update documentation on deprecated functions

mostly : note that these functions will soon generate deprecation warnings

doc/zstd_manual.html

@@ -27,10 +27,16 @@
 <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">Buffer-less and synchronous inner streaming functions</a></li>
+<li><a href="#Chapter20">! ZSTD_initCStream_usingDict() :</a></li>
-<li><a href="#Chapter21">Buffer-less streaming compression (synchronous mode)</a></li>
+<li><a href="#Chapter21">! ZSTD_initCStream_advanced() :</a></li>
-<li><a href="#Chapter22">Buffer-less streaming decompression (synchronous mode)</a></li>
+<li><a href="#Chapter22">! ZSTD_initCStream_usingCDict() :</a></li>
-<li><a href="#Chapter23">Block level API</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>
 </ol>
 <hr>
 <a name="Chapter1"></a><h2>Introduction</h2><pre>
@@ -157,9 +163,13 @@ size_t     ZSTD_freeCCtx(ZSTD_CCtx* cctx);
                          void* dst, size_t dstCapacity,
                    const void* src, size_t srcSize,
                          int compressionLevel);
-</b><p>  Same as ZSTD_compress(), using an explicit ZSTD_CCtx
+</b><p>  Same as ZSTD_compress(), using an explicit ZSTD_CCtx.
-  The function will compress at requested compression level,
+  Important : in order to behave similarly to `ZSTD_compress()`,
-  ignoring any other parameter 
+  this function compresses at requested compression level,
+  __ignoring any other parameter__ .
+  If any advanced parameter was set using the advanced API,
+  they will all be reset. Only `compressionLevel` remains.
+ 
 </p></pre><BR>
 
 <h3>Decompression context</h3><pre>  When decompressing many times,
@@ -199,18 +209,26 @@ size_t     ZSTD_freeDCtx(ZSTD_DCtx* dctx);
 
     </b>/* compression parameters<b>
      * Note: When compressing with a ZSTD_CDict these parameters are superseded
-     * by the parameters used to construct the ZSTD_CDict. See ZSTD_CCtx_refCDict()
+     * by the parameters used to construct the ZSTD_CDict.
-     * for more info (superseded-by-cdict). */
+     * See ZSTD_CCtx_refCDict() for more info (superseded-by-cdict). */
-    ZSTD_c_compressionLevel=100, </b>/* Update all compression parameters according to pre-defined cLevel table<b>
+    ZSTD_c_compressionLevel=100, </b>/* Set compression parameters according to pre-defined cLevel table.<b>
+                              * Note that exact compression parameters are dynamically determined,
+                              * depending on both compression level and srcSize (when known).
                               * Default level is ZSTD_CLEVEL_DEFAULT==3.
                               * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT.
                               * Note 1 : it's possible to pass a negative compression level.
-                              * Note 2 : setting a level sets all default values of other compression parameters */
+                              * Note 2 : setting a level resets all other compression parameters to default */
+    </b>/* Advanced compression parameters :<b>
+     * It's possible to pin down compression parameters to some specific values.
+     * In which case, these values are no longer dynamically selected by the compressor */
     ZSTD_c_windowLog=101,    </b>/* Maximum allowed back-reference distance, expressed as power of 2.<b>
+                              * This will set a memory budget for streaming decompression,
+                              * with larger values requiring more memory
+                              * and typically compressing more.
                               * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX.
                               * Special: value 0 means "use default windowLog".
                               * Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT
-                              *       requires explicitly allowing such window size at decompression stage if using streaming. */
+                              *       requires explicitly allowing such size at streaming decompression stage. */
     ZSTD_c_hashLog=102,      </b>/* Size of the initial probe table, as a power of 2.<b>
                               * Resulting memory usage is (1 << (hashLog+2)).
                               * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX.
@@ -221,13 +239,13 @@ size_t     ZSTD_freeDCtx(ZSTD_DCtx* dctx);
                               * Resulting memory usage is (1 << (chainLog+2)).
                               * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX.
                               * Larger tables result in better and slower compression.
-                              * This parameter is useless when using "fast" strategy.
+                              * This parameter is useless for "fast" strategy.
                               * It's still useful when using "dfast" strategy,
                               * in which case it defines a secondary probe table.
                               * Special: value 0 means "use default chainLog". */
     ZSTD_c_searchLog=104,    </b>/* Number of search attempts, as a power of 2.<b>
                               * More attempts result in better and slower compression.
-                              * This parameter is useless when using "fast" and "dFast" strategies.
+                              * This parameter is useless for "fast" and "dFast" strategies.
                               * Special: value 0 means "use default searchLog". */
     ZSTD_c_minMatch=105,     </b>/* Minimum size of searched matches.<b>
                               * Note that Zstandard can still find matches of smaller size,
@@ -282,7 +300,7 @@ size_t     ZSTD_freeDCtx(ZSTD_DCtx* dctx);
     ZSTD_c_contentSizeFlag=200, </b>/* Content size will be written into frame header _whenever known_ (default:1)<b>
                               * Content size must be known at the beginning of compression.
                               * This is automatically the case when using ZSTD_compress2(),
-                              * For streaming variants, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */
+                              * For streaming scenarios, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */
     ZSTD_c_checksumFlag=201, </b>/* A 32-bits checksum of content is written at end of frame (default:0) */<b>
     ZSTD_c_dictIDFlag=202,   </b>/* When applicable, dictionary's ID is written into frame header (default:1) */<b>
 
