mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-15 10:17:20 +00:00
681 lines
16 KiB
C
681 lines
16 KiB
C
/* ET-trees datastructure implementation.
|
|
Contributed by Pavel Nejedly
|
|
Copyright (C) 2002 Free Software Foundation, Inc.
|
|
|
|
This file is part of the libiberty library.
|
|
Libiberty is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2 of the License, or (at your option) any later version.
|
|
|
|
Libiberty 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with libiberty; see the file COPYING.LIB. If
|
|
not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA.
|
|
|
|
The ET-forest structure is described in:
|
|
D. D. Sleator and R. E. Tarjan. A data structure for dynamic trees.
|
|
J. G'omput. System Sci., 26(3):362 381, 1983.
|
|
*/
|
|
|
|
#include "config.h"
|
|
#include "system.h"
|
|
#include "et-forest.h"
|
|
|
|
struct et_forest_occurrence;
|
|
typedef struct et_forest_occurrence* et_forest_occurrence_t;
|
|
|
|
/* The ET-forest type. */
|
|
struct et_forest
|
|
{
|
|
/* Linked list of nodes is used to destroy the structure. */
|
|
int nnodes;
|
|
};
|
|
|
|
/* Single occurrence of node in ET-forest.
|
|
A single node may have multiple occurrences.
|
|
*/
|
|
struct et_forest_occurrence
|
|
{
|
|
/* Parent in the splay-tree. */
|
|
et_forest_occurrence_t parent;
|
|
|
|
/* Children in the splay-tree. */
|
|
et_forest_occurrence_t left, right;
|
|
|
|
/* Counts of vertices in the two splay-subtrees. */
|
|
int count_left, count_right;
|
|
|
|
/* Next occurrence of this node in the sequence. */
|
|
et_forest_occurrence_t next;
|
|
|
|
/* The node, which this occurrence is of. */
|
|
et_forest_node_t node;
|
|
};
|
|
|
|
|
|
/* ET-forest node. */
|
|
struct et_forest_node
|
|
{
|
|
et_forest_t forest;
|
|
void *value;
|
|
|
|
/* First and last occurrence of this node in the sequence. */
|
|
et_forest_occurrence_t first, last;
|
|
};
|
|
|
|
|
|
static et_forest_occurrence_t splay PARAMS ((et_forest_occurrence_t));
|
|
static void remove_all_occurrences PARAMS ((et_forest_node_t));
|
|
static inline et_forest_occurrence_t find_leftmost_node
|
|
PARAMS ((et_forest_occurrence_t));
|
|
static inline et_forest_occurrence_t find_rightmost_node
|
|
PARAMS ((et_forest_occurrence_t));
|
|
static int calculate_value PARAMS ((et_forest_occurrence_t));
|
|
|
|
/* Return leftmost node present in the tree roted by OCC. */
|
|
static inline et_forest_occurrence_t
|
|
find_leftmost_node (occ)
|
|
et_forest_occurrence_t occ;
|
|
{
|
|
while (occ->left)
|
|
occ = occ->left;
|
|
|
|
return occ;
|
|
}
|
|
|
|
/* Return rightmost node present in the tree roted by OCC. */
|
|
static inline et_forest_occurrence_t
|
|
find_rightmost_node (occ)
|
|
et_forest_occurrence_t occ;
|
|
{
|
|
while (occ->right)
|
|
occ = occ->right;
|
|
return occ;
|
|
}
|
|
|
|
|
|
/* Operation splay for splay tree structure representing ocuurences. */
|
|
static et_forest_occurrence_t
|
|
splay (node)
|
|
et_forest_occurrence_t node;
|
|
{
|
|
et_forest_occurrence_t parent;
|
|
et_forest_occurrence_t grandparent;
|
|
|
|
while (1)
|
|
{
|
|
parent = node->parent;
|
|
|
|
if (! parent)
|
|
return node; /* node == root. */
|
|
|
|
grandparent = parent->parent;
|
|
|
|
if (! grandparent)
|
|
break;
|
|
|
|
/* Now there are four possible combinations: */
|
|
|
|
if (node == parent->left)
|
|
{
|
|
if (parent == grandparent->left)
|
|
{
|
|
et_forest_occurrence_t node1, node2;
|
|
int count1, count2;
|
|
|
|
node1 = node->right;
|
|
count1 = node->count_right;
|
|
node2 = parent->right;
|
|
count2 = parent->count_right;
|
|
|
|
grandparent->left = node2;
|
|
grandparent->count_left = count2;
|
|
if (node2)
|
|
