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564 lines
10 KiB
C
564 lines
10 KiB
C
/*
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Libraries for fields, doubly-linked lists and red-black trees.
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Copyright (C) 2001 James S. Plank
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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---------------------------------------------------------------------------
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Please see http://www.cs.utk.edu/~plank/plank/classes/cs360/360/notes/Libfdr/
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for instruction on how to use this library.
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Jim Plank
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plank@cs.utk.edu
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http://www.cs.utk.edu/~plank
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Associate Professor
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Department of Computer Science
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University of Tennessee
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203 Claxton Complex
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1122 Volunteer Blvd.
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Knoxville, TN 37996-3450
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865-974-4397
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Fax: 865-974-4404
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*/
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/* Revision 1.2. Jim Plank */
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/* Original code by Jim Plank (plank@cs.utk.edu) */
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/* modified for THINK C 6.0 for Macintosh by Chris Bartley */
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/* Heavily edited and reformatted to K&R style 2010 by Werner Almesberger */
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#include <stdio.h>
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#include <stdlib.h>
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#include "jrb.h"
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#define isred(n) (n->red)
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#define isblack(n) (!isred(n))
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#define isleft(n) (n->left)
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#define isright(n) (!isleft(n))
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#define isint(n) (n->internal)
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#define isext(n) (!isint(n))
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#define ishead(n) (n->roothead & 2)
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#define isroot(n) (n->roothead & 1)
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#define getlext(n) ((struct jrb *) (n->key))
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#define setlext(node, val) node->key = (void *) (val)
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#define getrext(n) ((struct jrb *) (n->val))
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#define setrext(node, value) node->val = (void *) (value)
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#define setred(n) n->red = 1
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#define setblack(n) n->red = 0
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#define setleft(n) n->left = 1
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#define setright(n) n->left = 0
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#define sethead(n) (n->roothead |= 2)
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#define setroot(n) (n->roothead |= 1)
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#define setint(n) n->internal = 1
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#define setext(n) n->internal = 0
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#define setnormal(n) n->roothead = 0
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#define sibling(n) (isleft(n) ? n->parent->blink : n->parent->flink)
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static void insert(struct jrb *item, struct jrb *list)
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/* Inserts to the end of a list */
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{
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struct jrb *last_node;
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last_node = list->blink;
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list->blink = item;
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last_node->flink = item;
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item->blink = last_node;
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item->flink = list;
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}
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static void delete_item(struct jrb *item) /* Deletes an arbitrary iterm */
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{
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item->flink->blink = item->blink;
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item->blink->flink = item->flink;
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}
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static void single_rotate(struct jrb *y, int l)
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{
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int rl = 0 /* for gcc */, ir;
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struct jrb *x, *yp;
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ir = isroot(y);
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yp = y->parent;
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if (!ir)
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rl = isleft(y);
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if (l) {
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x = y->flink;
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y->flink = x->blink;
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setleft(y->flink);
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y->flink->parent = y;
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x->blink = y;
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setright(y);
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} else {
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x = y->blink;
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y->blink = x->flink;
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setright(y->blink);
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y->blink->parent = y;
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x->flink = y;
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setleft(y);
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}
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x->parent = yp;
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y->parent = x;
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if (ir) {
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yp->parent = x;
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setnormal(y);
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setroot(x);
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} else {
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if (rl) {
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yp->flink = x;
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setleft(x);
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} else {
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yp->blink = x;
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setright(x);
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}
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}
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}
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static void recolor(struct jrb *n)
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{
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struct jrb *p, *gp, *s;
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int done = 0;
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while (!done) {
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if (isroot(n)) {
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setblack(n);
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return;
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}
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p = n->parent;
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if (isblack(p))
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return;
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if (isroot(p)) {
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setblack(p);
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return;
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}
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gp = p->parent;
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s = sibling(p);
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if (isred(s)) {
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setblack(p);
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setred(gp);
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setblack(s);
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n = gp;
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} else {
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done = 1;
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}
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}
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/* p's sibling is black, p is red, gp is black */
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if ((isleft(n) == 0) == (isleft(p) == 0)) {
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single_rotate(gp, isleft(n));
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setblack(p);
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setred(gp);
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} else {
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single_rotate(p, isleft(n));
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single_rotate(gp, isleft(n));
