-/* Produced by texiweb from libavl.w on 2004/01/08 at 23:19. */
+/* src/toolbox/avl.c - AVL tree implementation
-/* libavl - library for manipulation of binary trees.
- Copyright (C) 1998-2002 Free Software Foundation, Inc.
+ Copyright (C) 1996-2005, 2006 R. Grafl, A. Krall, C. Kruegel,
+ C. Oates, R. Obermaisser, M. Platter, M. Probst, S. Ring,
+ E. Steiner, C. Thalinger, D. Thuernbeck, P. Tomsich, C. Ullrich,
+ J. Wenninger, Institut f. Computersprachen - TU Wien
+
+ This file is part of CACAO.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version.
+ published by the Free Software Foundation; either version 2, or (at
+ your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
- See the GNU General Public License for more details.
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
- 02111-1307, USA.
+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ 02110-1301, USA.
+
+ Contact: cacao@cacaojvm.org
+
+ Authors: Christian Thalinger
+
+ Changes:
+
+ $Id: avl.c 5123 2006-07-12 21:45:34Z twisti $
- The author may be contacted at <blp@gnu.org> on the Internet, or
- write to Ben Pfaff, Stanford University, Computer Science Dept., 353
- Serra Mall, Stanford CA 94305, USA.
*/
+
+#include "config.h"
+
#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
+
+#include "vm/types.h"
+
+#include "mm/memory.h"
#include "toolbox/avl.h"
-/* Creates and returns a new table
- with comparison function |compare| using parameter |param|
- and memory allocator |allocator|.
- Returns |NULL| if memory allocation failed. */
-struct avl_table *
-avl_create (avl_comparison_func *compare, void *param,
- struct libavl_allocator *allocator)
+#if defined(ENABLE_THREADS)
+# include "threads/native/lock.h"
+# include "threads/native/threads.h"
+#else
+# include "threads/none/lock.h"
+#endif
+
+
+/* avl_create ******************************************************************
+
+ Creates a AVL tree structure.
+
+*******************************************************************************/
+
+avl_tree *avl_create(avl_comparator *compar)
{
- struct avl_table *tree;
+ avl_tree *t;
- assert (compare != NULL);
+ t = NEW(avl_tree);
- if (allocator == NULL)
- allocator = &avl_allocator_default;
+ t->root = NULL;
+ t->comparator = compar;
+ t->entries = 0;
- tree = allocator->libavl_malloc (allocator, sizeof *tree);
- if (tree == NULL)
- return NULL;
+#if defined(ENABLE_THREADS)
+ /* create lock object for this tree */
- tree->avl_root = NULL;
- tree->avl_compare = compare;
- tree->avl_param = param;
- tree->avl_alloc = allocator;
- tree->avl_count = 0;
- tree->avl_generation = 0;
+ t->lock = NEW(java_objectheader);
- return tree;
-}
+ lock_init_object_lock(t->lock);
+#endif
-/* Search |tree| for an item matching |item|, and return it if found.
- Otherwise return |NULL|. */
-void *
-avl_find (const struct avl_table *tree, const void *item)
-{
- const struct avl_node *p;
-
- assert (tree != NULL && item != NULL);
- for (p = tree->avl_root; p != NULL; )
- {
- int cmp = tree->avl_compare (item, p->avl_data, tree->avl_param);
-
- if (cmp < 0)
- p = p->avl_link[0];
- else if (cmp > 0)
- p = p->avl_link[1];
- else /* |cmp == 0| */
- return p->avl_data;
- }
-
- return NULL;
+ return t;
}
-/* Inserts |item| into |tree| and returns a pointer to |item|'s address.
- If a duplicate item is found in the tree,
- returns a pointer to the duplicate without inserting |item|.
