--- /dev/null
+/* Produced by texiweb from libavl.w. */
+
+/* libavl - library for manipulation of binary trees.
+ Copyright (C) 1998-2002, 2004 Free Software Foundation, Inc.
+
+ 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.
+
+ 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.
+
+ 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.
+
+ 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 <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "tavl.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 tavl_table *
+tavl_create (tavl_comparison_func *compare, void *param,
+ struct libavl_allocator *allocator)
+{
+ struct tavl_table *tree;
+
+ assert (compare != NULL);
+
+ if (allocator == NULL)
+ allocator = &tavl_allocator_default;
+
+ tree = allocator->libavl_malloc (allocator, sizeof *tree);
+ if (tree == NULL)
+ return NULL;
+
+ tree->tavl_root = NULL;
+ tree->tavl_compare = compare;
+ tree->tavl_param = param;
+ tree->tavl_alloc = allocator;
+ tree->tavl_count = 0;
+
+ return tree;
+}
+
+/* Search |tree| for an item matching |item|, and return it if found.
+ Otherwise return |NULL|. */
+void *
+tavl_find (const struct tavl_table *tree, const void *item)
+{
+ const struct tavl_node *p;
+
+ assert (tree != NULL && item != NULL);
+
+ p = tree->tavl_root;
+ if (p == NULL)
+ return NULL;
+
+ for (;;)
+ {
+ int cmp, dir;
+
+ cmp = tree->tavl_compare (item, p->tavl_data, tree->tavl_param);
+ if (cmp == 0)
+ return p->tavl_data;
+
+ dir = cmp > 0;
+ if (p->tavl_tag[dir] == TAVL_CHILD)
+ p = p->tavl_link[dir];
+ else
+ return NULL;
+ }
+}
+
+/* Search |tree| for an item matching |item|, and return it if found.
+ Otherwise return |NULL| and set predecessor and successor to point to
+ the relevant nodes. */
+void *
+tavl_bracket (const struct tavl_table *tree, const void *item, const void **predecessor, const void **successor)
+{
+ const struct tavl_node *p;
+
+ assert (tree != NULL && item != NULL);
+
+ *predecessor = NULL;
+ *successor = NULL;
+ p = tree->tavl_root;
+ if (p == NULL)
+ return NULL;
+
+ for (;;)
+ {
+ int cmp, dir;
+
+ cmp = tree->tavl_compare (item, p->tavl_data, tree->tavl_param);
+ if (cmp == 0)
+ return p->tavl_data;
+
+ dir = cmp > 0;
+ if (p->tavl_tag[dir] == TAVL_CHILD)
+ p = p->tavl_link[dir];
+ else /* no match, bracket */
+ {
+ if (dir) /* match would have been above p */
+ {
+ *predecessor = p->tavl_data;
+ p = p->tavl_link[dir]; /* follow thread up */
+ if (p != NULL)
+ *successor = p->tavl_data;
+ }
+ else /* match would have been below p */
+ {
+ *successor = p->tavl_data;
+ p = p->tavl_link[dir]; /* follow thread down */
+ if (p != NULL)
