MdePkg/Library/UefiMemoryLib/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     UefiMemoryLib
  23
  24 **/
  25
  26 /**
  27   This function copies a source GUID to a destination GUID.
  28
  29   This function copies the contents of the 128-bit GUID specified by SourceGuid
  30   to DestinationGuid, and returns DestinationGuid.
  31
  32   If DestinationGuid is NULL, then ASSERT().
  33   If SourceGuid is NULL, then ASSERT().
  34
  35   @param  DestinationGuid Pointer to the destination GUID.
  36   @param  SourceGuid Pointer to the source GUID.
  37
  38   @return DestinationGuid
  39
  40 **/
  41 GUID *
  42 EFIAPI
  43 CopyGuid (
  44   OUT     GUID                      *DestinationGuid,
  45   IN      CONST GUID                *SourceGuid
  46   )
  47 {
  48   WriteUnaligned64 (
  49     (UINT64*)DestinationGuid,
  50     ReadUnaligned64 ((CONST UINT64*)SourceGuid)
  51     );
  52   WriteUnaligned64 (
  53     (UINT64*)DestinationGuid + 1,
  54     ReadUnaligned64 ((CONST UINT64*)SourceGuid + 1)
  55     );
  56   return DestinationGuid;
  57 }
  58
  59 /**
  60   Compares two GUIDs
  61
  62   This function compares Guid1 to Guid2. If the GUIDs are identical then TRUE
  63   is returned. If there are any bit differences in the two GUIDs, then FALSE is
  64   returned.
  65
  66   If Guid1 is NULL, then ASSERT().
  67   If Guid2 is NULL, then ASSERT().
  68
  69   @param  Guid1 guid to compare
  70   @param  Guid2 guid to compare
  71
  72   @retval TRUE  if Guid1 == Guid2
  73   @retval FALSE if Guid1 != Guid2
  74
  75 **/
  76 BOOLEAN
  77 EFIAPI
  78 CompareGuid (
  79   IN      CONST GUID                *Guid1,
  80   IN      CONST GUID                *Guid2
  81   )
  82 {
  83   return (BOOLEAN)(
  84            ReadUnaligned64 ((CONST UINT64*)Guid1)
  85              == ReadUnaligned64 ((CONST UINT64*)Guid2) &&
  86            ReadUnaligned64 ((CONST UINT64*)Guid1 + 1)
  87              == ReadUnaligned64 ((CONST UINT64*)Guid2 + 1)
  88            );
  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 target the buffer specified by Buffer and Length from
  96   the lowest address to the highest address at 128-bit increments for the
  97   128-bit GUID value that matches Guid. If a match is found, then a pointer to
  98   the matching GUID in the target buffer is returned. If no match is found,
  99   then NULL is returned. If Length is 0, then NULL is returned.
 100
 101   If Buffer is NULL, then ASSERT().
 102   If Buffer is not aligned on a 64-bit boundary, then ASSERT().
 103   If Length is greater than (MAX_ADDRESS - Buffer + 1), then ASSERT().
 104
 105   @param  Buffer  Pointer to the target buffer to scan.
 106   @param  Length  Number of bytes in Buffer to scan.
 107   @param  Guid    Value to search for in the target buffer.
 108
 109   @return Pointer to the first occurrence.
 110   @retval NULL  if Length == 0 or Guid was not found.
 111 **/
 112 VOID *
 113 EFIAPI
 114 ScanGuid (
 115   IN      CONST VOID                *Buffer,
 116   IN      UINTN                     Length,
 117   IN      CONST GUID                *Guid
 118   )
 119 {
 120   CONST GUID                        *GuidPtr;
 121
 122   GuidPtr = (GUID*)Buffer;
 123   Buffer = GuidPtr + Length / sizeof (*GuidPtr);
 124   while (GuidPtr < (CONST GUID*)Buffer) {
 125     if (CompareGuid (GuidPtr, Guid)) {
 126       return (VOID*)GuidPtr;
 127     }
 128     GuidPtr++;
 129   }
 130   return NULL;
 131 }