node2->parent = grandparent;
|
|
parent->left = node1;
|
|
parent->count_left = count1;
|
|
if (node1)
|
|
node1->parent = parent;
|
|
parent->right = grandparent;
|
|
parent->count_right = count2 + grandparent->count_right + 1;
|
|
node->right = parent;
|
|
node->count_right = count1 + parent->count_right + 1;
|
|
|
|
node->parent = grandparent->parent;
|
|
parent->parent = node;
|
|
grandparent->parent = parent;
|
|
|
|
if (node->parent)
|
|
{
|
|
if (node->parent->left == grandparent)
|
|
node->parent->left = node;
|
|
else
|
|
node->parent->right = node;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* parent == grandparent->right && node == parent->left*/
|
|
et_forest_occurrence_t node1, node2;
|
|
int count1, count2;
|
|
|
|
node1 = node->left;
|
|
count1 = node->count_left;
|
|
node2 = node->right;
|
|
count2 = node->count_right;
|
|
|
|
grandparent->right = node1;
|
|
grandparent->count_right = count1;
|
|
if (node1)
|
|
node1->parent = grandparent;
|
|
parent->left = node2;
|
|
parent->count_left = count2;
|
|
if (node2)
|
|
node2->parent = parent;
|
|
node->left = grandparent;
|
|
node->count_left = grandparent->count_left + count1 + 1;
|
|
node->right = parent;
|
|
node->count_right = parent->count_right + count2 + 1;
|
|
|
|
node->parent = grandparent->parent;
|
|
parent->parent = node;
|
|
grandparent->parent = node;
|
|
|
|
if (node->parent)
|
|
{
|
|
if (node->parent->left == grandparent)
|
|
node->parent->left = node;
|
|
else
|
|
node->parent->right = node;
|
|
}
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* node == parent->right. */
|
|
if (parent == grandparent->left)
|
|
{
|
|
et_forest_occurrence_t node1, node2;
|
|
int count1, count2;
|
|
|
|
node1 = node->left;
|
|
count1 = node->count_left;
|
|
node2 = node->right;
|
|
count2 = node->count_right;
|
|
|
|
parent->right = node1;
|
|
parent->count_right = count1;
|
|
if (node1)
|
|
node1->parent = parent;
|
|
grandparent->left = node2;
|
|
grandparent->count_left = count2;
|
|
if (node2)
|
|
node2->parent = grandparent;
|
|
node->left = parent;
|
|
node->count_left = parent->count_left + count1 + 1;
|
|
node->right = grandparent;
|
|
node->count_right = grandparent->count_right + count2 + 1;
|
|
|
|
node->parent = grandparent->parent;
|
|
parent->parent = node;
|
|
grandparent->parent = node;
|
|
|
|
if (node->parent)
|
|
{
|
|
if (node->parent->left == grandparent)
|
|
node->parent->left = node;
|
|
else
|
|
node->parent->right = node;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* parent == grandparent->right && node == parent->right*/
|
|
et_forest_occurrence_t node1, node2;
|
|
int count1, count2;
|
|
|
|
node1 = node->left;
|
|
count1 = node->count_left;
|
|
node2 = parent->left;
|
|
count2 = parent->count_left;
|
|
|
|
grandparent->right = node2;
|
|
grandparent->count_right = count2;
|
|
if (node2)
|
|
node2->parent = grandparent;
|
|
parent->right = node1;
|
|
parent->count_right = count1;
|
|
if (node1)
|
|
node1->parent = parent;
|
|
parent->left = grandparent;
|
|
parent->count_left = count2 + grandparent->count_left + 1;
|
|
node->left = parent;
|
|
node->count_left = count1 + parent->count_left + 1;
|
|
|
|
node->parent = grandparent->parent;
|
|
parent->parent = node;
|
|
grandparent->parent = parent;
|
|
|
|
if (node->parent)
|
|
{
|
|
if (node->parent->left == grandparent)
|
|
node->parent->left = node;
|
|
else
|
|
node->parent->right = node;
|
|
}
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
/* parent == root. */
|
|
/* There are two possible combinations: */
|
|
|
|
if (node == parent->left)
|
|
{
|
|
et_forest_occurrence_t node1;
|
|
int count1;
|
|
|
|
node1 = node->right;
|
|
count1 = node->count_right;
