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   The following BaseMemoryLib instances share the same version of this file:
  14
  15     BaseMemoryLib
  16     BaseMemoryLibMmx
  17     BaseMemoryLibSse2
  18     BaseMemoryLibRepStr
  19     PeiMemoryLib
  20     DxeMemoryLib
  21
  22 **/
  23
  24
  25 #include <MemLibInternals.h>
  26
  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   If DestinationGuid is NULL, then ASSERT().
  34   If SourceGuid is NULL, then ASSERT().
  35
  36   @param  DestinationGuid   Pointer to the destination GUID.
  37   @param  SourceGuid        Pointer to the source GUID.
  38
  39   @return DestinationGuid.
  40
  41 **/
  42 GUID *
  43 EFIAPI
  44 CopyGuid (
  45   OUT GUID       *DestinationGuid,
  46   IN CONST GUID  *SourceGuid
  47   )
  48 {
  49   WriteUnaligned64 (
  50     (UINT64*)DestinationGuid,
  51     ReadUnaligned64 ((CONST UINT64*)SourceGuid)
  52     );
  53   WriteUnaligned64 (
  54     (UINT64*)DestinationGuid + 1,
  55     ReadUnaligned64 ((CONST UINT64*)SourceGuid + 1)
  56     );
  57   return DestinationGuid;
  58 }
  59
  60 /**
  61   Compares two GUIDs.
  62
  63   This function compares Guid1 to Guid2.  If the GUIDs are identical then TRUE is returned.
  64   If there are any bit differences in the two GUIDs, then FALSE is returned.
  65   If Guid1 is NULL, then ASSERT().
  66   If Guid2 is NULL, then ASSERT().
  67
  68   @param  Guid1       A pointer to a 128 bit GUID.
  69   @param  Guid2       A pointer to a 128 bit GUID.
  70
  71   @retval TRUE        Guid1 and Guid2 are identical.
  72   @retval FALSE       Guid1 and Guid2 are not identical.
  73
  74 **/
  75 BOOLEAN
  76 EFIAPI
  77 CompareGuid (
  78   IN CONST GUID  *Guid1,
  79   IN CONST GUID  *Guid2
  80   )
  81 {
  82   UINT64  LowPartOfGuid1;
  83   UINT64  LowPartOfGuid2;
  84   UINT64  HighPartOfGuid1;
  85   UINT64  HighPartOfGuid2;
  86
  87   LowPartOfGuid1  = ReadUnaligned64 ((CONST UINT64*) Guid1);
  88   LowPartOfGuid2  = ReadUnaligned64 ((CONST UINT64*) Guid2);
  89   HighPartOfGuid1 = ReadUnaligned64 ((CONST UINT64*) Guid1 + 1);
  90   HighPartOfGuid2 = ReadUnaligned64 ((CONST UINT64*) Guid2 + 1);
  91
  92   return (BOOLEAN) (LowPartOfGuid1 == LowPartOfGuid2 && HighPartOfGuid1 == HighPartOfGuid2);
  93 }
  94
  95 /**
  96   Scans a target buffer for a GUID, and returns a pointer to the matching GUID
  97   in the target buffer.
  98
  99   This function searches target the buffer specified by Buffer and Length from
 100   the lowest address to the highest address at 128-bit increments for the 128-bit
 101   GUID value that matches Guid.  If a match is found, then a pointer to the matching
 102   GUID in the target buffer is returned.  If no match is found, then NULL is returned.
 103   If Length is 0, then NULL is returned.
 104   If Length > 0 and Buffer is NULL, then ASSERT().
 105   If Buffer is not aligned on a 32-bit boundary, then ASSERT().
 106   If Length is not aligned on a 128-bit boundary, then ASSERT().
 107   If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().
 108
 109   @param  Buffer  Pointer to the target buffer to scan.
 110   @param  Length  Number of bytes in Buffer to scan.
 111   @param  Guid    Value to search for in the target buffer.
 112
 113   @return A pointer to the matching Guid in the target buffer or NULL otherwise.
 114
 115 **/
 116 VOID *
 117 EFIAPI
 118 ScanGuid (
 119   IN CONST VOID  *Buffer,
 120   IN UINTN       Length,
 121   IN CONST GUID  *Guid
 122   )
 123 {
 124   CONST GUID                        *GuidPtr;
 125
 126   ASSERT (((UINTN)Buffer & (sizeof (Guid->Data1) - 1)) == 0);
 127   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
 128   ASSERT ((Length & (sizeof (*GuidPtr) - 1)) == 0);
 129
 130   GuidPtr = (GUID*)Buffer;
 131   Buffer  = GuidPtr + Length / sizeof (*GuidPtr);
 132   while (GuidPtr < (CONST GUID*)Buffer) {
 133     if (CompareGuid (GuidPtr, Guid)) {
 134       return (VOID*)GuidPtr;
 135     }
 136     GuidPtr++;
 137   }
 138   return NULL;
 139 }