fix minor UBs

- check alignment before casting a pointer
- saveDict : don't memmove() on NULL dst

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/lz4.c b/lib/lz4.c
index c41a084..427673e 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -1661,7 +1661,9 @@ int LZ4_saveDict (LZ4_stream_t* LZ4_dict, char* safeBuffer, int dictSize)
     if ((U32)dictSize > 64 KB) { dictSize = 64 KB; } /* useless to define a dictionary > 64 KB */
     if ((U32)dictSize > dict->dictSize) { dictSize = (int)dict->dictSize; }
 
-    memmove(safeBuffer, previousDictEnd - dictSize, dictSize);
+    if (safeBuffer == NULL) assert(dictSize == 0);
+    if (safeBuffer != NULL)
+        memmove(safeBuffer, previousDictEnd - dictSize, dictSize);
 
     dict->dictionary = (const BYTE*)safeBuffer;
     dict->dictSize = (U32)dictSize;