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- /** @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;
- }
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