419 lines
12 KiB
C
419 lines
12 KiB
C
/*
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* Red-black search tree support
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*
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* Copyright 2009 Henri Verbeet
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* Copyright 2009 Andrew Riedi
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* Copyright 2016 Jacek Caban for CodeWeavers
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#ifndef __WINE_WINE_RBTREE_H
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#define __WINE_WINE_RBTREE_H
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#define RB_ENTRY_VALUE(element, type, field) \
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((type *)((char *)(element) - offsetof(type, field)))
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struct rb_entry
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{
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struct rb_entry *parent;
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struct rb_entry *left;
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struct rb_entry *right;
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unsigned int flags;
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};
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typedef int (*rb_compare_func_t)(const void *key, const struct rb_entry *entry);
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struct rb_tree
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{
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rb_compare_func_t compare;
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struct rb_entry *root;
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};
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typedef void (rb_traverse_func_t)(struct rb_entry *entry, void *context);
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#define RB_FLAG_RED 0x1
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static inline int rb_is_red(struct rb_entry *entry)
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{
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return entry && (entry->flags & RB_FLAG_RED);
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}
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static inline void rb_rotate_left(struct rb_tree *tree, struct rb_entry *e)
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{
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struct rb_entry *right = e->right;
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if (!e->parent)
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tree->root = right;
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else if (e->parent->left == e)
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e->parent->left = right;
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else
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e->parent->right = right;
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e->right = right->left;
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if (e->right) e->right->parent = e;
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right->left = e;
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right->parent = e->parent;
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e->parent = right;
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}
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static inline void rb_rotate_right(struct rb_tree *tree, struct rb_entry *e)
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{
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struct rb_entry *left = e->left;
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if (!e->parent)
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tree->root = left;
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else if (e->parent->left == e)
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e->parent->left = left;
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else
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e->parent->right = left;
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e->left = left->right;
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if (e->left) e->left->parent = e;
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left->right = e;
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left->parent = e->parent;
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e->parent = left;
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}
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static inline void rb_flip_color(struct rb_entry *entry)
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{
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entry->flags ^= RB_FLAG_RED;
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entry->left->flags ^= RB_FLAG_RED;
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entry->right->flags ^= RB_FLAG_RED;
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}
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static inline struct rb_entry *rb_head(struct rb_entry *iter)
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{
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if (!iter) return NULL;
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while (iter->left) iter = iter->left;
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return iter;
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}
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static inline struct rb_entry *rb_tail(struct rb_entry *iter)
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{
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if (!iter) return NULL;
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while (iter->right) iter = iter->right;
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return iter;
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}
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static inline struct rb_entry *rb_next(struct rb_entry *iter)
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{
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if (iter->right) return rb_head(iter->right);
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while (iter->parent && iter->parent->right == iter) iter = iter->parent;
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return iter->parent;
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}
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static inline struct rb_entry *rb_prev(struct rb_entry *iter)
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{
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if (iter->left) return rb_tail(iter->left);
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while (iter->parent && iter->parent->left == iter) iter = iter->parent;
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return iter->parent;
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}
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static inline struct rb_entry *rb_postorder_head(struct rb_entry *iter)
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{
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if (!iter) return NULL;
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for (;;) {
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while (iter->left) iter = iter->left;
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if (!iter->right) return iter;
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iter = iter->right;
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}
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}
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static inline struct rb_entry *rb_postorder_next(struct rb_entry *iter)
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{
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if (!iter->parent) return NULL;
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if (iter == iter->parent->right || !iter->parent->right) return iter->parent;
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return rb_postorder_head(iter->parent->right);
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}
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/* iterate through the tree */
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#define RB_FOR_EACH(cursor, tree) \
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for ((cursor) = rb_head((tree)->root); (cursor); (cursor) = rb_next(cursor))
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/* iterate through the tree using a tree entry */
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#define RB_FOR_EACH_ENTRY(elem, tree, type, field) \
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for ((elem) = RB_ENTRY_VALUE(rb_head((tree)->root), type, field); \
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(elem) != RB_ENTRY_VALUE(0, type, field); \
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(elem) = RB_ENTRY_VALUE(rb_next(&elem->field), type, field))
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/* iterate through the tree using using postorder, making it safe to free the entry */
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#define RB_FOR_EACH_DESTRUCTOR(cursor, cursor2, tree) \
