/* Ordered set data type implemented by a binary tree.
- Copyright (C) 2006 Free Software Foundation, Inc.
+ Copyright (C) 2006-2007, 2009-2013 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2006.
- This program is free software; you can redistribute it and/or modify
+ 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, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 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
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
-#ifdef HAVE_CONFIG_H
-# include <config.h>
-#endif
+#include <config.h>
/* Specification. */
#include "gl_avltree_oset.h"
#include <stdlib.h>
-#include "xalloc.h"
-
/* An AVL tree is a binary tree where
1. The height of each node is calculated as
- heightof(node) = 1 + max (heightof(node.left), heightof(node.right)).
+ heightof(node) = 1 + max (heightof(node.left), heightof(node.right)).
2. The heights of the subtrees of each node differ by at most 1:
- | heightof(right) - heightof(left) | <= 1.
+ | heightof(right) - heightof(left) | <= 1.
3. The index of the elements in the node.left subtree are smaller than
the index of node.
The index of the elements in the node.right subtree are larger than
gl_oset_add_before, gl_oset_add_after can be implemented. */
struct gl_oset_node_impl *parent;
int balance; /* heightof(right) - heightof(left),
- always = -1 or 0 or 1 */
+ always = -1 or 0 or 1 */
const void *value;
};
typedef struct gl_oset_node_impl * gl_oset_node_t;
Rotation operations are performed starting at PARENT (not NODE itself!). */
static void
rebalance (gl_oset_t set,
- gl_oset_node_t node, int height_diff, gl_oset_node_t parent)
+ gl_oset_node_t node, int height_diff, gl_oset_node_t parent)
{
for (;;)
{
previous_balance = node->balance;
/* The balance of NODE is incremented by BALANCE_DIFF: +1 if the right
- branch's height has increased by 1 or the left branch's height has
- decreased by 1, -1 if the right branch's height has decreased by 1 or
- the left branch's height has increased by 1, 0 if no height change. */
+ branch's height has increased by 1 or the left branch's height has
+ decreased by 1, -1 if the right branch's height has decreased by 1 or
+ the left branch's height has increased by 1, 0 if no height change. */
if (node->left != NULL || node->right != NULL)
- balance_diff = (child == node->right ? height_diff : -height_diff);
+ balance_diff = (child == node->right ? height_diff : -height_diff);
else
- /* Special case where above formula doesn't work, because the caller
- didn't tell whether node's left or right branch shrunk from height 1
- to NULL. */
- balance_diff = - previous_balance;
+ /* Special case where above formula doesn't work, because the caller
+ didn't tell whether node's left or right branch shrunk from height 1
+ to NULL. */
+ balance_diff = - previous_balance;
node->balance += balance_diff;
if (balance_diff == previous_balance)
- {
- /* node->balance is outside the range [-1,1]. Must rotate. */
- gl_oset_node_t *nodep;
-
- if (node->parent == NULL)
- /* node == set->root */
- nodep = &set->root;
- else if (node->parent->left == node)
- nodep = &node->parent->left;
- else if (node->parent->right == node)
- nodep = &node->parent->right;
- else
- abort ();
-
- nodeleft = node->left;
- noderight = node->right;
-
- if (balance_diff < 0)
- {
- /* node->balance = -2. The subtree is heavier on the left side.
