/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS system libraries
* PURPOSE: Unicode Prefix implementation
* FILE: lib/rtl/unicodeprefix.c
* PROGRAMMER: Alex Ionescu (alex@relsoft.net)
*/
/* INCLUDES *****************************************************************/
#include <rtl.h>
#define NDEBUG
#include <debug.h>
/*
* FIXME: Try to find the official names and add to NDK
* Definitions come from fastfat driver.
*/
typedef USHORT NODE_TYPE_CODE;
#define PFX_NTC_TABLE ((NODE_TYPE_CODE)0x0800)
#define PFX_NTC_ROOT ((NODE_TYPE_CODE)0x0801)
#define PFX_NTC_CHILD ((NODE_TYPE_CODE)0x0802)
#define PFX_NTC_CASE_MATCH ((NODE_TYPE_CODE)0x0803)
/* FUNCTIONS ***************************************************************/
ULONG
NTAPI
ComputeUnicodeNameLength(IN PUNICODE_STRING UnicodeName)
{
ULONG Chars = UnicodeName->Length / sizeof(WCHAR);
ULONG i, NamesFound = 1;
/* Loop the string */
for (i = 0; i < (Chars - 1); i++)
{
/* Check if we found a backslash, meaning another name */
if (UnicodeName->Buffer[i] == '\\') NamesFound++;
}
/* Return the number of names found */
return NamesFound;
}
RTL_GENERIC_COMPARE_RESULTS
NTAPI
CompareUnicodeStrings(IN PUNICODE_STRING Prefix,
IN PUNICODE_STRING String,
IN ULONG CaseCheckChar)
{
ULONG StringLength = String->Length / sizeof(WCHAR);
ULONG PrefixLength = Prefix->Length / sizeof(WCHAR);
ULONG ScanLength = min(StringLength, PrefixLength);
ULONG i;
WCHAR FoundPrefix, FoundString;
PWCHAR p, p1;
/* Handle case noticed in npfs when Prefix = '\' and name starts with '\' */
if ((PrefixLength == 1) &&
(Prefix->Buffer[0] == '\\') &&
(StringLength > 1) &&
(String->Buffer[0] == '\\'))
{
/* The string is actually a prefix */
return -1;
}
/* Validate the Case Check Character Position */
if (CaseCheckChar > ScanLength) CaseCheckChar = ScanLength;
/* Do the case sensitive comparison first */
for (i = 0; i < CaseCheckChar; i++)
{
/* Compare the two characters */
if (Prefix->Buffer[i] != String->Buffer[i]) break;
}
/* Save the characters we found */
FoundPrefix = Prefix->Buffer[i];
FoundString = String->Buffer[i];
/* Check if we exausted the search above */
if (i == CaseCheckChar)
{
/* Do a case-insensitive search */
p = &Prefix->Buffer[i];
p1 = &String->Buffer[i];
do
{
/* Move to the next character */
FoundPrefix = *p++;
FoundString = *p1++;
/* Compare it */
if (FoundPrefix != FoundString)
{
/* Upcase the characters */
FoundPrefix = RtlpUpcaseUnicodeChar(FoundPrefix);
FoundString = RtlpUpcaseUnicodeChar(FoundString);
/* Compare them again */
if (FoundPrefix != FoundString) break;
}
/* Move to the next char */
i++;
} while (i < ScanLength);
}
/* Check if we weren't able to find a match in the loops */
if (i < ScanLength)
{
/* If the prefix character found was a backslash, this is a less */
if (FoundPrefix == '\\') return GenericLessThan;
/* If the string character found was a backslack, then this is a more */
if (FoundString == '\\') return GenericGreaterThan;
/* None of those two special cases, do a normal check */
if (FoundPrefix < FoundString) return GenericLessThan;
/* The only choice left is that Prefix > String */
return GenericGreaterThan;
}
/* If we got here, a match was found. Check if the prefix is smaller */
if (PrefixLength < StringLength)
{
/* Check if the string is actually a prefix */
if (String->Buffer[PrefixLength] == '\\') return -1;
/* It's not a prefix, and it's shorter, so it's a less */