|
|
|
|
parent->left = node1;
|
|
parent->count_left = count1;
|
|
if (node1)
|
|
node1->parent = parent;
|
|
node->right = parent;
|
|
node->count_right = parent->count_right + 1 + count1;
|
|
node->parent = parent->parent; /* the same as = 0; */
|
|
parent->parent = node;
|
|
|
|
if (node->parent)
|
|
{
|
|
if (node->parent->left == parent)
|
|
node->parent->left = node;
|
|
else
|
|
node->parent->right = node;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* node == parent->right. */
|
|
et_forest_occurrence_t node1;
|
|
int count1;
|
|
|
|
node1 = node->left;
|
|
count1 = node->count_left;
|
|
|
|
parent->right = node1;
|
|
parent->count_right = count1;
|
|
if (node1)
|
|
node1->parent = parent;
|
|
node->left = parent;
|
|
node->count_left = parent->count_left + 1 + count1;
|
|
node->parent = parent->parent; /* the same as = 0; */
|
|
parent->parent = node;
|
|
|
|
if (node->parent)
|
|
{
|
|
if (node->parent->left == parent)
|
|
node->parent->left = node;
|
|
else
|
|
node->parent->right = node;
|
|
}
|
|
}
|
|
|
|
return node;
|
|
}
|
|
|
|
/* Remove all occurences of the given node before destroying the node. */
|
|
static void
|
|
remove_all_occurrences (forest_node)
|
|
et_forest_node_t forest_node;
|
|
{
|
|
et_forest_occurrence_t first = forest_node->first;
|
|
et_forest_occurrence_t last = forest_node->last;
|
|
et_forest_occurrence_t node;
|
|
|
|
splay (first);
|
|
|
|
if (first->left)
|
|
first->left->parent = 0;
|
|
if (first->right)
|
|
first->right->parent = 0;
|
|
|
|
if (last != first)
|
|
{
|
|
splay (last);
|
|
|
|
if (last->left)
|
|
last->left->parent = 0;
|
|
if (last->right)
|
|
last->right->parent = 0;
|
|
}
|
|
|
|
if (last->right && first->left) /* actually, first->left would suffice. */
|
|
{
|
|
/* Need to join them. */
|
|
et_forest_occurrence_t prev_node, next_node;
|
|
|
|
prev_node = splay (find_rightmost_node (first->left));
|
|
next_node = splay (find_leftmost_node (last->right));
|
|
/* prev_node and next_node are consecutive occurencies
|
|
of the same node. */
|
|
if (prev_node->next != next_node)
|
|
abort ();
|
|
|
|
prev_node->right = next_node->right;
|
|
prev_node->count_right = next_node->count_right;
|
|
prev_node->next = next_node->next;
|
|
if (prev_node->right)
|
|
prev_node->right->parent = prev_node;
|
|
|
|
if (prev_node->node->last == next_node)
|
|
prev_node->node->last = prev_node;
|
|
|
|
free (next_node);
|
|
}
|
|
|
|
if (first != last)
|
|
{
|
|
node = first->next;
|
|
|
|
while (node != last)
|
|
{
|
|
et_forest_occurrence_t next_node;
|
|
|
|
splay (node);
|
|
|
|
if (node->left)
|
|
node->left->parent = 0;
|
|
if (node->right)
|
|
node->right->parent = 0;
|
|
|
|
next_node = node->next;
|
|
free (node);
|
|
node = next_node;
|
|
}
|
|
}
|
|
|
|
free (first);
|
|
if (first != last)
|
|
free (last);
|
|
}
|
|
|
|
/* Calculate ET value of the given node. */
|
|
static inline int
|
|
calculate_value (node)
|
|
et_forest_occurrence_t node;
|
|
{
|
|
int value = node->count_left;
|
|
|
|
while (node->parent)
|
|
{
|
|
if (node == node->parent->right)
|
|
value += node->parent->count_left + 1;
|
|
|
|
node = node->parent;
|
|
}
|
|
|
|
return value;
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Create ET-forest structure. */
|
|
et_forest_t
|
|
et_forest_create ()
|
|
{
|
|
|
|
et_forest_t forest = xmalloc (sizeof (struct et_forest));
|
|
|
|
forest->nnodes = 0;
|
|
return forest;
|
|
}
|
|
|
|
|
|
|
|
/* Deallocate the structure. */
|
|
void
|
|
et_forest_delete (forest)
|
|
et_forest_t forest;
|
|
{
|
|
if (forest->nnodes)
|
|
abort ();
|
|
|
|
free (forest);
|
|
}
|
|
|
|
/* Create new node with VALUE and return the edge.
