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Merge branch 'dev' into adapt
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Yann Collet
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
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<title>zstd 1.3.5 Manual</title>
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<title>zstd 1.3.6 Manual</title>
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<body>
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<h1>zstd 1.3.5 Manual</h1>
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<h1>zstd 1.3.6 Manual</h1>
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<hr>
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<a name="Contents"></a><h2>Contents</h2>
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<ol>
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@ -18,20 +18,17 @@
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<li><a href="#Chapter8">Streaming</a></li>
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<li><a href="#Chapter9">Streaming compression - HowTo</a></li>
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<li><a href="#Chapter10">Streaming decompression - HowTo</a></li>
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<li><a href="#Chapter11">START OF ADVANCED AND EXPERIMENTAL FUNCTIONS</a></li>
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<li><a href="#Chapter12">Advanced types</a></li>
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<li><a href="#Chapter13">Frame size functions</a></li>
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<li><a href="#Chapter14">ZSTD_frameHeaderSize() :</a></li>
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<li><a href="#Chapter15">Memory management</a></li>
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<li><a href="#Chapter16">Advanced compression functions</a></li>
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<li><a href="#Chapter17">Advanced decompression functions</a></li>
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<li><a href="#Chapter18">Advanced streaming functions</a></li>
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<li><a href="#Chapter19">Buffer-less and synchronous inner streaming functions</a></li>
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<li><a href="#Chapter20">Buffer-less streaming compression (synchronous mode)</a></li>
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<li><a href="#Chapter21">Buffer-less streaming decompression (synchronous mode)</a></li>
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<li><a href="#Chapter22">New advanced API (experimental)</a></li>
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<li><a href="#Chapter23">ZSTD_getFrameHeader_advanced() :</a></li>
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<li><a href="#Chapter24">Block level API</a></li>
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<li><a href="#Chapter11">ADVANCED AND EXPERIMENTAL FUNCTIONS</a></li>
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<li><a href="#Chapter12">Frame size functions</a></li>
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<li><a href="#Chapter13">Memory management</a></li>
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<li><a href="#Chapter14">Advanced compression functions</a></li>
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<li><a href="#Chapter15">Advanced decompression functions</a></li>
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<li><a href="#Chapter16">Advanced streaming functions</a></li>
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<li><a href="#Chapter17">Buffer-less and synchronous inner streaming functions</a></li>
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<li><a href="#Chapter18">Buffer-less streaming compression (synchronous mode)</a></li>
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<li><a href="#Chapter19">Buffer-less streaming decompression (synchronous mode)</a></li>
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<li><a href="#Chapter20">New advanced API (experimental)</a></li>
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<li><a href="#Chapter21">Block level API</a></li>
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</ol>
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<hr>
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<a name="Chapter1"></a><h2>Introduction</h2><pre>
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@ -336,15 +333,16 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
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</b></pre><BR>
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<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>
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</b></pre><BR>
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<a name="Chapter11"></a><h2>START OF ADVANCED AND EXPERIMENTAL FUNCTIONS</h2><pre> The definitions in this section are considered experimental.
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<a name="Chapter11"></a><h2>ADVANCED AND EXPERIMENTAL FUNCTIONS</h2><pre>
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The definitions in this section are considered experimental.
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They should never be used with a dynamic library, as prototypes may change in the future.
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They are provided for advanced scenarios.
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Use them only in association with static linking.
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<BR></pre>
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<a name="Chapter12"></a><h2>Advanced types</h2><pre></pre>
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<pre><b>int ZSTD_minCLevel(void); </b>/*!< minimum negative compression level allowed */<b>
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</b></pre><BR>
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<pre><b>typedef enum { ZSTD_fast=1, ZSTD_dfast, ZSTD_greedy, ZSTD_lazy, ZSTD_lazy2,
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ZSTD_btlazy2, ZSTD_btopt, ZSTD_btultra } ZSTD_strategy; </b>/* from faster to stronger */<b>
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</b></pre><BR>
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@ -380,7 +378,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
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ZSTD_dlm_byRef, </b>/**< Reference dictionary content -- the dictionary buffer must outlive its users. */<b>
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} ZSTD_dictLoadMethod_e;
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</b></pre><BR>
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<a name="Chapter13"></a><h2>Frame size functions</h2><pre></pre>
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<a name="Chapter12"></a><h2>Frame size functions</h2><pre></pre>
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<pre><b>size_t ZSTD_findFrameCompressedSize(const void* src, size_t srcSize);
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</b><p> `src` should point to the start of a ZSTD encoded frame or skippable frame
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@ -413,12 +411,13 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
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however it does mean that all frame data must be present and valid.
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</p></pre><BR>
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<a name="Chapter14"></a><h2>ZSTD_frameHeaderSize() :</h2><pre> srcSize must be >= ZSTD_frameHeaderSize_prefix.
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<pre><b>size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize);
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</b><p> srcSize must be >= ZSTD_frameHeaderSize_prefix.