@@ -301,7 +319,7 @@ size_t     ZSTD_freeDCtx(ZSTD_DCtx* dctx);
                               * 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.
                               * Job size must be a minimum of overlap size, or 1 MB, whichever is largest.
-                              * The minimum size is automatically and transparently enforced */
+                              * The minimum size is automatically and transparently enforced. */
     ZSTD_c_overlapLog=402,   </b>/* Control the overlap size, as a fraction of window size.<b>
                               * The overlap size is an amount of data reloaded from previous job at the beginning of a new job.
                               * It helps preserve compression ratio, while each job is compressed in parallel.
@@ -335,7 +353,7 @@ 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_cParameter;
 </b></pre><BR>
 <pre><b>typedef struct {
@@ -913,21 +931,12 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
 </b></pre><BR>
 <pre><b>typedef enum {
     ZSTD_dlm_byCopy = 0,  </b>/**< Copy dictionary content internally */<b>
-    ZSTD_dlm_byRef = 1,   </b>/**< Reference dictionary content -- the dictionary buffer must outlive its users. */<b>
+    ZSTD_dlm_byRef = 1    </b>/**< Reference dictionary content -- the dictionary buffer must outlive its users. */<b>
 } ZSTD_dictLoadMethod_e;
 </b></pre><BR>
 <pre><b>typedef enum {
-    </b>/* Opened question : should we have a format ZSTD_f_auto ?<b>
-     * Today, it would mean exactly the same as ZSTD_f_zstd1.
-     * But, in the future, should several formats become supported,
-     * on the compression side, it would mean "default format".
-     * On the decompression side, it would mean "automatic format detection",
-     * so that ZSTD_f_zstd1 would mean "accept *only* zstd frames".
-     * Since meaning is a little different, another option could be to define different enums for compression and decompression.
-     * This question could be kept for later, when there are actually multiple formats to support,
-     * but there is also the question of pinning enum values, and pinning value `0` is especially important */
     ZSTD_f_zstd1 = 0,           </b>/* zstd frame format, specified in zstd_compression_format.md (default) */<b>
-    ZSTD_f_zstd1_magicless = 1, </b>/* Variant of zstd frame format, without initial 4-bytes magic number.<b>
+    ZSTD_f_zstd1_magicless = 1  </b>/* Variant of zstd frame format, without initial 4-bytes magic number.<b>
                                  * Useful to save 4 bytes per generated frame.
                                  * Decoder cannot recognise automatically this format, requiring this instruction. */
 } ZSTD_format_e;
@@ -961,7 +970,7 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
      */
     ZSTD_dictDefaultAttach = 0, </b>/* Use the default heuristic. */<b>
     ZSTD_dictForceAttach   = 1, </b>/* Never copy the dictionary. */<b>
-    ZSTD_dictForceCopy     = 2, </b>/* Always copy the dictionary. */<b>
+    ZSTD_dictForceCopy     = 2  </b>/* Always copy the dictionary. */<b>
 } ZSTD_dictAttachPref_e;
 </b></pre><BR>
 <pre><b>typedef enum {
@@ -970,7 +979,7 @@ size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict);
                                *   levels will be compressed. */
   ZSTD_lcm_huffman = 1,       </b>/**< Always attempt Huffman compression. Uncompressed literals will still be<b>
                                *   emitted if Huffman compression is not profitable. */
-  ZSTD_lcm_uncompressed = 2,  </b>/**< Always emit uncompressed literals. */<b>
+  ZSTD_lcm_uncompressed = 2   </b>/**< Always emit uncompressed literals. */<b>
 } ZSTD_literalCompressionMode_e;
 </b></pre><BR>
 <a name="Chapter15"></a><h2>Frame size functions</h2><pre></pre>
@@ -1123,7 +1132,8 @@ static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL };  </b>/**< t
 </b><p>  Create a digested dictionary for compression
   Dictionary content is just referenced, not duplicated.
   As a consequence, `dictBuffer` **must** outlive CDict,
-  and its content must remain unmodified throughout the lifetime of CDict. 
+  and its content must remain unmodified throughout the lifetime of CDict.
+  note: equivalent to ZSTD_createCDict_advanced(), with dictLoadMethod==ZSTD_dlm_byRef 
 </p></pre><BR>
 
