Merge pull request #1114 from lz4/blockSize

minor : proper interface for LZ4F_getBlockSize()

5 files changed, 39 insertions, 50 deletions

diff --git a/doc/lz4_manual.html b/doc/lz4_manual.html
index 037cfc08..5461ab92 100644
--- a/doc/lz4_manual.html
+++ b/doc/lz4_manual.html
@@ -50,9 +50,9 @@
 
 <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>
+<pre><b>int LZ4_versionNumber (void);  </b>/**< library version number; useful to check dll version; requires v1.3.0+ */<b>
 </b></pre><BR>
-<pre><b>const char* LZ4_versionString (void);   </b>/**< library version string; useful to check dll version */<b>
+<pre><b>const char* LZ4_versionString (void);   </b>/**< library version string; useful to check dll version; requires v1.7.5+ */<b>
 </b></pre><BR>
 <a name="Chapter3"></a><h2>Tuning parameter</h2><pre></pre>
 
@@ -452,28 +452,9 @@ int                 LZ4_freeStreamDecode (LZ4_streamDecode_t* LZ4_stream);
  Accessing members will expose user code to API and/or ABI break in future versions of the library.
 <BR></pre>
 
-<pre><b>typedef struct {
-    const LZ4_byte* externalDict;
-    size_t extDictSize;
-    const LZ4_byte* prefixEnd;
-    size_t prefixSize;
-} LZ4_streamDecode_t_internal;
-</b></pre><BR>
-<pre><b>#define LZ4_STREAMSIZE       ((1UL << LZ4_MEMORY_USAGE) + 32)  </b>/* static size, for inter-version compatibility */<b>
-#define LZ4_STREAMSIZE_VOIDP (LZ4_STREAMSIZE / sizeof(void*))
-union LZ4_stream_u {
-    void* table[LZ4_STREAMSIZE_VOIDP];
-    LZ4_stream_t_internal internal_donotuse;
-}; </b>/* previously typedef'd to LZ4_stream_t */<b>
-</b><p>  Do not use below internal definitions directly !
-  Declare or allocate an LZ4_stream_t instead.
-  LZ4_stream_t can also be created using LZ4_createStream(), which is recommended.
-  The structure definition can be convenient for static allocation
-  (on stack, or as part of larger structure).
-  Init this structure with LZ4_initStream() before first use.
-  note : only use this definition in association with static linking !
-  this definition is not API/ABI safe, and may change in future versions.
- 
+<pre><b></b><p>  Never ever use below internal definitions directly !
+  These definitions are not API/ABI safe, and may change in future versions.
+  If you need static allocation, declare or allocate an LZ4_stream_t object.
 </p></pre><BR>
 
 <pre><b>LZ4_stream_t* LZ4_initStream (void* buffer, size_t size);
@@ -489,21 +470,17 @@ union LZ4_stream_u {
          In which case, the function will @return NULL.
   Note2: An LZ4_stream_t structure guarantees correct alignment and size.
   Note3: Before v1.9.0, use LZ4_resetStream() instead
- 
 </p></pre><BR>
 
-<pre><b>#define LZ4_STREAMDECODESIZE_U64 (4 + ((sizeof(void*)==16) ? 2 : 0) </b>/*AS-400*/ )<b>
-#define LZ4_STREAMDECODESIZE     (LZ4_STREAMDECODESIZE_U64 * sizeof(unsigned long long))
-union LZ4_streamDecode_u {
-    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() 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 !
- 
+<pre><b>typedef struct {
+    const LZ4_byte* externalDict;
+    const LZ4_byte* prefixEnd;
+    size_t extDictSize;
+    size_t prefixSize;
+} LZ4_streamDecode_t_internal;
+</b><p>  Never ever use below internal definitions directly !
+  These definitions are not API/ABI safe, and may change in future versions.
+  If you need static allocation, declare or allocate an LZ4_streamDecode_t object.
 </p></pre><BR>
 
 <a name="Chapter10"></a><h2>Obsolete Functions</h2><pre></pre>
diff --git a/doc/lz4frame_manual.html b/doc/lz4frame_manual.html
index 0ae51505..196881e4 100644
--- a/doc/lz4frame_manual.html
+++ b/doc/lz4frame_manual.html
@@ -135,13 +135,16 @@
 
 <pre><b>LZ4F_errorCode_t LZ4F_createCompressionContext(LZ4F_cctx** cctxPtr, unsigned version);
 LZ4F_errorCode_t LZ4F_freeCompressionContext(LZ4F_cctx* cctx);
-</b><p> The first thing to do is to create a compressionContext object, which will be used in all compression operations.
+</b><p> The first thing to do is to create a compressionContext object,
+ which will keep track of operation state during streaming compression.
  This is achieved using LZ4F_createCompressionContext(), which takes as argument a version.
  The version provided MUST be LZ4F_VERSION. It is intended to track potential version mismatch, notably when using DLL.
  The function will provide a pointer to a fully allocated LZ4F_cctx object.
- If @return != zero, there was an error during context creation.
- Object can be released using LZ4F_freeCompressionContext();
- Note: LZ4F_freeCompressionContext() works with NULL pointers (do nothing).
+ If @return != zero, there context creation failed.
+ Once all streaming compression jobs are completed,
+ the state object can be released using LZ4F_freeCompressionContext().
+ Note1 : LZ4F_freeCompressionContext() is always successful. Its return value can be ignored.
+ Note2 : LZ4F_freeCompressionContext() works fine with NULL input pointers (do nothing).
  
