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 common header file for this module.
  26 //
  27 #include <MemLibInternals.h>
  28
  29
  30 /**
  31   Copies a source GUID to a destination GUID.
  32
  33   This function copies the contents of the 128-bit GUID specified by SourceGuid to
  34   DestinationGuid, and returns DestinationGuid.
  35   If DestinationGuid is NULL, then ASSERT().
  36   If SourceGuid is NULL, then ASSERT().
  37
  38   @param  DestinationGuid   Pointer to the destination GUID.
  39   @param  SourceGuid        Pointer to the source GUID.
  40
  41   @return DestinationGuid.
  42
  43 **/
  44 GUID *
  45 EFIAPI
  46 CopyGuid (
  47   OUT GUID       *DestinationGuid,
  48   IN CONST GUID  *SourceGuid
  49   )
  50 {
  51   WriteUnaligned64 (
  52     (UINT64*)DestinationGuid,
  53     ReadUnaligned64 ((CONST UINT64*)SourceGuid)
  54     );
  55   WriteUnaligned64 (
  56     (UINT64*)DestinationGuid + 1,
  57     ReadUnaligned64 ((CONST UINT64*)SourceGuid + 1)
  58     );
  59   return DestinationGuid;
  60 }
  61
  62 /**
  63   Compares two GUIDs.
  64
  65   This function compares Guid1 to Guid2.  If the GUIDs are identical then TRUE is returned.
  66   If there are any bit differences in the two GUIDs, then FALSE is returned.
  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
  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 target the 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   If Length > 0 and Buffer is NULL, then ASSERT().
 107   If Buffer is not aligned on a 32-bit boundary, then ASSERT().
 108   If Length is not aligned on a 128-bit boundary, then ASSERT().
 109   If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().
 110
 111   @param  Buffer  Pointer to the target buffer to scan.
 112   @param  Length  Number of bytes in Buffer to scan.
 113   @param  Guid    Value to search for in the target buffer.
 114
 115   @return A pointer to the matching Guid in the target buffer or NULL otherwise.
 116
 117 **/
 118 VOID *
 119 EFIAPI
 120 ScanGuid (
 121   IN CONST VOID  *Buffer,
 122   IN UINTN       Length,
 123   IN CONST GUID  *Guid
 124   )
 125 {
 126   CONST GUID                        *GuidPtr;
 127
 128   ASSERT (((UINTN)Buffer & (sizeof (Guid->Data1) - 1)) == 0);
 129   ASSERT (Length <= (MAX_ADDRESS - (UINTN)Buffer + 1));
 130   ASSERT ((Length & (sizeof (*GuidPtr) - 1)) == 0);
 131
 132   GuidPtr = (GUID*)Buffer;
 133   Buffer  = GuidPtr + Length / sizeof (*GuidPtr);
 134   while (GuidPtr < (CONST GUID*)Buffer) {
 135     if (CompareGuid (GuidPtr, Guid)) {
 136       return (VOID*)GuidPtr;
 137     }
 138     GuidPtr++;
 139   }
 140   return NULL;
 141 }