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setblack(n);
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setred(gp);
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}
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}
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static struct jrb *mk_new_ext(void *key, void *val)
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{
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struct jrb *new;
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new = (struct jrb *) malloc(sizeof(struct jrb));
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new->val = val;
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new->key = key;
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setext(new);
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setblack(new);
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setnormal(new);
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return new;
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}
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static void mk_new_int(struct jrb *l, struct jrb *r, struct jrb *p, int il)
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{
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struct jrb *newnode;
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newnode = (struct jrb *) malloc(sizeof(struct jrb));
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setint(newnode);
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setred(newnode);
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setnormal(newnode);
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newnode->flink = l;
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newnode->blink = r;
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newnode->parent = p;
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setlext(newnode, l);
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setrext(newnode, r);
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l->parent = newnode;
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r->parent = newnode;
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setleft(l);
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setright(r);
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if (ishead(p)) {
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p->parent = newnode;
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setroot(newnode);
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} else if (il) {
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setleft(newnode);
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p->flink = newnode;
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} else {
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setright(newnode);
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p->blink = newnode;
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}
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recolor(newnode);
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}
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static struct jrb *lprev(struct jrb *n)
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{
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if (ishead(n))
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return n;
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while (!isroot(n)) {
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if (isright(n))
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return n->parent;
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n = n->parent;
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}
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return n->parent;
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}
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static struct jrb *rprev(struct jrb *n)
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{
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if (ishead(n))
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return n;
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while (!isroot(n)) {
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if (isleft(n))
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return n->parent;
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n = n->parent;
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}
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return n->parent;
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}
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struct jrb *make_jrb(void)
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{
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struct jrb *head;
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head = (struct jrb *) malloc(sizeof(struct jrb));
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head->flink = head;
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head->blink = head;
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head->parent = head;
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head->key = NULL;
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sethead(head);
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return head;
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}
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struct jrb *jrb_find_gte(struct jrb *n, const void *key,
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int (*fxn)(const void *, const void *), int *fnd)
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{
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int cmp;
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*fnd = 0;
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if (!ishead(n)) {
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fprintf(stderr, "jrb_find_gte_str called on non-head %p\n", n);
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exit(1);
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}
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if (n->parent == n)
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return n;
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cmp = (*fxn)(key, n->blink->key);
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if (cmp == 0) {
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*fnd = 1;
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return n->blink;
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}
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if (cmp > 0)
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return n;
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else
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n = n->parent;
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while (1) {
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if (isext(n))
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return n;
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cmp = (*fxn)(key, getlext(n)->key);
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if (cmp == 0) {
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*fnd = 1;
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return getlext(n);
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}
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if (cmp < 0)
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n = n->flink;
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else
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n = n->blink;
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}
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}
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struct jrb *jrb_find(struct jrb *n, const void *key,
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int (*fxn)(const void *a, const void *b))
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{
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int fnd;
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struct jrb *j;
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j = jrb_find_gte(n, key, fxn, &fnd);
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if (fnd)
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return j;
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else
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return NULL;
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}
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static struct jrb *jrb_insert_b(struct jrb *n, void *key, void *val)
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{
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struct jrb *newleft, *newright, *newnode, *p;
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if (ishead(n)) {
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if (n->parent == n) { /* Tree is empty */
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newnode = mk_new_ext(key, val);
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insert(newnode, n);
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n->parent = newnode;
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newnode->parent = n;
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setroot(newnode);
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return newnode;
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} else {
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newright = mk_new_ext(key, val);
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insert(newright, n);
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newleft = newright->blink;
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setnormal(newleft);
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mk_new_int(newleft, newright, newleft->parent,
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isleft(newleft));
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p = rprev(newright);
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if (!ishead(p))
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setlext(p, newright);
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return newright;
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}
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} else {
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newleft = mk_new_ext(key, val);
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insert(newleft, n);
