const void* dictBuffer, size_t dictSize, int compressionLevel);
</b><p> When compressing multiple messages / blocks with the same dictionary, it's recommended to load it just once.
ZSTD_createCDict() will create a digested dictionary, ready to start future compression operations without startup delay.
ZSTD_CDict can be created once and used by multiple threads concurrently, as its usage is read-only.
`dict` can be released after ZSTD_CDict creation.
`dictBuffer` can be released after ZSTD_CDict creation, as its content is copied within CDict
</p></pre><BR>
<pre><b>size_t ZSTD_freeCDict(ZSTD_CDict* CDict);
@ -151,9 +170,9 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
Note that compression level is decided during dictionary creation.
</p></pre><BR>
<pre><b>ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize);
<pre><b>ZSTD_DDict* ZSTD_createDDict(const void* dictBuffer, size_t dictSize);
</b><p> Create a digested dictionary, ready to start decompression operation without startup delay.
`dict` can be released after creation.
dictBuffer can be released after DDict creation, as its content is copied inside DDict
</p></pre><BR>
<pre><b>size_t ZSTD_freeDDict(ZSTD_DDict* ddict);
@ -271,9 +290,9 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
} ZSTD_compressionParameters;
</b></pre><BR>
<pre><b>typedef struct {
unsigned contentSizeFlag; </b>/**< 1: content size will be in frame header (if known). */<b>
unsigned checksumFlag; </b>/**< 1: will generate a 22-bits checksum at end of frame, to be used for error detection by decompressor */<b>
unsigned noDictIDFlag; </b>/**< 1: no dict ID will be saved into frame header (if dictionary compression) */<b>
unsigned contentSizeFlag; </b>/**< 1: content size will be in frame header (when known) */<b>
unsigned checksumFlag; </b>/**< 1: generate a 32-bits checksum at end of frame, for error detection */<b>
unsigned noDictIDFlag; </b>/**< 1: no dictID will be saved into frame header (if dictionary compression) */<b>
} ZSTD_frameParameters;
</b></pre><BR>
<pre><b>typedef struct {
@ -281,11 +300,56 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
ZSTD_frameParameters fParams;
} ZSTD_parameters;
</b></pre><BR>
<h3>Custom memory allocation functions</h3><pre><b>typedef void* (*ZSTD_allocFunction) (void* opaque, size_t size);
<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;
</b></pre><BR>
<a name="Chapter12"></a><h2>Advanced compression functions</h2><pre></pre>
</pre></b><BR>
<a name="Chapter12"></a><h2>Compressed size functions</h2><pre></pre>
<pre><b>size_t ZSTD_getFrameCompressedSize(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
@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 occured (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
(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
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="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.
@ -300,7 +364,22 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
</b><p> Gives the amount of memory used by a given ZSTD_CCtx
</p></pre><BR>
<pre><b>ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize,
<pre><b>typedef enum {
ZSTD_p_forceWindow </b>/* Force back-references to remain < windowSize, even when referencing Dictionary content (default:0)*/<b>
} ZSTD_CCtxParameter;
</b></pre><BR>
<pre><b>size_t ZSTD_setCCtxParameter(ZSTD_CCtx* cctx, ZSTD_CCtxParameter param, unsigned value);
</b><p> Set advanced parameters, selected through enum ZSTD_CCtxParameter
@result : 0, or an error code (which can be tested with ZSTD_isError())
</p></pre><BR>
<pre><b>ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
</b><p> Create a digested dictionary for compression
Dictionary content is simply referenced, and therefore stays in dictBuffer.
It is important that dictBuffer outlives CDict, it must remain read accessible throughout the lifetime of CDict
</p></pre><BR>
<pre><b>ZSTD_CDict* ZSTD_createCDict_advanced(const void* dict, size_t dictSize, unsigned byReference,
ZSTD_parameters params, ZSTD_customMem customMem);
</b><p> Create a ZSTD_CDict using external alloc and free, and customized compression parameters
</p></pre><BR>
@ -336,7 +415,7 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
</b><p> Same as ZSTD_compress_usingDict(), with fine-tune control of each compression parameter
</p></pre><BR>
<a name="Chapter13"></a><h2>Advanced decompression functions</h2><pre></pre>
<a name="Chapter15"></a><h2>Advanced decompression functions</h2><pre></pre>
<pre><b>unsigned ZSTD_isFrame(const void* buffer, size_t size);
</b><p> Tells if the content of `buffer` starts with a valid Frame Identifier.