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for ((cursor) = rb_postorder_head((tree)->root); \
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(cursor) && (((cursor2) = rb_postorder_next(cursor)) || 1); \
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(cursor) = (cursor2))
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/* iterate through the tree using a tree entry and postorder, making it safe to free the entry */
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#define RB_FOR_EACH_ENTRY_DESTRUCTOR(elem, elem2, tree, type, field) \
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for ((elem) = RB_ENTRY_VALUE(rb_postorder_head((tree)->root), type, field); \
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(elem) != RB_ENTRY_VALUE(0, type, field) \
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&& (((elem2) = RB_ENTRY_VALUE(rb_postorder_next(&(elem)->field), type, field)) || 1); \
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(elem) = (elem2))
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static inline void rb_postorder(struct rb_tree *tree, rb_traverse_func_t *callback, void *context)
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{
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struct rb_entry *iter, *next;
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RB_FOR_EACH_DESTRUCTOR(iter, next, tree) callback(iter, context);
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}
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static inline void rb_init(struct rb_tree *tree, rb_compare_func_t compare)
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{
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tree->compare = compare;
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tree->root = NULL;
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}
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static inline void rb_for_each_entry(struct rb_tree *tree, rb_traverse_func_t *callback, void *context)
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{
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struct rb_entry *iter;
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RB_FOR_EACH(iter, tree) callback(iter, context);
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}
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static inline void rb_destroy(struct rb_tree *tree, rb_traverse_func_t *callback, void *context)
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{
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/* Note that we use postorder here because the callback will likely free the entry. */
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if (callback) rb_postorder(tree, callback, context);
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tree->root = NULL;
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}
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static inline struct rb_entry *rb_get(const struct rb_tree *tree, const void *key)
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{
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struct rb_entry *entry = tree->root;
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while (entry)
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{
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int c = tree->compare(key, entry);
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if (!c) return entry;
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entry = c < 0 ? entry->left : entry->right;
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}
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return NULL;
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}
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static inline int rb_put(struct rb_tree *tree, const void *key, struct rb_entry *entry)
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{
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struct rb_entry **iter = &tree->root, *parent = tree->root;
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while (*iter)
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{
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int c;
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parent = *iter;
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c = tree->compare(key, parent);
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if (!c) return -1;
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else if (c < 0) iter = &parent->left;
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else iter = &parent->right;
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}
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entry->flags = RB_FLAG_RED;
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entry->parent = parent;
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entry->left = NULL;
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entry->right = NULL;
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*iter = entry;
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while (rb_is_red(entry->parent))
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{
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if (entry->parent == entry->parent->parent->left)
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{
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if (rb_is_red(entry->parent->parent->right))
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{
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rb_flip_color(entry->parent->parent);
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entry = entry->parent->parent;
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}
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else
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{
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if (entry == entry->parent->right)
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{
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entry = entry->parent;
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rb_rotate_left(tree, entry);
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}
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entry->parent->flags &= ~RB_FLAG_RED;
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entry->parent->parent->flags |= RB_FLAG_RED;
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rb_rotate_right(tree, entry->parent->parent);
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}
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}
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else
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{
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if (rb_is_red(entry->parent->parent->left))
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{
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rb_flip_color(entry->parent->parent);
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entry = entry->parent->parent;
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}
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else
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{
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if (entry == entry->parent->left)
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{
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entry = entry->parent;
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rb_rotate_right(tree, entry);
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}
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entry->parent->flags &= ~RB_FLAG_RED;
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entry->parent->parent->flags |= RB_FLAG_RED;
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rb_rotate_left(tree, entry->parent->parent);
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}
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}
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}
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tree->root->flags &= ~RB_FLAG_RED;
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return 0;
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}
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static inline void rb_remove(struct rb_tree *tree, struct rb_entry *entry)
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{
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struct rb_entry *iter, *child, *parent, *w;
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int need_fixup;
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if (entry->right && entry->left)
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for(iter = entry->right; iter->left; iter = iter->left);
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else
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iter = entry;
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child = iter->left ? iter->left : iter->right;
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if (!iter->parent)
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tree->root = child;
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else if (iter == iter->parent->left)