- Returns |NULL| in case of memory allocation failure. */
-void **
-avl_probe (struct avl_table *tree, void *item)
-{
- struct avl_node *y, *z; /* Top node to update balance factor, and parent. */
- struct avl_node *p, *q; /* Iterator, and parent. */
- struct avl_node *n; /* Newly inserted node. */
- struct avl_node *w; /* New root of rebalanced subtree. */
- int dir; /* Direction to descend. */
-
- unsigned char da[AVL_MAX_HEIGHT]; /* Cached comparison results. */
- int k = 0; /* Number of cached results. */
-
- assert (tree != NULL && item != NULL);
-
- z = (struct avl_node *) &tree->avl_root;
- y = tree->avl_root;
- dir = 0;
- for (q = z, p = y; p != NULL; q = p, p = p->avl_link[dir])
- {
- int cmp = tree->avl_compare (item, p->avl_data, tree->avl_param);
- if (cmp == 0)
- return &p->avl_data;
-
- if (p->avl_balance != 0)
- z = q, y = p, k = 0;
- da[k++] = dir = cmp > 0;
- }
-
- n = q->avl_link[dir] =
- tree->avl_alloc->libavl_malloc (tree->avl_alloc, sizeof *n);
- if (n == NULL)
- return NULL;
-
- tree->avl_count++;
- n->avl_data = item;
- n->avl_link[0] = n->avl_link[1] = NULL;
- n->avl_balance = 0;
- if (y == NULL)
- return &n->avl_data;
-
- for (p = y, k = 0; p != n; p = p->avl_link[da[k]], k++)
- if (da[k] == 0)
- p->avl_balance--;
- else
- p->avl_balance++;
-
- if (y->avl_balance == -2)
- {
- struct avl_node *x = y->avl_link[0];
- if (x->avl_balance == -1)
- {
- w = x;
- y->avl_link[0] = x->avl_link[1];
- x->avl_link[1] = y;
- x->avl_balance = y->avl_balance = 0;
- }
- else
- {
- assert (x->avl_balance == +1);
- w = x->avl_link[1];
- x->avl_link[1] = w->avl_link[0];
- w->avl_link[0] = x;
- y->avl_link[0] = w->avl_link[1];
- w->avl_link[1] = y;
- if (w->avl_balance == -1)
- x->avl_balance = 0, y->avl_balance = +1;
- else if (w->avl_balance == 0)
- x->avl_balance = y->avl_balance = 0;
- else /* |w->avl_balance == +1| */
- x->avl_balance = -1, y->avl_balance = 0;
- w->avl_balance = 0;
- }
- }
- else if (y->avl_balance == +2)
- {
- struct avl_node *x = y->avl_link[1];
- if (x->avl_balance == +1)
- {
- w = x;
- y->avl_link[1] = x->avl_link[0];
- x->avl_link[0] = y;
- x->avl_balance = y->avl_balance = 0;
- }
- else
- {
- assert (x->avl_balance == -1);
- w = x->avl_link[0];
- x->avl_link[0] = w->avl_link[1];
- w->avl_link[1] = x;
- y->avl_link[1] = w->avl_link[0];
- w->avl_link[0] = y;
- if (w->avl_balance == +1)
- x->avl_balance = 0, y->avl_balance = -1;
- else if (w->avl_balance == 0)
- x->avl_balance = y->avl_balance = 0;
- else /* |w->avl_balance == -1| */
- x->avl_balance = +1, y->avl_balance = 0;
- w->avl_balance = 0;
- }
- }
- else
- return &n->avl_data;
- z->avl_link[y != z->avl_link[0]] = w;
-
- tree->avl_generation++;
- return &n->avl_data;
-}
-/* Inserts |item| into |table|.
- Returns |NULL| if |item| was successfully inserted
- or if a memory allocation error occurred.
- Otherwise, returns the duplicate item. */
-void *
-avl_insert (struct avl_table *table, void *item)
-{
- void **p = avl_probe (table, item);
- return p == NULL || *p == item ? NULL : *p;
-}
+/* avl_newnode *****************************************************************
-/* Inserts |item| into |table|, replacing any duplicate item.
- Returns |NULL| if |item| was inserted without replacing a duplicate,
- or if a memory allocation error occurred.
- Otherwise, returns the item that was replaced. */
-void *
-avl_replace (struct avl_table *table, void *item)
-{
- void **p = avl_probe (table, item);
- if (p == NULL || *p == item)
- return NULL;
- else
- {
- void *r = *p;
- *p = item;
- return r;
- }
-}
+ Creates a new AVL node and sets the pointers correctly.
-/* Deletes from |tree| and returns an item matching |item|.