@ -357,6 +436,12 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
</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
</p></pre><BR>
@ -385,33 +470,33 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
When identifying the exact failure cause, it's possible to used ZSTD_getFrameParams(), which will provide a more precise error code.
</p></pre><BR>
<a name="Chapter14"></a><h2>Advanced streaming functions</h2><pre></pre>
<a name="Chapter16"></a><h2>Advanced streaming functions</h2><pre></pre>
<h3>Advanced Streaming compression functions</h3><pre><b>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 */<b>
size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel);
<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_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
ZSTD_parameters params, unsigned long long pledgedSrcSize); </b>/**< pledgedSrcSize is optional and can be zero == unknown */<b>
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 */<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);
</b></pre><BR>
<h3>Advanced Streaming decompression functions</h3><pre><b>typedef enum { ZSTDdsp_maxWindowSize } ZSTD_DStreamParameter_e;
</pre></b><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);
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_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);
</b></pre><BR>
<a name="Chapter15"></a><h2>Buffer-less and synchronous inner streaming functions</h2><pre>
</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.
But it's also a complex one, with many restrictions (documented below).
Prefer using normal streaming API for an easier experience
<BR></pre>
<a name="Chapter16"></a><h2>Buffer-less streaming compression (synchronous mode)</h2><pre>
<a name="Chapter18"></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.
@ -434,20 +519,21 @@ size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds);
In which case, it will "discard" the relevant memory section from its history.
Finish a frame with ZSTD_compressEnd(), which will write the last block(s) and optional checksum.
It's possible to use a NULL,0 src content, in which case, it will write a final empty block to end the frame,
Without last block mark, frames will be considered unfinished (broken) by decoders.
It's possible to use srcSize==0, in which case, it will write a final empty block to end the frame.
Without last block mark, frames will be considered unfinished (corrupted) by decoders.
You can then reuse `ZSTD_CCtx` (ZSTD_compressBegin()) to compress some new frame.
`ZSTD_CCtx` object can be re-used (ZSTD_compressBegin()) to compress some new frame.
<BR></pre>
<h3>Buffer-less streaming compression functions</h3><pre><b>size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, int compressionLevel);
<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);
size_t ZSTD_copyCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx, unsigned long long pledgedSrcSize);
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_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);
</b></pre><BR>
<a name="Chapter17"></a><h2>Buffer-less streaming decompression (synchronous mode)</h2><pre>
</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.
Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
A ZSTD_DCtx object can be re-used multiple times.
@ -490,7 +576,7 @@ 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 :
@ -509,7 +595,7 @@ size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t dstCapacity, const vo
unsigned checksumFlag;
} ZSTD_frameParams;
</b></pre><BR>
<h3>Buffer-less streaming decompression functions</h3><pre><b>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_getFrameParams(ZSTD_frameParams* fparamsPtr, 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);
@ -517,8 +603,8 @@ 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);
</b></pre><BR>
<a name="Chapter18"></a><h2>Block functions</h2><pre>
</pre></b><BR>
<a name="Chapter20"></a><h2>Block functions</h2><pre>
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).
User will have to take in charge required information to regenerate data, such as compressed and content sizes.
@ -542,10 +628,10 @@ ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
Use ZSTD_insertBlock() in such a case.
<BR></pre>
<h3>Raw zstd block functions</h3><pre><b>size_t ZSTD_getBlockSizeMax(ZSTD_CCtx* cctx);
<h3>Raw zstd block functions</h3><pre></pre><b><pre>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); </b>/**< insert block into `dctx` history. Useful for uncompressed blocks */<b>
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