return GenericLessThan;
}
/* Check if the prefix is longer */
if (PrefixLength > StringLength) return GenericGreaterThan;
/* If we got here, then they are 100% equal */
return GenericEqual;
}
/*
* @implemented
*/
PUNICODE_PREFIX_TABLE_ENTRY
NTAPI
RtlFindUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
PUNICODE_STRING FullName,
ULONG CaseInsensitiveIndex)
{
ULONG NameCount;
PUNICODE_PREFIX_TABLE_ENTRY CurrentEntry, PreviousEntry, Entry, NextEntry;
PRTL_SPLAY_LINKS SplayLinks;
RTL_GENERIC_COMPARE_RESULTS Result;
DPRINT("RtlFindUnicodePrefix(): Table %p, FullName %wZ, "
"CaseInsensitive %lu\n", PrefixTable, FullName, CaseInsensitiveIndex);
/* Find out how many names there are */
NameCount = ComputeUnicodeNameLength(FullName);
/* Find the right spot where to start looking for this entry */
PreviousEntry = (PUNICODE_PREFIX_TABLE_ENTRY)PrefixTable;
CurrentEntry = PreviousEntry->NextPrefixTree;
while (CurrentEntry->NameLength > (CSHORT)NameCount)
{
/* Not a match, move to the next entry */
PreviousEntry = CurrentEntry;
CurrentEntry = CurrentEntry->NextPrefixTree;
}
/* Loop every entry which has valid entries */
while (CurrentEntry->NameLength)
{
/* Get the splay links and loop */
SplayLinks = &CurrentEntry->Links;
while (SplayLinks)
{
/* Get the entry */
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
/* Do the comparison */
Result = CompareUnicodeStrings(Entry->Prefix, FullName, 0);
if (Result == GenericGreaterThan)
{
/* Prefix is greater, so restart on the left child */
SplayLinks = RtlLeftChild(SplayLinks);
continue;
}
else if (Result == GenericLessThan)
{
/* Prefix is smaller, so restart on the right child */
SplayLinks = RtlRightChild(SplayLinks);
continue;
}
/*
* We have a match, check if this was a case-sensitive search
* NOTE: An index of 0 means case-insensitive(ie, we'll be case
* insensitive since index 0, ie, all the time)
*/
if (!CaseInsensitiveIndex)
{
/*
* Check if this entry was a child. We need to return the root,
* so if this entry was a child, we'll splay the tree and get
* the root, and set the current entry as a child.
*/
if (Entry->NodeTypeCode == PFX_NTC_CHILD)
{
/* Get the next entry */
NextEntry = CurrentEntry->NextPrefixTree;
/* Make the current entry become a child */
CurrentEntry->NodeTypeCode = PFX_NTC_CHILD;
CurrentEntry->NextPrefixTree = NULL;
/* Splay the tree */
SplayLinks = RtlSplay(&Entry->Links);
/* Get the new root entry */
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
/* Set it as a root entry */
Entry->NodeTypeCode = PFX_NTC_ROOT;
/* Add it to the root entries list */
PreviousEntry->NextPrefixTree = Entry;
Entry->NextPrefixTree = NextEntry;
}
/* Return the entry */
return Entry;
}
/* We'll do a case-sensitive search if we've reached this point */
NextEntry = Entry;
do
{
/* Do the case-sensitive search */
Result = CompareUnicodeStrings(NextEntry->Prefix,
FullName,
CaseInsensitiveIndex);
if ((Result != GenericLessThan) &&
(Result != GenericGreaterThan))
{
/* This is a positive match, return it */
return NextEntry;
}
/* No match yet, continue looping the circular list */
NextEntry = NextEntry->CaseMatch;
} while (NextEntry != Entry);
/*
* If we got here, then we found a non-case-sensitive match, but
* we need to find a case-sensitive match, so we'll just keep
* searching the next tree (NOTE: we need to break out for this).
