diff --git a/doc/zstd_compression_format.md b/doc/zstd_compression_format.md
index b58b43f5..b48b3910 100644
--- a/doc/zstd_compression_format.md
+++ b/doc/zstd_compression_format.md
@@ -1135,7 +1135,8 @@ When `Repeated_Offset2` is used, it's swapped with `Repeated_Offset1`.
Dictionary format
-----------------
-`zstd` is compatible with "raw content" dictionaries, free of any format restriction.
+`zstd` is compatible with "raw content" dictionaries, free of any format restriction,
+except that they must be at least 8 bytes.
But dictionaries created by `zstd --train` follow a format, described here.
__Pre-requisites__ : a dictionary has a size,
diff --git a/doc/zstd_manual.html b/doc/zstd_manual.html
index 2470a455..33ea13c3 100644
--- a/doc/zstd_manual.html
+++ b/doc/zstd_manual.html
@@ -58,7 +58,7 @@
Compresses `src` content as a single zstd compressed frame into already allocated `dst`.
Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
@return : compressed size written into `dst` (<= `dstCapacity),
- or an error code if it fails (which can be tested using ZSTD_isError())
+ or an error code if it fails (which can be tested using ZSTD_isError()).
size_t ZSTD_decompress( void* dst, size_t dstCapacity,
@@ -67,7 +67,7 @@
`dstCapacity` is an upper bound of originalSize.
If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.
@return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
- or an errorCode if it fails (which can be tested using ZSTD_isError())
+ or an errorCode if it fails (which can be tested using ZSTD_isError()).
unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize);
@@ -96,7 +96,7 @@ const char* ZSTD_getErrorName(size_t code); /*!< provides readable strin
Explicit memory management
size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel);
- Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx())
+
Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()).
Decompression context
typedef struct ZSTD_DCtx_s ZSTD_DCtx;
@@ -104,7 +104,7 @@ ZSTD_DCtx* ZSTD_createDCtx(void);
size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
- Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx())
+
Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()).
Simple dictionary API
@@ -115,7 +115,8 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
const void* dict,size_t dictSize,
int compressionLevel);
Compression using a predefined Dictionary (see dictBuilder/zdict.h).
- Note : This function load the dictionary, resulting in significant startup delay.
+ Note : This function loads the dictionary, resulting in significant startup delay.
+ Note : When `dict == NULL || dictSize < 8` no dictionary is used.
size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
@@ -124,7 +125,8 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
const void* dict,size_t dictSize);
Decompression using a predefined Dictionary (see dictBuilder/zdict.h).
Dictionary must be identical to the one used during compression.
- Note : This function load the dictionary, resulting in significant startup delay
+ Note : This function loads the dictionary, resulting in significant startup delay.
+ Note : When `dict == NULL || dictSize < 8` no dictionary is used.
Fast dictionary API
@@ -133,11 +135,11 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
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
+ `dict` can be released after ZSTD_CDict creation.
size_t ZSTD_freeCDict(ZSTD_CDict* CDict);
- Function frees memory allocated by ZSTD_createCDict()
+
Function frees memory allocated by ZSTD_createCDict().
size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
@@ -146,12 +148,12 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
const ZSTD_CDict* cdict);
Compression using a digested Dictionary.
Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
- Note that compression level is decided during dictionary creation
+ Note that compression level is decided during dictionary creation.
ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize);
Create a digested dictionary, ready to start decompression operation without startup delay.
- `dict` can be released after creation
+ `dict` can be released after creation.
size_t ZSTD_freeDDict(ZSTD_DDict* ddict);
@@ -162,7 +164,7 @@ size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const ZSTD_DDict* ddict);
- Decompression using a digested Dictionary
+
Decompression using a digested Dictionary.
Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times.
diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index e7f7d991..32059f84 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -2695,6 +2695,7 @@ size_t ZSTD_compress_advanced (ZSTD_CCtx* ctx,
size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, const void* dict, size_t dictSize, int compressionLevel)
{
+ if (!dict) dictSize = 0;
ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize, dictSize);
params.fParams.contentSizeFlag = 1;
return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, params);
diff --git a/lib/zstd.h b/lib/zstd.h
index ea5caf14..d57c2092 100644
--- a/lib/zstd.h
+++ b/lib/zstd.h
@@ -72,7 +72,7 @@ ZSTDLIB_API unsigned ZSTD_versionNumber (void); /**< returns version number of
Compresses `src` content as a single zstd compressed frame into already allocated `dst`.
Hint : compression runs faster if `dstCapacity` >= `ZSTD_compressBound(srcSize)`.