|
|
Return NULL when memory allocation failed. */
|
|
et_forest_node_t
|
|
et_forest_add_node (forest, value)
|
|
et_forest_t forest;
|
|
void *value;
|
|
{
|
|
/* Create node with one occurrence. */
|
|
et_forest_node_t node;
|
|
et_forest_occurrence_t occ;
|
|
|
|
node = xmalloc (sizeof (struct et_forest_node));
|
|
occ = xmalloc (sizeof (struct et_forest_occurrence));
|
|
|
|
node->first = node->last = occ;
|
|
node->value = value;
|
|
forest->nnodes++;
|
|
|
|
occ->node = node;
|
|
occ->left = occ->right = occ->parent = 0;
|
|
occ->next = 0;
|
|
occ->count_left = occ->count_right = 0;
|
|
return node;
|
|
}
|
|
|
|
/* Add new edge to the tree, return 1 if succesfull.
|
|
0 indicates that creation of the edge will close the cycle in graph. */
|
|
int
|
|
et_forest_add_edge (forest, parent_node, child_node)
|
|
et_forest_t forest ATTRIBUTE_UNUSED;
|
|
et_forest_node_t parent_node;
|
|
et_forest_node_t child_node;
|
|
{
|
|
et_forest_occurrence_t new_occ, parent_occ, child_occ;
|
|
|
|
if (! parent_node || ! child_node)
|
|
abort ();
|
|
|
|
parent_occ = parent_node->first;
|
|
child_occ = child_node->first;
|
|
|
|
splay (parent_occ);
|
|
splay (child_occ);
|
|
|
|
if (parent_occ->parent)
|
|
return 0; /* Both child and parent are in the same tree. */
|
|
|
|
if (child_occ->left)
|
|
abort (); /* child must be root of its containing tree. */
|
|
|
|
new_occ = xmalloc (sizeof (struct et_forest_occurrence));
|
|
|
|
new_occ->node = parent_node;
|
|
new_occ->left = child_occ;
|
|
new_occ->count_left = child_occ->count_right + 1; /* count_left is 0. */
|
|
new_occ->right = parent_occ->right;
|
|
new_occ->count_right = parent_occ->count_right;
|
|
new_occ->parent = parent_occ;
|
|
new_occ->next = parent_occ->next;
|
|
child_occ->parent = new_occ;
|
|
parent_occ->right = new_occ;
|
|
parent_occ->count_right = new_occ->count_left + new_occ->count_right + 1;
|
|
parent_occ->next = new_occ;
|
|
if (new_occ->right)
|
|
new_occ->right->parent = new_occ;
|
|
|
|
if (parent_node->last == parent_occ)
|
|
parent_node->last = new_occ;
|
|
return 1;
|
|
}
|
|
|
|
/* Remove NODE from the tree and all connected edges. */
|
|
void
|
|
et_forest_remove_node (forest, node)
|
|
et_forest_t forest;
|
|
et_forest_node_t node;
|
|
{
|
|
remove_all_occurrences (node);
|
|
forest->nnodes--;
|
|
|
|
free (node);
|
|
}
|
|
|
|
/* Remove edge from the tree, return 1 if sucesfull,
|
|
0 indicates nonexisting edge. */
|
|
int
|
|
et_forest_remove_edge (forest, parent_node, child_node)
|
|
et_forest_t forest ATTRIBUTE_UNUSED;
|
|
et_forest_node_t parent_node;
|
|
et_forest_node_t child_node;
|
|
{
|
|
et_forest_occurrence_t parent_pre_occ, parent_post_occ;
|
|
|
|
splay (child_node->first);
|
|
|
|
if (! child_node->first->left)
|
|
return 0;
|
|
|
|
parent_pre_occ = find_rightmost_node (child_node->first->left);
|
|
if (parent_pre_occ->node != parent_node)
|
|
abort ();
|
|
|
|
splay (parent_pre_occ);
|
|
parent_pre_occ->right->parent = 0;
|
|
|
|
parent_post_occ = parent_pre_occ->next;