*/
break;
}
/* Splay links exhausted, move to next entry */
PreviousEntry = CurrentEntry;
CurrentEntry = CurrentEntry->NextPrefixTree;
}
/* If we got here, nothing was found */
return NULL;
}
/*
* @implemented
*/
VOID
NTAPI
RtlInitializeUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable)
{
DPRINT("RtlInitializeUnicodePrefix(): Table %p\n",
PrefixTable);
/* Setup the table */
PrefixTable->NameLength = 0;
PrefixTable->LastNextEntry = NULL;
PrefixTable->NodeTypeCode = PFX_NTC_TABLE;
PrefixTable->NextPrefixTree = (PUNICODE_PREFIX_TABLE_ENTRY)PrefixTable;
}
/*
* @implemented
*/
BOOLEAN
NTAPI
RtlInsertUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
PUNICODE_STRING Prefix,
PUNICODE_PREFIX_TABLE_ENTRY PrefixTableEntry)
{
PUNICODE_PREFIX_TABLE_ENTRY CurrentEntry, PreviousEntry, Entry, NextEntry;
ULONG NameCount;
RTL_GENERIC_COMPARE_RESULTS Result;
PRTL_SPLAY_LINKS SplayLinks;
DPRINT("RtlInsertUnicodePrefix(): Table %p, Prefix %wZ, "
"TableEntry %p\n", PrefixTable, Prefix, PrefixTableEntry);
/* Find out how many names there are */
NameCount = ComputeUnicodeNameLength(Prefix);
/* Set up the initial entry data */
PrefixTableEntry->NameLength = (CSHORT)NameCount;
PrefixTableEntry->Prefix = Prefix;
RtlInitializeSplayLinks(&PrefixTableEntry->Links);
/* Find the right spot where to insert this entry */
PreviousEntry = (PUNICODE_PREFIX_TABLE_ENTRY)PrefixTable;
CurrentEntry = PreviousEntry->NextPrefixTree;
while (CurrentEntry->NameLength > (CSHORT)NameCount)
{
/* Not a match, move to the next entry */
PreviousEntry = CurrentEntry;
CurrentEntry = CurrentEntry->NextPrefixTree;
}
/* Check if we did find a tree by now */
if (CurrentEntry->NameLength != (CSHORT)NameCount)
{
/* We didn't, so insert a new entry in the list */
PreviousEntry->NextPrefixTree = PrefixTableEntry;
PrefixTableEntry->NextPrefixTree = CurrentEntry;
/* This is now a root entry with case match */
PrefixTableEntry->NodeTypeCode = PFX_NTC_ROOT;
PrefixTableEntry->CaseMatch = PrefixTableEntry;
/* Quick return */
return TRUE;
}
/* We found a tree, so start the search loop */
Entry = CurrentEntry;
while (TRUE)
{
/* Do a case-insensitive comparison to find out the match level */
Result = CompareUnicodeStrings(Entry->Prefix, Prefix, 0);
if (Result == GenericEqual)
{
/* We have a match, start doing a case-sensitive search */
NextEntry = Entry;
/* Search the circular case-match list */
do
{
/* Check if we found a match */
if (CompareUnicodeStrings(NextEntry->Prefix, Prefix, -1) ==
(GenericEqual))
{
/* We must fail the insert: it already exists */
return FALSE;
}
/* Move to the next entry in the circular list */
NextEntry = NextEntry->CaseMatch;
}
while (NextEntry != Entry);
/*
* No match found, so we can safely insert it. Remember that a
* case insensitive match was found, so this is not a ROOT NTC
* but a Case Match NTC instead.