- Returns a null pointer if no matching item found. */
-void *
-avl_delete (struct avl_table *tree, const void *item)
-{
- /* Stack of nodes. */
- struct avl_node *pa[AVL_MAX_HEIGHT]; /* Nodes. */
- unsigned char da[AVL_MAX_HEIGHT]; /* |avl_link[]| indexes. */
- int k; /* Stack pointer. */
-
- struct avl_node *p; /* Traverses tree to find node to delete. */
- int cmp; /* Result of comparison between |item| and |p|. */
-
- assert (tree != NULL && item != NULL);
-
- k = 0;
- p = (struct avl_node *) &tree->avl_root;
- for (cmp = -1; cmp != 0;
- cmp = tree->avl_compare (item, p->avl_data, tree->avl_param))
- {
- int dir = cmp > 0;
-
- pa[k] = p;
- da[k++] = dir;
-
- p = p->avl_link[dir];
- if (p == NULL)
- return NULL;
- }
- item = p->avl_data;
-
- if (p->avl_link[1] == NULL)
- pa[k - 1]->avl_link[da[k - 1]] = p->avl_link[0];
- else
- {
- struct avl_node *r = p->avl_link[1];
- if (r->avl_link[0] == NULL)
- {
- r->avl_link[0] = p->avl_link[0];
- r->avl_balance = p->avl_balance;
- pa[k - 1]->avl_link[da[k - 1]] = r;
- da[k] = 1;
- pa[k++] = r;
- }
- else
- {
- struct avl_node *s;
- int j = k++;
-
- for (;;)
- {
- da[k] = 0;
- pa[k++] = r;
- s = r->avl_link[0];
- if (s->avl_link[0] == NULL)
- break;
-
- r = s;
- }
-
- s->avl_link[0] = p->avl_link[0];
- r->avl_link[0] = s->avl_link[1];
- s->avl_link[1] = p->avl_link[1];
- s->avl_balance = p->avl_balance;
-
- pa[j - 1]->avl_link[da[j - 1]] = s;
- da[j] = 1;
- pa[j] = s;
- }
- }
-
- tree->avl_alloc->libavl_free (tree->avl_alloc, p);
-
- assert (k > 0);
- while (--k > 0)
- {
- struct avl_node *y = pa[k];
-
- if (da[k] == 0)
- {
- y->avl_balance++;
- if (y->avl_balance == +1)
- break;
- else if (y->avl_balance == +2)
- {
- struct avl_node *x = y->avl_link[1];
- if (x->avl_balance == -1)
- {
- struct avl_node *w;
- assert (x->avl_balance == -1);
- w = x->avl_link[0];
- x->avl_link[0] = w->avl_link[1];
- w->avl_link[1] = x;
- y->avl_link[1] = w->avl_link[0];
- w->avl_link[0] = y;
- if (w->avl_balance == +1)
- x->avl_balance = 0, y->avl_balance = -1;
- else if (w->avl_balance == 0)
- x->avl_balance = y->avl_balance = 0;
- else /* |w->avl_balance == -1| */
- x->avl_balance = +1, y->avl_balance = 0;
- w->avl_balance = 0;
- pa[k - 1]->avl_link[da[k - 1]] = w;
- }
- else
- {
- y->avl_link[1] = x->avl_link[0];
- x->avl_link[0] = y;
- pa[k - 1]->avl_link[da[k - 1]] = x;
- if (x->avl_balance == 0)
- {
- x->avl_balance = -1;
- y->avl_balance = +1;
- break;
- }
- else
- x->avl_balance = y->avl_balance = 0;
- }
- }
- }
- else
- {
- y->avl_balance--;
- if (y->avl_balance == -1)
- break;
- else if (y->avl_balance == -2)
- {
- struct avl_node *x = y->avl_link[0];
- if (x->avl_balance == +1)
- {
- struct avl_node *w;
- assert (x->avl_balance == +1);
- w = x->avl_link[1];
- x->avl_link[1] = w->avl_link[0];
- w->avl_link[0] = x;
- y->avl_link[0] = w->avl_link[1];
- w->avl_link[1] = y;
- if (w->avl_balance == -1)
- x->avl_balance = 0, y->avl_balance = +1;
- else if (w->avl_balance == 0)
- x->avl_balance = y->avl_balance = 0;
- else /* |w->avl_balance == +1| */
- x->avl_balance = -1, y->avl_balance = 0;
- w->avl_balance = 0;
- pa[k - 1]->avl_link[da[k - 1]] = w;
- }
- else
- {
- y->avl_link[0] = x->avl_link[1];
- x->avl_link[1] = y;
- pa[k - 1]->avl_link[da[k - 1]] = x;
- if (x->avl_balance == 0)
- {
- x->avl_balance = +1;
- y->avl_balance = -1;
- break;
- }
- else
- x->avl_balance = y->avl_balance = 0;
- }
- }
- }
- }
-
- tree->avl_count--;
- tree->avl_generation++;
- return (void *) item;
-}
+*******************************************************************************/
-/* Refreshes the stack of parent pointers in |trav|
- and updates its generation number. */
-static void
-trav_refresh (struct avl_traverser *trav)
+static avl_node *avl_newnode(void *data)
{
- assert (trav != NULL);
-
