1 /** @file 2 CompareMem() implementation. 3 4 The following BaseMemoryLib instances contain the same copy of this file: 5 BaseMemoryLib 6 BaseMemoryLibMmx 7 BaseMemoryLibSse2 8 BaseMemoryLibRepStr 9 BaseMemoryLibOptDxe 10 BaseMemoryLibOptPei 11 PeiMemoryLib 12 UefiMemoryLib 13 14 Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR> 15 This program and the accompanying materials 16 are licensed and made available under the terms and conditions of the BSD License 17 which accompanies this distribution. The full text of the license may be found at 18 http://opensource.org/licenses/bsd-license.php 19 20 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 21 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 22 23 **/ 24 25 #include "MemLibInternals.h" 26 27 /** 28 Compares the contents of two buffers. 29 30 This function compares Length bytes of SourceBuffer to Length bytes of DestinationBuffer. 31 If all Length bytes of the two buffers are identical, then 0 is returned. Otherwise, the 32 value returned is the first mismatched byte in SourceBuffer subtracted from the first 33 mismatched byte in DestinationBuffer. 34 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 @param DestinationBuffer Pointer to the destination buffer to compare. 41 @param SourceBuffer Pointer to the source buffer to compare. 42 @param Length Number of bytes to compare. 43 44 @return 0 All Length bytes of the two buffers are identical. 45 @retval Non-zero The first mismatched byte in SourceBuffer subtracted from the first 46 mismatched byte in DestinationBuffer. 47 48 **/ 49 INTN 50 EFIAPI 51 CompareMem ( 52 IN CONST VOID *DestinationBuffer, 53 IN CONST VOID *SourceBuffer, 54 IN UINTN Length 55 ) 56 { 57 if (Length == 0 || DestinationBuffer == SourceBuffer) { 58 return 0; 59 } 60 ASSERT (DestinationBuffer != NULL); 61 ASSERT (SourceBuffer != NULL); 62 ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)DestinationBuffer)); 63 ASSERT ((Length - 1) <= (MAX_ADDRESS - (UINTN)SourceBuffer)); 64 65 return InternalMemCompareMem (DestinationBuffer, SourceBuffer, Length); 66 } 67