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 - 2009, Intel Corporation. All rights reserved.<BR>
16   This program and the accompanying materials
17   are licensed and made available under the terms and conditions of the BSD License
18   which accompanies this distribution.  The full text of the license may be found at
19   http://opensource.org/licenses/bsd-license.php.
20 
21   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
22   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
23 
24 **/
25 
26 #include "MemLibInternals.h"
27 
28 /**
29   Copies a source GUID to a destination GUID.
30 
31   This function copies the contents of the 128-bit GUID specified by SourceGuid to
32   DestinationGuid, and returns DestinationGuid.
33 
34   If DestinationGuid is NULL, then ASSERT().
35   If SourceGuid is NULL, then ASSERT().
36 
37   @param  DestinationGuid   The pointer to the destination GUID.
38   @param  SourceGuid        The pointer to the source GUID.
39 
40   @return DestinationGuid.
41 
42 **/
43 GUID *
44 EFIAPI
CopyGuid(OUT GUID * DestinationGuid,IN CONST GUID * SourceGuid)45 CopyGuid (
46   OUT GUID       *DestinationGuid,
47   IN CONST GUID  *SourceGuid
48   )
49 {
50   WriteUnaligned64 (
51     (UINT64*)DestinationGuid,
52     ReadUnaligned64 ((CONST UINT64*)SourceGuid)
53     );
54   WriteUnaligned64 (
55     (UINT64*)DestinationGuid + 1,
56     ReadUnaligned64 ((CONST UINT64*)SourceGuid + 1)
57     );
58   return DestinationGuid;
59 }
60 
61 /**
62   Compares two GUIDs.
63 
64   This function compares Guid1 to Guid2.  If the GUIDs are identical then TRUE is returned.
65   If there are any bit differences in the two GUIDs, then FALSE is returned.
66 
67   If Guid1 is NULL, then ASSERT().
68   If Guid2 is NULL, then ASSERT().
69 
70   @param  Guid1       A pointer to a 128 bit GUID.
71   @param  Guid2       A pointer to a 128 bit GUID.
72 
73   @retval TRUE        Guid1 and Guid2 are identical.
74   @retval FALSE       Guid1 and Guid2 are not identical.
75 
76 **/
77 BOOLEAN
78 EFIAPI
CompareGuid(IN CONST GUID * Guid1,IN CONST GUID * Guid2)79 CompareGuid (
80   IN CONST GUID  *Guid1,
81   IN CONST GUID  *Guid2
82   )
83 {
84   UINT64  LowPartOfGuid1;
85   UINT64  LowPartOfGuid2;
86   UINT64  HighPartOfGuid1;
87   UINT64  HighPartOfGuid2;
88 
89   LowPartOfGuid1  = ReadUnaligned64 ((CONST UINT64*) Guid1);
90   LowPartOfGuid2  = ReadUnaligned64 ((CONST UINT64*) Guid2);
91   HighPartOfGuid1 = ReadUnaligned64 ((CONST UINT64*) Guid1 + 1);
92   HighPartOfGuid2 = ReadUnaligned64 ((CONST UINT64*) Guid2 + 1);
93 
94   return (BOOLEAN) (LowPartOfGuid1 == LowPartOfGuid2 && HighPartOfGuid1 == HighPartOfGuid2);
95 }
96 
97 /**
98   Scans a target buffer for a GUID, and returns a pointer to the matching GUID
99   in the target buffer.
100 
101   This function searches the target buffer specified by Buffer and Length from
102   the lowest address to the highest address at 128-bit increments for the 128-bit
103   GUID value that matches Guid.  If a match is found, then a pointer to the matching
104   GUID in the target buffer is returned.  If no match is found, then NULL is returned.
105   If Length is 0, then NULL is returned.
106 
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  The pointer to the target buffer to scan.
113   @param  Length  The number of bytes in Buffer to scan.
114   @param  Guid    The 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
ScanGuid(IN CONST VOID * Buffer,IN UINTN Length,IN CONST GUID * Guid)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 }
143