*/
PrefixTableEntry->NodeTypeCode = PFX_NTC_CASE_MATCH;
PrefixTableEntry->NextPrefixTree = NULL;
/* Insert it into the circular list */
PrefixTableEntry->CaseMatch = Entry->CaseMatch;
Entry->CaseMatch = PrefixTableEntry;
break;
}
/* Check if the result was greater or lesser than */
if (Result == GenericGreaterThan)
{
/* Check out if we have a left child */
if (RtlLeftChild(&Entry->Links))
{
/* We do, enter it and restart the loop */
SplayLinks = RtlLeftChild(&Entry->Links);
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
}
else
{
/* We don't, set this entry as a child */
PrefixTableEntry->NodeTypeCode = PFX_NTC_CHILD;
PrefixTableEntry->NextPrefixTree = NULL;
PrefixTableEntry->CaseMatch = PrefixTableEntry;
/* Insert us into the tree */
RtlInsertAsLeftChild(&Entry->Links, &PrefixTableEntry->Links);
break;
}
}
else
{
/* Check out if we have a right child */
if (RtlRightChild(&Entry->Links))
{
/* We do, enter it and restart the loop */
SplayLinks = RtlRightChild(&Entry->Links);
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
}
else
{
/* We don't, set this entry as a child */
PrefixTableEntry->NodeTypeCode = PFX_NTC_CHILD;
PrefixTableEntry->NextPrefixTree = NULL;
PrefixTableEntry->CaseMatch = PrefixTableEntry;
/* Insert us into the tree */
RtlInsertAsRightChild(&Entry->Links, &PrefixTableEntry->Links);
break;
}
}
}
/* Get the next tree entry */
NextEntry = CurrentEntry->NextPrefixTree;
/* Set what was the current entry to a child entry */
CurrentEntry->NodeTypeCode = PFX_NTC_CHILD;
CurrentEntry->NextPrefixTree = NULL;
/* Splay the tree */
SplayLinks = RtlSplay(&Entry->Links);
/* The link points to the root, get it */
Entry = CONTAINING_RECORD(SplayLinks, UNICODE_PREFIX_TABLE_ENTRY, Links);
/* Mark the root as a root entry */
Entry->NodeTypeCode = PFX_NTC_ROOT;
/* Add it to the tree list */
PreviousEntry->NextPrefixTree = Entry;
Entry->NextPrefixTree = NextEntry;
/* Return success */
return TRUE;
}
/*
* @implemented
*/
PUNICODE_PREFIX_TABLE_ENTRY
NTAPI
RtlNextUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
BOOLEAN Restart)
{
PRTL_SPLAY_LINKS SplayLinks;
PUNICODE_PREFIX_TABLE_ENTRY Entry, CaseMatchEntry = NULL;
DPRINT("RtlNextUnicodePrefix(): Table %p Restart %u\n",
PrefixTable, Restart);
/* We might need this entry 2/3rd of the time, so cache it now */
if (PrefixTable->LastNextEntry)
CaseMatchEntry = PrefixTable->LastNextEntry->CaseMatch;
/* Check if this is a restart or if we don't have a last entry */
if ((Restart) || !(PrefixTable->LastNextEntry))
{
/* Get the next entry and validate it */
Entry = PrefixTable->NextPrefixTree;
if (Entry->NodeTypeCode == PFX_NTC_TABLE) return NULL;
/* Now get the Splay Tree Links */
SplayLinks = &Entry->Links;
/* Loop until we get the first node in the tree */
while (RtlLeftChild(SplayLinks)) SplayLinks = RtlLeftChild(SplayLinks);
/* Get the entry from it */
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
}
else if (CaseMatchEntry->NodeTypeCode == PFX_NTC_CASE_MATCH)
{
/* If the last entry was a Case Match, then return it */
Entry = CaseMatchEntry;
}
else
{
/* Find the successor */
SplayLinks = RtlRealSuccessor(&CaseMatchEntry->Links);
if (!SplayLinks)
{
/* Didn't find one, we'll have to search the tree */
SplayLinks = &PrefixTable->LastNextEntry->Links;
/* Get the topmost node (root) */
while (!RtlIsRoot(SplayLinks)) SplayLinks = RtlParent(SplayLinks);
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
/* Get its tree and make sure somethign is in it */
Entry = Entry->NextPrefixTree;
if (Entry->NameLength <= 0) return NULL;
/* Select these new links and find the first node */
while (RtlLeftChild(SplayLinks)) SplayLinks = RtlLeftChild(SplayLinks);
}
/* Get the entry from it */
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
}
/* Save this entry as the last one returned, and return it */
PrefixTable->LastNextEntry = Entry;
return Entry;
}
/*
* @implemented
*/
VOID
NTAPI
RtlRemoveUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