- trav->avl_generation = trav->avl_table->avl_generation;
-
- if (trav->avl_node != NULL)
- {
- avl_comparison_func *cmp = trav->avl_table->avl_compare;
- void *param = trav->avl_table->avl_param;
- struct avl_node *node = trav->avl_node;
- struct avl_node *i;
-
- trav->avl_height = 0;
- for (i = trav->avl_table->avl_root; i != node; )
- {
- assert (trav->avl_height < AVL_MAX_HEIGHT);
- assert (i != NULL);
-
- trav->avl_stack[trav->avl_height++] = i;
- i = i->avl_link[cmp (node->avl_data, i->avl_data, param) > 0];
- }
- }
-}
+ avl_node *n;
-/* Initializes |trav| for use with |tree|
- and selects the null node. */
-void
-avl_t_init (struct avl_traverser *trav, struct avl_table *tree)
-{
- trav->avl_table = tree;
- trav->avl_node = NULL;
- trav->avl_height = 0;
- trav->avl_generation = tree->avl_generation;
+ n = NEW(avl_node);
+
+ n->data = data;
+
+ /* ATTENTION: NEW allocates memory zeroed out */
+
+/* n->balance = 0; */
+/* n->childs[0] = NULL; */
+/* n->childs[1] = NULL; */
+
+ return n;
}
-/* Initializes |trav| for |tree|
- and selects and returns a pointer to its least-valued item.
- Returns |NULL| if |tree| contains no nodes. */
-void *
-avl_t_first (struct avl_traverser *trav, struct avl_table *tree)
-{
- struct avl_node *x;
- assert (tree != NULL && trav != NULL);
+/* avl_rotate_left *************************************************************
- trav->avl_table = tree;
- trav->avl_height = 0;
- trav->avl_generation = tree->avl_generation;
+ Does a left rotation on an AVL node.
- x = tree->avl_root;
- if (x != NULL)
- while (x->avl_link[0] != NULL)
- {
- assert (trav->avl_height < AVL_MAX_HEIGHT);
- trav->avl_stack[trav->avl_height++] = x;
- x = x->avl_link[0];
- }
- trav->avl_node = x;
+ A (node) B
+ \ / \
+ B --> A C
+ \
+ C
- return x != NULL ? x->avl_data : NULL;
-}
+*******************************************************************************/
-/* Initializes |trav| for |tree|
- and selects and returns a pointer to its greatest-valued item.
- Returns |NULL| if |tree| contains no nodes. */
-void *
-avl_t_last (struct avl_traverser *trav, struct avl_table *tree)
+static void avl_rotate_left(avl_node **node)
{
- struct avl_node *x;
+ avl_node *tmp;
+ avl_node *tmpnode;
- assert (tree != NULL && trav != NULL);
+ /* rotate the node */
- trav->avl_table = tree;
- trav->avl_height = 0;
- trav->avl_generation = tree->avl_generation;
+ tmp = *node;
+ tmpnode = tmp->childs[AVL_RIGHT];
+ tmp->childs[AVL_RIGHT] = tmpnode->childs[AVL_LEFT];
+ tmpnode->childs[AVL_LEFT] = tmp;
- x = tree->avl_root;
- if (x != NULL)
- while (x->avl_link[1] != NULL)
- {
- assert (trav->avl_height < AVL_MAX_HEIGHT);
- trav->avl_stack[trav->avl_height++] = x;
- x = x->avl_link[1];
- }
- trav->avl_node = x;
+ /* set new parent node */
- return x != NULL ? x->avl_data : NULL;
+ *node = tmpnode;
}
-/* Searches for |item| in |tree|.
- If found, initializes |trav| to the item found and returns the item
- as well.
- If there is no matching item, initializes |trav| to the null item
- and returns |NULL|. */
-void *
-avl_t_find (struct avl_traverser *trav, struct avl_table *tree, void *item)
-{
- struct avl_node *p, *q;
-
- assert (trav != NULL && tree != NULL && item != NULL);
- trav->avl_table = tree;
- trav->avl_height = 0;
- trav->avl_generation = tree->avl_generation;
- for (p = tree->avl_root; p != NULL; p = q)
- {
- int cmp = tree->avl_compare (item, p->avl_data, tree->avl_param);
-
- if (cmp < 0)
- q = p->avl_link[0];
- else if (cmp > 0)
- q = p->avl_link[1];
- else /* |cmp == 0| */
- {
- trav->avl_node = p;
- return p->avl_data;
- }
-
- assert (trav->avl_height < AVL_MAX_HEIGHT);
- trav->avl_stack[trav->avl_height++] = p;
- }
-
- trav->avl_height = 0;
- trav->avl_node = NULL;
- return NULL;
-}
-/* Attempts to insert |item| into |tree|.
