MdePkg/Library/PeiMemoryLib/MemLibGuid.c

   1 /** @file
   2   Implementation of GUID functions.
   3
   4   The following BaseMemoryLib instances contain the same copy of this file:
   5
   6     BaseMemoryLib
   7     BaseMemoryLibMmx
   8     BaseMemoryLibSse2
   9     BaseMemoryLibRepStr
  10     BaseMemoryLibOptDxe
  11     BaseMemoryLibOptPei
  12     PeiMemoryLib
  13     UefiMemoryLib
  14
  15   Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
  16   SPDX-License-Identifier: BSD-2-Clause-Patent
  17
  18 **/
  19
  20 #include "MemLibInternals.h"
  21
  22 /**
  23   Copies a source GUID to a destination GUID.
  24
  25   This function copies the contents of the 128-bit GUID specified by SourceGuid to
  26   DestinationGuid, and returns DestinationGuid.
  27
  28   If DestinationGuid is NULL, then ASSERT().
  29   If SourceGuid is NULL, then ASSERT().
  30
  31   @param  DestinationGuid   The pointer to the destination GUID.
  32   @param  SourceGuid        The pointer to the source GUID.
  33
  34   @return DestinationGuid.
  35
  36 **/
  37 GUID *
  38 EFIAPI
  39 CopyGuid (
  40   OUT GUID       *DestinationGuid,
  41   IN CONST GUID  *SourceGuid
  42   )
  43 {
  44   WriteUnaligned64 (
  45     (UINT64 *)DestinationGuid,
  46     ReadUnaligned64 ((CONST UINT64 *)SourceGuid)
  47     );
  48   WriteUnaligned64 (
  49     (UINT64 *)DestinationGuid + 1,
  50     ReadUnaligned64 ((CONST UINT64 *)SourceGuid + 1)
  51     );
  52   return DestinationGuid;
  53 }
  54
  55 /**
  56   Compares two GUIDs.
  57
  58   This function compares Guid1 to Guid2.  If the GUIDs are identical then TRUE is returned.
  59   If there are any bit differences in the two GUIDs, then FALSE is returned.
  60
  61   If Guid1 is NULL, then ASSERT().
  62   If Guid2 is NULL, then ASSERT().
  63
  64   @param  Guid1       A pointer to a 128 bit GUID.
  65   @param  Guid2       A pointer to a 128 bit GUID.
  66
  67   @retval TRUE        Guid1 and Guid2 are identical.
  68   @retval FALSE       Guid1 and Guid2 are not identical.
  69
  70 **/
  71 BOOLEAN
  72 EFIAPI
  73 CompareGuid (
  74   IN CONST GUID  *Guid1,
  75   IN CONST GUID  *Guid2
  76   )
  77 {
  78   UINT64  LowPartOfGuid1;
  79   UINT64  LowPartOfGuid2;
  80   UINT64  HighPartOfGuid1;
  81   UINT64  HighPartOfGuid2;
  82
  83   LowPartOfGuid1  = ReadUnaligned64 ((CONST UINT64 *)Guid1);
  84   LowPartOfGuid2  = ReadUnaligned64 ((CONST UINT64 *)Guid2);
  85   HighPartOfGuid1 = ReadUnaligned64 ((CONST UINT64 *)Guid1 + 1);
  86   HighPartOfGuid2 = ReadUnaligned64 ((CONST UINT64 *)Guid2 + 1);
  87
  88   return (BOOLEAN)(LowPartOfGuid1 == LowPartOfGuid2 && HighPartOfGuid1 == HighPartOfGuid2);
  89 }
  90
  91 /**
  92   Scans a target buffer for a GUID, and returns a pointer to the matching GUID
  93   in the target buffer.
  94
  95   This function searches the target buffer specified by Buffer and Length from
  96   the lowest address to the highest address at 128-bit increments for the 128-bit
  97   GUID value that matches Guid.  If a match is found, then a pointer to the matching
  98   GUID in the target buffer is returned.  If no match is found, then NULL is returned.
  99   If Length is 0, then NULL is returned.
 100
 101   If Length > 0 and Buffer is NULL, then ASSERT().
 102   If Buffer is not aligned on a 32-bit boundary, then ASSERT().
 103   If Length is not aligned on a 128-bit boundary, then ASSERT().
 104   If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().
 105
 106   @param  Buffer  The pointer to the target buffer to scan.
 107   @param  Length  The number of bytes in Buffer to scan.
 108   @param  Guid    The value to search for in the target buffer.
 109
 110   @return A pointer to the matching Guid in the target buffer or NULL otherwise.
 111
 112 **/
 113 VOID *
 114 EFIAPI
 115 ScanGuid (
 116   IN CONST VOID  *Buffer,
 117   IN UINTN       Length,
 118   IN CONST GUID  *Guid
 119   )
 120 {
 121   CONST GUID  *GuidPtr;
 122
 123   ASSERT (((UINTN)Buffer & (sizeof (Guid->Data1) - 1)) == 0);
 124   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
 125   ASSERT ((Length & (sizeof (*GuidPtr) - 1)) == 0);
 126
 127   GuidPtr = (GUID *)Buffer;
 128   Buffer  = GuidPtr + Length / sizeof (*GuidPtr);
 129   while (GuidPtr < (CONST GUID *)Buffer) {
 130     if (CompareGuid (GuidPtr, Guid)) {
 131       return (VOID *)GuidPtr;
 132     }
 133
 134     GuidPtr++;
 135   }
 136
 137   return NULL;
 138 }
 139
 140 /**
 141   Checks if the given GUID is a zero GUID.
 142
 143   This function checks whether the given GUID is a zero GUID. If the GUID is
 144   identical to a zero GUID then TRUE is returned. Otherwise, FALSE is returned.
 145
 146   If Guid is NULL, then ASSERT().
 147
 148   @param  Guid        The pointer to a 128 bit GUID.
 149
 150   @retval TRUE        Guid is a zero GUID.
 151   @retval FALSE       Guid is not a zero GUID.
 152
 153 **/
 154 BOOLEAN
 155 EFIAPI
 156 IsZeroGuid (
 157   IN CONST GUID  *Guid
 158   )
 159 {
 160   UINT64  LowPartOfGuid;
 161   UINT64  HighPartOfGuid;
 162
 163   LowPartOfGuid  = ReadUnaligned64 ((CONST UINT64 *)Guid);
 164   HighPartOfGuid = ReadUnaligned64 ((CONST UINT64 *)Guid + 1);
 165
 166   return (BOOLEAN)(LowPartOfGuid == 0 && HighPartOfGuid == 0);
 167 }