unpublish static-only function
these functions are now unpublished in dll by default.
One needs to opt-in, using macro LZ4_PUBLISH_STATIC_FUNCTIONS.
used this opportunity to update a bunch of api comments in lz4.h
diff --git a/doc/lz4_manual.html b/doc/lz4_manual.html
index 6ebf8d2..39a48f3 100644
--- a/doc/lz4_manual.html
+++ b/doc/lz4_manual.html
@@ -21,7 +21,7 @@
</ol>
<hr>
<a name="Chapter1"></a><h2>Introduction</h2><pre>
- LZ4 is lossless compression algorithm, providing compression speed at 400 MB/s per core,
+ LZ4 is lossless compression algorithm, providing compression speed at 500 MB/s per core,
scalable with multi-cores CPU. It features an extremely fast decoder, with speed in
multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.
@@ -37,15 +37,15 @@
An additional format, called LZ4 frame specification (doc/lz4_Frame_format.md),
take care of encoding standard metadata alongside LZ4-compressed blocks.
- If your application requires interoperability, it's recommended to use it.
- A library is provided to take care of it, see lz4frame.h.
+ Frame format is required for interoperability.
+ It is delivered through a companion API, declared in lz4frame.h.
<BR></pre>
<a name="Chapter2"></a><h2>Version</h2><pre></pre>
<pre><b>int LZ4_versionNumber (void); </b>/**< library version number; useful to check dll version */<b>
</b></pre><BR>
-<pre><b>const char* LZ4_versionString (void); </b>/**< library version string; unseful to check dll version */<b>
+<pre><b>const char* LZ4_versionString (void); </b>/**< library version string; useful to check dll version */<b>
</b></pre><BR>
<a name="Chapter3"></a><h2>Tuning parameter</h2><pre></pre>
@@ -53,8 +53,8 @@
# define LZ4_MEMORY_USAGE 14
#endif
</b><p> Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
- Increasing memory usage improves compression ratio
- Reduced memory usage may improve speed, thanks to cache effect
+ Increasing memory usage improves compression ratio.
+ Reduced memory usage may improve speed, thanks to better cache locality.
Default value is 14, for 16KB, which nicely fits into Intel x86 L1 cache
</p></pre><BR>
@@ -68,21 +68,21 @@
It also runs faster, so it's a recommended setting.
If the function cannot compress 'src' into a more limited 'dst' budget,
compression stops *immediately*, and the function result is zero.
- Note : as a consequence, 'dst' content is not valid.
- Note 2 : This function is protected against buffer overflow scenarios (never writes outside 'dst' buffer, nor read outside 'source' buffer).
+ In which case, 'dst' content is undefined (invalid).
srcSize : max supported value is LZ4_MAX_INPUT_SIZE.
dstCapacity : size of buffer 'dst' (which must be already allocated)
- return : the number of bytes written into buffer 'dst' (necessarily <= dstCapacity)
- or 0 if compression fails
+ @return : the number of bytes written into buffer 'dst' (necessarily <= dstCapacity)
+ or 0 if compression fails
+ Note : This function is protected against buffer overflow scenarios (never writes outside 'dst' buffer, nor read outside 'source' buffer).
</p></pre><BR>
<pre><b>int LZ4_decompress_safe (const char* src, char* dst, int compressedSize, int dstCapacity);
</b><p> compressedSize : is the exact complete size of the compressed block.
dstCapacity : is the size of destination buffer, which must be already allocated.
- return : the number of bytes decompressed into destination buffer (necessarily <= dstCapacity)
+ @return : the number of bytes decompressed into destination buffer (necessarily <= dstCapacity)
If destination buffer is not large enough, decoding will stop and output an error code (negative value).
If the source stream is detected malformed, the function will stop decoding and return a negative result.
- This function is protected against malicious data packets.
+ Note : This function is protected against malicious data packets (never writes outside 'dst' buffer, nor read outside 'source' buffer).
</p></pre><BR>
<a name="Chapter5"></a><h2>Advanced Functions</h2><pre></pre>
@@ -107,10 +107,11 @@
<pre><b>int LZ4_sizeofState(void);
int LZ4_compress_fast_extState (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
-</b><p> Same compression function, just using an externally allocated memory space to store compression state.
- Use LZ4_sizeofState() to know how much memory must be allocated,
- and allocate it on 8-bytes boundaries (using malloc() typically).
- Then, provide this buffer as 'void* state' to compression function.
+</b><p> Same as LZ4_compress_fast(), using an externally allocated memory space for its state.
+ Use LZ4_sizeofState() to know how much memory must be allocated,
+ and allocate it on 8-bytes boundaries (using `malloc()` typically).
+ Then, provide this buffer as `void* state` to compression function.
+
</p></pre><BR>
<pre><b>int LZ4_compress_destSize (const char* src, char* dst, int* srcSizePtr, int targetDstSize);
@@ -132,7 +133,7 @@
and now `LZ4_decompress_safe()` can be as fast and sometimes faster than `LZ4_decompress_fast()`.