- If |item| is inserted successfully, it is returned and |trav| is
- initialized to its location.
- If a duplicate is found, it is returned and |trav| is initialized to
- its location. No replacement of the item occurs.
- If a memory allocation failure occurs, |NULL| is returned and |trav|
- is initialized to the null item. */
-void *
-avl_t_insert (struct avl_traverser *trav, struct avl_table *tree, void *item)
-{
- void **p;
-
- assert (trav != NULL && tree != NULL && item != NULL);
-
- p = avl_probe (tree, item);
- if (p != NULL)
- {
- trav->avl_table = tree;
- trav->avl_node =
- ((struct avl_node *)
- ((char *) p - offsetof (struct avl_node, avl_data)));
- trav->avl_generation = tree->avl_generation - 1;
- return *p;
- }
- else
- {
- avl_t_init (trav, tree);
- return NULL;
- }
-}
+/* avl_rotate_right ************************************************************
-/* Initializes |trav| to have the same current node as |src|. */
-void *
-avl_t_copy (struct avl_traverser *trav, const struct avl_traverser *src)
-{
- assert (trav != NULL && src != NULL);
-
- if (trav != src)
- {
- trav->avl_table = src->avl_table;
- trav->avl_node = src->avl_node;
- trav->avl_generation = src->avl_generation;
- if (trav->avl_generation == trav->avl_table->avl_generation)
- {
- trav->avl_height = src->avl_height;
- memcpy (trav->avl_stack, (const void *) src->avl_stack,
- sizeof *trav->avl_stack * trav->avl_height);
- }
- }
-
- return trav->avl_node != NULL ? trav->avl_node->avl_data : NULL;
-}
+ Does a right rotation on an AVL node.
-/* Returns the next data item in inorder
- within the tree being traversed with |trav|,
- or if there are no more data items returns |NULL|. */
-void *
-avl_t_next (struct avl_traverser *trav)
-{
- struct avl_node *x;
-
- assert (trav != NULL);
-
- if (trav->avl_generation != trav->avl_table->avl_generation)
- trav_refresh (trav);
-
- x = trav->avl_node;
- if (x == NULL)
- {
- return avl_t_first (trav, trav->avl_table);
- }
- else if (x->avl_link[1] != NULL)
- {
- assert (trav->avl_height < AVL_MAX_HEIGHT);
- trav->avl_stack[trav->avl_height++] = x;
- x = x->avl_link[1];
-
- while (x->avl_link[0] != NULL)
- {
- assert (trav->avl_height < AVL_MAX_HEIGHT);
- trav->avl_stack[trav->avl_height++] = x;
- x = x->avl_link[0];
- }
- }
- else
- {
- struct avl_node *y;
-
- do
- {
- if (trav->avl_height == 0)
- {
- trav->avl_node = NULL;
- return NULL;
- }
-
- y = x;
- x = trav->avl_stack[--trav->avl_height];
- }
- while (y == x->avl_link[1]);
- }
- trav->avl_node = x;
-
- return x->avl_data;
-}
+ C (node) B
+ / / \
+ B --> A C
+ /
+ A
-/* Returns the previous data item in inorder
- within the tree being traversed with |trav|,
- or if there are no more data items returns |NULL|. */
-void *
-avl_t_prev (struct avl_traverser *trav)
-{
- struct avl_node *x;
-
- assert (trav != NULL);
-
- if (trav->avl_generation != trav->avl_table->avl_generation)
- trav_refresh (trav);
-
- x = trav->avl_node;
- if (x == NULL)
- {
- return avl_t_last (trav, trav->avl_table);
- }
- else if (x->avl_link[0] != NULL)
- {
- assert (trav->avl_height < AVL_MAX_HEIGHT);
- trav->avl_stack[trav->avl_height++] = x;
- x = x->avl_link[0];
-
- while (x->avl_link[1] != NULL)
- {
- assert (trav->avl_height < AVL_MAX_HEIGHT);
- trav->avl_stack[trav->avl_height++] = x;
- x = x->avl_link[1];
- }
- }
- else
- {
- struct avl_node *y;
-
- do
- {
- if (trav->avl_height == 0)
- {
- trav->avl_node = NULL;
- return NULL;
- }
-
- y = x;
- x = trav->avl_stack[--trav->avl_height];
- }
- while (y == x->avl_link[0]);
- }
- trav->avl_node = x;
-
- return x->avl_data;
-}
+*******************************************************************************/
-/* Returns |trav|'s current item. */
-void *
-avl_t_cur (struct avl_traverser *trav)
+static void avl_rotate_right(avl_node **node)
{
- assert (trav != NULL);
+ avl_node *tmp;
+ avl_node *tmpnode;
- return trav->avl_node != NULL ? trav->avl_node->avl_data : NULL;
-}
+ /* rotate the node */
-/* Replaces the current item in |trav| by |new| and returns the item replaced.