+ *predecessor = p->tavl_data;
+ }
+ return NULL;
+ }
+ }
+}
+
+/* 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 **
+tavl_probe (struct tavl_table *tree, void *item)
+{
+ struct tavl_node *y, *z; /* Top node to update balance factor, and parent. */
+ struct tavl_node *p, *q; /* Iterator, and parent. */
+ struct tavl_node *n; /* Newly inserted node. */
+ struct tavl_node *w; /* New root of rebalanced subtree. */
+ int dir; /* Direction to descend. */
+
+ unsigned char da[TAVL_MAX_HEIGHT]; /* Cached comparison results. */
+ int k = 0; /* Number of cached results. */
+
+ assert (tree != NULL && item != NULL);
+
+ z = (struct tavl_node *) &tree->tavl_root;
+ y = tree->tavl_root;
+ if (y != NULL)
+ {
+ for (q = z, p = y; ; q = p, p = p->tavl_link[dir])
+ {
+ int cmp = tree->tavl_compare (item, p->tavl_data, tree->tavl_param);
+ if (cmp == 0)
+ return &p->tavl_data;
+
+ if (p->tavl_balance != 0)
+ z = q, y = p, k = 0;
+ da[k++] = dir = cmp > 0;
+
+ if (p->tavl_tag[dir] == TAVL_THREAD)
+ break;
+ }
+ }
+ else
+ {
+ p = z;
+ dir = 0;
+ }
+
+ n = tree->tavl_alloc->libavl_malloc (tree->tavl_alloc, sizeof *n);
+ if (n == NULL)
+ return NULL;
+
+ tree->tavl_count++;
+ n->tavl_data = item;
+ n->tavl_tag[0] = n->tavl_tag[1] = TAVL_THREAD;
+ n->tavl_link[dir] = p->tavl_link[dir];
+ if (tree->tavl_root != NULL)
+ {
+ p->tavl_tag[dir] = TAVL_CHILD;
+ n->tavl_link[!dir] = p;
+ }
+ else
+ n->tavl_link[1] = NULL;
+ p->tavl_link[dir] = n;
+ n->tavl_balance = 0;
+ if (tree->tavl_root == n)
+ return &n->tavl_data;
+
+ for (p = y, k = 0; p != n; p = p->tavl_link[da[k]], k++)
+ if (da[k] == 0)
+ p->tavl_balance--;
+ else
+ p->tavl_balance++;
+
+ if (y->tavl_balance == -2)
+ {
+ struct tavl_node *x = y->tavl_link[0];
+ if (x->tavl_balance == -1)
+ {
+ w = x;
+ if (x->tavl_tag[1] == TAVL_THREAD)
+ {
+ x->tavl_tag[1] = TAVL_CHILD;
+ y->tavl_tag[0] = TAVL_THREAD;
+ y->tavl_link[0] = x;
+ }
+ else
+ y->tavl_link[0] = x->tavl_link[1];
+ x->tavl_link[1] = y;
+ x->tavl_balance = y->tavl_balance = 0;
+ }
+ else
+ {
+ assert (x->tavl_balance == +1);
+ w = x->tavl_link[1];
+ x->tavl_link[1] = w->tavl_link[0];
+ w->tavl_link[0] = x;
+ y->tavl_link[0] = w->tavl_link[1];
+ w->tavl_link[1] = y;
+ if (w->tavl_balance == -1)
+ x->tavl_balance = 0, y->tavl_balance = +1;
+ else if (w->tavl_balance == 0)
+ x->tavl_balance = y->tavl_balance = 0;
+ else /* |w->tavl_balance == +1| */
+ x->tavl_balance = -1, y->tavl_balance = 0;
+ w->tavl_balance = 0;
+ if (w->tavl_tag[0] == TAVL_THREAD)
+ {
+ x->tavl_tag[1] = TAVL_THREAD;
+ x->tavl_link[1] = w;
+ w->tavl_tag[0] = TAVL_CHILD;
+ }
+ if (w->tavl_tag[1] == TAVL_THREAD)
+ {
+ y->tavl_tag[0] = TAVL_THREAD;