Moreover, LZ4_decompress_fast() is not protected vs malformed input, as it doesn't perform full validation of compressed data.
As a consequence, this function is no longer recommended, and may be deprecated in future versions.
- It's only remaining specificity is that it can decompress data without knowing its compressed size.
+ It's last remaining specificity is that it can decompress data without knowing its compressed size.
originalSize : is the uncompressed size to regenerate.
`dst` must be already allocated, its size must be >= 'originalSize' bytes.
@@ -175,13 +176,6 @@
<a name="Chapter6"></a><h2>Streaming Compression Functions</h2><pre></pre>
-<pre><b>LZ4_stream_t* LZ4_createStream(void);
-int LZ4_freeStream (LZ4_stream_t* streamPtr);
-</b><p> LZ4_createStream() will allocate and initialize an `LZ4_stream_t` structure.
- LZ4_freeStream() releases its memory.
-
-</p></pre><BR>
-
<pre><b>void LZ4_resetStream (LZ4_stream_t* streamPtr);
</b><p> An LZ4_stream_t structure can be allocated once and re-used multiple times.
Use this function to start compressing a new stream.
@@ -198,7 +192,7 @@
<pre><b>int LZ4_compress_fast_continue (LZ4_stream_t* streamPtr, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
</b><p> Compress 'src' content using data from previously compressed blocks, for better compression ratio.
- 'dst' buffer must be already allocated.
+ 'dst' buffer must be already allocated.
If dstCapacity >= LZ4_compressBound(srcSize), compression is guaranteed to succeed, and runs faster.
@return : size of compressed block
@@ -206,10 +200,10 @@
Note 1 : Each invocation to LZ4_compress_fast_continue() generates a new block.
Each block has precise boundaries.
+ Each block must be decompressed separately, calling LZ4_decompress_*() with relevant metadata.
It's not possible to append blocks together and expect a single invocation of LZ4_decompress_*() to decompress them together.
- Each block must be decompressed separately, calling LZ4_decompress_*() with associated metadata.
- Note 2 : The previous 64KB of source data is __assumed__ to remain present, unmodified, at same address in memory!
+ Note 2 : The previous 64KB of source data is __assumed__ to remain present, unmodified, at same address in memory !
Note 3 : When input is structured as a double-buffer, each buffer can have any size, including < 64 KB.
Make sure that buffers are separated, by at least one byte.
@@ -217,7 +211,7 @@
Note 4 : If input buffer is a ring-buffer, it can have any size, including < 64 KB.
- Note 5 : After an error, the stream status is invalid, it can only be reset or freed.
+ Note 5 : After an error, the stream status is undefined (invalid), it can only be reset or freed.
</p></pre><BR>
@@ -250,7 +244,7 @@
</p></pre><BR>
<pre><b>int LZ4_decoderRingBufferSize(int maxBlockSize);
-#define LZ4_DECODER_RING_BUFFER_SIZE(mbs) (65536 + 14 + (mbs)) </b>/* for static allocation; mbs presumed valid */<b>
+#define LZ4_DECODER_RING_BUFFER_SIZE(maxBlockSize) (65536 + 14 + (maxBlockSize)) </b>/* for static allocation; maxBlockSize presumed valid */<b>
</b><p> Note : in a ring buffer scenario (optional),
blocks are presumed decompressed next to each other
up to the moment there is not enough remaining space for next block (remainingSize < maxBlockSize),
@@ -295,32 +289,34 @@
</b><p> These decoding functions work the same as
a combination of LZ4_setStreamDecode() followed by LZ4_decompress_*_continue()
They are stand-alone, and don't need an LZ4_streamDecode_t structure.
- Dictionary is presumed stable : it must remain accessible and unmodified during next decompression.
+ Dictionary is presumed stable : it must remain accessible and unmodified during decompression.
+ Performance tip : Decompression speed can be substantially increased
+ when dst == dictStart + dictSize.
</p></pre><BR>
<a name="Chapter8"></a><h2>Unstable declarations</h2><pre>
- Declarations in this section should be considered unstable.
- Use at your own peril, etc., etc.
- They may be removed in the future.
- Their signatures may change.
+ Declarations in this section must be considered unstable.
+ Their signatures may change, or may be removed in the future.
+ They are therefore only safe to depend on
+ when the caller is statically linked against the library.
+ To access their declarations, define LZ4_STATIC_LINKING_ONLY.
<BR></pre>
-<pre><b>void LZ4_resetStream_fast (LZ4_stream_t* streamPtr);
+<pre><b>LZ4LIB_STATIC_API void LZ4_resetStream_fast (LZ4_stream_t* streamPtr);
</b><p> Use this, like LZ4_resetStream(), to prepare a context for a new chain of
calls to a streaming API (e.g., LZ4_compress_fast_continue()).
Note:
- Using this in advance of a non- streaming-compression function is redundant,
- and potentially bad for performance, since they all perform their own custom
- reset internally.
