MdePkg/Library/UefiMemoryLib/CopyMemWrapper.c

   1 /** @file
   2   CopyMem() implementation.
   3
   4   Copyright (c) 2006, Intel Corporation<BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13   Module Name:  CopyMemWrapper.c
  14
  15   The following BaseMemoryLib instances share the same version of this file:
  16
  17     BaseMemoryLib
  18     BaseMemoryLibMmx
  19     BaseMemoryLibSse2
  20     BaseMemoryLibRepStr
  21     PeiMemoryLib
  22     UefiMemoryLib
  23
  24 **/
  25
  26 #include "MemLibInternals.h"
  27
  28 /**
  29   Copies a source buffer to a destination buffer, and returns the destination buffer.
  30
  31   This function copies Length bytes from SourceBuffer to DestinationBuffer, and returns
  32   DestinationBuffer.  The implementation must be reentrant, and it must handle the case
  33   where SourceBuffer overlaps DestinationBuffer.
  34   If Length is greater than (MAX_ADDRESS - DestinationBuffer + 1), then ASSERT().
  35   If Length is greater than (MAX_ADDRESS - SourceBuffer + 1), then ASSERT().
  36
  37   @param  DestinationBuffer   Pointer to the destination buffer of the memory copy.
  38   @param  SourceBuffer        Pointer to the source buffer of the memory copy.
  39   @param  Length              Number of bytes to copy from SourceBuffer to DestinationBuffer.
  40
  41   @return DestinationBuffer.
  42
  43 **/
  44 VOID *
  45 EFIAPI
  46 CopyMem (
  47   OUT VOID       *DestinationBuffer,
  48   IN CONST VOID  *SourceBuffer,
  49   IN UINTN       Length
  50   )
  51 {
  52   if (Length == 0) {
  53     return DestinationBuffer;
  54   }
  55   ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)DestinationBuffer));
  56   ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)SourceBuffer));
  57
  58   if (DestinationBuffer == SourceBuffer) {
  59     return DestinationBuffer;
  60   }
  61   return InternalMemCopyMem (DestinationBuffer, SourceBuffer, Length);
  62 }