+ y->tavl_link[0] = w;
+ w->tavl_tag[1] = TAVL_CHILD;
+ }
+ }
+ }
+ else if (y->tavl_balance == +2)
+ {
+ struct tavl_node *x = y->tavl_link[1];
+ if (x->tavl_balance == +1)
+ {
+ w = x;
+ if (x->tavl_tag[0] == TAVL_THREAD)
+ {
+ x->tavl_tag[0] = TAVL_CHILD;
+ y->tavl_tag[1] = TAVL_THREAD;
+ y->tavl_link[1] = x;
+ }
+ else
+ y->tavl_link[1] = x->tavl_link[0];
+ x->tavl_link[0] = y;
+ x->tavl_balance = y->tavl_balance = 0;
+ }
+ else
+ {
+ assert (x->tavl_balance == -1);
+ w = x->tavl_link[0];
+ x->tavl_link[0] = w->tavl_link[1];
+ w->tavl_link[1] = x;
+ y->tavl_link[1] = w->tavl_link[0];
+ w->tavl_link[0] = y;
+ if (w->tavl_balance == +1)
+ x->tavl_balance = 0, y->tavl_balance = -1;
+ else if (w->tavl_balance == 0)
+ x->tavl_balance = y->tavl_balance = 0;
+ else /* |w->tavl_balance == -1| */
+ x->tavl_balance = +1, y->tavl_balance = 0;
+ w->tavl_balance = 0;
+ if (w->tavl_tag[0] == TAVL_THREAD)
+ {
+ y->tavl_tag[1] = TAVL_THREAD;
+ y->tavl_link[1] = w;
+ w->tavl_tag[0] = TAVL_CHILD;
+ }
+ if (w->tavl_tag[1] == TAVL_THREAD)
+ {
+ x->tavl_tag[0] = TAVL_THREAD;
+ x->tavl_link[0] = w;
+ w->tavl_tag[1] = TAVL_CHILD;
+ }
+ }
+ }
+ else
+ return &n->tavl_data;
+ z->tavl_link[y != z->tavl_link[0]] = w;
+
+ return &n->tavl_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 *
+tavl_insert (struct tavl_table *table, void *item)
+{
+ void **p = tavl_probe (table, item);
+ return p == NULL || *p == item ? NULL : *p;
+}
+
+/* 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 *
+tavl_replace (struct tavl_table *table, void *item)
+{
+ void **p = tavl_probe (table, item);
+ if (p == NULL || *p == item)
+ return NULL;
+ else
+ {
+ void *r = *p;
+ *p = item;
+ return r;
+ }
+}
+
+/* Returns the parent of |node| within |tree|,
+ or a pointer to |tavl_root| if |s| is the root of the tree. */
+static struct tavl_node *
+find_parent (struct tavl_table *tree, struct tavl_node *node)
+{
+ if (node != tree->tavl_root)
+ {
+ struct tavl_node *x, *y;
+
+ for (x = y = node; ; x = x->tavl_link[0], y = y->tavl_link[1])
+ if (y->tavl_tag[1] == TAVL_THREAD)
+ {
+ struct tavl_node *p = y->tavl_link[1];
+ if (p == NULL || p->tavl_link[0] != node)
+ {
+ while (x->tavl_tag[0] == TAVL_CHILD)
+ x = x->tavl_link[0];
+ p = x->tavl_link[0];
+ }
+ return p;
+ }
+ else if (x->tavl_tag[0] == TAVL_THREAD)
+ {
+ struct tavl_node *p = x->tavl_link[0];
+ if (p == NULL || p->tavl_link[1] != node)
+ {
+ while (y->tavl_tag[1] == TAVL_CHILD)
+ y = y->tavl_link[1];
+ p = y->tavl_link[1];
+ }
+ return p;
+ }
+ }
+ else
+ return (struct tavl_node *) &tree->tavl_root;
+}
+
+/* Deletes from |tree| and returns an item matching |item|.
