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