reactos/dll/appcompat/apphelp/sdbstringtable.c

   1 /*
   2  * Copyright 2016 Mark Jansen
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  17  */
  18
  19 #if !defined(SDBWRITE_HOSTTOOL)
  20 #define WIN32_NO_STATUS
  21 #include "windows.h"
  22 #include "sdbtypes.h"
  23 #include "sdbpapi.h"
  24 #else /* !defined(SDBWRITE_HOSTTOOL) */
  25 #include <typedefs.h>
  26 #include "sdbtypes.h"
  27 #include "sdbpapi.h"
  28 #endif /* !defined(SDBWRITE_HOSTTOOL) */
  29
  30 #include "sdbstringtable.h"
  31
  32 #define DEFAULT_TABLE_SIZE    0x100
  33
  34 typedef struct SdbHashEntry
  35 {
  36     struct SdbHashEntry* Next;
  37     TAGID Tagid;
  38     WCHAR Name[1];
  39 } SdbHashEntry;
  40
  41 struct SdbStringHashTable
  42 {
  43     DWORD Size;
  44     struct SdbHashEntry** Entries;
  45 };
  46
  47
  48 static struct SdbStringHashTable* HashCreate(void)
  49 {
  50     struct SdbStringHashTable* tab = SdbAlloc(sizeof(*tab));
  51     if (!tab)
  52     {
  53         SHIM_ERR("Failed to allocate 8 bytes.\r\n");
  54         return tab;
  55     }
  56     tab->Size = DEFAULT_TABLE_SIZE;
  57     tab->Entries = SdbAlloc(tab->Size * sizeof(*tab->Entries));
  58     return tab;
  59 }
  60
  61
  62 void SdbpTableDestroy(struct SdbStringHashTable** pTable)
  63 {
  64     struct SdbStringHashTable* table = *pTable;
  65     struct SdbHashEntry* entry, *next;
  66     DWORD n, depth = 0, once = 1;
  67
  68     *pTable = NULL;
  69     for (n = 0; n < table->Size; ++n)
  70     {
  71         depth = 0;
  72         entry = next = table->Entries[n];
  73         while (entry)
  74         {
  75             next = entry->Next;
  76             SdbFree(entry);
  77             entry = next;
  78             depth++;
  79         }
  80         if (once && depth > 3)
  81         {
  82             // warn
  83             once = 0;
  84         }
  85     }
  86     SdbFree(table->Entries);
  87     SdbFree(table);
  88 }
  89
  90 /* Based on RtlHashUnicodeString */
  91 static DWORD StringHash(const WCHAR* str)
  92 {
  93     DWORD hash = 0;
  94     for (; *str; str++)
  95     {
  96         hash = ((65599 * hash) + (ULONG)(*str));
  97     }
  98     return hash;
  99 }
 100
 101 static struct SdbHashEntry** TableFindPtr(struct SdbStringHashTable* table, const WCHAR* str)
 102 {
 103     DWORD hash = StringHash(str);
 104     struct SdbHashEntry** entry = &table->Entries[hash % table->Size];
 105     while (*entry)
 106     {
 107         if (!wcscmp((*entry)->Name, str))
 108             return entry;
 109         entry = &(*entry)->Next;
 110     }
 111     return entry;
 112 }
 113
 114 static BOOL HashAddString(struct SdbStringHashTable* table, struct SdbHashEntry** position, const WCHAR* str, TAGID tagid)
 115 {
 116     struct SdbHashEntry* entry;
 117     SIZE_T size;
 118
 119     if (!position)
 120         position = TableFindPtr(table, str);
 121
 122     size = offsetof(struct SdbHashEntry, Name[SdbpStrlen(str) + 2]);
 123     entry = (*position) = SdbAlloc(size);
 124     if (!entry)
 125     {
 126         SHIM_ERR("Failed to allocate %u bytes.", size);
 127         return FALSE;
 128     }
 129     entry->Tagid = tagid;
 130     wcscpy(entry->Name, str);
 131     return TRUE;
 132 }
 133
 134
 135 BOOL SdbpAddStringToTable(struct SdbStringHashTable** table, const WCHAR* str, TAGID* tagid)
 136 {
 137     struct SdbHashEntry** entry;
 138
 139     if (!*table)
 140     {
 141         *table = HashCreate();
 142         if (!*table)
 143         {
 144             SHIM_ERR("Error creating hash table\n");
 145             return FALSE;
 146         }
 147     }
 148
 149     entry = TableFindPtr(*table, str);
 150     if (*entry)
 151     {
 152         *tagid = (*entry)->Tagid;
 153         return FALSE;
 154     }
 155     return HashAddString(*table, entry, str, *tagid);
 156 }
 157