+ Returns a null pointer if no matching item found. */
+void *
+tavl_delete (struct tavl_table *tree, const void *item)
+{
+ struct tavl_node *p; /* Traverses tree to find node to delete. */
+ struct tavl_node *q; /* Parent of |p|. */
+ int dir; /* Index into |q->tavl_link[]| to get |p|. */
+ int cmp; /* Result of comparison between |item| and |p|. */
+
+ assert (tree != NULL && item != NULL);
+
+ if (tree->tavl_root == NULL)
+ return NULL;
+
+ q = (struct tavl_node *) &tree->tavl_root;
+ p = tree->tavl_root;
+ dir = 0;
+ for (;;)
+ {
+ cmp = tree->tavl_compare (item, p->tavl_data, tree->tavl_param);
+ if (cmp == 0)
+ break;
+ dir = cmp > 0;
+
+ q = p;
+ if (p->tavl_tag[dir] == TAVL_THREAD)
+ return NULL;
+ p = p->tavl_link[dir];
+ }
+ item = p->tavl_data;
+
+ if (p->tavl_tag[1] == TAVL_THREAD)
+ {
+ if (p->tavl_tag[0] == TAVL_CHILD)
+ {
+ struct tavl_node *t = p->tavl_link[0];
+ while (t->tavl_tag[1] == TAVL_CHILD)
+ t = t->tavl_link[1];
+ t->tavl_link[1] = p->tavl_link[1];
+ q->tavl_link[dir] = p->tavl_link[0];
+ }
+ else
+ {
+ q->tavl_link[dir] = p->tavl_link[dir];
+ if (q != (struct tavl_node *) &tree->tavl_root)
+ q->tavl_tag[dir] = TAVL_THREAD;
+ }
+ }
+ else
+ {
+ struct tavl_node *r = p->tavl_link[1];
+ if (r->tavl_tag[0] == TAVL_THREAD)
+ {
+ r->tavl_link[0] = p->tavl_link[0];
+ r->tavl_tag[0] = p->tavl_tag[0];
+ if (r->tavl_tag[0] == TAVL_CHILD)
+ {
+ struct tavl_node *t = r->tavl_link[0];
+ while (t->tavl_tag[1] == TAVL_CHILD)
+ t = t->tavl_link[1];
+ t->tavl_link[1] = r;
+ }
+ q->tavl_link[dir] = r;
+ r->tavl_balance = p->tavl_balance;
+ q = r;
+ dir = 1;
+ }
+ else
+ {
+ struct tavl_node *s;
+
+ for (;;)
+ {
+ s = r->tavl_link[0];
+ if (s->tavl_tag[0] == TAVL_THREAD)
+ break;
+
+ r = s;
+ }
+
+ if (s->tavl_tag[1] == TAVL_CHILD)
+ r->tavl_link[0] = s->tavl_link[1];
+ else
+ {
+ r->tavl_link[0] = s;
+ r->tavl_tag[0] = TAVL_THREAD;
+ }
+
+ s->tavl_link[0] = p->tavl_link[0];
+ if (p->tavl_tag[0] == TAVL_CHILD)
+ {
+ struct tavl_node *t = p->tavl_link[0];
+ while (t->tavl_tag[1] == TAVL_CHILD)
+ t = t->tavl_link[1];
+ t->tavl_link[1] = s;
+
+ s->tavl_tag[0] = TAVL_CHILD;
+ }
+
+ s->tavl_link[1] = p->tavl_link[1];
+ s->tavl_tag[1] = TAVL_CHILD;
+
+ q->tavl_link[dir] = s;
+ s->tavl_balance = p->tavl_balance;
+ q = r;
+ dir = 0;
+ }
+ }
+
+ tree->tavl_alloc->libavl_free (tree->tavl_alloc, p);
+
+ while (q != (struct tavl_node *) &tree->tavl_root)
+ {
+ struct tavl_node *y = q;
+
+ q = find_parent (tree, y);
+
+ if (dir == 0)
+ {
+ dir = q->tavl_link[0] != y;
+ y->tavl_balance++;
+ if (y->tavl_balance == +1)
+ break;
+ else if (y->tavl_balance == +2)
+ {
+ struct tavl_node *x = y->tavl_link[1];
+
+ assert (x != NULL);
+ if (x->tavl_balance == -1)
+ {
+ struct tavl_node *w;
+
+ assert (x->tavl_balance == -1);
+ w = x->tavl_link[0];
+ x->tavl_link[0] = w->tavl_link[1];