- Rotate from left to right:
-
- *
- / \
- h+2 h
- */
- gl_oset_node_t nodeleftright = nodeleft->right;
- if (nodeleft->balance <= 0)
- {
- /*
- * h+2|h+3
- / \ / \
- h+2 h --> / h+1|h+2
- / \ | / \
- h+1 h|h+1 h+1 h|h+1 h
- */
- node->left = nodeleftright;
- nodeleft->right = node;
-
- nodeleft->parent = node->parent;
- node->parent = nodeleft;
- if (nodeleftright != NULL)
- nodeleftright->parent = node;
-
- nodeleft->balance += 1;
- node->balance = - nodeleft->balance;
-
- *nodep = nodeleft;
- height_diff = (height_diff < 0
- ? /* noderight's height had been decremented from
- h+1 to h. The subtree's height changes from
- h+3 to h+2|h+3. */
- nodeleft->balance - 1
- : /* nodeleft's height had been incremented from
- h+1 to h+2. The subtree's height changes from
- h+2 to h+2|h+3. */
- nodeleft->balance);
- }
- else
- {
- /*
- * h+2
- / \ / \
- h+2 h --> h+1 h+1
- / \ / \ / \
- h h+1 h L R h
- / \
- L R
-
- */
- gl_oset_node_t L = nodeleft->right = nodeleftright->left;
- gl_oset_node_t R = node->left = nodeleftright->right;
- nodeleftright->left = nodeleft;
- nodeleftright->right = node;
-
- nodeleftright->parent = node->parent;
- if (L != NULL)
- L->parent = nodeleft;
- if (R != NULL)
- R->parent = node;
- nodeleft->parent = nodeleftright;
- node->parent = nodeleftright;
-
- nodeleft->balance = (nodeleftright->balance > 0 ? -1 : 0);
- node->balance = (nodeleftright->balance < 0 ? 1 : 0);
- nodeleftright->balance = 0;
-
- *nodep = nodeleftright;
- height_diff = (height_diff < 0
- ? /* noderight's height had been decremented from
- h+1 to h. The subtree's height changes from
- h+3 to h+2. */
- -1
- : /* nodeleft's height had been incremented from
- h+1 to h+2. The subtree's height changes from
- h+2 to h+2. */
- 0);
- }
- }
- else
- {
- /* node->balance = 2. The subtree is heavier on the right side.
- Rotate from right to left:
-
- *
- / \
- h h+2
- */
- gl_oset_node_t noderightleft = noderight->left;
- if (noderight->balance >= 0)
- {
- /*
- * h+2|h+3
- / \ / \
- h h+2 --> h+1|h+2 \
- / \ / \ |
- h|h+1 h+1 h h|h+1 h+1
- */
- node->right = noderightleft;
- noderight->left = node;
-
- noderight->parent = node->parent;
- node->parent = noderight;
- if (noderightleft != NULL)
- noderightleft->parent = node;
-
- noderight->balance -= 1;
- node->balance = - noderight->balance;
-
- *nodep = noderight;
- height_diff = (height_diff < 0
- ? /* nodeleft's height had been decremented from
- h+1 to h. The subtree's height changes from
- h+3 to h+2|h+3. */
- - noderight->balance - 1
- : /* noderight's height had been incremented from
- h+1 to h+2. The subtree's height changes from
- h+2 to h+2|h+3. */
- - noderight->balance);
- }
- else
- {
- /*
- * h+2
- / \ / \
- h h+2 --> h+1 h+1
- / \ / \ / \
- h+1 h h L R h
- / \
- L R
-
- */
- gl_oset_node_t L = node->right = noderightleft->left;
- gl_oset_node_t R = noderight->left = noderightleft->right;
- noderightleft->left = node;
- noderightleft->right = noderight;
-
- noderightleft->parent = node->parent;
- if (L != NULL)
- L->parent = node;
- if (R != NULL)
- R->parent = noderight;
- node->parent = noderightleft;
- noderight->parent = noderightleft;
-
- node->balance = (noderightleft->balance > 0 ? -1 : 0);
- noderight->balance = (noderightleft->balance < 0 ? 1 : 0);
- noderightleft->balance = 0;
-
- *nodep = noderightleft;
- height_diff = (height_diff < 0
- ? /* nodeleft's height had been decremented from
- h+1 to h. The subtree's height changes from
- h+3 to h+2. */
- -1
- : /* noderight's height had been incremented from
- h+1 to h+2. The subtree's height changes from
- h+2 to h+2. */
- 0);
- }
- }
- node = *nodep;
- }
+ {
+ /* node->balance is outside the range [-1,1]. Must rotate. */
+ gl_oset_node_t *nodep;
+
+ if (node->parent == NULL)
+ /* node == set->root */
+ nodep = &set->root;
+ else if (node->parent->left == node)
+ nodep = &node->parent->left;
+ else if (node->parent->right == node)
+ nodep = &node->parent->right;
+ else
+ abort ();
+
+ nodeleft = node->left;
+ noderight = node->right;
+
+ if (balance_diff < 0)
+ {
+ /* node->balance = -2. The subtree is heavier on the left side.
