include/wine/rbtree.h

   1 /*
   2  * Red-black search tree support
   3  *
   4  * Copyright 2009 Henri Verbeet
   5  * Copyright 2009 Andrew Riedi
   6  * Copyright 2016 Jacek Caban for CodeWeavers
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  21  */
  22
  23 #ifndef __WINE_WINE_RBTREE_H
  24 #define __WINE_WINE_RBTREE_H
  25
  26 #define WINE_RB_ENTRY_VALUE(element, type, field) \
  27     ((type *)((char *)(element) - offsetof(type, field)))
  28
  29 struct wine_rb_entry
  30 {
  31     struct wine_rb_entry *parent;
  32     struct wine_rb_entry *left;
  33     struct wine_rb_entry *right;
  34     unsigned int flags;
  35 };
  36
  37 typedef int (*wine_rb_compare_func_t)(const void *key, const struct wine_rb_entry *entry);
  38
  39 struct wine_rb_tree
  40 {
  41     wine_rb_compare_func_t compare;
  42     struct wine_rb_entry *root;
  43 };
  44
  45 typedef void (wine_rb_traverse_func_t)(struct wine_rb_entry *entry, void *context);
  46
  47 #define WINE_RB_FLAG_RED                0x1
  48
  49 static inline int wine_rb_is_red(struct wine_rb_entry *entry)
  50 {
  51     return entry && (entry->flags & WINE_RB_FLAG_RED);
  52 }
  53
  54 static inline void wine_rb_rotate_left(struct wine_rb_tree *tree, struct wine_rb_entry *e)
  55 {
  56     struct wine_rb_entry *right = e->right;
  57
  58     if (!e->parent)
  59         tree->root = right;
  60     else if (e->parent->left == e)
  61         e->parent->left = right;
  62     else
  63         e->parent->right = right;
  64
  65     e->right = right->left;
  66     if (e->right) e->right->parent = e;
  67     right->left = e;
  68     right->parent = e->parent;
  69     e->parent = right;
  70 }
  71
  72 static inline void wine_rb_rotate_right(struct wine_rb_tree *tree, struct wine_rb_entry *e)
  73 {
  74     struct wine_rb_entry *left = e->left;
  75
  76     if (!e->parent)
  77         tree->root = left;
  78     else if (e->parent->left == e)
  79         e->parent->left = left;
  80     else
  81         e->parent->right = left;
  82
  83     e->left = left->right;
  84     if (e->left) e->left->parent = e;
  85     left->right = e;
  86     left->parent = e->parent;
  87     e->parent = left;
  88 }
  89
  90 static inline void wine_rb_flip_color(struct wine_rb_entry *entry)
  91 {
  92     entry->flags ^= WINE_RB_FLAG_RED;
  93     entry->left->flags ^= WINE_RB_FLAG_RED;
  94     entry->right->flags ^= WINE_RB_FLAG_RED;
  95 }
  96
  97 static inline struct wine_rb_entry *wine_rb_head(struct wine_rb_entry *iter)
  98 {
  99     if (!iter) return NULL;
 100     while (iter->left) iter = iter->left;
 101     return iter;
 102 }
 103
 104 static inline struct wine_rb_entry *wine_rb_tail(struct wine_rb_entry *iter)
 105 {
 106     if (!iter) return NULL;
 107     while (iter->right) iter = iter->right;
 108     return iter;
 109 }
 110
 111 static inline struct wine_rb_entry *wine_rb_next(struct wine_rb_entry *iter)
 112 {
 113     if (iter->right) return wine_rb_head(iter->right);
 114     while (iter->parent && iter->parent->right == iter) iter = iter->parent;
 115     return iter->parent;
 116 }
 117
 118 static inline struct wine_rb_entry *wine_rb_prev(struct wine_rb_entry *iter)
 119 {
 120     if (iter->left) return wine_rb_tail(iter->left);
 121     while (iter->parent && iter->parent->left == iter) iter = iter->parent;
 122     return iter->parent;
 123 }
 124
 125 static inline struct wine_rb_entry *wine_rb_postorder_head(struct wine_rb_entry *iter)
 126 {
 127     if (!iter) return NULL;
 128
 129     for (;;) {
 130         while (iter->left) iter = iter->left;
 131         if (!iter->right) return iter;
 132         iter = iter->right;
 133     }
 134 }
 135
 136 static inline struct wine_rb_entry *wine_rb_postorder_next(struct wine_rb_entry *iter)
 137 {
 138     if (!iter->parent) return NULL;
 139     if (iter == iter->parent->right || !iter->parent->right) return iter->parent;
 140     return wine_rb_postorder_head(iter->parent->right);
 141 }
 142
 143 /* iterate through the tree */
 144 #define WINE_RB_FOR_EACH(cursor, tree) \
 145     for ((cursor) = wine_rb_head((tree)->root); (cursor); (cursor) = wine_rb_next(cursor))
 146
 147 /* iterate through the tree using a tree entry */
 148 #define WINE_RB_FOR_EACH_ENTRY(elem, tree, type, field) \
 149     for ((elem) = WINE_RB_ENTRY_VALUE(wine_rb_head((tree)->root), type, field); \
 150          (elem) != WINE_RB_ENTRY_VALUE(0, type, field); \
 151          (elem) = WINE_RB_ENTRY_VALUE(wine_rb_next(&elem->field), type, field))
 152