+ w->tavl_link[1] = x;
+ y->tavl_link[1] = w->tavl_link[0];
+ w->tavl_link[0] = y;
+ if (w->tavl_balance == +1)
+ x->tavl_balance = 0, y->tavl_balance = -1;
+ else if (w->tavl_balance == 0)
+ x->tavl_balance = y->tavl_balance = 0;
+ else /* |w->tavl_balance == -1| */
+ x->tavl_balance = +1, y->tavl_balance = 0;
+ w->tavl_balance = 0;
+ if (w->tavl_tag[0] == TAVL_THREAD)
+ {
+ y->tavl_tag[1] = TAVL_THREAD;
+ y->tavl_link[1] = w;
+ w->tavl_tag[0] = TAVL_CHILD;
+ }
+ if (w->tavl_tag[1] == TAVL_THREAD)
+ {
+ x->tavl_tag[0] = TAVL_THREAD;
+ x->tavl_link[0] = w;
+ w->tavl_tag[1] = TAVL_CHILD;
+ }
+ q->tavl_link[dir] = w;
+ }
+ else
+ {
+ q->tavl_link[dir] = x;
+
+ if (x->tavl_balance == 0)
+ {
+ y->tavl_link[1] = x->tavl_link[0];
+ x->tavl_link[0] = y;
+ x->tavl_balance = -1;
+ y->tavl_balance = +1;
+ break;
+ }
+ else /* |x->tavl_balance == +1| */
+ {
+ if (x->tavl_tag[0] == TAVL_CHILD)
+ y->tavl_link[1] = x->tavl_link[0];
+ else
+ {
+ y->tavl_tag[1] = TAVL_THREAD;
+ x->tavl_tag[0] = TAVL_CHILD;
+ }
+ x->tavl_link[0] = y;
+ y->tavl_balance = x->tavl_balance = 0;
+ }
+ }
+ }
+ }
+ else
+ {
+ dir = q->tavl_link[0] != y;
+ y->tavl_balance--;
+ if (y->tavl_balance == -1)
+ break;
+ else if (y->tavl_balance == -2)
+ {
+ struct tavl_node *x = y->tavl_link[0];
+ assert (x != NULL);
+ if (x->tavl_balance == +1)
+ {
+ struct tavl_node *w;
+
+ assert (x->tavl_balance == +1);
+ w = x->tavl_link[1];
+ x->tavl_link[1] = w->tavl_link[0];
+ w->tavl_link[0] = x;
+ y->tavl_link[0] = w->tavl_link[1];
+ w->tavl_link[1] = y;
+ if (w->tavl_balance == -1)
+ x->tavl_balance = 0, y->tavl_balance = +1;
+ else if (w->tavl_balance == 0)
+ x->tavl_balance = y->tavl_balance = 0;
+ else /* |w->tavl_balance == +1| */
+ x->tavl_balance = -1, y->tavl_balance = 0;
+ w->tavl_balance = 0;
+ if (w->tavl_tag[0] == TAVL_THREAD)
+ {
+ x->tavl_tag[1] = TAVL_THREAD;
+ x->tavl_link[1] = w;
+ w->tavl_tag[0] = TAVL_CHILD;
+ }
+ if (w->tavl_tag[1] == TAVL_THREAD)
+ {
+ y->tavl_tag[0] = TAVL_THREAD;
+ y->tavl_link[0] = w;
+ w->tavl_tag[1] = TAVL_CHILD;
+ }
+ q->tavl_link[dir] = w;
+ }
+ else
+ {
+ q->tavl_link[dir] = x;
+
+ if (x->tavl_balance == 0)
+ {
+ y->tavl_link[0] = x->tavl_link[1];
+ x->tavl_link[1] = y;
+ x->tavl_balance = +1;
+ y->tavl_balance = -1;
+ break;
+ }
+ else /* |x->tavl_balance == -1| */
+ {
+ if (x->tavl_tag[1] == TAVL_CHILD)
+ y->tavl_link[0] = x->tavl_link[1];
+ else
+ {
+ y->tavl_tag[0] = TAVL_THREAD;
+ x->tavl_tag[1] = TAVL_CHILD;
+ }
+ x->tavl_link[1] = y;
+ y->tavl_balance = x->tavl_balance = 0;
+ }
+ }
+ }
+ }
+ }
+
+ tree->tavl_count--;
+ return (void *) item;
+}
+
+/* Initializes |trav| for use with |tree|
+ and selects the null node. */
+void
+tavl_t_init (struct tavl_traverser *trav, struct tavl_table *tree)
+{
+ trav->tavl_table = tree;
+ trav->tavl_node = NULL;
+}
+
+/* Initializes |trav| for |tree|.