+ Rotate from left to right:
+
+ *
+ / \
+ h+2 h
+ */
+ gl_oset_node_t nodeleftright = nodeleft->right;
+ if (nodeleft->balance <= 0)
+ {
+ /*
+ * h+2|h+3
+ / \ / \
+ h+2 h --> / h+1|h+2
+ / \ | / \
+ h+1 h|h+1 h+1 h|h+1 h
+ */
+ node->left = nodeleftright;
+ nodeleft->right = node;
+
+ nodeleft->parent = node->parent;
+ node->parent = nodeleft;
+ if (nodeleftright != NULL)
+ nodeleftright->parent = node;
+
+ nodeleft->balance += 1;
+ node->balance = - nodeleft->balance;
+
+ *nodep = nodeleft;
+ height_diff = (height_diff < 0
+ ? /* noderight's height had been decremented from
+ h+1 to h. The subtree's height changes from
+ h+3 to h+2|h+3. */
+ nodeleft->balance - 1
+ : /* nodeleft's height had been incremented from
+ h+1 to h+2. The subtree's height changes from
+ h+2 to h+2|h+3. */
+ nodeleft->balance);
+ }
+ else
+ {
+ /*
+ * h+2
+ / \ / \
+ h+2 h --> h+1 h+1
+ / \ / \ / \
+ h h+1 h L R h
+ / \
+ L R
+
+ */
+ gl_oset_node_t L = nodeleft->right = nodeleftright->left;
+ gl_oset_node_t R = node->left = nodeleftright->right;
+ nodeleftright->left = nodeleft;
+ nodeleftright->right = node;
+
+ nodeleftright->parent = node->parent;
+ if (L != NULL)
+ L->parent = nodeleft;
+ if (R != NULL)
+ R->parent = node;
+ nodeleft->parent = nodeleftright;
+ node->parent = nodeleftright;
+
+ nodeleft->balance = (nodeleftright->balance > 0 ? -1 : 0);
+ node->balance = (nodeleftright->balance < 0 ? 1 : 0);
+ nodeleftright->balance = 0;
+
+ *nodep = nodeleftright;
+ height_diff = (height_diff < 0
+ ? /* noderight's height had been decremented from
+ h+1 to h. The subtree's height changes from
+ h+3 to h+2. */
+ -1
+ : /* nodeleft's height had been incremented from
+ h+1 to h+2. The subtree's height changes from
+ h+2 to h+2. */
+ 0);
+ }
+ }
+ else
+ {
+ /* node->balance = 2. The subtree is heavier on the right side.
+ Rotate from right to left:
+
+ *
+ / \
+ h h+2
+ */
+ gl_oset_node_t noderightleft = noderight->left;
+ if (noderight->balance >= 0)
+ {
+ /*
+ * h+2|h+3
+ / \ / \
+ h h+2 --> h+1|h+2 \
+ / \ / \ |
+ h|h+1 h+1 h h|h+1 h+1
+ */
+ node->right = noderightleft;
+ noderight->left = node;
+
+ noderight->parent = node->parent;
+ node->parent = noderight;
+ if (noderightleft != NULL)
+ noderightleft->parent = node;
+
+ noderight->balance -= 1;
+ node->balance = - noderight->balance;
+
+ *nodep = noderight;
+ height_diff = (height_diff < 0
+ ? /* nodeleft's height had been decremented from
+ h+1 to h. The subtree's height changes from
+ h+3 to h+2|h+3. */
+ - noderight->balance - 1
+ : /* noderight's height had been incremented from
+ h+1 to h+2. The subtree's height changes from
+ h+2 to h+2|h+3. */
+ - noderight->balance);
+ }
+ else
+ {
+ /*
+ * h+2
+ / \ / \
+ h h+2 --> h+1 h+1
+ / \ / \ / \
+ h+1 h h L R h
+ / \
+ L R
+
+ */
+ gl_oset_node_t L = node->right = noderightleft->left;
+ gl_oset_node_t R = noderight->left = noderightleft->right;
+ noderightleft->left = node;
+ noderightleft->right = noderight;
+
+ noderightleft->parent = node->parent;
+ if (L != NULL)
+ L->parent = node;
+ if (R != NULL)
+ R->parent = noderight;
+ node->parent = noderightleft;
+ noderight->parent = noderightleft;
+
+ node->balance = (noderightleft->balance > 0 ? -1 : 0);
+ noderight->balance = (noderightleft->balance < 0 ? 1 : 0);
+ noderightleft->balance = 0;
+
+ *nodep = noderightleft;
+ height_diff = (height_diff < 0
+ ? /* nodeleft's height had been decremented from
+ h+1 to h. The subtree's height changes from