 <pre><b>ZSTD_compressionParameters ZSTD_getCParams(int compressionLevel, unsigned long long estimatedSrcSize, size_t dictSize);
@@ -1154,7 +1164,9 @@ static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL };  </b>/**< t
                         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 compression parameters (by structure) 
+</b><p>  Note : this function is now DEPRECATED.
+         It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_setParameter() and other parameter setters.
+  This prototype will be marked as deprecated and generate compilation warning on reaching v1.5.x 
 </p></pre><BR>
 
 <pre><b>size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
@@ -1162,7 +1174,9 @@ static ZSTD_customMem const ZSTD_defaultCMem = { NULL, NULL, NULL };  </b>/**< t
                             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 
+</b><p>  Note : this function is now REDUNDANT.
+         It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_loadDictionary() and other parameter setters.
+  This prototype will be marked as deprecated and generate compilation warning in some future version 
 </p></pre><BR>
 
 <pre><b>size_t ZSTD_CCtx_loadDictionary_byReference(ZSTD_CCtx* cctx, const void* dict, size_t dictSize);
@@ -1339,59 +1353,67 @@ size_t ZSTD_freeCCtxParams(ZSTD_CCtx_params* params);
  * 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 ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize);
+size_t
-</b>/**! ZSTD_initCStream_usingDict() :<b>
+ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
- * This function is deprecated, and is equivalent to:
+                         int compressionLevel,
- *     ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
+                         unsigned long long pledgedSrcSize);
- *     ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
- *     ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
- *
- * 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_dct_auto (treated as a full zstd dictionary if
- * it begins with ZSTD_MAGIC_DICTIONARY, else as raw content) and ZSTD_dlm_byCopy.
- */
-size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel);
-</b>/**! ZSTD_initCStream_advanced() :<b>
- * 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) {
- *         ZSTD_CCtx_setParameter(zcs, param, value);
- *     }
- *     ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
- *     ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
- *
- * pledgedSrcSize must be correct. If srcSize is not known at init time, use
- * value ZSTD_CONTENTSIZE_UNKNOWN. dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy.
- */
-size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
-                                             ZSTD_parameters params, unsigned long long pledgedSrcSize);
-</b>/**! ZSTD_initCStream_usingCDict() :<b>
- * 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
- */
-size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict);
-</b>/**! ZSTD_initCStream_usingCDict_advanced() :<b>
- * 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) {
- *         ZSTD_CCtx_setParameter(zcs, fParam, value);
- *     }
- *     ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
- *     ZSTD_CCtx_refCDict(zcs, cdict);
- *
- * same as ZSTD_initCStream_usingCDict(), with control over frame parameters.
- * pledgedSrcSize must be correct. If srcSize is not known at init time, use
- * value ZSTD_CONTENTSIZE_UNKNOWN.
- */
-size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, ZSTD_frameParameters fParams, 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:
+     ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
+     ZSTD_CCtx_setParameter(zcs, ZSTD_c_compressionLevel, compressionLevel);
+     ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
+
+ 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_dct_auto (treated as a full zstd dictionary if
+ 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>
+
+<a name="Chapter21"></a><h2>! ZSTD_initCStream_advanced() :</h2><pre> 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) {
+         ZSTD_CCtx_setParameter(zcs, param, value);
+     }
+     ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
+     ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
+
+ dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy.
+ pledgedSrcSize must be correct.
+ 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>
+
+<a name="Chapter22"></a><h2>! ZSTD_initCStream_usingCDict() :</h2><pre> 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>
+
+<a name="Chapter23"></a><h2>! ZSTD_initCStream_usingCDict_advanced() :</h2><pre>   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) {
+         ZSTD_CCtx_setParameter(zcs, fParam, value);
+     }
+     ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
+     ZSTD_CCtx_refCDict(zcs, cdict);
+
+ same as ZSTD_initCStream_usingCDict(), with control over frame parameters.
+ pledgedSrcSize must be correct. 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>
+
 <pre><b>size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize);
 </b><p> This function is deprecated, and is equivalent to:
      ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
@@ -1405,6 +1427,7 @@ size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict*
   For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs,
   but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead.
  @return : 0, or an error code (which can be tested using ZSTD_isError())
+  Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
  