 153 /* iterate through the tree using using postorder, making it safe to free the entry */
 154 #define WINE_RB_FOR_EACH_DESTRUCTOR(cursor, cursor2, tree) \
 155     for ((cursor) = wine_rb_postorder_head((tree)->root); \
 156          (cursor) && (((cursor2) = wine_rb_postorder_next(cursor)) || 1); \
 157          (cursor) = (cursor2))
 158
 159 /* iterate through the tree using a tree entry and postorder, making it safe to free the entry */
 160 #define WINE_RB_FOR_EACH_ENTRY_DESTRUCTOR(elem, elem2, tree, type, field) \
 161     for ((elem) = WINE_RB_ENTRY_VALUE(wine_rb_postorder_head((tree)->root), type, field); \
 162          (elem) != WINE_RB_ENTRY_VALUE(0, type, field) \
 163              && (((elem2) = WINE_RB_ENTRY_VALUE(wine_rb_postorder_next(&(elem)->field), type, field)) || 1); \
 164          (elem) = (elem2))
 165
 166
 167 static inline void wine_rb_postorder(struct wine_rb_tree *tree, wine_rb_traverse_func_t *callback, void *context)
 168 {
 169     struct wine_rb_entry *iter, *next;
 170     WINE_RB_FOR_EACH_DESTRUCTOR(iter, next, tree) callback(iter, context);
 171 }
 172
 173 static inline void wine_rb_init(struct wine_rb_tree *tree, wine_rb_compare_func_t compare)
 174 {
 175     tree->compare = compare;
 176     tree->root = NULL;
 177 }
 178
 179 static inline void wine_rb_for_each_entry(struct wine_rb_tree *tree, wine_rb_traverse_func_t *callback, void *context)
 180 {
 181     struct wine_rb_entry *iter;
 182     WINE_RB_FOR_EACH(iter, tree) callback(iter, context);
 183 }
 184
 185 static inline void wine_rb_clear(struct wine_rb_tree *tree, wine_rb_traverse_func_t *callback, void *context)
 186 {
 187     /* Note that we use postorder here because the callback will likely free the entry. */
 188     if (callback) wine_rb_postorder(tree, callback, context);
 189     tree->root = NULL;
 190 }
 191
 192 static inline void wine_rb_destroy(struct wine_rb_tree *tree, wine_rb_traverse_func_t *callback, void *context)
 193 {
 194     wine_rb_clear(tree, callback, context);
 195 }
 196
 197 static inline struct wine_rb_entry *wine_rb_get(const struct wine_rb_tree *tree, const void *key)
 198 {
 199     struct wine_rb_entry *entry = tree->root;
 200     while (entry)
 201     {
 202         int c = tree->compare(key, entry);
 203         if (!c) return entry;
 204         entry = c < 0 ? entry->left : entry->right;
 205     }
 206     return NULL;
 207 }
 208
 209 static inline int wine_rb_put(struct wine_rb_tree *tree, const void *key, struct wine_rb_entry *entry)
 210 {
 211     struct wine_rb_entry **iter = &tree->root, *parent = tree->root;
 212
 213     while (*iter)
 214     {
 215         int c;
 216
 217         parent = *iter;
 218         c = tree->compare(key, parent);
 219         if (!c) return -1;
 220         else if (c < 0) iter = &parent->left;
 221         else iter = &parent->right;
 222     }
 223
 224     entry->flags = WINE_RB_FLAG_RED;
 225     entry->parent = parent;
 226     entry->left = NULL;
 227     entry->right = NULL;
 228     *iter = entry;
 229
 230     while (wine_rb_is_red(entry->parent))
 231     {
 232         if (entry->parent == entry->parent->parent->left)
 233         {
 234             if (wine_rb_is_red(entry->parent->parent->right))
 235             {
 236                 wine_rb_flip_color(entry->parent->parent);
 237                 entry = entry->parent->parent;
 238             }
 239             else
 240             {
 241                 if (entry == entry->parent->right)
 242                 {
 243                     entry = entry->parent;
 244                     wine_rb_rotate_left(tree, entry);
 245                 }
 246                 entry->parent->flags &= ~WINE_RB_FLAG_RED;
 247                 entry->parent->parent->flags |= WINE_RB_FLAG_RED;
 248                 wine_rb_rotate_right(tree, entry->parent->parent);
 249             }
 250         }
 251         else
 252         {
 253             if (wine_rb_is_red(entry->parent->parent->left))
 254             {
 255                 wine_rb_flip_color(entry->parent->parent);
 256                 entry = entry->parent->parent;
 257             }
 258             else
 259             {
 260                 if (entry == entry->parent->left)
 261                 {
 262                     entry = entry->parent;
 263                     wine_rb_rotate_right(tree, entry);
 264                 }
 265                 entry->parent->flags &= ~WINE_RB_FLAG_RED;
 266                 entry->parent->parent->flags |= WINE_RB_FLAG_RED;
 267                 wine_rb_rotate_left(tree, entry->parent->parent);
 268             }
