Merge pull request #460 from lz4/frameCompress

refactored frameCompress.c example

1 files changed, 8 insertions, 4 deletions

diff --git a/lib/lz4frame.h b/lib/lz4frame.h
index eb55e45..15484d7 100644
--- a/lib/lz4frame.h
+++ b/lib/lz4frame.h
@@ -189,8 +189,10 @@ LZ4FLIB_API int LZ4F_compressionLevel_max(void);
 *  Simple compression function
 ***********************************/
 /*! LZ4F_compressFrameBound() :
- *  Returns the maximum possible size of a frame compressed with LZ4F_compressFrame() given srcSize content and preferences.
- *  Note : this result is only usable with LZ4F_compressFrame(), not with multi-segments compression.
+ *  Returns the maximum possible compressed size with LZ4F_compressFrame() given srcSize and preferences.
+ * `preferencesPtr` is optional. It can be replaced by NULL, in which case, the function will assume default preferences.
+ *  Note : this result is only usable with LZ4F_compressFrame().
+ *         It may also be used with LZ4F_compressUpdate() _if no flush() operation_ is performed.
  */
 LZ4FLIB_API size_t LZ4F_compressFrameBound(size_t srcSize, const LZ4F_preferences_t* preferencesPtr);
 
@@ -235,7 +237,7 @@ LZ4FLIB_API LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx);
 
 /*----    Compression    ----*/
 
-#define LZ4F_HEADER_SIZE_MAX 19
+#define LZ4F_HEADER_SIZE_MAX 19   /* LZ4 Frame header size can vary from 7 to 19 bytes */
 /*! LZ4F_compressBegin() :
  *  will write the frame header into dstBuffer.
  *  dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes.
@@ -248,7 +250,9 @@ LZ4FLIB_API size_t LZ4F_compressBegin(LZ4F_cctx* cctx,
                                       const LZ4F_preferences_t* prefsPtr);
 
 /*! LZ4F_compressBound() :
- *  Provides minimum dstCapacity for a given srcSize to guarantee operation success in worst case situations.
+ *  Provides minimum dstCapacity for a given srcSize to guarantee operation success in worst case scenarios.
+ *  Estimation includes frame footer, which would be generated by LZ4F_compressEnd().
+ *  Estimation doesn't include frame header, already generated by LZ4F_compressBegin().
  *  prefsPtr is optional : when NULL is provided, preferences will be set to cover worst case scenario.
  *  Result is always the same for a srcSize and prefsPtr, so it can be trusted to size reusable buffers.
  *  When srcSize==0, LZ4F_compressBound() provides an upper bound for LZ4F_flush() and LZ4F_compressEnd() operations.