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/** @file runtime/bushpriv.h
* Definitions of generic tree operations
*/
/* Copyright 2000-2002 Marko Mkel (msmakela@tcs.hut.fi).
This file is part of MARIA, a reachability analyzer and model checker
for high-level Petri nets.
MARIA 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.
MARIA 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.
The GNU General Public License is often shipped with GNU software, and
is generally kept in a file called COPYING or LICENSE. If you do not
have a copy of the license, write to the Free Software Foundation,
59 Temple Place, Suite 330, Boston, MA 02111 USA. */
#include "mset.h"
/** deallocate a tree
* @param node the root of the tree
*/
void
freetree (void* node)
{
register struct tree* t = node;
if (t->left) freetree (t->left);
if (t->right) freetree (t->right);
free (t);
}
/** determine whether the multi-set a tree represents is singleton
* @param node the root of the tree
* @return the singleton node, or 0 if the tree is not singleton
*/
void*
singleton (void* node)
{
struct tree* u = 0;
register struct tree* t = node;
FIRST (t);
while (t) {
if (!t->count);
else if (t->count > 1 || u)
return 0;
else
u = t;
NEXT (t);
}
return u ? u + 1 : 0;
}
/** determine whether the multi-set a tree represents is empty
* @param node the root of the tree
* @return pointer to the first non-empty item, or 0 if the tree is empty
*/
const void*
nonempty (const void* node)
{
register const struct tree* t = node;
FIRST (t);
while (t) {
if (t->count)
return t;
NEXT (t);
}
return 0;
}
#ifdef DEBUG
/** climb to the root of a tree
* @param node a tree node
* @return the root of the tree
*/
struct tree*
root (void* node)
{
register struct tree* t = node;
if (t) while (t->up) t = t->up;
return t;
}
/** get the minimum item in a tree
* @param node the root of the tree
* @return minimum item in the tree
*/
struct tree*
first (void* node)
{
register struct tree* t = node;
if (t) while (t->left) t = t->left;
return t;
}
/** get the successor of a tree node
* @param node the tree node
* @return the successor of the node
*/
struct tree*
next (void* node)
{
register struct tree* t = node;
if (t) {
if (t->right)
return first (t->right);
while (t->up && t == t->up->right)
t = t->up;
t = t->up;
}
return t;
}
#endif /* DEBUG */
#ifdef RED_BLACK
/** left rotate a tree
* @param node tree node to be rotated
*/
static void
left_rotate (void* node)
{
register struct tree *t = node, *u = t->right;
if ((t->right = u->left))
u->left->up = t;
if ((u->up = t->up)) {
if (t == t->up->left) t->up->left = u; else t->up->right = u;
}
u->left = t, t->up = u;
}
/** right rotate a tree
* @param node tree node to be rotated
*/
static void
right_rotate (void* node)
{
register struct tree *t = node, *u = t->left;
if ((t->left = u->right))
u->right->up = t;
if ((u->up = t->up)) {
if (t == t->up->right) t->up->right = u; else t->up->left = u;
}
u->right = t, t->up = u;
}
/** balance a tree
* @param node a newly inserted node
*/
static void
balance (void* node)
{
register struct tree* t = node;
t->red = 1;
while (t->up && t->up->red) {
register struct tree* u = t->up->up;
if (!u) break;
if (t->up == u->left) {
if (u->right && u->right->red)
u->left->red = u->right->red = 0, u->red = 1, t = u;
else {
if (t == t->up->right)
left_rotate (t = t->up);
if (t->up) t->up->red = 0;
u->red = 1;
right_rotate (u);
}
}
else {
if (u->left && u->left->red) {
if (u->right) u->right->red = 0;
u->left->red = 0, u->red = 1, t = u;
}
else {
if (t == t->up->left)
right_rotate (t = t->up);
if (t->up) t->up->red = 0;
u->red = 1;
left_rotate (u);
}
}
}
}
#endif /* RED_BLACK */
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