+ h+3 to h+2. */
+ -1
+ : /* noderight's height had been incremented from
+ h+1 to h+2. The subtree's height changes from
+ h+2 to h+2. */
+ 0);
+ }
+ }
+ node = *nodep;
+ }
else
- {
- /* No rotation needed. Only propagation of the height change to the
- next higher level. */
- if (height_diff < 0)
- height_diff = (previous_balance == 0 ? 0 : -1);
- else
- height_diff = (node->balance == 0 ? 0 : 1);
- }
+ {
+ /* No rotation needed. Only propagation of the height change to the
+ next higher level. */
+ if (height_diff < 0)
+ height_diff = (previous_balance == 0 ? 0 : -1);
+ else
+ height_diff = (node->balance == 0 ? 0 : 1);
+ }
if (height_diff == 0)
- break;
+ break;
parent = node->parent;
if (parent == NULL)
- break;
+ break;
}
}
static gl_oset_node_t
-gl_tree_add_first (gl_oset_t set, const void *elt)
+gl_tree_nx_add_first (gl_oset_t set, const void *elt)
{
/* Create new node. */
gl_oset_node_t new_node =
- (struct gl_oset_node_impl *) xmalloc (sizeof (struct gl_oset_node_impl));
+ (struct gl_oset_node_impl *) malloc (sizeof (struct gl_oset_node_impl));
+
+ if (new_node == NULL)
+ return NULL;
new_node->left = NULL;
new_node->right = NULL;
gl_oset_node_t node;
for (node = set->root; node->left != NULL; )
- node = node->left;
+ node = node->left;
node->left = new_node;
new_node->parent = node;
/* Rebalance. */
if (node->right == NULL && node->parent != NULL)
- rebalance (set, node, 1, node->parent);
+ rebalance (set, node, 1, node->parent);
}
set->count++;
}
static gl_oset_node_t
-gl_tree_add_before (gl_oset_t set, gl_oset_node_t node, const void *elt)
+gl_tree_nx_add_before (gl_oset_t set, gl_oset_node_t node, const void *elt)
{
/* Create new node. */
gl_oset_node_t new_node =
- (struct gl_oset_node_impl *) xmalloc (sizeof (struct gl_oset_node_impl));
+ (struct gl_oset_node_impl *) malloc (sizeof (struct gl_oset_node_impl));
bool height_inc;
+ if (new_node == NULL)
+ return NULL;
+
new_node->left = NULL;
new_node->right = NULL;
new_node->balance = 0;
else
{
for (node = node->left; node->right != NULL; )
- node = node->right;
+ node = node->right;
node->right = new_node;
node->balance++;
height_inc = (node->left == NULL);
}
static gl_oset_node_t
-gl_tree_add_after (gl_oset_t set, gl_oset_node_t node, const void *elt)
+gl_tree_nx_add_after (gl_oset_t set, gl_oset_node_t node, const void *elt)
{
/* Create new node. */
gl_oset_node_t new_node =
- (struct gl_oset_node_impl *) xmalloc (sizeof (struct gl_oset_node_impl));
+ (struct gl_oset_node_impl *) malloc (sizeof (struct gl_oset_node_impl));
bool height_inc;
+ if (new_node == NULL)
+ return NULL;
+
new_node->left = NULL;
new_node->right = NULL;
new_node->balance = 0;
else
{
for (node = node->right; node->left != NULL; )
- node = node->left;
+ node = node->left;
node->left = new_node;
node->balance--;
height_inc = (node->right == NULL);
gl_oset_node_t child = node->right;
if (child != NULL)
- child->parent = parent;
+ child->parent = parent;
if (parent == NULL)
- set->root = child;
+ set->root = child;
else
- {
- if (parent->left == node)
- parent->left = child;
- else /* parent->right == node */
- parent->right = child;
-
- rebalance (set, child, -1, parent);
- }
+ {
+ if (parent->left == node)
+ parent->left = child;
+ else /* parent->right == node */
+ parent->right = child;
+
+ rebalance (set, child, -1, parent);
+ }
}
else if (node->right == NULL)
{
/* It is not absolutely necessary to treat this case. But the more
