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//+-------------------------------------------------------------------------
//
// 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.h>
//--------------------------------------------------------------------------
//
// 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
//
//----------------------------------------------------------------------------
externNTSTATUS _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
//
//----------------------------------------------------------------------------
externNTSTATUS_InitializePrefixTableEntryAllocation(PDFS_PREFIX_TABLE pTable);
externPWSTR _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__
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