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