MdePkg/Library/BaseMemoryLibOptDxe/Arm/ScanMemGeneric.c

   1 /** @file
   2   Architecture Independent Base Memory Library Implementation.
   3
   4   The following BaseMemoryLib instances contain the same copy of this file:
   5     BaseMemoryLib
   6     PeiMemoryLib
   7     UefiMemoryLib
   8
   9   Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
  10   This program and the accompanying materials
  11   are licensed and made available under the terms and conditions of the BSD License
  12   which accompanies this distribution.  The full text of the license may be found at
  13   http://opensource.org/licenses/bsd-license.php.
  14
  15   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  16   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  17
  18 **/
  19
  20 #include "../MemLibInternals.h"
  21
  22 /**
  23   Scans a target buffer for a 16-bit value, and returns a pointer to the
  24   matching 16-bit value in the target buffer.
  25
  26   @param  Buffer  The pointer to the target buffer to scan.
  27   @param  Length  The count of 16-bit value to scan. Must be non-zero.
  28   @param  Value   The value to search for in the target buffer.
  29
  30   @return The pointer to the first occurrence, or NULL if not found.
  31
  32 **/
  33 CONST VOID *
  34 EFIAPI
  35 InternalMemScanMem16 (
  36   IN      CONST VOID                *Buffer,
  37   IN      UINTN                     Length,
  38   IN      UINT16                    Value
  39   )
  40 {
  41   CONST UINT16                      *Pointer;
  42
  43   Pointer = (CONST UINT16*)Buffer;
  44   do {
  45     if (*Pointer == Value) {
  46       return Pointer;
  47     }
  48     ++Pointer;
  49   } while (--Length != 0);
  50   return NULL;
  51 }
  52
  53 /**
  54   Scans a target buffer for a 32-bit value, and returns a pointer to the
  55   matching 32-bit value in the target buffer.
  56
  57   @param  Buffer  The pointer to the target buffer to scan.
  58   @param  Length  The count of 32-bit value to scan. Must be non-zero.
  59   @param  Value   The value to search for in the target buffer.
  60
  61   @return The pointer to the first occurrence, or NULL if not found.
  62
  63 **/
  64 CONST VOID *
  65 EFIAPI
  66 InternalMemScanMem32 (
  67   IN      CONST VOID                *Buffer,
  68   IN      UINTN                     Length,
  69   IN      UINT32                    Value
  70   )
  71 {
  72   CONST UINT32                      *Pointer;
  73
  74   Pointer = (CONST UINT32*)Buffer;
  75   do {
  76     if (*Pointer == Value) {
  77       return Pointer;
  78     }
  79     ++Pointer;
  80   } while (--Length != 0);
  81   return NULL;
  82 }
  83
  84 /**
  85   Scans a target buffer for a 64-bit value, and returns a pointer to the
  86   matching 64-bit value in the target buffer.
  87
  88   @param  Buffer  The pointer to the target buffer to scan.
  89   @param  Length  The count of 64-bit value to scan. Must be non-zero.
  90   @param  Value   The value to search for in the target buffer.
  91
  92   @return The pointer to the first occurrence, or NULL if not found.
  93
  94 **/
  95 CONST VOID *
  96 EFIAPI
  97 InternalMemScanMem64 (
  98   IN      CONST VOID                *Buffer,
  99   IN      UINTN                     Length,
 100   IN      UINT64                    Value
 101   )
 102 {
 103   CONST UINT64                      *Pointer;
 104
 105   Pointer = (CONST UINT64*)Buffer;
 106   do {
 107     if (*Pointer == Value) {
 108       return Pointer;
 109     }
 110     ++Pointer;
 111   } while (--Length != 0);
 112   return NULL;
 113 }
 114
 115 /**
 116   Checks whether the contents of a buffer are all zeros.
 117
 118   @param  Buffer  The pointer to the buffer to be checked.
 119   @param  Length  The size of the buffer (in bytes) to be checked.
 120
 121   @retval TRUE    Contents of the buffer are all zeros.
 122   @retval FALSE   Contents of the buffer are not all zeros.
 123
 124 **/
 125 BOOLEAN
 126 EFIAPI
 127 InternalMemIsZeroBuffer (
 128   IN CONST VOID  *Buffer,
 129   IN UINTN       Length
 130   )
 131 {
 132   CONST UINT8 *BufferData;
 133   UINTN       Index;
 134
 135   BufferData = Buffer;
 136   for (Index = 0; Index < Length; Index++) {
 137     if (BufferData[Index] != 0) {
 138       return FALSE;
 139     }
 140   }
 141   return TRUE;
 142 }