MdePkg/Library/BaseMemoryLib/MemLibGuid.c

   1 /** @file
   2   Implementation of GUID functions.
   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:  MemLibGuid.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     DxeMemoryLib
  23
  24 **/
  25
  26 //
  27 // Include common header file for this module.
  28 //
  29 #include "CommonHeader.h"
  30
  31 /**
  32   Copies a source GUID to a destination GUID.
  33
  34   This function copies the contents of the 128-bit GUID specified by SourceGuid to
  35   DestinationGuid, and returns DestinationGuid.
  36   If DestinationGuid is NULL, then ASSERT().
  37   If SourceGuid is NULL, then ASSERT().
  38
  39   @param  DestinationGuid   Pointer to the destination GUID.
  40   @param  SourceGuid        Pointer to the source GUID.
  41
  42   @return DestinationGuid.
  43
  44 **/
  45 GUID *
  46 EFIAPI
  47 CopyGuid (
  48   OUT GUID       *DestinationGuid,
  49   IN CONST GUID  *SourceGuid
  50   )
  51 {
  52   WriteUnaligned64 (
  53     (UINT64*)DestinationGuid,
  54     ReadUnaligned64 ((CONST UINT64*)SourceGuid)
  55     );
  56   WriteUnaligned64 (
  57     (UINT64*)DestinationGuid + 1,
  58     ReadUnaligned64 ((CONST UINT64*)SourceGuid + 1)
  59     );
  60   return DestinationGuid;
  61 }
  62
  63 /**
  64   Compares two GUIDs.
  65
  66   This function compares Guid1 to Guid2.  If the GUIDs are identical then TRUE is returned.
  67   If there are any bit differences in the two GUIDs, then FALSE is returned.
  68   If Guid1 is NULL, then ASSERT().
  69   If Guid2 is NULL, then ASSERT().
  70
  71   @param  Guid1       A pointer to a 128 bit GUID.
  72   @param  Guid2       A pointer to a 128 bit GUID.
  73
  74   @retval TRUE        Guid1 and Guid2 are identical.
  75   @retval FALSE       Guid1 and Guid2 are not identical.
  76
  77 **/
  78 BOOLEAN
  79 EFIAPI
  80 CompareGuid (
  81   IN CONST GUID  *Guid1,
  82   IN CONST GUID  *Guid2
  83   )
  84 {
  85   UINT64  LowPartOfGuid1;
  86   UINT64  LowPartOfGuid2;
  87   UINT64  HighPartOfGuid1;
  88   UINT64  HighPartOfGuid2;
  89
  90   LowPartOfGuid1  = ReadUnaligned64 ((CONST UINT64*) Guid1);
  91   LowPartOfGuid2  = ReadUnaligned64 ((CONST UINT64*) Guid2);
  92   HighPartOfGuid1 = ReadUnaligned64 ((CONST UINT64*) Guid1 + 1);
  93   HighPartOfGuid2 = ReadUnaligned64 ((CONST UINT64*) Guid2 + 1);
  94
  95   return (BOOLEAN) (LowPartOfGuid1 == LowPartOfGuid2 && HighPartOfGuid1 == HighPartOfGuid2);
  96 }
  97
  98 /**
  99   Scans a target buffer for a GUID, and returns a pointer to the matching GUID
 100   in the target buffer.
 101
 102   This function searches target the buffer specified by Buffer and Length from
 103   the lowest address to the highest address at 128-bit increments for the 128-bit
 104   GUID value that matches Guid.  If a match is found, then a pointer to the matching
 105   GUID in the target buffer is returned.  If no match is found, then NULL is returned.
 106   If Length is 0, then NULL is returned.
 107   If Length > 0 and Buffer is NULL, then ASSERT().
 108   If Buffer is not aligned on a 32-bit boundary, then ASSERT().
 109   If Length is not aligned on a 128-bit boundary, then ASSERT().
 110   If Length is greater than (MAX_ADDRESS ? Buffer + 1), then ASSERT().
 111
 112   @param  Buffer  Pointer to the target buffer to scan.
 113   @param  Length  Number of bytes in Buffer to scan.
 114   @param  Guid    Value to search for in the target buffer.
 115
 116   @return A pointer to the matching Guid in the target buffer or NULL otherwise.
 117
 118 **/
 119 VOID *
 120 EFIAPI
 121 ScanGuid (
 122   IN CONST VOID  *Buffer,
 123   IN UINTN       Length,
 124   IN CONST GUID  *Guid
 125   )
 126 {
 127   CONST GUID                        *GuidPtr;
 128
 129   ASSERT (((UINTN)Buffer & (sizeof (Guid->Data1) - 1)) == 0);
 130   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
 131   ASSERT ((Length & (sizeof (*GuidPtr) - 1)) == 0);
 132
 133   GuidPtr = (GUID*)Buffer;
 134   Buffer  = GuidPtr + Length / sizeof (*GuidPtr);
 135   while (GuidPtr < (CONST GUID*)Buffer) {
 136     if (CompareGuid (GuidPtr, Guid)) {
 137       return (VOID*)GuidPtr;
 138     }
 139     GuidPtr++;
 140   }
 141   return NULL;
 142 }