 </p></pre><BR>
 
@@ -1439,34 +1462,35 @@ size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict*
  *     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);
-</b>/**<b>
- * This function is deprecated, and is equivalent to:
- *
- *     ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
- *     ZSTD_DCtx_refDDict(zds, ddict);
- *
- * note : ddict is referenced, it must outlive decompression session
- */
-size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict);
-</b>/**<b>
- * This function is deprecated, and is equivalent to:
- *
- *     ZSTD_DCtx_reset(zds, ZSTD_reset_session_only);
- *
- * re-use decompression parameters from previous init; saves dictionary loading
- */
-size_t ZSTD_resetDStream(ZSTD_DStream* zds);
 </pre></b><BR>
-<a name="Chapter20"></a><h2>Buffer-less and synchronous inner streaming functions</h2><pre>
+<a name="Chapter24"></a><h2>This function is deprecated, and is equivalent to:</h2><pre>
+     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>
+
+<a name="Chapter25"></a><h2>This function is deprecated, and is equivalent to:</h2><pre>
+     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>
+
+<a name="Chapter26"></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="Chapter21"></a><h2>Buffer-less streaming compression (synchronous mode)</h2><pre>
+<a name="Chapter27"></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.
@@ -1502,7 +1526,7 @@ 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="Chapter22"></a><h2>Buffer-less streaming decompression (synchronous mode)</h2><pre>
+<a name="Chapter28"></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.
@@ -1598,9 +1622,9 @@ 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="Chapter23"></a><h2>Block level API</h2><pre></pre>
+<a name="Chapter29"></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).
+<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.
 
     A few rules to respect :

lib/zstd.h

@@ -197,9 +197,13 @@ ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void);
 ZSTDLIB_API size_t     ZSTD_freeCCtx(ZSTD_CCtx* cctx);
 
 /*! ZSTD_compressCCtx() :
- *  Same as ZSTD_compress(), using an explicit ZSTD_CCtx
+ *  Same as ZSTD_compress(), using an explicit ZSTD_CCtx.
- *  The function will compress at requested compression level,
+ *  Important : in order to behave similarly to `ZSTD_compress()`,
- *  ignoring any other parameter */
+ *  this function compresses at requested compression level,
+ *  __ignoring any other parameter__ .
+ *  If any advanced parameter was set using the advanced API,
+ *  they will all be reset. Only `compressionLevel` remains.
+ */
 ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* cctx,
                                      void* dst, size_t dstCapacity,
                                const void* src, size_t srcSize,
@@ -234,7 +238,7 @@ ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx,
  *   using ZSTD_CCtx_set*() functions.
  *   Pushed parameters are sticky : they are valid for next compressed frame, and any subsequent frame.
  *   "sticky" parameters are applicable to `ZSTD_compress2()` and `ZSTD_compressStream*()` !
- *   They do not apply to "simple" one-shot variants such as ZSTD_compressCCtx()
+ *   __They do not apply to "simple" one-shot variants such as ZSTD_compressCCtx()__ .
  *
  *   It's possible to reset all parameters to "default" using ZSTD_CCtx_reset().
  *
@@ -262,18 +266,26 @@ typedef enum {
 