 </p></pre><BR>
 
@@ -344,6 +347,11 @@ LZ4F_errorCode_t LZ4F_freeDecompressionContext(LZ4F_dctx* dctx);
 <pre><b>typedef enum { LZ4F_LIST_ERRORS(LZ4F_GENERATE_ENUM)
               _LZ4F_dummy_error_enum_for_c89_never_used } LZ4F_errorCodes;
 </b></pre><BR>
+<pre><b>LZ4FLIB_STATIC_API size_t LZ4F_getBlockSize(LZ4F_blockSizeID_t blockSizeID);
+</b><p>  Return, in scalar format (size_t),
+  the maximum block size associated with blockSizeID.
+</p></pre><BR>
+
 <pre><b>LZ4FLIB_STATIC_API size_t LZ4F_uncompressedUpdate(LZ4F_cctx* cctx,
                                                   void* dstBuffer, size_t dstCapacity,
                                                   const void* srcBuffer, size_t srcSize,
diff --git a/lib/lz4frame.c b/lib/lz4frame.c
index aec27281..5373083c 100644
--- a/lib/lz4frame.c
+++ b/lib/lz4frame.c
@@ -285,16 +285,16 @@ unsigned LZ4F_getVersion(void) { return LZ4F_VERSION; }
 
 int LZ4F_compressionLevel_max(void) { return LZ4HC_CLEVEL_MAX; }
 
-size_t LZ4F_getBlockSize(unsigned blockSizeID)
+size_t LZ4F_getBlockSize(LZ4F_blockSizeID_t blockSizeID)
 {
     static const size_t blockSizes[4] = { 64 KB, 256 KB, 1 MB, 4 MB };
 
     if (blockSizeID == 0) blockSizeID = LZ4F_BLOCKSIZEID_DEFAULT;
     if (blockSizeID < LZ4F_max64KB || blockSizeID > LZ4F_max4MB)
         RETURN_ERROR(maxBlockSize_invalid);
-    blockSizeID -= LZ4F_max64KB;
-    return blockSizes[blockSizeID];
-}
+    {   int const blockSizeIdx = (int)blockSizeID - (int)LZ4F_max64KB;
+        return blockSizes[blockSizeIdx];
+}   }
 
 /*-************************************
 *  Private functions
@@ -1291,7 +1291,7 @@ static size_t LZ4F_decodeHeader(LZ4F_dctx* dctx, const void* src, size_t srcSize
     dctx->frameInfo.blockChecksumFlag = (LZ4F_blockChecksum_t)blockChecksumFlag;
     dctx->frameInfo.contentChecksumFlag = (LZ4F_contentChecksum_t)contentChecksumFlag;
     dctx->frameInfo.blockSizeID = (LZ4F_blockSizeID_t)blockSizeID;
-    dctx->maxBlockSize = LZ4F_getBlockSize(blockSizeID);
+    dctx->maxBlockSize = LZ4F_getBlockSize((LZ4F_blockSizeID_t)blockSizeID);
     if (contentSizeFlag)
         dctx->frameRemainingSize =
             dctx->frameInfo.contentSize = LZ4F_readLE64(srcPtr+6);
diff --git a/lib/lz4frame.h b/lib/lz4frame.h
index 2c5a559a..1de09d8e 100644
--- a/lib/lz4frame.h
+++ b/lib/lz4frame.h
@@ -545,7 +545,11 @@ typedef enum { LZ4F_LIST_ERRORS(LZ4F_GENERATE_ENUM)
 
 LZ4FLIB_STATIC_API LZ4F_errorCodes LZ4F_getErrorCode(size_t functionResult);
 
-LZ4FLIB_STATIC_API size_t LZ4F_getBlockSize(unsigned);
+/*! LZ4F_getBlockSize() :
+ *  Return, in scalar format (size_t),
+ *  the maximum block size associated with blockSizeID.
+**/
+LZ4FLIB_STATIC_API size_t LZ4F_getBlockSize(LZ4F_blockSizeID_t blockSizeID);
 
 /*! LZ4F_uncompressedUpdate() :
  *  LZ4F_uncompressedUpdate() can be called repetitively to add as much data uncompressed data as necessary.
diff --git a/tests/frametest.c b/tests/frametest.c
index a496c3ce..58eac38f 100644
--- a/tests/frametest.c
+++ b/tests/frametest.c
@@ -686,20 +686,20 @@ int basicTests(U32 seed, double compressibility)
     { size_t result;
       unsigned blockSizeID;
       for (blockSizeID = 4; blockSizeID < 8; ++blockSizeID) {
-        result = LZ4F_getBlockSize(blockSizeID);
+        result = LZ4F_getBlockSize((LZ4F_blockSizeID_t)blockSizeID);
         CHECK(result);
         DISPLAYLEVEL(3, "Returned block size of %u bytes for blockID %u \n",
                          (unsigned)result, blockSizeID);
       }
 
       /* Test an invalid input that's too large */
-      result = LZ4F_getBlockSize(8);
+      result = LZ4F_getBlockSize((LZ4F_blockSizeID_t)8);
       if(!LZ4F_isError(result) ||
           LZ4F_getErrorCode(result) != LZ4F_ERROR_maxBlockSize_invalid)
         goto _output_error;
 
       /* Test an invalid input that's too small */
-      result = LZ4F_getBlockSize(3);
+      result = LZ4F_getBlockSize((LZ4F_blockSizeID_t)3);
       if(!LZ4F_isError(result) ||
           LZ4F_getErrorCode(result) != LZ4F_ERROR_maxBlockSize_invalid)
         goto _output_error;