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@return : size of the Frame Header,
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or an error code (if srcSize is too small)
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<BR></pre>
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</p></pre><BR>
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<a name="Chapter15"></a><h2>Memory management</h2><pre></pre>
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<a name="Chapter13"></a><h2>Memory management</h2><pre></pre>
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<pre><b>size_t ZSTD_sizeof_CCtx(const ZSTD_CCtx* cctx);
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size_t ZSTD_sizeof_DCtx(const ZSTD_DCtx* dctx);
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@ -508,7 +507,7 @@ static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; </b>/**< t
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</p></pre><BR>
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<a name="Chapter16"></a><h2>Advanced compression functions</h2><pre></pre>
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<a name="Chapter14"></a><h2>Advanced compression functions</h2><pre></pre>
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<pre><b>ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
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</b><p> Create a digested dictionary for compression
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@ -550,7 +549,7 @@ static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; </b>/**< t
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</b><p> Same as ZSTD_compress_usingCDict(), with fine-tune control over frame parameters
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</p></pre><BR>
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<a name="Chapter17"></a><h2>Advanced decompression functions</h2><pre></pre>
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<a name="Chapter15"></a><h2>Advanced decompression functions</h2><pre></pre>
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<pre><b>unsigned ZSTD_isFrame(const void* buffer, size_t size);
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</b><p> Tells if the content of `buffer` starts with a valid Frame Identifier.
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@ -590,7 +589,7 @@ static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL }; </b>/**< t
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When identifying the exact failure cause, it's possible to use ZSTD_getFrameHeader(), which will provide a more precise error code.
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</p></pre><BR>
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<a name="Chapter18"></a><h2>Advanced streaming functions</h2><pre></pre>
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<a name="Chapter16"></a><h2>Advanced streaming functions</h2><pre></pre>
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<h3>Advanced Streaming compression functions</h3><pre></pre><b><pre>size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize); </b>/**< 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. */<b>
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size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel); </b>/**< creates of an internal CDict (incompatible with static CCtx), except if dict == NULL or dictSize < 8, in which case no dict is used. Note: dict is loaded with ZSTD_dm_auto (treated as a full zstd dictionary if it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy.*/<b>
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@ -623,14 +622,14 @@ size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t di
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size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict); </b>/**< note : ddict is referenced, it must outlive decompression session */<b>
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size_t ZSTD_resetDStream(ZSTD_DStream* zds); </b>/**< re-use decompression parameters from previous init; saves dictionary loading */<b>
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</pre></b><BR>
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<a name="Chapter19"></a><h2>Buffer-less and synchronous inner streaming functions</h2><pre>
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<a name="Chapter17"></a><h2>Buffer-less and synchronous inner streaming functions</h2><pre>
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This is an advanced API, giving full control over buffer management, for users which need direct control over memory.
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But it's also a complex one, with several restrictions, documented below.
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Prefer normal streaming API for an easier experience.
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<BR></pre>
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<a name="Chapter20"></a><h2>Buffer-less streaming compression (synchronous mode)</h2><pre>
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<a name="Chapter18"></a><h2>Buffer-less streaming compression (synchronous mode)</h2><pre>
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A ZSTD_CCtx object is required to track streaming operations.
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Use ZSTD_createCCtx() / ZSTD_freeCCtx() to manage resource.
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ZSTD_CCtx object can be re-used multiple times within successive compression operations.
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@ -666,7 +665,7 @@ size_t ZSTD_compressBegin_usingCDict(ZSTD_CCtx* cctx, const ZSTD_CDict* cdict);
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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>
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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>
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</pre></b><BR>
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<a name="Chapter21"></a><h2>Buffer-less streaming decompression (synchronous mode)</h2><pre>
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<a name="Chapter19"></a><h2>Buffer-less streaming decompression (synchronous mode)</h2><pre>
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A ZSTD_DCtx object is required to track streaming operations.
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Use ZSTD_createDCtx() / ZSTD_freeDCtx() to manage it.
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A ZSTD_DCtx object can be re-used multiple times.
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@ -757,7 +756,7 @@ size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long
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</pre></b><BR>
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<pre><b>typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
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</b></pre><BR>
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<a name="Chapter22"></a><h2>New advanced API (experimental)</h2><pre></pre>
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<a name="Chapter20"></a><h2>New advanced API (experimental)</h2><pre></pre>
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<pre><b>typedef enum {
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</b>/* Opened question : should we have a format ZSTD_f_auto ?<b>
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@ -1194,9 +1193,11 @@ size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx,
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</p></pre><BR>
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<a name="Chapter23"></a><h2>ZSTD_getFrameHeader_advanced() :</h2><pre> same as ZSTD_getFrameHeader(),
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<pre><b>size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr,
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const void* src, size_t srcSize, ZSTD_format_e format);
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</b><p> same as ZSTD_getFrameHeader(),
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with added capability to select a format (like ZSTD_f_zstd1_magicless)
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<BR></pre>
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</p></pre><BR>
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<pre><b>size_t ZSTD_decompress_generic(ZSTD_DCtx* dctx,
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ZSTD_outBuffer* output,
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@ -1230,7 +1231,7 @@ size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx,
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</p></pre><BR>
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<a name="Chapter24"></a><h2>Block level API</h2><pre></pre>
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<a name="Chapter21"></a><h2>Block level API</h2><pre></pre>
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<pre><b></b><p> Frame metadata cost is typically ~18 bytes, which can be non-negligible for very small blocks (< 100 bytes).
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User will have to take in charge required information to regenerate data, such as compressed and content sizes.
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