//+------------------------------------------------------------------------- // // Microsoft Windows // Copyright (C) Microsoft Corporation, 1992 - 1992. // // File: prefix.hxx // // Contents: PREFIX table definition // // History: SethuR -- Implemented // // Notes: The DFS prefix table data structure consists of three // entities and methods to manipulate them. They are the // DFS_PREFIX_TABLE_ENTRY,DFS_PREFIX_TABLE_BUCKET and the // DFS_PREFIX_TABLE. // // The DFS_PREFIX_TABLE is a hash table of DFS_PREFIX_TABLE_ENTRY's // wherein collisions are resolved through linear chaining. The // hash table is organized as an array of collision lists // (DFS_PREFIX_TABLE_BUCKET). A brief description with each of // these entities is attached to the declaration. // // There are certain characterstics that distinguish this // hash table from other hash tables. These are the extensions // provided to accomodate the special operations. // //-------------------------------------------------------------------------- #ifndef __PREFIXP_H__ #define __PREFIXP_H__ #include //-------------------------------------------------------------------------- // // PREFIX TABLE UTILITIES // // A Path is a sequence of one or more name segments alternated with a // distinguished concatenation character ( typically \ in FAT,NTFS,HPFS and // / in UNIX file systems). These utilities are used to split a given path // into the first path segment followed by the remainder of the path. // // SPLIT_PATH("foo\bar\bar1",Name,RemainingPath) binds Name to foo and // RemainingPath to bar\bar1 // // Similarly PROCESS_CASE_SENSITIVE_NAME and PROCESS_CASE_INSENSITIVE_NAME // compute the hash signatures ( bucket no. ) for a given string. // //-------------------------------------------------------------------------- // // MAX_PATH_SEGMENT_SIZE is simply used as a good size buffer to do prefix // lookups and insertions. This should save us from having to allocate for // most cases. // #define MAX_PATH_SEGMENT_SIZE 256 #define PATH_DELIMITER L'\\' //+--------------------------------------------------------------------------- // // Function: SPLIT_CASE_INSENSITIVE_PATH // // Synopsis: Split the path name around deleimiters. // // Arguments: [pPath] -- path to be split(PUNICODE_STRING) // // [pName] -- the leftmost component of the path(PUNICODE_STRING) // // [BucketNo] -- Hash Bucket no. corresponding to the name(ULONG) // // SideEffects: the UNICODE_STRING pointed to by pName and BucketNo are // modified. // // PreRequisite: pName be associated with a valid buffer. // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- #define SPLIT_CASE_INSENSITIVE_PATH(pPath,pName,BucketNo) \ { \ WCHAR *pPathBuffer = (pPath)->Buffer; \ WCHAR *pNameBuffer = (pName)->Buffer; \ WCHAR *pPathBufferEnd = &pPathBuffer[(pPath)->Length / sizeof(WCHAR)]; \ \ BucketNo = 0; \ while ((pPathBufferEnd != pPathBuffer) && \ ((*pNameBuffer = *pPathBuffer++) != PATH_DELIMITER)) \ { \ *pNameBuffer = (*pNameBuffer < L'a') \ ? *pNameBuffer \ : ((*pNameBuffer < L'z') \ ? (*pNameBuffer - L'a' + L'A') \ : RtlUpcaseUnicodeChar(*pNameBuffer)); \ BucketNo *= 131; \ BucketNo += *pNameBuffer; \ pNameBuffer++; \ } \ \ BucketNo = BucketNo % NO_OF_HASH_BUCKETS; \ *pNameBuffer = L'\0'; \ (pName)->Length = (USHORT)((CHAR *)pNameBuffer - (CHAR *)(pName)->Buffer);\ \ (pPath)->Length = (USHORT)((CHAR *)pPathBufferEnd - (CHAR *)pPathBuffer);\ (pPath)->Buffer = pPathBuffer; \ DebugTrace(0, Dbg, "SPLIT_PATH:Path (%wZ)",pPath); \ DebugTrace(0, Dbg, " Name (%wZ)\n",pName); \ } \ //+--------------------------------------------------------------------------- // // Function: SPLIT_CASE_SENSITIVE_PATH // // Synopsis: Split the patah name around deleimiters. // // Arguments: [pPath] -- path to be split(PUNICODE_STRING) // // [pName] -- the leftmost component of the path(PUNICODE_STRING) // // [BucketNo] -- Hash Bucket no. corresponding to the name(ULONG) // // SideEffects: the UNICODE_STRING pointed to by pName and BucketNo are modified. // // PreRequisite: pName be associated with a valid buffer. // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- #define SPLIT_CASE_SENSITIVE_PATH(pPath,pName,BucketNo) \ { \ WCHAR *pPathBuffer = (pPath)->Buffer; \ WCHAR *pNameBuffer = (pName)->Buffer; \ WCHAR *pPathBufferEnd = &pPathBuffer[(pPath)->Length / sizeof(WCHAR)]; \ \ BucketNo = 0; \ while ((pPathBufferEnd != pPathBuffer) && \ ((*pNameBuffer = *pPathBuffer++) != PATH_DELIMITER)) \ { \ BucketNo *= 131; \ BucketNo += *pNameBuffer; \ pNameBuffer++; \ } \ \ BucketNo = BucketNo % NO_OF_HASH_BUCKETS; \ *pNameBuffer = L'\0'; \ (pName)->Length = (USHORT)((CHAR *)pNameBuffer - (CHAR *)(pName)->Buffer);\ \ (pPath)->Length = (USHORT)((CHAR *)pPathBufferEnd - (CHAR *)pPathBuffer); \ (pPath)->Buffer = pPathBuffer; \ DebugTrace(0, Dbg, "SPLIT_PATH:Path (%wZ)",pPath); \ DebugTrace(0, Dbg, " Name (%wZ)\n",pName); \ } \ //+--------------------------------------------------------------------------- // // Function: INITIALIZE_BUCKET // // Synopsis: Initializes a hash bucket. // // Arguments: [Bucket] -- the bucket to be initialized(DFS_PREFIX_TABLE_BUCKET) // // SideEffects: the bucket is intialized ( the collision list and count are // initialized // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- #define INITIALIZE_BUCKET(Bucket) \ { \ (Bucket).SentinelEntry.pNextEntry = &(Bucket).SentinelEntry; \ (Bucket).SentinelEntry.pPrevEntry = &(Bucket).SentinelEntry; \ (Bucket).NoOfEntries = 0; \ } \ //+--------------------------------------------------------------------------- // // Function: LOOKUP_BUCKET // // Synopsis: lookups the bucket for an entry. // // Arguments: [Bucket] -- the bucket to be used (DFS_PREFIX_TABLE_BUCKET) // // [Name] -- the name to be looked up (UNICODE_STRING) // // [pParentEntry] -- the parent entry of the entry we are // searching for. // // [pEntry] -- placeholder for the desired entry. // // [fNameFound] -- indicates if the name was found. // // SideEffects: Name,fNameFound and pEntry are modified // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // // We only store one copy of a string irrespective of the no. of // places it appears in, e.g. foo\bar and foo1\bar will result // in only one copy of bar being stored. This implies that the // lookup routine will have to return sufficient info. to prevent // the allocation of memory space for a string. If on exit // fNameFound is set to TRUE then this indicates that a similar // string was located in the table and the Name.Buffer field is // modified to point to the first instance of the string in // the table. // //---------------------------------------------------------------------------- #define LOOKUP_BUCKET(Bucket,Name,pParentEntry,pEntry,fNameFound) \ { \ PDFS_PREFIX_TABLE_ENTRY pCurEntry = Bucket.SentinelEntry.pNextEntry; \ \ DebugTrace(0, Dbg, "LOOKUP_BUCKET: Looking for (%wZ)\n", &Name); \ fNameFound = FALSE; \ pEntry = NULL; \ \ while (pCurEntry != &Bucket.SentinelEntry) \ { \ if (pCurEntry->PathSegment.Length == Name.Length) \ { \ DebugTrace(0, Dbg, "LOOKUP_BUCKET: Looking at Entry with Name (%wZ)\n",&pCurEntry->PathSegment); \ if (fNameFound && \ (pCurEntry->PathSegment.Buffer == Name.Buffer)) \ { \ if (pCurEntry->pParentEntry == pParentEntry) \ { \ pEntry = pCurEntry; \ break; \ } \ } \ else if (!COMPARE_MEMORY(pCurEntry->PathSegment.Buffer, \ Name.Buffer, \ Name.Length)) \ { \ fNameFound = TRUE; \ Name.Buffer = pCurEntry->PathSegment.Buffer; \ if (pCurEntry->pParentEntry == pParentEntry) \ { \ pEntry = pCurEntry; \ break; \ } \ } \ } \ \ pCurEntry = pCurEntry->pNextEntry; \ } \ } \ //+--------------------------------------------------------------------------- // // Function: INSERT_IN_BUCKET // // Synopsis: inserts the entry in the bucket // // Arguments: [Bucket] -- the bucket to be initialized(DFS_PREFIX_TABLE_BUCKET) // // [pEntry] -- the entry to be inserted // // SideEffects: Bucket is modified to include the entry // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- #define INSERT_IN_BUCKET(Bucket,pEntry) \ { \ (Bucket).NoOfEntries++; \ (pEntry)->pPrevEntry = (Bucket).SentinelEntry.pPrevEntry; \ (pEntry)->pNextEntry = &((Bucket).SentinelEntry); \ ((Bucket).SentinelEntry.pPrevEntry)->pNextEntry = (pEntry); \ (Bucket).SentinelEntry.pPrevEntry = (pEntry); \ } \ //+--------------------------------------------------------------------------- // // Function: REMOVE_FROM_BUCKET // // Synopsis: removes the entry from the bucket // // Arguments: [pEntry] -- the entry to be inserted // // SideEffects: Bucket is modified to exclude the entry // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- #define REMOVE_FROM_BUCKET(pEntry) \ { \ PDFS_PREFIX_TABLE_ENTRY pPrevEntry = (pEntry)->pPrevEntry; \ PDFS_PREFIX_TABLE_ENTRY pNextEntry = (pEntry)->pNextEntry; \ \ pPrevEntry->pNextEntry = pNextEntry; \ pNextEntry->pPrevEntry = pPrevEntry; \ } \ //+--------------------------------------------------------------------------- // // Function: INSERT_IN_CHILD_LIST // // Synopsis: Inserts this entry in the parent's list of children // // Arguments: [pEntry] -- the entry to be inserted // // [pParentEntry] -- the entry into whose list of children // pEntry has to be inserted. // // SideEffects: Parent's list of children is modified. // // History: 01-09-96 MilanS Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- #define INSERT_IN_CHILD_LIST(pEntry, pParentEntry) \ { \ PDFS_PREFIX_TABLE_ENTRY pLastChild; \ \ if (pParentEntry->pFirstChildEntry == NULL) { \ pParentEntry->pFirstChildEntry = pEntry; \ } else { \ for (pLastChild = pParentEntry->pFirstChildEntry; \ pLastChild->pSiblingEntry != NULL; \ pLastChild = pLastChild->pSiblingEntry) { \ NOTHING; \ } \ pLastChild->pSiblingEntry = pEntry; \ } \ } //+---------------------------------------------------------------------------- // // Function: REMOVE_FROM_CHILD_LIST // // Synopsis: Removes an entry from its parent's list of children // // Arguments: [pEntry] -- the Entry to remove from children list. // // SideEffects: The children list of pParentEntry is modified. // // History: 01-09-96 MilanS Created // // Notes: Defined as a macro for inlining. // // This routine will ASSERT if pEntry is not in the parent's // list of children. // //----------------------------------------------------------------------------- #define REMOVE_FROM_CHILD_LIST(pEntry) \ { \ PDFS_PREFIX_TABLE_ENTRY pParentEntry = pEntry->pParentEntry; \ PDFS_PREFIX_TABLE_ENTRY pPrevSibling; \ \ if (pParentEntry->pFirstChildEntry == pEntry) { \ pParentEntry->pFirstChildEntry = pEntry->pSiblingEntry; \ } else { \ for (pPrevSibling = pParentEntry->pFirstChildEntry; \ pPrevSibling->pSiblingEntry != pEntry; \ pPrevSibling = pPrevSibling->pSiblingEntry) { \ ASSERT(pPrevSibling->pSiblingEntry != NULL); \ } \ pPrevSibling->pSiblingEntry = pEntry->pSiblingEntry; \ } \ } //+--------------------------------------------------------------------------- // // Function: INITIALIZE_NAME_PAGE // // Synopsis: initializes the name page // // Arguments: [pNamePage] -- the NAME_PAGE to be initialized // // SideEffects: the name page is initialized // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- #define INITIALIZE_NAME_PAGE(pNamePage) \ { \ pNamePage->pNextPage = NULL; \ pNamePage->cFreeSpace = FREESPACE_IN_NAME_PAGE - 1; \ pNamePage->Names[FREESPACE_IN_NAME_PAGE - 1] = L'\0'; \ } \ //+--------------------------------------------------------------------------- // // Function: INITIALIZE_PREFIX_TABLE_ENTRY // // Synopsis: initializes the prefix table entry // // Arguments: [pEntry] -- the entry to be initialized // // SideEffects: the prefix table entry is modified // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- #define INITIALIZE_PREFIX_TABLE_ENTRY(pEntry) \ { \ RtlZeroMemory( pEntry, sizeof( DFS_PREFIX_TABLE_ENTRY ) ); \ (pEntry)->NoOfChildren = 1; \ } \ //+--------------------------------------------------------------------------- // // Function: private fns. extern declarations // //---------------------------------------------------------------------------- extern NTSTATUS _LookupPrefixTable(PDFS_PREFIX_TABLE pTable, UNICODE_STRING *pPath, UNICODE_STRING *pSuffix, PDFS_PREFIX_TABLE_ENTRY *ppEntry); //+--------------------------------------------------------------------------- // // Function: ALLOCATION ROUTINES // // Synopsis: all the allocation routines are defined to be used in the KERNEL as // well as user mode. The KERNEL mode is turned on by defining KERNEL // // History: 04-18-94 SethuR Created // // Notes: defined as a macro for inlining // //---------------------------------------------------------------------------- extern NTSTATUS _InitializePrefixTableEntryAllocation(PDFS_PREFIX_TABLE pTable); extern PWSTR _AllocateNamePageEntry(PNAME_PAGE_LIST pPageList,ULONG cLength); #ifdef KERNEL_MODE #define ALLOCATE_NAME_PAGE() (PNAME_PAGE)ExAllocatePoolWithTag(PagedPool,sizeof(NAME_PAGE), ' sfD') #define FREE_NAME_PAGE(pPage) ExFreePool(pPage) #define ALLOCATE_NAME_PAGE_ENTRY(PageList,cLength) \ ExAllocatePoolWithTag(PagedPool, cLength * sizeof(WCHAR), ' sfD'); \ #define FREE_NAME_PAGE_ENTRY(PageList,pName) #define ALLOCATE_DFS_PREFIX_TABLE_ENTRY(pTable) \ (PDFS_PREFIX_TABLE_ENTRY) ExAllocatePoolWithTag(PagedPool,sizeof(DFS_PREFIX_TABLE_ENTRY), ' sfD') #define FREE_DFS_PREFIX_TABLE_ENTRY(pTable,pEntry) \ if ((pEntry)->PathSegment.Buffer != NULL) { \ ExFreePool((pEntry)->PathSegment.Buffer); \ } \ ExFreePool((pEntry)); #define COMPARE_MEMORY(s,d,l) (!RtlEqualMemory(s,d,l)) #else #define ALLOCATE_NAME_PAGE() (PNAME_PAGE)malloc(sizeof(NAME_PAGE)) #define FREE_NAME_PAGE(pPage) free(pPage) #define ALLOCATE_NAME_PAGE_ENTRY(PageList,cLength) malloc(cLength * sizeof(WCHAR)) #define FREE_NAME_PAGE_ENTRY(PageList,pName) #define ALLOCATE_DFS_PREFIX_TABLE_ENTRY(pTable) \ (PDFS_PREFIX_TABLE_ENTRY)malloc(sizeof(DFS_PREFIX_TABLE_ENTRY)) #define FREE_DFS_PREFIX_TABLE_ENTRY(pTable,pEntry) free((pEntry)) #define COMPARE_MEMORY(s,d,l) memcmp(s,d,l) #endif #endif // __PREFIXP_H__