MdePkg/Library/BaseMemoryLibOptPei/CompareMemWrapper.c

   1 /** @file
   2   CompareMem() 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   The following BaseMemoryLib instances share the same version of this file:
  14
  15     BaseMemoryLib
  16     BaseMemoryLibMmx
  17     BaseMemoryLibSse2
  18     BaseMemoryLibRepStr
  19     PeiMemoryLib
  20     DxeMemoryLib
  21
  22 **/
  23
  24
  25
  26
  27 #include "MemLibInternals.h"
  28
  29 /**
  30   Compares the contents of two buffers.
  31
  32   This function compares Length bytes of SourceBuffer to Length bytes of DestinationBuffer.
  33   If all Length bytes of the two buffers are identical, then 0 is returned.  Otherwise, the
  34   value returned is the first mismatched byte in SourceBuffer subtracted from the first
  35   mismatched byte in DestinationBuffer.
  36   If Length > 0 and DestinationBuffer is NULL and Length > 0, then ASSERT().
  37   If Length > 0 and SourceBuffer is NULL and Length > 0, then ASSERT().
  38   If Length is greater than (MAX_ADDRESS - DestinationBuffer + 1), then ASSERT().
  39   If Length is greater than (MAX_ADDRESS - SourceBuffer + 1), then ASSERT().
  40
  41
  42   @param  DestinationBuffer Pointer to the destination buffer to compare.
  43   @param  SourceBuffer      Pointer to the source buffer to compare.
  44   @param  Length            Number of bytes to compare.
  45
  46   @return 0                 All Length bytes of the two buffers are identical.
  47   @retval Non-zero          The first mismatched byte in SourceBuffer subtracted from the first
  48                             mismatched byte in DestinationBuffer.
  49
  50 **/
  51 INTN
  52 EFIAPI
  53 CompareMem (
  54   IN CONST VOID  *DestinationBuffer,
  55   IN CONST VOID  *SourceBuffer,
  56   IN UINTN       Length
  57   )
  58 {
  59   if (Length == 0 || DestinationBuffer == SourceBuffer) {
  60     return 0;
  61   }
  62   ASSERT (DestinationBuffer != NULL);
  63   ASSERT (SourceBuffer != NULL);
  64   ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)DestinationBuffer));
  65   ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)SourceBuffer));
  66
  67   return InternalMemCompareMem (DestinationBuffer, SourceBuffer, Length);
  68 }