PUNICODE_PREFIX_TABLE_ENTRY PrefixTableEntry)
{
PUNICODE_PREFIX_TABLE_ENTRY Entry, RefEntry, NewEntry;
PRTL_SPLAY_LINKS SplayLinks;
DPRINT("RtlRemoveUnicodePrefix(): Table %p, TableEntry %p\n",
PrefixTable, PrefixTableEntry);
/* Erase the last entry */
PrefixTable->LastNextEntry = NULL;
/* Check if this was a Case Match Entry */
if (PrefixTableEntry->NodeTypeCode == PFX_NTC_CASE_MATCH)
{
/* Get the case match entry */
Entry = PrefixTableEntry->CaseMatch;
/* Now loop until we find one referencing what the caller sent */
while (Entry->CaseMatch != PrefixTableEntry) Entry = Entry->CaseMatch;
/* We found the entry that was sent, link them to delete this entry */
Entry->CaseMatch = PrefixTableEntry->CaseMatch;
}
else if ((PrefixTableEntry->NodeTypeCode == PFX_NTC_ROOT) ||
(PrefixTableEntry->NodeTypeCode == PFX_NTC_CHILD))
{
/* Check if this entry is a case match */
if (PrefixTableEntry->CaseMatch != PrefixTableEntry)
{
/* Get the case match entry */
Entry = PrefixTableEntry->CaseMatch;
/* Now loop until we find one referencing what the caller sent */
while (Entry->CaseMatch != PrefixTableEntry) Entry = Entry->CaseMatch;
/* We found the entry that was sent, link them to delete this entry */
Entry->CaseMatch = PrefixTableEntry->CaseMatch;
/* Copy the data */
Entry->NodeTypeCode = PrefixTableEntry->NodeTypeCode;
Entry->NextPrefixTree = PrefixTableEntry->NextPrefixTree;
Entry->Links = PrefixTableEntry->Links;
/* Now check if we are a root entry */
if (RtlIsRoot(&PrefixTableEntry->Links))
{
/* We are, so make this entry root as well */
Entry->Links.Parent = &Entry->Links;
/* Find the entry referencing us */
RefEntry = Entry->NextPrefixTree;
while (RefEntry->NextPrefixTree != Entry)
{
/* Not this one, move to the next entry */
RefEntry = RefEntry->NextPrefixTree;
}
/* Link them to us now */
RefEntry->NextPrefixTree = Entry;
}
else if (RtlIsLeftChild(&PrefixTableEntry->Links))
{
/* We were the left child, so make us as well */
RtlParent(&PrefixTableEntry->Links)->LeftChild = &Entry->Links;
}
else
{
/* We were the right child, so make us as well */
RtlParent(&PrefixTableEntry->Links)->RightChild = &Entry->Links;
}
/* Check if we have a left child */
if (RtlLeftChild(&Entry->Links))
{
/* Update its parent link */
RtlLeftChild(&Entry->Links)->Parent = &Entry->Links;
}
/* Check if we have a right child */
if (RtlRightChild(&Entry->Links))
{
/* Update its parent link */
RtlRightChild(&Entry->Links)->Parent = &Entry->Links;
}
}
else
{
/* It's not a case match, so we'll delete the actual entry */
SplayLinks = &PrefixTableEntry->Links;
/* Find the root entry */
while (!RtlIsRoot(SplayLinks)) SplayLinks = RtlParent(SplayLinks);
Entry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
/* Delete the entry and check if the whole tree is gone */
SplayLinks = RtlDelete(&PrefixTableEntry->Links);
if (!SplayLinks)
{
/* The tree is also gone now, find the entry referencing us */
RefEntry = Entry->NextPrefixTree;
while (RefEntry->NextPrefixTree != Entry)
{
/* Not this one, move to the next entry */
RefEntry = RefEntry->NextPrefixTree;
}
/* Link them so this entry stops being referenced */
RefEntry->NextPrefixTree = Entry->NextPrefixTree;
}
else if (&Entry->Links != SplayLinks)
{
/* The tree is still here, but we got moved to a new one */
NewEntry = CONTAINING_RECORD(SplayLinks,
UNICODE_PREFIX_TABLE_ENTRY,
Links);
/* Find the entry referencing us */
RefEntry = Entry->NextPrefixTree;
while (RefEntry->NextPrefixTree != Entry)
{
/* Not this one, move to the next entry */
RefEntry = RefEntry->NextPrefixTree;
}
/* Since we got moved, make us the new root entry */
NewEntry->NodeTypeCode = PFX_NTC_ROOT;
/* Link us with the entry referencing the old root */
RefEntry->NextPrefixTree = NewEntry;
/* And link us with the old tree */
NewEntry->NextPrefixTree = Entry->NextPrefixTree;
/* Set the old tree as a child */
Entry->NodeTypeCode = PFX_NTC_CHILD;
Entry->NextPrefixTree = NULL;
}
}
}
}
/* EOF */