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_next(struct wine_rb_entry *iter)
 105 {
 106     if (iter->right) return wine_rb_head(iter->right);
 107     while (iter->parent && iter->parent->right == iter) iter = iter->parent;
 108     return iter->parent;
 109 }
 110
 111 static inline struct wine_rb_entry *wine_rb_postorder_head(struct wine_rb_entry *iter)
 112 {
 113     if (!iter) return NULL;
 114
 115     for (;;) {
 116         while (iter->left) iter = iter->left;
 117         if (!iter->right) return iter;
 118         iter = iter->right;
 119     }
 120 }
 121
 122 static inline struct wine_rb_entry *wine_rb_postorder_next(struct wine_rb_entry *iter)
 123 {
 124     if (!iter->parent) return NULL;
 125     if (iter == iter->parent->right || !iter->parent->right) return iter->parent;
 126     return wine_rb_postorder_head(iter->parent->right);
 127 }
 128
 129 /* iterate through the tree */
 130 #define WINE_RB_FOR_EACH(cursor, tree) \
 131     for ((cursor) = wine_rb_head((tree)->root); (cursor); (cursor) = wine_rb_next(cursor))
 132
 133 /* iterate through the tree using a tree entry */
 134 #define WINE_RB_FOR_EACH_ENTRY(elem, tree, type, field) \
 135     for ((elem) = WINE_RB_ENTRY_VALUE(wine_rb_head((tree)->root), type, field); \
 136          &(elem)->field; \
 137          (elem) = WINE_RB_ENTRY_VALUE(wine_rb_next(&elem->field), type, field))
 138
 139
 140 static inline void wine_rb_postorder(struct wine_rb_tree *tree, wine_rb_traverse_func_t *callback, void *context)
 141 {
 142     struct wine_rb_entry *iter, *next;
 143
 144     for (iter = wine_rb_postorder_head(tree->root); iter; iter = next)
 145     {
 146         next = wine_rb_postorder_next(iter);
 147         callback(iter, context);
 148     }
 149 }
 150
 151 static inline void wine_rb_init(struct wine_rb_tree *tree, wine_rb_compare_func_t compare)
 152 {
 153     tree->compare = compare;
 154     tree->root = NULL;
 155 }
 156
 157 static inline void wine_rb_for_each_entry(struct wine_rb_tree *tree, wine_rb_traverse_func_t *callback, void *context)
 158 {
 159     struct wine_rb_entry *iter;
 160     WINE_RB_FOR_EACH(iter, tree) callback(iter, context);
 161 }
 162
 163 static inline void wine_rb_clear(struct wine_rb_tree *tree, wine_rb_traverse_func_t *callback, void *context)
 164 {
 165     /* Note that we use postorder here because the callback will likely free the entry. */
 166     if (callback) wine_rb_postorder(tree, callback, context);
 167     tree->root = NULL;
 168 }
 169
 170 static inline void wine_rb_destroy(struct wine_rb_tree *tree, wine_rb_traverse_func_t *callback, void *context)
 171 {
 172     wine_rb_clear(tree, callback, context);
 173 }
 174
 175 static inline struct wine_rb_entry *wine_rb_get(const struct wine_rb_tree *tree, const void *key)
 176 {
 177     struct wine_rb_entry *entry = tree->root;
 178     while (entry)
 179     {
 180         int c = tree->compare(key, entry);
 181         if (!c) return entry;
 182         entry = c < 0 ? entry->left : entry->right;
 183     }
 184     return NULL;
 185 }
 186
 187 static inline int wine_rb_put(struct wine_rb_tree *tree, const void *key, struct wine_rb_entry *entry)
 188 {
 189     struct wine_rb_entry **iter = &tree->root, *parent = tree->root;
 190
 191     while (*iter)
 192     {
 193         int c;
 194
 195         parent = *iter;
 196         c = tree->compare(key, parent);
 197         if (!c) return -1;
 198         else if (c < 0) iter = &parent->left;
 199         else iter = &parent->right;
 200     }
 201
 202     entry->flags = WINE_RB_FLAG_RED;
 203     entry->parent = parent;
 204     entry->left = NULL;
 205     entry->right = NULL;
 206     *iter = entry;
 207
 208     while (wine_rb_is_red(entry->parent))
 209     {
 210         if (entry->parent == entry->parent->parent->left)
 211         {
 212             if (wine_rb_is_red(entry->parent->parent->right))
 213             {
 214                 wine_rb_flip_color(entry->parent->parent);
 215                 entry = entry->parent->parent;
 216             }
 217             else
 218             {
 219                 if (entry == entry->parent->right)
 220                 {
 221                     entry = entry->parent;
 222                     wine_rb_rotate_left(tree, entry);
 223                 }
 224                 entry->parent->flags &= ~WINE_RB_FLAG_RED;
 225                 entry->parent->parent->flags |= WINE_RB_FLAG_RED;
 226                 wine_rb_rotate_right(tree, entry->parent->parent);
 227             }
 228         }
 229         else
 230         {
 231             if (wine_rb_is_red(entry->parent->parent->left))
 232             {
 233                 wine_rb_flip_color(entry->parent->parent);
 234                 entry = entry->parent->parent;
 235             }
 236             else
 237             {
 238                 if (entry == entry->parent->left)
 239                 {