+ Returns data item in |tree| with the least value,
+ or |NULL| if |tree| is empty. */
+void *
+tavl_t_first (struct tavl_traverser *trav, struct tavl_table *tree)
+{
+ assert (tree != NULL && trav != NULL);
+
+ trav->tavl_table = tree;
+ trav->tavl_node = tree->tavl_root;
+ if (trav->tavl_node != NULL)
+ {
+ while (trav->tavl_node->tavl_tag[0] == TAVL_CHILD)
+ trav->tavl_node = trav->tavl_node->tavl_link[0];
+ return trav->tavl_node->tavl_data;
+ }
+ else
+ return NULL;
+}
+
+/* Initializes |trav| for |tree|.
+ Returns data item in |tree| with the greatest value,
+ or |NULL| if |tree| is empty. */
+void *
+tavl_t_last (struct tavl_traverser *trav, struct tavl_table *tree)
+{
+ assert (tree != NULL && trav != NULL);
+
+ trav->tavl_table = tree;
+ trav->tavl_node = tree->tavl_root;
+ if (trav->tavl_node != NULL)
+ {
+ while (trav->tavl_node->tavl_tag[1] == TAVL_CHILD)
+ trav->tavl_node = trav->tavl_node->tavl_link[1];
+ return trav->tavl_node->tavl_data;
+ }
+ else
+ return NULL;
+}
+
+/* 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 *
+tavl_t_find (struct tavl_traverser *trav, struct tavl_table *tree, void *item)
+{
+ struct tavl_node *p;
+
+ assert (trav != NULL && tree != NULL && item != NULL);
+
+ trav->tavl_table = tree;
+ trav->tavl_node = NULL;
+
+ p = tree->tavl_root;
+ if (p == NULL)
+ return NULL;
+
+ for (;;)
+ {
+ int cmp, dir;
+
+ cmp = tree->tavl_compare (item, p->tavl_data, tree->tavl_param);
+ if (cmp == 0)
+ {
+ trav->tavl_node = p;
+ return p->tavl_data;
+ }
+
+ dir = cmp > 0;
+ if (p->tavl_tag[dir] == TAVL_CHILD)
+ p = p->tavl_link[dir];
+ else
+ 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 *
+tavl_t_insert (struct tavl_traverser *trav,
+ struct tavl_table *tree, void *item)
+{
+ void **p;
+
+ assert (trav != NULL && tree != NULL && item != NULL);
+
+ p = tavl_probe (tree, item);
+ if (p != NULL)
+ {
+ trav->tavl_table = tree;
+ trav->tavl_node =
+ ((struct tavl_node *)
+ ((char *) p - offsetof (struct tavl_node, tavl_data)));
+ return *p;
+ }
+ else
+ {
+ tavl_t_init (trav, tree);
+ return NULL;
+ }
+}
+
+/* Initializes |trav| to have the same current node as |src|. */
+void *
+tavl_t_copy (struct tavl_traverser *trav, const struct tavl_traverser *src)
+{
+ assert (trav != NULL && src != NULL);
+
+ trav->tavl_table = src->tavl_table;
+ trav->tavl_node = src->tavl_node;
+
+ return trav->tavl_node != NULL ? trav->tavl_node->tavl_data : NULL;
+}
+
+/* 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 *
+tavl_t_next (struct tavl_traverser *trav)
+{
+ assert (trav != NULL);
+
+ if (trav->tavl_node == NULL)
+ return tavl_t_first (trav, trav->tavl_table);
+ else if (trav->tavl_node->tavl_tag[1] == TAVL_THREAD)
+ {
+ trav->tavl_node = trav->tavl_node->tavl_link[1];
+ return trav->tavl_node != NULL ? trav->tavl_node->tavl_data : NULL;
+ }
+ else
+ {
+ trav->tavl_node = trav->tavl_node->tavl_link[1];
+ while (trav->tavl_node->tavl_tag[0] == TAVL_CHILD)
