MdePkg/Library/BaseMemoryLibOptPei/CopyMemWrapper.c

   1 /** @file
   2   CopyMem() implementation.
   3
   4   The following BaseMemoryLib instances contain the same copy of this file:
   5
   6     BaseMemoryLib
   7     BaseMemoryLibMmx
   8     BaseMemoryLibSse2
   9     BaseMemoryLibRepStr
  10     BaseMemoryLibOptDxe
  11     BaseMemoryLibOptPei
  12     PeiMemoryLib
  13     UefiMemoryLib
  14
  15   Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
  16   SPDX-License-Identifier: BSD-2-Clause-Patent
  17
  18 **/
  19
  20 #include "MemLibInternals.h"
  21
  22 /**
  23   Copies a source buffer to a destination buffer, and returns the destination buffer.
  24
  25   This function copies Length bytes from SourceBuffer to DestinationBuffer, and returns
  26   DestinationBuffer.  The implementation must be reentrant, and it must handle the case
  27   where SourceBuffer overlaps DestinationBuffer.
  28
  29   If Length is greater than (MAX_ADDRESS - DestinationBuffer + 1), then ASSERT().
  30   If Length is greater than (MAX_ADDRESS - SourceBuffer + 1), then ASSERT().
  31
  32   @param  DestinationBuffer   The pointer to the destination buffer of the memory copy.
  33   @param  SourceBuffer        The pointer to the source buffer of the memory copy.
  34   @param  Length              The number of bytes to copy from SourceBuffer to DestinationBuffer.
  35
  36   @return DestinationBuffer.
  37
  38 **/
  39 VOID *
  40 EFIAPI
  41 CopyMem (
  42   OUT VOID       *DestinationBuffer,
  43   IN CONST VOID  *SourceBuffer,
  44   IN UINTN       Length
  45   )
  46 {
  47   if (Length == 0) {
  48     return DestinationBuffer;
  49   }
  50   ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)DestinationBuffer));
  51   ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)SourceBuffer));
  52
  53   if (DestinationBuffer == SourceBuffer) {
  54     return DestinationBuffer;
  55   }
  56   return InternalMemCopyMem (DestinationBuffer, SourceBuffer, Length);
  57 }