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added ZSTD_decompress_generic()

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same as ZSTD_decompressStream(),
just for a similar feeling as the compression side, which uses ZSTD_compress_generic()
This commit is contained in:
Yann Collet 2017-09-25 15:41:48 -07:00
parent b8d4a3887f
commit 6ee05a02b8
4 changed files with 53 additions and 22 deletions
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33
doc/zstd_manual.html
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@ -27,8 +27,8 @@
<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">=== New advanced API (experimental) ===</a></li>
<li><a href="#Chapter21">=== Block level API ===</a></li>
<li><a href="#Chapter20">New advanced API (experimental)</a></li>
<li><a href="#Chapter21">Block level API</a></li>
</ol>
<hr>
<a name="Chapter1"></a><h2>Introduction</h2><pre>
@ -783,7 +783,7 @@ size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long
</pre></b><BR>
<pre><b>typedef enum { ZSTDnit_frameHeader, ZSTDnit_blockHeader, ZSTDnit_block, ZSTDnit_lastBlock, ZSTDnit_checksum, ZSTDnit_skippableFrame } ZSTD_nextInputType_e;
</b></pre><BR>
<a name="Chapter20"></a><h2>=== New advanced API (experimental) ===</h2><pre></pre>
<a name="Chapter20"></a><h2>New advanced API (experimental)</h2><pre></pre>
<pre><b>typedef enum {
ZSTD_f_zstd1 = 0, </b>/* Normal zstd frame format, specified in zstd_compression_format.md (default) */<b>
@ -1070,9 +1070,9 @@ size_t ZSTD_CCtx_refPrefix_advanced(ZSTD_CCtx* cctx, const void* prefix, size_t
</p></pre><BR>
<h3>Advanced parameters for decompression API</h3><pre></pre><b><pre></pre></b><BR>
<pre><b>size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize);
size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode);
<pre><b>size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); </b>/* not implemented */<b>
size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize); </b>/* not implemented */<b>
size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictMode_e dictMode); </b>/* not implemented */<b>
</b><p> Create an internal DDict from dict buffer,
to be used to decompress next frames.
@result : 0, or an error code (which can be tested with ZSTD_isError()).
@ -1089,7 +1089,7 @@ size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size
</p></pre><BR>
<pre><b>size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict);
<pre><b>size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict); </b>/* not implemented */<b>
</b><p> Reference a prepared dictionary, to be used to decompress next frames.
The dictionary remains active for decompression of future frames using same DCtx.
@result : 0, or an error code (which can be tested with ZSTD_isError()).
@ -1100,8 +1100,8 @@ size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size
</p></pre><BR>
<pre><b>size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize);
size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictMode_e dictMode);
<pre><b>size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize); </b>/* not implemented */<b>
size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictMode_e dictMode); </b>/* not implemented */<b>
</b><p> Reference a prefix (single-usage dictionary) for next compression job.
Prefix is **only used once**. It must be explicitly referenced before each frame.
If there is a need to use same prefix multiple times, consider embedding it into a ZSTD_DDict instead.
@ -1110,7 +1110,7 @@ size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t
Note 2 : Prefix buffer is referenced. It must outlive compression job.
Note 3 : By default, the prefix is treated as raw content (ZSTD_dm_rawContent).
Use ZSTD_CCtx_refPrefix_advanced() to alter dictMode.
Note 4 : Referencing a raw content prefix costs almost nothing cpu and memory wise.
Note 4 : Referencing a raw content prefix has almost no cpu nor memory cost.
</p></pre><BR>
@ -1131,7 +1131,18 @@ size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t
</p></pre><BR>
<a name="Chapter21"></a><h2>=== Block level API ===</h2><pre></pre>
<pre><b>size_t ZSTD_decompress_generic(ZSTD_DCtx* dctx,
ZSTD_outBuffer* output,
ZSTD_inBuffer* input);
</b><p> Behave the same as ZSTD_decompressStream.
Decompression parameters cannot be changed once decompression is started.
@return : an error code, which can be tested using ZSTD_isError()
if >0, a hint, nb of expected input bytes for next invocation.
`0` means : a frame has just been fully decoded and flushed.
</p></pre><BR>
<a name="Chapter21"></a><h2>Block level API</h2><pre></pre>
<pre><b></b><p> 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.

1
lib/compress/zstd_compress.c
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@ -2574,6 +2574,7 @@ MEM_STATIC size_t ZSTD_limitCopy(void* dst, size_t dstCapacity,
/** ZSTD_compressStream_generic():
* internal function for all *compressStream*() variants and *compress_generic()
* non-static, because can be called from zstdmt.c
* @return : hint size for next input */
size_t ZSTD_compressStream_generic(ZSTD_CStream* zcs,
ZSTD_outBuffer* output,

9
lib/decompress/zstd_decompress.c
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@ -2379,7 +2379,10 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
U32 someMoreWork = 1;
DEBUGLOG(5, "ZSTD_decompressStream");
if (input->pos > input->size) return ERROR(GENERIC); /* forbidden */
if (output->pos > output->size) return ERROR(GENERIC); /* forbidden */
DEBUGLOG(5, "input size : %u", (U32)(input->size - input->pos));
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
if (zds->legacyVersion) {
/* legacy support is incompatible with static dctx */
@ -2590,3 +2593,9 @@ size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inB
return nextSrcSizeHint;
}
}
size_t ZSTD_decompress_generic(ZSTD_DCtx* dctx, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
{
return ZSTD_decompressStream(dctx, output, input);
}

32
lib/zstd.h
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@ -908,7 +908,9 @@ ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
/** === New advanced API (experimental) === **/
/* ============================================ */
/** New advanced API (experimental) */
/* ============================================ */
/* notes on API design :
* In this proposal, parameters are pushed one by one into an existing context,
@ -1295,23 +1297,31 @@ ZSTDLIB_API size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowS
* such ZSTD_f_zstd1_magicless for example.
* @return : 0, or an error code (which can be tested using ZSTD_isError()).
*/
ZSTDLIB_API size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format); /* implemented, but not functional */
ZSTDLIB_API size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format);
/* How to decompress ?
*
* currently, use ZSTD_decompressStream().
* We could also create a ZSTD_decompress_generic(),
* for an API experience similar to the compression one.
* It would effectively works exactly the same as ZSTD_decompressStream().
*
/*! ZSTD_decompress_generic() :
* Behave the same as ZSTD_decompressStream.
* Decompression parameters cannot be changed once decompression is started.
* @return : an error code, which can be tested using ZSTD_isError()
* if >0, a hint, nb of expected input bytes for next invocation.
* `0` means : a frame has just been fully decoded and flushed.
*/
ZSTDLIB_API size_t ZSTD_decompress_generic(ZSTD_DCtx* dctx,
ZSTD_outBuffer* output,
ZSTD_inBuffer* input);
/*
* Also : to re-init a decoding context, use ZSTD_initDStream().
* Here also, for a similar API logic, we could create ZSTD_DCtx_reset().
* Here for a similar API logic, we could create ZSTD_DCtx_reset().
* It would behave the same.
*/
/** === Block level API === **/
/* ============================ */
/** Block level API */
/* ============================ */
/*!
Block functions produce and decode raw zstd blocks, without frame metadata.