1 files changed, 22 insertions, 26 deletions
diff --git a/MdePkg/Library/BaseMemoryLib/CopyMemWrapper.c b/MdePkg/Library/BaseMemoryLib/CopyMemWrapper.c
index 5ca62f5047..1fd00acabd 100644
--- a/MdePkg/Library/BaseMemoryLib/CopyMemWrapper.c
+++ b/MdePkg/Library/BaseMemoryLib/CopyMemWrapper.c
@@ -26,41 +26,37 @@
 #include "MemLibInternals.h"
 
 /**
-  Copy Length bytes from Source to Destination.
+  Copies a source buffer to a destination buffer, and returns the destination buffer.
 
-  This function copies Length bytes from SourceBuffer to DestinationBuffer, and
-  returns DestinationBuffer. The implementation must be reentrant, and it must
-  handle the case where SourceBuffer overlaps DestinationBuffer.
+  This function copies Length bytes from SourceBuffer to DestinationBuffer, and returns
+  DestinationBuffer.  The implementation must be reentrant, and it must handle the case
+  where SourceBuffer overlaps DestinationBuffer.
+  If Length is greater than (MAX_ADDRESS - DestinationBuffer + 1), then ASSERT(). 
+  If Length is greater than (MAX_ADDRESS - SourceBuffer + 1), then ASSERT(). 
 
-  If Length is greater than (MAX_ADDRESS - DestinationBuffer + 1), then
-  ASSERT().
-  If Length is greater than (MAX_ADDRESS - SourceBuffer + 1), then ASSERT().
+  @param  DestinationBuffer   Pointer to the destination buffer of the memory copy.
+  @param  SourceBuffer        Pointer to the source buffer of the memory copy.
+  @param  Length              Number of bytes to copy from SourceBuffer to DestinationBuffer.
 
-  @param  Destination Target of copy
-  @param  Source Place to copy from
-  @param  Length Number of bytes to copy
-
-  @return Destination
+  @return DestinationBuffer.
 
 **/
 VOID *
 EFIAPI
 CopyMem (
-  OUT     VOID                      *Destination,
-  IN      CONST VOID                *Source,
-  IN      UINTN                     Length
+  OUT VOID       *DestinationBuffer,
+  IN CONST VOID  *SourceBuffer,
+  IN UINTN       Length
   )
 {
-  ASSERT (
-    Destination == NULL ||
-    Length <= MAX_ADDRESS - (UINTN)Destination + 1
-    );
-  ASSERT (
-    Source == NULL ||
-    Length <= MAX_ADDRESS - (UINTN)Source + 1
-    );
-  if (Destination == Source || Length == 0) {
-    return Destination;
+  if (Length == 0) {
+    return DestinationBuffer;
+  }
+  ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)DestinationBuffer));
+  ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)SourceBuffer));
+
+  if (DestinationBuffer == SourceBuffer) {
+    return DestinationBuffer;
   }
-  return InternalMemCopyMem (Destination, Source, Length);
+  return InternalMemCopyMem (DestinationBuffer, SourceBuffer, Length);
 }