- Finish implementing RtlFindUnicodePrefix. The Windows NPFS driver should load now...
[reactos.git] / reactos / lib / rtl / unicodeprefix.c
index 0740078..a9079d2 100644 (file)
@@ -44,8 +44,98 @@ ComputeUnicodeNameLength(IN PUNICODE_STRING UnicodeName)
     return NamesFound;
 }
 
+
+STATIC
+RTL_GENERIC_COMPARE_RESULTS
+NTAPI
+CompareUnicodeStrings(IN PUNICODE_STRING String,
+                      IN PUNICODE_STRING Prefix,
+                      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;
+
+    /* 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 = RtlUpcaseUnicodeChar(FoundPrefix);
+                FoundString = RtlUpcaseUnicodeChar(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;
+}
+
 /*
- * @unimplemented
+ * @implemented
  */
 PUNICODE_PREFIX_TABLE_ENTRY
 NTAPI
@@ -53,8 +143,136 @@ RtlFindUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
                      PUNICODE_STRING FullName,
                      ULONG CaseInsensitiveIndex)
 {
-       UNIMPLEMENTED;
-       return 0;
+    ULONG NameCount;
+    PUNICODE_PREFIX_TABLE_ENTRY CurrentEntry, PreviousEntry, Entry, NextEntry;
+    PRTL_SPLAY_LINKS SplayLinks;
+    RTL_GENERIC_COMPARE_RESULTS Result;
+
+    /* 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 > 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 */
+        while ((SplayLinks = &CurrentEntry->Links))
+        {
+            /*
+             * Implementation notes:
+             *  - get the entry
+             *  - compare the entry's prefix with the fullname:
+             *    if greater: restart on the left child
+             *    if lesser: restart on the right child
+             *  - else if equal:
+             *    for caseinsensitive, just return the entry and
+             *        splay it and set it as root if it's a child
+             *    for casesensitive, loop the circular case match list and
+             *        keep comparing for each 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 exausted, move to next entry */
+        PreviousEntry = CurrentEntry;
+        CurrentEntry = CurrentEntry->NextPrefixTree;
+    }
+
+       /* If we got here, nothing was found */
+       return NULL;
 }
 
 /*
@@ -72,7 +290,7 @@ RtlInitializeUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable)
 }
 
 /*
- * @unimplemented
+ * @implemented
  */
 BOOLEAN
 NTAPI
@@ -80,19 +298,10 @@ RtlInsertUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
                        PUNICODE_STRING Prefix,
                        PUNICODE_PREFIX_TABLE_ENTRY PrefixTableEntry)
 {
-    /*
-     * implementation notes:
-     * - get name length (number of names) DONE
-     * - init splay links DONE
-     * - find a matching tree DONE
-     * - if !found, insert a new NTC_ROOT entry and return TRUE; DONE
-     * - if found, loop tree and compare strings:
-     *   if equal, handle casematch/nomatch
-     *   if greater or lesser equal, then add left/right childs accordingly
-     * - splay the tree
-     */
-    PUNICODE_PREFIX_TABLE_ENTRY CurrentEntry, PreviousEntry;
+    PUNICODE_PREFIX_TABLE_ENTRY CurrentEntry, PreviousEntry, Entry, NextEntry;
     ULONG NameCount;
+    RTL_GENERIC_COMPARE_RESULTS Result;
+    PRTL_SPLAY_LINKS SplayLinks;
 
     /* Find out how many names there are */
     NameCount = ComputeUnicodeNameLength(Prefix);
@@ -127,9 +336,115 @@ RtlInsertUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
         return TRUE;
     }
 
-    /* FIXME */
-       UNIMPLEMENTED;
-       return FALSE;
+    /* We found a tree, so star thte 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;
+        }
+        else 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 = 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 */
+                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;
 }
 
 /*
@@ -269,12 +584,12 @@ RtlRemoveUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
             else if (RtlIsLeftChild(&PrefixTableEntry->Links))
             {
                 /* We were the left child, so make us as well */
-                Entry->Links.LeftChild = &Entry->Links;
+                RtlParent(&PrefixTableEntry->Links)->LeftChild = &Entry->Links;
             }
             else
             {
                 /* We were the right child, so make us as well */
-                Entry->Links.RightChild = &Entry->Links;
+                RtlParent(&PrefixTableEntry->Links)->RightChild = &Entry->Links;
             }
 
             /* Check if we have a left child */