- |trav| must not have the null item selected.
- The new item must not upset the ordering of the tree. */
-void *
-avl_t_replace (struct avl_traverser *trav, void *new)
-{
- void *old;
+ tmp = *node;
+ tmpnode = tmp->childs[AVL_LEFT];
+ tmp->childs[AVL_LEFT] = tmpnode->childs[AVL_RIGHT];
+ tmpnode->childs[AVL_RIGHT] = tmp;
- assert (trav != NULL && trav->avl_node != NULL && new != NULL);
- old = trav->avl_node->avl_data;
- trav->avl_node->avl_data = new;
- return old;
+ /* set new parent node */
+
+ *node = tmpnode;
}
-static void
-copy_error_recovery (struct avl_node **stack, int height,
- struct avl_table *new, avl_item_func *destroy)
-{
- assert (stack != NULL && height >= 0 && new != NULL);
- for (; height > 2; height -= 2)
- stack[height - 1]->avl_link[1] = NULL;
- avl_destroy (new, destroy);
-}
+/* avl_adjust_balance **********************************************************
-/* Copies |org| to a newly created tree, which is returned.
- If |copy != NULL|, each data item in |org| is first passed to |copy|,
- and the return values are inserted into the tree,
- with |NULL| return values taken as indications of failure.
- On failure, destroys the partially created new tree,
- applying |destroy|, if non-null, to each item in the new tree so far,
- and returns |NULL|.
- If |allocator != NULL|, it is used for allocation in the new tree.
- Otherwise, the same allocator used for |org| is used. */
-struct avl_table *
-avl_copy (const struct avl_table *org, avl_copy_func *copy,
- avl_item_func *destroy, struct libavl_allocator *allocator)
-{
- struct avl_node *stack[2 * (AVL_MAX_HEIGHT + 1)];
- int height = 0;
-
- struct avl_table *new;
- const struct avl_node *x;
- struct avl_node *y;
-
- assert (org != NULL);
- new = avl_create (org->avl_compare, org->avl_param,
- allocator != NULL ? allocator : org->avl_alloc);
- if (new == NULL)
- return NULL;
- new->avl_count = org->avl_count;
- if (new->avl_count == 0)
- return new;
-
- x = (const struct avl_node *) &org->avl_root;
- y = (struct avl_node *) &new->avl_root;
- for (;;)
- {
- while (x->avl_link[0] != NULL)
- {
- assert (height < 2 * (AVL_MAX_HEIGHT + 1));
-
- y->avl_link[0] =
- new->avl_alloc->libavl_malloc (new->avl_alloc,
- sizeof *y->avl_link[0]);
- if (y->avl_link[0] == NULL)
- {
- if (y != (struct avl_node *) &new->avl_root)
- {
- y->avl_data = NULL;
- y->avl_link[1] = NULL;
- }
-
- copy_error_recovery (stack, height, new, destroy);
- return NULL;
- }
-
- stack[height++] = (struct avl_node *) x;
- stack[height++] = y;
- x = x->avl_link[0];
- y = y->avl_link[0];
- }
- y->avl_link[0] = NULL;
-
- for (;;)
- {
- y->avl_balance = x->avl_balance;
- if (copy == NULL)
- y->avl_data = x->avl_data;
- else
- {
- y->avl_data = copy (x->avl_data, org->avl_param);
- if (y->avl_data == NULL)
- {
- y->avl_link[1] = NULL;
- copy_error_recovery (stack, height, new, destroy);
- return NULL;
- }
- }
-
- if (x->avl_link[1] != NULL)
- {
- y->avl_link[1] =
- new->avl_alloc->libavl_malloc (new->avl_alloc,
- sizeof *y->avl_link[1]);
- if (y->avl_link[1] == NULL)
- {
- copy_error_recovery (stack, height, new, destroy);
- return NULL;
- }
-
- x = x->avl_link[1];
- y = y->avl_link[1];
- break;
- }
- else
- y->avl_link[1] = NULL;
-
- if (height <= 2)
- return new;
-
- y = stack[--height];
- x = stack[--height];
- }
- }
-}
+ Does a balance adjustment after a double rotation.