+ trav->tavl_node = trav->tavl_node->tavl_link[0];
+ return trav->tavl_node->tavl_data;
+ }
+}
+
+/* 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 *
+tavl_t_prev (struct tavl_traverser *trav)
+{
+ assert (trav != NULL);
+
+ if (trav->tavl_node == NULL)
+ return tavl_t_last (trav, trav->tavl_table);
+ else if (trav->tavl_node->tavl_tag[0] == TAVL_THREAD)
+ {
+ trav->tavl_node = trav->tavl_node->tavl_link[0];
+ return trav->tavl_node != NULL ? trav->tavl_node->tavl_data : NULL;
+ }
+ else
+ {
+ trav->tavl_node = trav->tavl_node->tavl_link[0];
+ while (trav->tavl_node->tavl_tag[1] == TAVL_CHILD)
+ trav->tavl_node = trav->tavl_node->tavl_link[1];
+ return trav->tavl_node->tavl_data;
+ }
+}
+
+/* Returns |trav|'s current item. */
+void *
+tavl_t_cur (struct tavl_traverser *trav)
+{
+ assert (trav != NULL);
+
+ return trav->tavl_node != NULL ? trav->tavl_node->tavl_data : NULL;
+}
+
+/* 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 *
+tavl_t_replace (struct tavl_traverser *trav, void *new)
+{
+ void *old;
+
+ assert (trav != NULL && trav->tavl_node != NULL && new != NULL);
+ old = trav->tavl_node->tavl_data;
+ trav->tavl_node->tavl_data = new;
+ return old;
+}
+
+/* Creates a new node as a child of |dst| on side |dir|.
+ Copies data and |tavl_balance| from |src| into the new node,
+ applying |copy()|, if non-null.
+ Returns nonzero only if fully successful.
+ Regardless of success, integrity of the tree structure is assured,
+ though failure may leave a null pointer in a |tavl_data| member. */
+static int
+copy_node (struct tavl_table *tree,
+ struct tavl_node *dst, int dir,
+ const struct tavl_node *src, tavl_copy_func *copy)
+{
+ struct tavl_node *new =
+ tree->tavl_alloc->libavl_malloc (tree->tavl_alloc, sizeof *new);
+ if (new == NULL)
+ return 0;
+
+ new->tavl_link[dir] = dst->tavl_link[dir];
+ new->tavl_tag[dir] = TAVL_THREAD;
+ new->tavl_link[!dir] = dst;
+ new->tavl_tag[!dir] = TAVL_THREAD;
+ dst->tavl_link[dir] = new;
+ dst->tavl_tag[dir] = TAVL_CHILD;
+
+ new->tavl_balance = src->tavl_balance;
+ if (copy == NULL)
+ new->tavl_data = src->tavl_data;
+ else
+ {
+ new->tavl_data = copy (src->tavl_data, tree->tavl_param);
+ if (new->tavl_data == NULL)
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Destroys |new| with |tavl_destroy (new, destroy)|,
+ first initializing the right link in |new| that has
+ not yet been initialized. */
+static void
+copy_error_recovery (struct tavl_node *p,
+ struct tavl_table *new, tavl_item_func *destroy)
+{
+ new->tavl_root = p;
+ if (p != NULL)
+ {
+ while (p->tavl_tag[1] == TAVL_CHILD)
+ p = p->tavl_link[1];
+ p->tavl_link[1] = NULL;
+ }
+ tavl_destroy (new, destroy);
+}
+
+/* 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 tavl_table *
+tavl_copy (const struct tavl_table *org, tavl_copy_func *copy,
+ tavl_item_func *destroy, struct libavl_allocator *allocator)
+{
+ struct tavl_table *new;
+
+ const struct tavl_node *p;
+ struct tavl_node *q;
+ struct tavl_node rp, rq;
