Merge pull request #1158 from lz4/fix1157

allocation optimization for lz4frame compression

GitOrigin-RevId: 72997c5a915ccf80459cd023c6322239c308c025
Change-Id: Id5b7709af7560010999eaeab9f3c535a32094c87

lib/lz4frame.c

diff --git a/lib/lz4frame.c b/lib/lz4frame.c
index 174f9ae..b4caff4 100644
--- a/lib/lz4frame.c
+++ b/lib/lz4frame.c
@@ -264,7 +264,7 @@
     LZ4F_CustomMem cmem;
     LZ4F_preferences_t prefs;
     U32    version;
-    U32    cStage;
+    U32    cStage;     /* 0 : compression uninitialized ; 1 : initialized, can compress */
     const LZ4F_CDict* cdict;
     size_t maxBlockSize;
     size_t maxBufferSize;
@@ -732,7 +732,7 @@
         if (cctxPtr->maxBufferSize < requiredBuffSize) {
             cctxPtr->maxBufferSize = 0;
             LZ4F_free(cctxPtr->tmpBuff, cctxPtr->cmem);
-            cctxPtr->tmpBuff = (BYTE*)LZ4F_calloc(requiredBuffSize, cctxPtr->cmem);
+            cctxPtr->tmpBuff = (BYTE*)LZ4F_malloc(requiredBuffSize, cctxPtr->cmem);
             RETURN_ERROR_IF(cctxPtr->tmpBuff == NULL, allocation_failed);
             cctxPtr->maxBufferSize = requiredBuffSize;
     }   }
@@ -1176,7 +1176,6 @@
     }
 
     cctxPtr->cStage = 0;   /* state is now re-usable (with identical preferences) */
-    cctxPtr->maxBufferSize = 0;  /* reuse HC context */
 
     if (cctxPtr->prefs.frameInfo.contentSize) {
         if (cctxPtr->prefs.frameInfo.contentSize != cctxPtr->totalInSize)
@@ -1722,10 +1721,10 @@
                     /* history management (linked blocks only)*/
                     if (dctx->frameInfo.blockMode == LZ4F_blockLinked) {
                         LZ4F_updateDict(dctx, dstPtr, sizeToCopy, dstStart, 0);
-                }   }
-
-                srcPtr += sizeToCopy;
-                dstPtr += sizeToCopy;
+                    }
+                    srcPtr += sizeToCopy;
+                    dstPtr += sizeToCopy;
+                }
                 if (sizeToCopy == dctx->tmpInTarget) {   /* all done */
                     if (dctx->frameInfo.blockChecksumFlag) {
                         dctx->tmpInSize = 0;

lib/lz4frame.h

diff --git a/lib/lz4frame.h b/lib/lz4frame.h
index 1bdf6c4..8d9380b 100644
--- a/lib/lz4frame.h
+++ b/lib/lz4frame.h
@@ -278,7 +278,7 @@
 /*! LZ4F_compressBegin() :
  *  will write the frame header into dstBuffer.
  *  dstCapacity must be >= LZ4F_HEADER_SIZE_MAX bytes.
- * `prefsPtr` is optional : you can provide NULL as argument, all preferences will then be set to default.
+ * `prefsPtr` is optional : NULL can be provided to set all preferences to default.
  * @return : number of bytes written into dstBuffer for the header
  *           or an error code (which can be tested using LZ4F_isError())
  */