|
|
splay (parent_post_occ);
|
|
|
|
parent_post_occ->left->parent = 0;
|
|
|
|
parent_pre_occ->right = parent_post_occ->right;
|
|
parent_pre_occ->count_right = parent_post_occ->count_right;
|
|
if (parent_post_occ->right)
|
|
parent_post_occ->right->parent = parent_pre_occ;
|
|
|
|
parent_pre_occ->next = parent_post_occ->next;
|
|
|
|
if (parent_post_occ == parent_node->last)
|
|
parent_node->last = parent_pre_occ;
|
|
|
|
free (parent_post_occ);
|
|
return 1;
|
|
}
|
|
|
|
/* Return the parent of the NODE if any, NULL otherwise. */
|
|
et_forest_node_t
|
|
et_forest_parent (forest, node)
|
|
et_forest_t forest ATTRIBUTE_UNUSED;
|
|
et_forest_node_t node;
|
|
{
|
|
splay (node->first);
|
|
|
|
if (node->first->left)
|
|
return find_rightmost_node (node->first->left)->node;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* Return nearest common ancestor of NODE1 and NODE2.
|
|
Return NULL of they are in different trees. */
|
|
et_forest_node_t
|
|
et_forest_common_ancestor (forest, node1, node2)
|
|
et_forest_t forest ATTRIBUTE_UNUSED;
|
|
et_forest_node_t node1;
|
|
et_forest_node_t node2;
|
|
{
|
|
int value1, value2, max_value;
|
|
et_forest_node_t ancestor;
|
|
|
|
if (node1 == node2)
|
|
return node1;
|
|
|
|
if (! node1 || ! node2)
|
|
abort ();
|
|
|
|
splay (node1->first);
|
|
splay (node2->first);
|
|
|
|
if (! node1->first->parent) /* The two vertices are in different trees. */
|
|
return 0;
|
|
|
|
value2 = calculate_value (node2->first);
|
|
value1 = calculate_value (node1->first);
|
|
|
|
if (value1 < value2)
|
|
{
|
|
ancestor = node1;
|
|
max_value = value2;
|
|
}
|
|
else
|
|
{
|
|
ancestor = node2;
|
|
max_value = value1;
|
|
}
|
|
|
|
while (calculate_value (ancestor->last) < max_value)
|
|
{
|
|
/* Find parent node. */
|
|
splay (ancestor->first);
|
|
ancestor = find_rightmost_node (ancestor->first->left) ->node;
|
|
}
|
|
|
|
return ancestor;
|
|
}
|
|
|
|
/* Return the value pointer of node set during it's creation. */
|
|
void *
|
|
et_forest_node_value (forest, node)
|
|
et_forest_t forest ATTRIBUTE_UNUSED;
|
|
et_forest_node_t node;
|
|
{
|
|
/* Alloc threading NULL as a special node of the forest. */
|
|
if (!node)
|
|
return NULL;
|
|
return node->value;
|
|
}
|
|
|
|
/* Find all sons of NODE and store them into ARRAY allocated by the caller.
|
|
Return number of nodes found. */
|
|
int
|
|
et_forest_enumerate_sons (forest, node, array)
|
|
et_forest_t forest ATTRIBUTE_UNUSED;
|
|
et_forest_node_t node;
|
|
et_forest_node_t *array;
|
|
{
|
|
int n = 0;
|
|
et_forest_occurrence_t occ = node->first, stop = node->last, occ1;
|
|
|
|
/* Parent is the rightmost node of the left successor.
|
|
Look for all occurences having no right succesor
|
|
and lookup the sons. */
|
|
while (occ != stop)
|
|
{
|
|
splay (occ);
|
|
if (occ->right)
|
|
{
|
|
occ1 = find_leftmost_node (occ->right);
|
|
if (occ1->node->first == occ1)
|
|
array[n++] = occ1->node;
|
|
}
|
|
occ = occ->next;
|
|
}
|
|
return n;
|
|
}
|