1 files changed, 217 insertions, 0 deletions
diff --git a/FatPkg/EnhancedFatDxe/Hash.c b/FatPkg/EnhancedFatDxe/Hash.c
new file mode 100644
index 0000000000..c0fbab2f1e
--- /dev/null
+++ b/FatPkg/EnhancedFatDxe/Hash.c
@@ -0,0 +1,217 @@
+/*++
+
+Copyright (c) 2005 - 2007, Intel Corporation
+All rights reserved. This program and the accompanying materials are licensed and made available
+under the terms and conditions of the BSD License which accompanies this
+distribution. The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+
+Module Name:
+
+  Hash.c
+
+Abstract:
+
+  Hash table operations
+
+Revision History
+
+--*/
+
+#include "Fat.h"
+
+STATIC
+UINT32
+FatHashLongName (
+  IN CHAR16   *LongNameString
+  )
+/*++
+
+Routine Description:
+
+  Get hash value for long name.
+
+Arguments:
+
+  LongNameString        - The long name string to be hashed.
+
+Returns:
+
+  HashValue.
+
+--*/
+{
+  UINT32  HashValue;
+  CHAR16  UpCasedLongFileName[EFI_PATH_STRING_LENGTH];
+  StrCpy (UpCasedLongFileName, LongNameString);
+  FatStrUpr (UpCasedLongFileName);
+  gBS->CalculateCrc32 (UpCasedLongFileName, StrSize (UpCasedLongFileName), &HashValue);
+  return (HashValue & HASH_TABLE_MASK);
+}
+
+STATIC
+UINT32
+FatHashShortName (
+  IN CHAR8   *ShortNameString
+  )
+/*++
+
+Routine Description:
+
+  Get hash value for short name.
+
+Arguments:
+
+  ShortNameString       - The short name string to be hashed.
+
+Returns:
+
+  HashValue
+
+--*/
+{
+  UINT32  HashValue;
+  gBS->CalculateCrc32 (ShortNameString, FAT_NAME_LEN, &HashValue);
+  return (HashValue & HASH_TABLE_MASK);
+}
+
+FAT_DIRENT **
+FatLongNameHashSearch (
+  IN FAT_ODIR       *ODir,
+  IN CHAR16         *LongNameString
+  )
+/*++
+
+Routine Description:
+
+  Search the long name hash table for the directory entry.
+
+Arguments:
+
+  ODir                  - The directory to be searched.
+  LongNameString        - The long name string to search.
+
+Returns:
+
+  The previous long name hash node of the directory entry.
+
+--*/
+{
+  FAT_DIRENT  **PreviousHashNode;
+  for (PreviousHashNode   = &ODir->LongNameHashTable[FatHashLongName (LongNameString)];
+       *PreviousHashNode != NULL;
+       PreviousHashNode   = &(*PreviousHashNode)->LongNameForwardLink
+      ) {
+    if (FatStriCmp (LongNameString, (*PreviousHashNode)->FileString) == 0) {
+      break;
+    }
+  }
+
+  return PreviousHashNode;
+}
+
+FAT_DIRENT **
+FatShortNameHashSearch (
+  IN FAT_ODIR      *ODir,
+  IN CHAR8         *ShortNameString
+  )
+/*++
+
+Routine Description:
+
+  Search the short name hash table for the directory entry.
+
+Arguments:
+
+  ODir                  - The directory to be searched.
+  ShortNameString       - The short name string to search.
+
+Returns:
+
+  The previous short name hash node of the directory entry.
+
+--*/
+{
+  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;
+}
+
+VOID
+FatInsertToHashTable (
+  IN FAT_ODIR     *ODir,
+  IN FAT_DIRENT   *DirEnt
+  )
+/*++
+
+Routine Description:
+
+  Insert directory entry to hash table.
+
+Arguments:
+
+  ODir                  - The parent directory.
+  DirEnt                - The directory entry node.
+
+Returns:
+
+  None.
+
+--*/
+{
+  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;
+}
+
+VOID
+FatDeleteFromHashTable (
+  IN FAT_ODIR     *ODir,
+  IN FAT_DIRENT   *DirEnt
+  )
+/*++
+
+Routine Description:
+
+  Delete directory entry from hash table.
+
+Arguments:
+
+  ODir                  - The parent directory.
+  DirEnt                - The directory entry node.
+
+Returns:
+
+  None.
+
+--*/
+{
+  *FatShortNameHashSearch (ODir, DirEnt->Entry.FileName) = DirEnt->ShortNameForwardLink;
+  *FatLongNameHashSearch (ODir, DirEnt->FileString)      = DirEnt->LongNameForwardLink;
+}