     /* compression parameters
      * Note: When compressing with a ZSTD_CDict these parameters are superseded
-     * by the parameters used to construct the ZSTD_CDict. See ZSTD_CCtx_refCDict()
+     * by the parameters used to construct the ZSTD_CDict.
-     * for more info (superseded-by-cdict). */
+     * See ZSTD_CCtx_refCDict() for more info (superseded-by-cdict). */
-    ZSTD_c_compressionLevel=100, /* Update all compression parameters according to pre-defined cLevel table
+    ZSTD_c_compressionLevel=100, /* Set compression parameters according to pre-defined cLevel table.
+                              * Note that exact compression parameters are dynamically determined,
+                              * depending on both compression level and srcSize (when known).
                               * Default level is ZSTD_CLEVEL_DEFAULT==3.
                               * Special: value 0 means default, which is controlled by ZSTD_CLEVEL_DEFAULT.
                               * Note 1 : it's possible to pass a negative compression level.
-                              * Note 2 : setting a level sets all default values of other compression parameters */
+                              * Note 2 : setting a level resets all other compression parameters to default */
+    /* Advanced compression parameters :
+     * It's possible to pin down compression parameters to some specific values.
+     * In which case, these values are no longer dynamically selected by the compressor */
     ZSTD_c_windowLog=101,    /* Maximum allowed back-reference distance, expressed as power of 2.
+                              * This will set a memory budget for streaming decompression,
+                              * with larger values requiring more memory
+                              * and typically compressing more.
                               * Must be clamped between ZSTD_WINDOWLOG_MIN and ZSTD_WINDOWLOG_MAX.
                               * Special: value 0 means "use default windowLog".
                               * Note: Using a windowLog greater than ZSTD_WINDOWLOG_LIMIT_DEFAULT
-                              *       requires explicitly allowing such window size at decompression stage if using streaming. */
+                              *       requires explicitly allowing such size at streaming decompression stage. */
     ZSTD_c_hashLog=102,      /* Size of the initial probe table, as a power of 2.
                               * Resulting memory usage is (1 << (hashLog+2)).
                               * Must be clamped between ZSTD_HASHLOG_MIN and ZSTD_HASHLOG_MAX.
@@ -284,13 +296,13 @@ typedef enum {
                               * Resulting memory usage is (1 << (chainLog+2)).
                               * Must be clamped between ZSTD_CHAINLOG_MIN and ZSTD_CHAINLOG_MAX.
                               * Larger tables result in better and slower compression.
-                              * This parameter is useless when using "fast" strategy.
+                              * This parameter is useless for "fast" strategy.
                               * It's still useful when using "dfast" strategy,
                               * in which case it defines a secondary probe table.
                               * Special: value 0 means "use default chainLog". */
     ZSTD_c_searchLog=104,    /* Number of search attempts, as a power of 2.
                               * More attempts result in better and slower compression.
-                              * This parameter is useless when using "fast" and "dFast" strategies.
+                              * This parameter is useless for "fast" and "dFast" strategies.
                               * Special: value 0 means "use default searchLog". */
     ZSTD_c_minMatch=105,     /* Minimum size of searched matches.
                               * Note that Zstandard can still find matches of smaller size,
@@ -345,7 +357,7 @@ typedef enum {
     ZSTD_c_contentSizeFlag=200, /* Content size will be written into frame header _whenever known_ (default:1)
                               * Content size must be known at the beginning of compression.
                               * This is automatically the case when using ZSTD_compress2(),
-                              * For streaming variants, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */
+                              * For streaming scenarios, content size must be provided with ZSTD_CCtx_setPledgedSrcSize() */
     ZSTD_c_checksumFlag=201, /* A 32-bits checksum of content is written at end of frame (default:0) */
     ZSTD_c_dictIDFlag=202,   /* When applicable, dictionary's ID is written into frame header (default:1) */
 
