1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
/** @file
Hash table operations.
Copyright (c) 2005 - 2015, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "Fat.h"
/**
Get hash value for long name.
@param LongNameString - The long name string to be hashed.
@return HashValue.
**/
STATIC
UINT32
FatHashLongName (
IN CHAR16 *LongNameString
)
{
UINT32 HashValue;
CHAR16 UpCasedLongFileName[EFI_PATH_STRING_LENGTH];
StrnCpyS (
UpCasedLongFileName,
ARRAY_SIZE (UpCasedLongFileName),
LongNameString,
ARRAY_SIZE (UpCasedLongFileName) - 1
);
FatStrUpr (UpCasedLongFileName);
gBS->CalculateCrc32 (UpCasedLongFileName, StrSize (UpCasedLongFileName), &HashValue);
return (HashValue & HASH_TABLE_MASK);
}
/**
Get hash value for short name.
@param ShortNameString - The short name string to be hashed.
@return HashValue
**/
STATIC
UINT32
FatHashShortName (
IN CHAR8 *ShortNameString
)
{
UINT32 HashValue;
gBS->CalculateCrc32 (ShortNameString, FAT_NAME_LEN, &HashValue);
return (HashValue & HASH_TABLE_MASK);
}
/**
Search the long name hash table for the directory entry.
@param ODir - The directory to be searched.
@param LongNameString - The long name string to search.
@return The previous long name hash node of the directory entry.
**/
FAT_DIRENT **
FatLongNameHashSearch (
IN FAT_ODIR *ODir,
IN CHAR16 *LongNameString
)
{
FAT_DIRENT **PreviousHashNode;
for (PreviousHashNode = &ODir->LongNameHashTable[FatHashLongName (LongNameString)];
*PreviousHashNode != NULL;
PreviousHashNode = &(*PreviousHashNode)->LongNameForwardLink
) {
if (FatStriCmp (LongNameString, (*PreviousHashNode)->FileString) == 0) {
break;
}
}
return PreviousHashNode;
}
/**
Search the short name hash table for the directory entry.
@param ODir - The directory to be searched.
@param ShortNameString - The short name string to search.
@return The previous short name hash node of the directory entry.
**/
FAT_DIRENT **
FatShortNameHashSearch (
IN FAT_ODIR *ODir,
IN CHAR8 *ShortNameString
)
{
FAT_DIRENT **PreviousHashNode;
for (PreviousHashNode = &ODir->ShortNameHashTable[FatHashShortName (ShortNameString)];
*PreviousHashNode != NULL;
PreviousHashNode = &(*PreviousHashNode)->ShortNameForwardLink
) {
if (CompareMem (ShortNameString, (*PreviousHashNode)->Entry.FileName, FAT_NAME_LEN) == 0) {
break;
}
}
return PreviousHashNode;
}
/**
Insert directory entry to hash table.
@param ODir - The parent directory.
@param DirEnt - The directory entry node.
**/
VOID
FatInsertToHashTable (
IN FAT_ODIR *ODir,
IN FAT_DIRENT *DirEnt
)
{
FAT_DIRENT **HashTable;
UINT32 HashTableIndex;
//
// Insert hash table index for short name
//
HashTableIndex = FatHashShortName (DirEnt->Entry.FileName);
HashTable = ODir->ShortNameHashTable;
DirEnt->ShortNameForwardLink = HashTable[HashTableIndex];
HashTable[HashTableIndex] = DirEnt;
//
// Insert hash table index for long name
//
HashTableIndex = FatHashLongName (DirEnt->FileString);
HashTable = ODir->LongNameHashTable;
DirEnt->LongNameForwardLink = HashTable[HashTableIndex];
HashTable[HashTableIndex] = DirEnt;
}
/**
Delete directory entry from hash table.
@param ODir - The parent directory.
@param DirEnt - The directory entry node.
**/
VOID
FatDeleteFromHashTable (
IN FAT_ODIR *ODir,
IN FAT_DIRENT *DirEnt
)
{
*FatShortNameHashSearch (ODir, DirEnt->Entry.FileName) = DirEnt->ShortNameForwardLink;
*FatLongNameHashSearch (ODir, DirEnt->FileString) = DirEnt->LongNameForwardLink;
}
|
