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