+ Using this in advance of a non-streaming-compression function is redundant,
+ since they all perform their own custom reset internally.
Differences from LZ4_resetStream():
When an LZ4_stream_t is known to be in a internally coherent state,
- it can often be prepared for a new compression with almost no work, only
- sometimes falling back to the full, expensive reset that is always required
- when the stream is in an indeterminate state (i.e., the reset performed by
- LZ4_resetStream()).
+ it can often be prepared for a new compression with almost no work,
+ only sometimes falling back to the full, expensive reset
+ that is always required when the stream is in an indeterminate state
+ (i.e., the reset performed by LZ4_resetStream()).
LZ4_streams are guaranteed to be in a valid state when:
- returned from LZ4_createStream()
@@ -339,22 +335,21 @@
</p></pre><BR>
-<pre><b>int LZ4_compress_fast_extState_fastReset (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
+<pre><b>LZ4LIB_STATIC_API int LZ4_compress_fast_extState_fastReset (void* state, const char* src, char* dst, int srcSize, int dstCapacity, int acceleration);
</b><p> A variant of LZ4_compress_fast_extState().
- Using this variant avoids an expensive initialization step. It is only safe
- to call if the state buffer is known to be correctly initialized already
- (see above comment on LZ4_resetStream_fast() for a definition of "correctly
- initialized"). From a high level, the difference is that this function
- initializes the provided state with a call to something like
- LZ4_resetStream_fast() while LZ4_compress_fast_extState() starts with a
- call to LZ4_resetStream().
+ Using this variant avoids an expensive initialization step.
+ It is only safe to call if the state buffer is known to be correctly initialized already
+ (see above comment on LZ4_resetStream_fast() for a definition of "correctly initialized").
+ From a high level, the difference is that
+ this function initializes the provided state with a call to something like LZ4_resetStream_fast()
+ while LZ4_compress_fast_extState() starts with a call to LZ4_resetStream().
</p></pre><BR>
-<pre><b>void LZ4_attach_dictionary(LZ4_stream_t *working_stream, const LZ4_stream_t *dictionary_stream);
-</b><p> This is an experimental API that allows for the efficient use of a
- static dictionary many times.
+<pre><b>LZ4LIB_STATIC_API void LZ4_attach_dictionary(LZ4_stream_t* workingStream, const LZ4_stream_t* dictionaryStream);
+</b><p> This is an experimental API that allows
+ efficient use of a static dictionary many times.
Rather than re-loading the dictionary buffer into a working context before
each compression, or copying a pre-loaded dictionary's LZ4_stream_t into a
@@ -365,8 +360,8 @@
Currently, only streams which have been prepared by LZ4_loadDict() should
be expected to work.
- Alternatively, the provided dictionary stream pointer may be NULL, in which
- case any existing dictionary stream is unset.
+ Alternatively, the provided dictionaryStream may be NULL,
+ in which case any existing dictionary stream is unset.
If a dictionary is provided, it replaces any pre-existing stream history.
The dictionary contents are the only history that can be referenced and
@@ -381,9 +376,9 @@
</p></pre><BR>
<a name="Chapter9"></a><h2>Private definitions</h2><pre>
- Do not use these definitions.
- They are exposed to allow static allocation of `LZ4_stream_t` and `LZ4_streamDecode_t`.
- Using these definitions will expose code to API and/or ABI break in future versions of the library.
+ Do not use these definitions directly.
+ They are only exposed to allow static allocation of `LZ4_stream_t` and `LZ4_streamDecode_t`.
+ Accessing members will expose code to API and/or ABI break in future versions of the library.
<BR></pre>
<pre><b>typedef struct {
@@ -406,11 +401,11 @@
unsigned long long table[LZ4_STREAMSIZE_U64];
LZ4_stream_t_internal internal_donotuse;
} ; </b>/* previously typedef'd to LZ4_stream_t */<b>
-</b><p> information structure to track an LZ4 stream.
- init this structure before first use.
- note : only use in association with static linking !
- this definition is not API/ABI safe,
- it may change in a future version !
+</b><p> information structure to track an LZ4 stream.
+ init this structure with LZ4_resetStream() before first use.
+ note : only use in association with static linking !
+ this definition is not API/ABI safe,
+ it may change in a future version !
</p></pre><BR>
@@ -420,11 +415,11 @@
unsigned long long table[LZ4_STREAMDECODESIZE_U64];
LZ4_streamDecode_t_internal internal_donotuse;
} ; </b>/* previously typedef'd to LZ4_streamDecode_t */<b>
-</b><p> information structure to track an LZ4 stream during decompression.
- init this structure using LZ4_setStreamDecode (or memset()) before first use
- note : only use in association with static linking !
- this definition is not API/ABI safe,
- and may change in a future version !
+</b><p> information structure to track an LZ4 stream during decompression.
+ init this structure using LZ4_setStreamDecode() before first use.
+ note : only use in association with static linking !
+ this definition is not API/ABI safe,
+ and may change in a future version !
</p></pre><BR>