@return : compressed size written into `dst` (<= `dstCapacity),
- or an error code if it fails (which can be tested using ZSTD_isError()) */
+ or an error code if it fails (which can be tested using ZSTD_isError()). */
ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
int compressionLevel);
@@ -82,7 +82,7 @@ ZSTDLIB_API size_t ZSTD_compress( void* dst, size_t dstCapacity,
`dstCapacity` is an upper bound of originalSize.
If user cannot imply a maximum upper bound, it's better to use streaming mode to decompress data.
@return : the number of bytes decompressed into `dst` (<= `dstCapacity`),
- or an errorCode if it fails (which can be tested using ZSTD_isError()) */
+ or an errorCode if it fails (which can be tested using ZSTD_isError()). */
ZSTDLIB_API size_t ZSTD_decompress( void* dst, size_t dstCapacity,
const void* src, size_t compressedSize);
@@ -125,7 +125,7 @@ ZSTDLIB_API ZSTD_CCtx* ZSTD_createCCtx(void);
ZSTDLIB_API size_t ZSTD_freeCCtx(ZSTD_CCtx* cctx);
/*! ZSTD_compressCCtx() :
- Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()) */
+ Same as ZSTD_compress(), requires an allocated ZSTD_CCtx (see ZSTD_createCCtx()). */
ZSTDLIB_API size_t ZSTD_compressCCtx(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize, int compressionLevel);
/*= Decompression context */
@@ -134,7 +134,7 @@ ZSTDLIB_API ZSTD_DCtx* ZSTD_createDCtx(void);
ZSTDLIB_API size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
/*! ZSTD_decompressDCtx() :
-* Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()) */
+* Same as ZSTD_decompress(), requires an allocated ZSTD_DCtx (see ZSTD_createDCtx()). */
ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize);
@@ -143,7 +143,8 @@ ZSTDLIB_API size_t ZSTD_decompressDCtx(ZSTD_DCtx* ctx, void* dst, size_t dstCapa
***************************/
/*! ZSTD_compress_usingDict() :
* Compression using a predefined Dictionary (see dictBuilder/zdict.h).
-* Note : This function load the dictionary, resulting in significant startup delay. */
+* Note : This function loads the dictionary, resulting in significant startup delay.
+* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
@@ -153,7 +154,8 @@ ZSTDLIB_API size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx,
/*! ZSTD_decompress_usingDict() :
* Decompression using a predefined Dictionary (see dictBuilder/zdict.h).
* Dictionary must be identical to the one used during compression.
-* Note : This function load the dictionary, resulting in significant startup delay */
+* Note : This function loads the dictionary, resulting in significant startup delay.
+* Note : When `dict == NULL || dictSize < 8` no dictionary is used. */
ZSTDLIB_API size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
@@ -169,17 +171,17 @@ typedef struct ZSTD_CDict_s ZSTD_CDict;
* 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 */
+* `dict` can be released after ZSTD_CDict creation. */
ZSTDLIB_API ZSTD_CDict* ZSTD_createCDict(const void* dict, size_t dictSize, int compressionLevel);
/*! ZSTD_freeCDict() :
-* Function frees memory allocated by ZSTD_createCDict() */
+* Function frees memory allocated by ZSTD_createCDict(). */
ZSTDLIB_API size_t ZSTD_freeCDict(ZSTD_CDict* CDict);
/*! ZSTD_compress_usingCDict() :
* Compression using a digested Dictionary.
* Faster startup than ZSTD_compress_usingDict(), recommended when same dictionary is used multiple times.
-* Note that compression level is decided during dictionary creation */
+* Note that compression level is decided during dictionary creation. */
ZSTDLIB_API size_t ZSTD_compress_usingCDict(ZSTD_CCtx* cctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
@@ -190,7 +192,7 @@ typedef struct ZSTD_DDict_s ZSTD_DDict;
/*! ZSTD_createDDict() :
* Create a digested dictionary, ready to start decompression operation without startup delay.
-* `dict` can be released after creation */
+* `dict` can be released after creation. */
ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize);
/*! ZSTD_freeDDict() :
@@ -198,7 +200,7 @@ ZSTDLIB_API ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize);
ZSTDLIB_API size_t ZSTD_freeDDict(ZSTD_DDict* ddict);
/*! ZSTD_decompress_usingDDict() :
-* Decompression using a digested Dictionary
+* Decompression using a digested Dictionary.
* Faster startup than ZSTD_decompress_usingDict(), recommended when same dictionary is used multiple times. */
ZSTDLIB_API size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,