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   SPDX-License-Identifier: BSD-2-Clause-Patent
  11
  12 **/
  13
  14 #include "../MemLibInternals.h"
  15
  16 /**
  17   Scans a target buffer for a 16-bit value, and returns a pointer to the
  18   matching 16-bit value in the target buffer.
  19
  20   @param  Buffer  The pointer to the target buffer to scan.
  21   @param  Length  The count of 16-bit value to scan. Must be non-zero.
  22   @param  Value   The value to search for in the target buffer.
  23
  24   @return The pointer to the first occurrence, or NULL if not found.
  25
  26 **/
  27 CONST VOID *
  28 EFIAPI
  29 InternalMemScanMem16 (
  30   IN      CONST VOID  *Buffer,
  31   IN      UINTN       Length,
  32   IN      UINT16      Value
  33   )
  34 {
  35   CONST UINT16  *Pointer;
  36
  37   Pointer = (CONST UINT16 *)Buffer;
  38   do {
  39     if (*Pointer == Value) {
  40       return Pointer;
  41     }
  42
  43     ++Pointer;
  44   } while (--Length != 0);
  45
  46   return NULL;
  47 }
  48
  49 /**
  50   Scans a target buffer for a 32-bit value, and returns a pointer to the
  51   matching 32-bit value in the target buffer.
  52
  53   @param  Buffer  The pointer to the target buffer to scan.
  54   @param  Length  The count of 32-bit value to scan. Must be non-zero.
  55   @param  Value   The value to search for in the target buffer.
  56
  57   @return The pointer to the first occurrence, or NULL if not found.
  58
  59 **/
  60 CONST VOID *
  61 EFIAPI
  62 InternalMemScanMem32 (
  63   IN      CONST VOID  *Buffer,
  64   IN      UINTN       Length,
  65   IN      UINT32      Value
  66   )
  67 {
  68   CONST UINT32  *Pointer;
  69
  70   Pointer = (CONST UINT32 *)Buffer;
  71   do {
  72     if (*Pointer == Value) {
  73       return Pointer;
  74     }
  75
  76     ++Pointer;
  77   } while (--Length != 0);
  78
  79   return NULL;
  80 }
  81
  82 /**
  83   Scans a target buffer for a 64-bit value, and returns a pointer to the
  84   matching 64-bit value in the target buffer.
  85
  86   @param  Buffer  The pointer to the target buffer to scan.
  87   @param  Length  The count of 64-bit value to scan. Must be non-zero.
  88   @param  Value   The value to search for in the target buffer.
  89
  90   @return The pointer to the first occurrence, or NULL if not found.
  91
  92 **/
  93 CONST VOID *
  94 EFIAPI
  95 InternalMemScanMem64 (
  96   IN      CONST VOID  *Buffer,
  97   IN      UINTN       Length,
  98   IN      UINT64      Value
  99   )
 100 {
 101   CONST UINT64  *Pointer;
 102
 103   Pointer = (CONST UINT64 *)Buffer;
 104   do {
 105     if (*Pointer == Value) {
 106       return Pointer;
 107     }
 108
 109     ++Pointer;
 110   } while (--Length != 0);
 111
 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
 142   return TRUE;
 143 }