reactos/lib/rtl/unicodeprefix.c

   1 /*
   2  * COPYRIGHT:         See COPYING in the top level directory
   3  * PROJECT:           ReactOS system libraries
   4  * PURPOSE:           Unicode Prefix implementation
   5  * FILE:              lib/rtl/unicodeprefix.c
   6  * PROGRAMMER:        Alex Ionescu (alex@relsoft.net)
   7  */
   8
   9 /* INCLUDES *****************************************************************/
  10
  11 #include <rtl.h>
  12
  13 #define NDEBUG
  14 #include <debug.h>
  15
  16 /*
  17  * FIXME: Try to find the official names and add to NDK
  18  * Definitions come from fastfat driver.
  19  */
  20 typedef USHORT NODE_TYPE_CODE;
  21 #define PFX_NTC_TABLE       ((NODE_TYPE_CODE)0x0800)
  22 #define PFX_NTC_ROOT        ((NODE_TYPE_CODE)0x0801)
  23 #define PFX_NTC_CHILD       ((NODE_TYPE_CODE)0x0802)
  24 #define PFX_NTC_CASE_MATCH  ((NODE_TYPE_CODE)0x0803)
  25
  26 /* FUNCTIONS ***************************************************************/
  27
  28 /*STATIC*/
  29 ULONG
  30 NTAPI
  31 ComputeUnicodeNameLength(IN PUNICODE_STRING UnicodeName)
  32 {
  33     ULONG Chars = UnicodeName->Length / sizeof(WCHAR);
  34     ULONG i, NamesFound = 1;
  35
  36     /* Loop the string */
  37     for (i = 0; i < (Chars - 1); i++)
  38     {
  39         /* Check if we found a backslash, meaning another name */
  40         if (UnicodeName->Buffer[i] == '\\') NamesFound++;
  41     }
  42
  43     /* Return the number of names found */
  44     return NamesFound;
  45 }
  46
  47 /*
  48 * @unimplemented
  49 */
  50 PUNICODE_PREFIX_TABLE_ENTRY
  51 NTAPI
  52 RtlFindUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
  53                      PUNICODE_STRING FullName,
  54                      ULONG CaseInsensitiveIndex)
  55 {
  56         UNIMPLEMENTED;
  57         return 0;
  58 }
  59
  60 /*
  61 * @implemented
  62 */
  63 VOID
  64 NTAPI
  65 RtlInitializeUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable)
  66 {
  67         /* Setup the table */
  68     PrefixTable->NameLength = 0;
  69     PrefixTable->LastNextEntry = NULL;
  70     PrefixTable->NodeTypeCode = PFX_NTC_TABLE;
  71     PrefixTable->NextPrefixTree = (PUNICODE_PREFIX_TABLE_ENTRY)PrefixTable;
  72 }
  73
  74 /*
  75 * @unimplemented
  76 */
  77 BOOLEAN
  78 NTAPI
  79 RtlInsertUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
  80                        PUNICODE_STRING Prefix,
  81                        PUNICODE_PREFIX_TABLE_ENTRY PrefixTableEntry)
  82 {
  83     /*
  84      * implementation notes:
  85      * - get name length (number of names)
  86      * - init splay links
  87      * - find a matching tree
  88      * - if !found, insert a new NTC_ROOT entry and return TRUE;
  89      * - if found, loop tree and compare strings:
  90      *   if equal, handle casematch/nomatch
  91      *   if greater or lesser equal, then add left/right childs accordingly
  92      * - splay the tree
  93      */
  94         UNIMPLEMENTED;
  95         return FALSE;
  96 }
  97
  98 /*
  99 * @implemented
 100 */
 101 PUNICODE_PREFIX_TABLE_ENTRY
 102 NTAPI
 103 RtlNextUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
 104                      BOOLEAN Restart)
 105 {
 106     PRTL_SPLAY_LINKS SplayLinks;
 107     PUNICODE_PREFIX_TABLE_ENTRY Entry;
 108     PUNICODE_PREFIX_TABLE_ENTRY CaseMatchEntry;
 109
 110     /* We might need this entry 2/3rd of the time, so cache it now */
 111     CaseMatchEntry = PrefixTable->LastNextEntry->CaseMatch;
 112
 113     /* Check if this is a restart or if we don't have a last entry */
 114     if ((Restart) || !(PrefixTable->LastNextEntry))
 115     {
 116         /* Get the next entry and validate it */
 117         Entry = PrefixTable->NextPrefixTree;
 118         if (Entry->NodeTypeCode == PFX_NTC_TABLE) return NULL;
 119
 120         /* Now get the Splay Tree Links */
 121         SplayLinks = &Entry->Links;
 122
 123         /* Loop until we get the first node in the tree */
 124         while (RtlLeftChild(SplayLinks)) SplayLinks = RtlLeftChild(SplayLinks);
 125
 126         /* Get the entry from it */
 127         Entry = CONTAINING_RECORD(SplayLinks,
 128                                   UNICODE_PREFIX_TABLE_ENTRY,
 129                                   Links);
 130     }
 131     else if (CaseMatchEntry->NodeTypeCode == PFX_NTC_CASE_MATCH)
 132     {
 133         /* If the last entry was a Case Match, then return it */
 134         Entry = CaseMatchEntry;
 135     }
 136     else
 137     {
 138         /* Find the successor */
 139         SplayLinks = RtlRealSuccessor(&CaseMatchEntry->Links);
 140         if (!SplayLinks)
 141         {
 142             /* Didn't find one, we'll have to search the tree */
 143             SplayLinks = &PrefixTable->LastNextEntry->Links;
 144
 145             /* Get the topmost node (root) */
 146             while (!RtlIsRoot(SplayLinks)) SplayLinks = RtlParent(SplayLinks);
 147             Entry = CONTAINING_RECORD(SplayLinks,
 148                                       UNICODE_PREFIX_TABLE_ENTRY,
 149                                       Links);
 150
 151             /* Get its tree and make sure somethign is in it */
 152             Entry = Entry->NextPrefixTree;
 153             if (Entry->NameLength <= 0) return NULL;
 154
 155             /* Select these new links and find the first node */
 156             while (RtlLeftChild(SplayLinks)) SplayLinks = RtlLeftChild(SplayLinks);
 157         }
 158
 159         /* Get the entry from it */
 160         Entry = CONTAINING_RECORD(SplayLinks,
 161                                   UNICODE_PREFIX_TABLE_ENTRY,
 162                                   Links);
 163     }
 164
 165     /* Save this entry as the last one returned, and return it */
 166     PrefixTable->LastNextEntry = Entry;
 167     return Entry;
 168 }
 169
 170 /*
 171 * @unimplemented
 172 */
 173 VOID
 174 NTAPI
 175 RtlRemoveUnicodePrefix(PUNICODE_PREFIX_TABLE PrefixTable,
 176                        PUNICODE_PREFIX_TABLE_ENTRY PrefixTableEntry)
 177 {
 178         UNIMPLEMENTED;
 179 }
 180
 181 /* EOF */