+
+*******************************************************************************/
-/* Frees storage allocated for |tree|.
- If |destroy != NULL|, applies it to each data item in inorder. */
-void
-avl_destroy (struct avl_table *tree, avl_item_func *destroy)
+static void avl_adjust_balance(avl_node *node)
{
- struct avl_node *p, *q;
-
- assert (tree != NULL);
-
- for (p = tree->avl_root; p != NULL; p = q)
- if (p->avl_link[0] == NULL)
- {
- q = p->avl_link[1];
- if (destroy != NULL && p->avl_data != NULL)
- destroy (p->avl_data, tree->avl_param);
- tree->avl_alloc->libavl_free (tree->avl_alloc, p);
- }
- else
- {
- q = p->avl_link[0];
- p->avl_link[0] = q->avl_link[1];
- q->avl_link[1] = p;
- }
-
- tree->avl_alloc->libavl_free (tree->avl_alloc, tree);
+ avl_node *left;
+ avl_node *right;
+
+ left = node->childs[AVL_LEFT];
+ right = node->childs[AVL_RIGHT];
+
+ switch (node->balance) {
+ case -1:
+ left->balance = 0;
+ right->balance = 1;
+ break;
+
+ case 0:
+ left->balance = 0;
+ right->balance = 0;
+ break;
+
+ case 1:
+ left->balance = -1;
+ right->balance = 0;
+ break;
+ }
+
+ node->balance = 0;
}
-/* Allocates |size| bytes of space using |malloc()|.
- Returns a null pointer if allocation fails. */
-void *
-avl_malloc (struct libavl_allocator *allocator, size_t size)
+
+/* avl_insert_intern ***********************************************************
+
+ Inserts a AVL node into a AVL tree.
+
+*******************************************************************************/
+
+static s4 avl_insert_intern(avl_tree *tree, avl_node **node, void *data)
{
- assert (allocator != NULL && size > 0);
- return malloc (size);
+ avl_node *tmpnode;
+ s4 res;
+ s4 direction;
+ s4 insert;
+ s4 balance;
+
+ /* set temporary variable */
+
+ tmpnode = *node;
+
+ /* per default no node was inserted */
+
+ insert = 0;
+
+ /* compare the current node */
+
+ res = tree->comparator(data, tmpnode->data);
+
+ /* is this node already in the tree? */
+
+ if (res == 0)
+ assert(0);
+
+ /* goto left or right child */
+
+ direction = (res < 0) ? AVL_LEFT : AVL_RIGHT;
+
+ /* there is a child, go recursive */
+
+ if (tmpnode->childs[direction]) {
+ balance = avl_insert_intern(tree, &tmpnode->childs[direction], data);
+
+ } else {
+ avl_node *newnode;
+
+ /* no child, create this node */
+
+ newnode = avl_newnode(data);
+
+ /* insert into parent node */
+
+ tmpnode->childs[direction] = newnode;
+
+ /* node was inserted, but don't set insert to 1, since this
+ insertion is handled in this recursion depth */
+
+ balance = 1;
+ }
+
+ /* add insertion value to node balance, value depends on the
+ direction */
+
+ tmpnode->balance += (direction == AVL_LEFT) ? -balance : balance;
+
+ if ((balance != 0) && (tmpnode->balance != 0)) {
+ if (tmpnode->balance < -1) {
+ /* left subtree too tall: right rotation needed */
+
+ if (tmpnode->childs[AVL_LEFT]->balance < 0) {
+ avl_rotate_right(&tmpnode);
+
+ /* simple balance adjustments */
+
+ tmpnode->balance = 0;
+ tmpnode->childs[AVL_RIGHT]->balance = 0;
+
+ } else {
+ avl_rotate_left(&tmpnode->childs[AVL_LEFT]);
+ avl_rotate_right(&tmpnode);
+ avl_adjust_balance(tmpnode);
+ }
+
+ } else if (tmpnode->balance > 1) {
+ /* right subtree too tall: left rotation needed */
+
+ if (tmpnode->childs[AVL_RIGHT]->balance > 0) {
+ avl_rotate_left(&tmpnode);
+
+ /* simple balance adjustments */
+
+ tmpnode->balance = 0;
+ tmpnode->childs[AVL_LEFT]->balance = 0;
+
+ } else {
+ avl_rotate_right(&tmpnode->childs[AVL_RIGHT]);
+ avl_rotate_left(&tmpnode);
+ avl_adjust_balance(tmpnode);
+ }
+
+ } else {
+ insert = 1;
+ }
+ }
+
+ /* set back node */
+
+ *node = tmpnode;
+
+ /* insertion was ok */
+
+ return insert;
}
-/* Frees |block|. */
-void
-avl_free (struct libavl_allocator *allocator, void *block)
+
+/* avl_insert ******************************************************************
+
+ Inserts a AVL node into a AVL tree.