+
+ assert (org != NULL);
+ new = tavl_create (org->tavl_compare, org->tavl_param,
+ allocator != NULL ? allocator : org->tavl_alloc);
+ if (new == NULL)
+ return NULL;
+
+ new->tavl_count = org->tavl_count;
+ if (new->tavl_count == 0)
+ return new;
+
+ p = &rp;
+ rp.tavl_link[0] = org->tavl_root;
+ rp.tavl_tag[0] = TAVL_CHILD;
+
+ q = &rq;
+ rq.tavl_link[0] = NULL;
+ rq.tavl_tag[0] = TAVL_THREAD;
+
+ for (;;)
+ {
+ if (p->tavl_tag[0] == TAVL_CHILD)
+ {
+ if (!copy_node (new, q, 0, p->tavl_link[0], copy))
+ {
+ copy_error_recovery (rq.tavl_link[0], new, destroy);
+ return NULL;
+ }
+
+ p = p->tavl_link[0];
+ q = q->tavl_link[0];
+ }
+ else
+ {
+ while (p->tavl_tag[1] == TAVL_THREAD)
+ {
+ p = p->tavl_link[1];
+ if (p == NULL)
+ {
+ q->tavl_link[1] = NULL;
+ new->tavl_root = rq.tavl_link[0];
+ return new;
+ }
+
+ q = q->tavl_link[1];
+ }
+
+ p = p->tavl_link[1];
+ q = q->tavl_link[1];
+ }
+
+ if (p->tavl_tag[1] == TAVL_CHILD)
+ if (!copy_node (new, q, 1, p->tavl_link[1], copy))
+ {
+ copy_error_recovery (rq.tavl_link[0], new, destroy);
+ return NULL;
+ }
+ }
+}
+
+/* Frees storage allocated for |tree|.
+ If |destroy != NULL|, applies it to each data item in inorder. */
+void
+tavl_destroy (struct tavl_table *tree, tavl_item_func *destroy)
+{
+ struct tavl_node *p; /* Current node. */
+ struct tavl_node *n; /* Next node. */
+
+ p = tree->tavl_root;
+ if (p != NULL)
+ while (p->tavl_tag[0] == TAVL_CHILD)
+ p = p->tavl_link[0];
+
+ while (p != NULL)
+ {
+ n = p->tavl_link[1];
+ if (p->tavl_tag[1] == TAVL_CHILD)
+ while (n->tavl_tag[0] == TAVL_CHILD)
+ n = n->tavl_link[0];
+
+ if (destroy != NULL && p->tavl_data != NULL)
+ destroy (p->tavl_data, tree->tavl_param);
+ tree->tavl_alloc->libavl_free (tree->tavl_alloc, p);
+
+ p = n;
+ }
+
+ tree->tavl_alloc->libavl_free (tree->tavl_alloc, tree);
+}
+
+/* Allocates |size| bytes of space using |malloc()|.
+ Returns a null pointer if allocation fails. */
+void *
+tavl_malloc (struct libavl_allocator *allocator, size_t size)
+{
+ assert (allocator != NULL && size > 0);
+ return malloc (size);
+}
+
+/* Frees |block|. */
+void
+tavl_free (struct libavl_allocator *allocator, void *block)
+{
+ assert (allocator != NULL && block != NULL);
+ free (block);
+}
+
+/* Default memory allocator that uses |malloc()| and |free()|. */
+struct libavl_allocator tavl_allocator_default =
+ {
+ tavl_malloc,
+ tavl_free
+ };
+
+#undef NDEBUG
+#include <assert.h>
+
+/* Asserts that |tavl_insert()| succeeds at inserting |item| into |table|. */
+void
+(tavl_assert_insert) (struct tavl_table *table, void *item)
+{
+ void **p = tavl_probe (table, item);
+ assert (p != NULL && *p == item);
+}
+
+/* Asserts that |tavl_delete()| really removes |item| from |table|,
+ and returns the removed item. */
+void *
+(tavl_assert_delete) (struct tavl_table *table, void *item)
+{
+ void *p = tavl_delete (table, item);
+ assert (p != NULL);
+ return p;
+}
+
projects / sawsim.git / commitdiff