 269         }
 270     }
 271
 272     tree->root->flags &= ~WINE_RB_FLAG_RED;
 273
 274     return 0;
 275 }
 276
 277 static inline void wine_rb_remove(struct wine_rb_tree *tree, struct wine_rb_entry *entry)
 278 {
 279     struct wine_rb_entry *iter, *child, *parent, *w;
 280     int need_fixup;
 281
 282     if (entry->right && entry->left)
 283         for(iter = entry->right; iter->left; iter = iter->left);
 284     else
 285         iter = entry;
 286
 287     child = iter->left ? iter->left : iter->right;
 288
 289     if (!iter->parent)
 290         tree->root = child;
 291     else if (iter == iter->parent->left)
 292         iter->parent->left = child;
 293     else
 294         iter->parent->right = child;
 295
 296     if (child) child->parent = iter->parent;
 297     parent = iter->parent;
 298
 299     need_fixup = !wine_rb_is_red(iter);
 300
 301     if (entry != iter)
 302     {
 303         *iter = *entry;
 304         if (!iter->parent)
 305             tree->root = iter;
 306         else if (entry == iter->parent->left)
 307             iter->parent->left = iter;
 308         else
 309             iter->parent->right = iter;
 310
 311         if (iter->right) iter->right->parent = iter;
 312         if (iter->left)  iter->left->parent = iter;
 313         if (parent == entry) parent = iter;
 314     }
 315
 316     if (need_fixup)
 317     {
 318         while (parent && !wine_rb_is_red(child))
 319         {
 320             if (child == parent->left)
 321             {
 322                 w = parent->right;
 323                 if (wine_rb_is_red(w))
 324                 {
 325                     w->flags &= ~WINE_RB_FLAG_RED;
 326                     parent->flags |= WINE_RB_FLAG_RED;
 327                     wine_rb_rotate_left(tree, parent);
 328                     w = parent->right;
 329                 }
 330                 if (wine_rb_is_red(w->left) || wine_rb_is_red(w->right))
 331                 {
 332                     if (!wine_rb_is_red(w->right))
 333                     {
 334                         w->left->flags &= ~WINE_RB_FLAG_RED;
 335                         w->flags |= WINE_RB_FLAG_RED;
 336                         wine_rb_rotate_right(tree, w);
 337                         w = parent->right;
 338                     }
 339                     w->flags = (w->flags & ~WINE_RB_FLAG_RED) | (parent->flags & WINE_RB_FLAG_RED);
 340                     parent->flags &= ~WINE_RB_FLAG_RED;
 341                     if (w->right)
 342                         w->right->flags &= ~WINE_RB_FLAG_RED;
 343                     wine_rb_rotate_left(tree, parent);
 344                     child = NULL;
 345                     break;
 346                 }
 347             }
 348             else
 349             {
 350                 w = parent->left;
 351                 if (wine_rb_is_red(w))
 352                 {
 353                     w->flags &= ~WINE_RB_FLAG_RED;
 354                     parent->flags |= WINE_RB_FLAG_RED;
 355                     wine_rb_rotate_right(tree, parent);
 356                     w = parent->left;
 357                 }
 358                 if (wine_rb_is_red(w->left) || wine_rb_is_red(w->right))
 359                 {
 360                     if (!wine_rb_is_red(w->left))
 361                     {
 362                         w->right->flags &= ~WINE_RB_FLAG_RED;
 363                         w->flags |= WINE_RB_FLAG_RED;
 364                         wine_rb_rotate_left(tree, w);
 365                         w = parent->left;
 366                     }
 367                     w->flags = (w->flags & ~WINE_RB_FLAG_RED) | (parent->flags & WINE_RB_FLAG_RED);
 368                     parent->flags &= ~WINE_RB_FLAG_RED;
 369                     if (w->left)
 370                         w->left->flags &= ~WINE_RB_FLAG_RED;
 371                     wine_rb_rotate_right(tree, parent);
 372                     child = NULL;
 373                     break;
 374                 }
 375             }
 376             w->flags |= WINE_RB_FLAG_RED;
 377             child = parent;
 378             parent = child->parent;
 379         }
 380         if (child) child->flags &= ~WINE_RB_FLAG_RED;
 381     }
 382
 383     if (tree->root) tree->root->flags &= ~WINE_RB_FLAG_RED;
 384 }
 385
 386 static inline void wine_rb_remove_key(struct wine_rb_tree *tree, const void *key)
 387 {
 388     struct wine_rb_entry *entry = wine_rb_get(tree, key);
 389     if (entry) wine_rb_remove(tree, entry);
 390 }
 391
 392 #endif  /* __WINE_WINE_RBTREE_H */