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iter->parent->left = child;
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else
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iter->parent->right = child;
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if (child) child->parent = iter->parent;
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parent = iter->parent;
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need_fixup = !rb_is_red(iter);
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if (entry != iter)
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{
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*iter = *entry;
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if (!iter->parent)
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tree->root = iter;
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else if (entry == iter->parent->left)
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iter->parent->left = iter;
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else
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iter->parent->right = iter;
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if (iter->right) iter->right->parent = iter;
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if (iter->left) iter->left->parent = iter;
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if (parent == entry) parent = iter;
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}
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if (need_fixup)
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{
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while (parent && !rb_is_red(child))
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{
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if (child == parent->left)
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{
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w = parent->right;
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if (rb_is_red(w))
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{
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w->flags &= ~RB_FLAG_RED;
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parent->flags |= RB_FLAG_RED;
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rb_rotate_left(tree, parent);
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w = parent->right;
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}
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if (rb_is_red(w->left) || rb_is_red(w->right))
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{
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if (!rb_is_red(w->right))
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{
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w->left->flags &= ~RB_FLAG_RED;
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w->flags |= RB_FLAG_RED;
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rb_rotate_right(tree, w);
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w = parent->right;
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}
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w->flags = (w->flags & ~RB_FLAG_RED) | (parent->flags & RB_FLAG_RED);
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parent->flags &= ~RB_FLAG_RED;
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if (w->right)
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w->right->flags &= ~RB_FLAG_RED;
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rb_rotate_left(tree, parent);
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child = NULL;
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break;
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}
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}
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else
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{
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w = parent->left;
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if (rb_is_red(w))
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{
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w->flags &= ~RB_FLAG_RED;
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parent->flags |= RB_FLAG_RED;
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rb_rotate_right(tree, parent);
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w = parent->left;
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}
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if (rb_is_red(w->left) || rb_is_red(w->right))
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{
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if (!rb_is_red(w->left))
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{
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w->right->flags &= ~RB_FLAG_RED;
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w->flags |= RB_FLAG_RED;
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rb_rotate_left(tree, w);
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w = parent->left;
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}
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w->flags = (w->flags & ~RB_FLAG_RED) | (parent->flags & RB_FLAG_RED);
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parent->flags &= ~RB_FLAG_RED;
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if (w->left)
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w->left->flags &= ~RB_FLAG_RED;
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rb_rotate_right(tree, parent);
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child = NULL;
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break;
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}
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}
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w->flags |= RB_FLAG_RED;
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child = parent;
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parent = child->parent;
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}
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if (child) child->flags &= ~RB_FLAG_RED;
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}
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if (tree->root) tree->root->flags &= ~RB_FLAG_RED;
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}
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static inline void rb_remove_key(struct rb_tree *tree, const void *key)
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{
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struct rb_entry *entry = rb_get(tree, key);
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if (entry) rb_remove(tree, entry);
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}
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static inline void rb_replace(struct rb_tree *tree, struct rb_entry *dst, struct rb_entry *src)
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{
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if (!(src->parent = dst->parent))
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tree->root = src;
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else if (dst->parent->left == dst)
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dst->parent->left = src;
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else
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dst->parent->right = src;
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if ((src->left = dst->left))
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src->left->parent = src;
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if ((src->right = dst->right))
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src->right->parent = src;
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src->flags = dst->flags;
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}
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/* old names for backwards compatibility */
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#define wine_rb_entry rb_entry
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#define wine_rb_tree rb_tree
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#define wine_rb_init rb_init
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#define wine_rb_for_each_entry rb_for_each_entry
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#define wine_rb_destroy rb_destroy
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#define wine_rb_get rb_get
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#define wine_rb_put rb_put
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#define wine_rb_remove rb_remove
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#define wine_rb_remove_key rb_remove_key
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#define wine_rb_replace rb_replace
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#define WINE_RB_ENTRY_VALUE RB_ENTRY_VALUE
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#define WINE_RB_FOR_EACH_ENTRY RB_FOR_EACH_ENTRY
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#define WINE_RB_FOR_EACH_ENTRY_DESTRUCTOR RB_FOR_EACH_ENTRY_DESTRUCTOR
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#endif /* __WINE_WINE_RBTREE_H */
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