@@ -364,7 +376,7 @@ typedef enum {
                               * 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.
                               * Job size must be a minimum of overlap size, or 1 MB, whichever is largest.
-                              * The minimum size is automatically and transparently enforced */
+                              * The minimum size is automatically and transparently enforced. */
     ZSTD_c_overlapLog=402,   /* Control the overlap size, as a fraction of window size.
                               * The overlap size is an amount of data reloaded from previous job at the beginning of a new job.
                               * It helps preserve compression ratio, while each job is compressed in parallel.
@@ -1128,15 +1140,6 @@ typedef enum {
 } ZSTD_dictLoadMethod_e;
 
 typedef enum {
-    /* Opened question : should we have a format ZSTD_f_auto ?
-     * Today, it would mean exactly the same as ZSTD_f_zstd1.
-     * But, in the future, should several formats become supported,
-     * on the compression side, it would mean "default format".
-     * On the decompression side, it would mean "automatic format detection",
-     * so that ZSTD_f_zstd1 would mean "accept *only* zstd frames".
-     * Since meaning is a little different, another option could be to define different enums for compression and decompression.
-     * This question could be kept for later, when there are actually multiple formats to support,
-     * but there is also the question of pinning enum values, and pinning value `0` is especially important */
     ZSTD_f_zstd1 = 0,           /* zstd frame format, specified in zstd_compression_format.md (default) */
     ZSTD_f_zstd1_magicless = 1  /* Variant of zstd frame format, without initial 4-bytes magic number.
                                  * Useful to save 4 bytes per generated frame.
@@ -1375,7 +1378,8 @@ ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictS
  *  Create a digested dictionary for compression
  *  Dictionary content is just referenced, not duplicated.
  *  As a consequence, `dictBuffer` **must** outlive CDict,
- *  and its content must remain unmodified throughout the lifetime of CDict. */
+ *  and its content must remain unmodified throughout the lifetime of CDict.
+ *  note: equivalent to ZSTD_createCDict_advanced(), with dictLoadMethod==ZSTD_dlm_byRef */
 ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict_byReference(const void* dictBuffer, size_t dictSize, int compressionLevel);
 
 /*! ZSTD_getCParams() :
@@ -1402,7 +1406,9 @@ ZSTDLIB_API size_t ZSTD_checkCParams(ZSTD_compressionParameters params);
 ZSTDLIB_API ZSTD_compressionParameters ZSTD_adjustCParams(ZSTD_compressionParameters cPar, unsigned long long srcSize, size_t dictSize);
 
 /*! ZSTD_compress_advanced() :
- *  Same as ZSTD_compress_usingDict(), with fine-tune control over compression parameters (by structure) */
+ *  Note : this function is now DEPRECATED.
+ *         It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_setParameter() and other parameter setters.
+ *  This prototype will be marked as deprecated and generate compilation warning on reaching v1.5.x */
 ZSTDLIB_API size_t ZSTD_compress_advanced(ZSTD_CCtx* cctx,
                                           void* dst, size_t dstCapacity,
                                     const void* src, size_t srcSize,
@@ -1410,7 +1416,9 @@ ZSTDLIB_API size_t ZSTD_compress_advanced(ZSTD_CCtx* cctx,
                                           ZSTD_parameters params);
 