 240                     entry = entry->parent;
 241                     wine_rb_rotate_right(tree, entry);
 242                 }
 243                 entry->parent->flags &= ~WINE_RB_FLAG_RED;
 244                 entry->parent->parent->flags |= WINE_RB_FLAG_RED;
 245                 wine_rb_rotate_left(tree, entry->parent->parent);
 246             }
 247         }
 248     }
 249
 250     tree->root->flags &= ~WINE_RB_FLAG_RED;
 251
 252     return 0;
 253 }
 254
 255 static inline void wine_rb_remove(struct wine_rb_tree *tree, struct wine_rb_entry *entry)
 256 {
 257     struct wine_rb_entry *iter, *child, *parent, *w;
 258     int need_fixup;
 259
 260     if (entry->right && entry->left)
 261         for(iter = entry->right; iter->left; iter = iter->left);
 262     else
 263         iter = entry;
 264
 265     child = iter->left ? iter->left : iter->right;
 266
 267     if (!iter->parent)
 268         tree->root = child;
 269     else if (iter == iter->parent->left)
 270         iter->parent->left = child;
 271     else
 272         iter->parent->right = child;
 273
 274     if (child) child->parent = iter->parent;
 275     parent = iter->parent;
 276
 277     need_fixup = !wine_rb_is_red(iter);
 278
 279     if (entry != iter)
 280     {
 281         *iter = *entry;
 282         if (!iter->parent)
 283             tree->root = iter;
 284         else if (entry == iter->parent->left)
 285             iter->parent->left = iter;
 286         else
 287             iter->parent->right = iter;
 288
 289         if (iter->right) iter->right->parent = iter;
 290         if (iter->left)  iter->left->parent = iter;
 291         if (parent == entry) parent = iter;
 292     }
 293
 294     if (need_fixup)
 295     {
 296         while (parent && !wine_rb_is_red(child))
 297         {
 298             if (child == parent->left)
 299             {
 300                 w = parent->right;
 301                 if (wine_rb_is_red(w))
 302                 {
 303                     w->flags &= ~WINE_RB_FLAG_RED;
 304                     parent->flags |= WINE_RB_FLAG_RED;
 305                     wine_rb_rotate_left(tree, parent);
 306                     w = parent->right;
 307                 }
 308                 if (wine_rb_is_red(w->left) || wine_rb_is_red(w->right))
 309                 {
 310                     if (!wine_rb_is_red(w->right))
 311                     {
 312                         w->left->flags &= ~WINE_RB_FLAG_RED;
 313                         w->flags |= WINE_RB_FLAG_RED;
 314                         wine_rb_rotate_right(tree, w);
 315                         w = parent->right;
 316                     }
 317                     w->flags = (w->flags & ~WINE_RB_FLAG_RED) | (parent->flags & WINE_RB_FLAG_RED);
 318                     parent->flags &= ~WINE_RB_FLAG_RED;
 319                     if (w->right)
 320                         w->right->flags &= ~WINE_RB_FLAG_RED;
 321                     wine_rb_rotate_left(tree, parent);
 322                     child = NULL;
 323                     break;
 324                 }
 325             }
 326             else
 327             {
 328                 w = parent->left;
 329                 if (wine_rb_is_red(w))
 330                 {
 331                     w->flags &= ~WINE_RB_FLAG_RED;
 332                     parent->flags |= WINE_RB_FLAG_RED;
 333                     wine_rb_rotate_right(tree, parent);
 334                     w = parent->left;
 335                 }
 336                 if (wine_rb_is_red(w->left) || wine_rb_is_red(w->right))
 337                 {
 338                     if (!wine_rb_is_red(w->left))
 339                     {
 340                         w->right->flags &= ~WINE_RB_FLAG_RED;
 341                         w->flags |= WINE_RB_FLAG_RED;
 342                         wine_rb_rotate_left(tree, w);
 343                         w = parent->left;
 344                     }
 345                     w->flags = (w->flags & ~WINE_RB_FLAG_RED) | (parent->flags & WINE_RB_FLAG_RED);
 346                     parent->flags &= ~WINE_RB_FLAG_RED;
 347                     if (w->left)
 348                         w->left->flags &= ~WINE_RB_FLAG_RED;
 349                     wine_rb_rotate_right(tree, parent);
 350                     child = NULL;
 351                     break;
 352                 }
 353             }
 354             w->flags |= WINE_RB_FLAG_RED;
 355             child = parent;
 356             parent = child->parent;
 357         }
 358         if (child) child->flags &= ~WINE_RB_FLAG_RED;
 359     }
 360
 361     if (tree->root) tree->root->flags &= ~WINE_RB_FLAG_RED;
 362 }
 363
 364 static inline void wine_rb_remove_key(struct wine_rb_tree *tree, const void *key)
 365 {
 366     struct wine_rb_entry *entry = wine_rb_get(tree, key);
 367     if (entry) wine_rb_remove(tree, entry);
 368 }
 369
 370 #endif  /* __WINE_WINE_RBTREE_H */