+
+*******************************************************************************/
+
+bool avl_insert(avl_tree *tree, void *data)
{
- assert (allocator != NULL && block != NULL);
- free (block);
+ assert(tree);
+ assert(data);
+
+ LOCK_MONITOR_ENTER(tree->lock);
+
+ /* if we don't have a root node, create one */
+
+ if (tree->root == NULL) {
+ tree->root = avl_newnode(data);
+
+ } else {
+ avl_insert_intern(tree, &tree->root, data);
+ }
+
+ /* increase entries count */
+
+ tree->entries++;
+
+#if 0
+ printf("tree=%p entries=%d\n", tree, tree->entries);
+
+ printf("-------------------\n");
+ avl_dump(tree->root, 0);
+ printf("-------------------\n");
+#endif
+
+ LOCK_MONITOR_EXIT(tree->lock);
+
+ /* insertion was ok */
+
+ return true;
}
-/* Default memory allocator that uses |malloc()| and |free()|. */
-struct libavl_allocator avl_allocator_default =
- {
- avl_malloc,
- avl_free
- };
-#undef NDEBUG
-#include <assert.h>
+/* avl_find ********************************************************************
+
+ Find a given data structure in the AVL tree, with the comparision
+ function of the tree.
+
+*******************************************************************************/
-/* Asserts that |avl_insert()| succeeds at inserting |item| into |table|. */
-void
-(avl_assert_insert) (struct avl_table *table, void *item)
+void *avl_find(avl_tree *tree, void *data)
{
- void **p = avl_probe (table, item);
- assert (p != NULL && *p == item);
+ avl_node *node;
+ s4 res;
+
+ assert(tree);
+ assert(data);
+
+ LOCK_MONITOR_ENTER(tree->lock);
+
+ /* search the tree for the given node */
+
+ for (node = tree->root; node != NULL; ) {
+ /* compare the current node */
+
+ res = tree->comparator(data, node->data);
+
+ /* was the entry found? return it */
+
+ if (res == 0) {
+ LOCK_MONITOR_EXIT(tree->lock);
+
+ return node->data;
+ }
+
+ /* goto left or right child */
+
+ node = node->childs[(res < 0) ? AVL_LEFT : AVL_RIGHT];
+ }
+
+ LOCK_MONITOR_EXIT(tree->lock);
+
+ /* entry was not found, returning NULL */
+
+ return NULL;
}
-/* Asserts that |avl_delete()| really removes |item| from |table|,
- and returns the removed item. */
-void *
-(avl_assert_delete) (struct avl_table *table, void *item)
+
+/* avl_dump ********************************************************************
+
+ Dumps the AVL tree starting with node.
+
+*******************************************************************************/
+
+#if !defined(NDEBUG)
+void avl_dump(avl_node* node, s4 indent)
{
- void *p = avl_delete (table, item);
- assert (p != NULL);
- return p;
-}
+ s4 tmp;
+
+ tmp = indent;
+
+ if (node == NULL)
+ return;
+ if (node->childs[AVL_RIGHT])
+ avl_dump(node->childs[AVL_RIGHT], tmp + 1);
+
+ while(indent--)
+ printf(" ");
+
+ printf("%p (%d)\n", node->data, node->balance);
+
+ if (node->childs[AVL_LEFT])
+ avl_dump(node->childs[AVL_LEFT], tmp + 1);
+}
+#endif
+
+
+/*
+ * These are local overrides for various environment variables in Emacs.
+ * Please do not remove this and leave it at the end of the file, where
+ * Emacs will automagically detect them.
+ * ---------------------------------------------------------------------
+ * Local variables:
+ * mode: c
+ * indent-tabs-mode: t
+ * c-basic-offset: 4
+ * tab-width: 4
+ * End:
+ */
projects / cacao.git / blobdiff