- general case below is more complicated, hence slower. */
+ general case below is more complicated, hence slower. */
/* Replace node with node->left. */
gl_oset_node_t child = node->left;
child->parent = parent;
if (parent == NULL)
- set->root = child;
+ set->root = child;
else
- {
- if (parent->left == node)
- parent->left = child;
- else /* parent->right == node */
- parent->right = child;
-
- rebalance (set, child, -1, parent);
- }
+ {
+ if (parent->left == node)
+ parent->left = child;
+ else /* parent->right == node */
+ parent->right = child;
+
+ rebalance (set, child, -1, parent);
+ }
}
else
{
gl_oset_node_t child;
for (subst = node->left; subst->right != NULL; )
- subst = subst->right;
+ subst = subst->right;
subst_parent = subst->parent;
child = subst->left;
/* The case subst_parent == node is special: If we do nothing special,
- we get confusion about node->left, subst->left and child->parent.
- subst_parent == node
- <==> The 'for' loop above terminated immediately.
- <==> subst == subst_parent->left
- [otherwise subst == subst_parent->right]
- In this case, we would need to first set
- child->parent = node; node->left = child;
- and later - when we copy subst into node's position - again
- child->parent = subst; subst->left = child;
- Altogether a no-op. */
+ we get confusion about node->left, subst->left and child->parent.
+ subst_parent == node
+ <==> The 'for' loop above terminated immediately.
+ <==> subst == subst_parent->left
+ [otherwise subst == subst_parent->right]
+ In this case, we would need to first set
+ child->parent = node; node->left = child;
+ and later - when we copy subst into node's position - again
+ child->parent = subst; subst->left = child;
+ Altogether a no-op. */
if (subst_parent != node)
- {
- if (child != NULL)
- child->parent = subst_parent;
- subst_parent->right = child;
- }
+ {
+ if (child != NULL)
+ child->parent = subst_parent;
+ subst_parent->right = child;
+ }
/* Copy subst into node's position.
- (This is safer than to copy subst's value into node, keep node in
- place, and free subst.) */
+ (This is safer than to copy subst's value into node, keep node in
+ place, and free subst.) */
if (subst_parent != node)
- {
- subst->left = node->left;
- subst->left->parent = subst;
- }
+ {
+ subst->left = node->left;
+ subst->left->parent = subst;
+ }
subst->right = node->right;
subst->right->parent = subst;
subst->balance = node->balance;
subst->parent = parent;
if (parent == NULL)
- set->root = subst;
+ set->root = subst;
else if (parent->left == node)
- parent->left = subst;
+ parent->left = subst;
else /* parent->right == node */
- parent->right = subst;
+ parent->right = subst;
/* Rebalancing starts at child's parent, that is subst_parent -
- except when subst_parent == node. In this case, we need to use
- its replacement, subst. */
+ except when subst_parent == node. In this case, we need to use
+ its replacement, subst. */
rebalance (set, child, -1, subst_parent != node ? subst_parent : subst);
}
set->count--;
+ if (set->base.dispose_fn != NULL)
+ set->base.dispose_fn (node->value);
free (node);
return true;
}
const struct gl_oset_implementation gl_avltree_oset_implementation =
{
- gl_tree_create_empty,
+ gl_tree_nx_create_empty,
gl_tree_size,
gl_tree_search,
- gl_tree_add,
+ gl_tree_search_atleast,
+ gl_tree_nx_add,
gl_tree_remove,
gl_tree_oset_free,
gl_tree_iterator,
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