 /*! ZSTD_compress_usingCDict_advanced() :
- *  Same as ZSTD_compress_usingCDict(), with fine-tune control over frame parameters */
+ *  Note : this function is now REDUNDANT.
+ *         It can be replaced by ZSTD_compress2(), in combination with ZSTD_CCtx_loadDictionary() and other parameter setters.
+ *  This prototype will be marked as deprecated and generate compilation warning in some future version */
 ZSTDLIB_API size_t ZSTD_compress_usingCDict_advanced(ZSTD_CCtx* cctx,
                                               void* dst, size_t dstCapacity,
                                         const void* src, size_t srcSize,
@@ -1660,8 +1668,13 @@ ZSTDLIB_API size_t ZSTD_decompressStream_simpleArgs (
  * 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
  */
-ZSTDLIB_API size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLevel, unsigned long long pledgedSrcSize);
+ZSTDLIB_API size_t
+ZSTD_initCStream_srcSize(ZSTD_CStream* zcs,
+                         int compressionLevel,
+                         unsigned long long pledgedSrcSize);
+
 /**! ZSTD_initCStream_usingDict() :
  * This function is deprecated, and is equivalent to:
  *     ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
@@ -1672,8 +1685,13 @@ ZSTDLIB_API size_t ZSTD_initCStream_srcSize(ZSTD_CStream* zcs, int compressionLe
  * dict == NULL or dictSize < 8, in which case no dict is used.
  * Note: dict is loaded with ZSTD_dct_auto (treated as a full zstd dictionary if
  * 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
  */
-ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dict, size_t dictSize, int compressionLevel);
+ZSTDLIB_API size_t
+ZSTD_initCStream_usingDict(ZSTD_CStream* zcs,
+                     const void* dict, size_t dictSize,
+                           int compressionLevel);
+
 /**! ZSTD_initCStream_advanced() :
  * This function is deprecated, and is approximately equivalent to:
  *     ZSTD_CCtx_reset(zcs, ZSTD_reset_session_only);
@@ -1684,21 +1702,29 @@ ZSTDLIB_API size_t ZSTD_initCStream_usingDict(ZSTD_CStream* zcs, const void* dic
  *     ZSTD_CCtx_setPledgedSrcSize(zcs, pledgedSrcSize);
  *     ZSTD_CCtx_loadDictionary(zcs, dict, dictSize);
  *
- * pledgedSrcSize must be correct. If srcSize is not known at init time, use
+ * dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy.
- * value ZSTD_CONTENTSIZE_UNKNOWN. dict is loaded with ZSTD_dct_auto and ZSTD_dlm_byCopy.
+ * pledgedSrcSize must be correct.
+ * 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
  */
-ZSTDLIB_API size_t ZSTD_initCStream_advanced(ZSTD_CStream* zcs, const void* dict, size_t dictSize,
+ZSTDLIB_API size_t
-                                             ZSTD_parameters params, unsigned long long pledgedSrcSize);
+ZSTD_initCStream_advanced(ZSTD_CStream* zcs,
+                    const void* dict, size_t dictSize,
+                          ZSTD_parameters params,
+                          unsigned long long pledgedSrcSize);
+
 /**! ZSTD_initCStream_usingCDict() :
  * 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
  */
 ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDict* cdict);
+
 /**! ZSTD_initCStream_usingCDict_advanced() :
- * This function is deprecated, and is approximately equivalent to:
+ *   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) {
@@ -1710,8 +1736,13 @@ ZSTDLIB_API size_t ZSTD_initCStream_usingCDict(ZSTD_CStream* zcs, const ZSTD_CDi
  * same as ZSTD_initCStream_usingCDict(), with control over frame parameters.
  * pledgedSrcSize must be correct. 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
  */
-ZSTDLIB_API size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const ZSTD_CDict* cdict, ZSTD_frameParameters fParams, unsigned long long pledgedSrcSize);
+ZSTDLIB_API size_t
+ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs,
+                               const ZSTD_CDict* cdict,
+                                     ZSTD_frameParameters fParams,
+                                     unsigned long long pledgedSrcSize);
 
 /*! ZSTD_resetCStream() :
  * This function is deprecated, and is equivalent to:
@@ -1726,6 +1757,7 @@ ZSTDLIB_API size_t ZSTD_initCStream_usingCDict_advanced(ZSTD_CStream* zcs, const
  *  For the time being, pledgedSrcSize==0 is interpreted as "srcSize unknown" for compatibility with older programs,
  *  but it will change to mean "empty" in future version, so use macro ZSTD_CONTENTSIZE_UNKNOWN instead.
  * @return : 0, or an error code (which can be tested using ZSTD_isError())
+ *  Note : this prototype will be marked as deprecated and generate compilation warnings on reaching v1.5.x
  */
 ZSTDLIB_API size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize);
 
@@ -1771,8 +1803,10 @@ ZSTDLIB_API size_t ZSTD_toFlushNow(ZSTD_CCtx* cctx);
  *     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
  */
 ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize);
+
 /**
  * This function is deprecated, and is equivalent to:
  *
@@ -1780,14 +1814,17 @@ ZSTDLIB_API size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dic
  *     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
  */
 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);
  *
  * 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
  */
 ZSTDLIB_API size_t ZSTD_resetDStream(ZSTD_DStream* zds);
 
@@ -1961,7 +1998,7 @@ ZSTDLIB_API ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx);
 
 /*!
     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).
+    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.
 
     A few rules to respect :