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setnormal(n);
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mk_new_int(newleft, n, n->parent, isleft(n));
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p = lprev(newleft);
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if (!ishead(p))
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setrext(p, newleft);
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return newleft;
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}
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}
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void jrb_delete_node(struct jrb *n)
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{
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struct jrb *s, *p, *gp, *x, *z;
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char ir, il;
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if (isint(n)) {
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fprintf(stderr, "Cannot delete an internal node: %p\n", n);
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exit(1);
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}
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if (ishead(n)) {
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fprintf(stderr,
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"Cannot delete the head of an jrb_tree: %p\n", n);
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exit(1);
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}
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delete_item(n); /* Delete it from the list */
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p = n->parent; /* The only node */
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if (isroot(n)) {
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p->parent = p;
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free(n);
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return;
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}
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s = sibling(n); /* The only node after deletion */
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if (isroot(p)) {
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s->parent = p->parent;
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s->parent->parent = s;
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setroot(s);
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free(p);
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free(n);
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return;
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}
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gp = p->parent; /* Set parent to sibling */
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s->parent = gp;
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if (isleft(p)) {
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gp->flink = s;
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setleft(s);
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} else {
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gp->blink = s;
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setright(s);
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}
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ir = isred(p);
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free(p);
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free(n);
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if (isext(s)) { /* Update proper rext and lext values */
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p = lprev(s);
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if (!ishead(p))
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setrext(p, s);
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p = rprev(s);
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if (!ishead(p))
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setlext(p, s);
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} else if (isblack(s)) {
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fprintf(stderr, "DELETION PROB -- sib is black, internal\n");
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exit(1);
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} else {
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p = lprev(s);
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if (!ishead(p))
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setrext(p, s->flink);
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p = rprev(s);
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if (!ishead(p))
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setlext(p, s->blink);
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setblack(s);
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return;
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}
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if (ir)
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return;
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/* Recolor */
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n = s;
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p = n->parent;
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s = sibling(n);
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while (isblack(p) && isblack(s) && isint(s) &&
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isblack(s->flink) && isblack(s->blink)) {
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setred(s);
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n = p;
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if (isroot(n))
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return;
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p = n->parent;
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s = sibling(n);
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}
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if (isblack(p) && isred(s)) { /* Rotation 2.3b */
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single_rotate(p, isright(n));
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setred(p);
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setblack(s);
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s = sibling(n);
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}
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if (isext(s)) {
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fprintf(stderr, "DELETION ERROR: sibling not internal\n");
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exit(1);
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}
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il = isleft(n);
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x = il ? s->flink : s->blink;
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z = sibling(x);
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if (isred(z)) { /* Rotation 2.3f */
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single_rotate(p, !il);
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setblack(z);
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if (isred(p))
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setred(s);
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else
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setblack(s);
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setblack(p);
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return;
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}
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if (isblack(x)) { /* Recoloring only (2.3c) */
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if (isred(s) || isblack(p)) {
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fprintf(stderr,
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"DELETION ERROR: 2.3c not quite right\n");
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exit(1);
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}
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setblack(p);
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setred(s);
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return;
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}
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if (isred(p)) { /* 2.3d */
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single_rotate(s, il);
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single_rotate(p, !il);
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setblack(x);
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setred(s);
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return;
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}
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/* 2.3e */
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single_rotate(s, il);
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single_rotate(p, !il);
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setblack(x);
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}
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int jrb_nblack(struct jrb *n)
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{
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int nb;
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if (ishead(n) || isint(n)) {
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fprintf(stderr,
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"ERROR: jrb_nblack called on a non-external node %p\n", n);
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exit(1);
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}
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nb = 0;
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while (!ishead(n)) {
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if (isblack(n)) nb++;
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n = n->parent;
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}
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return nb;
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}
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int jrb_plength(struct jrb *n)
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{
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int pl;
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if (ishead(n) || isint(n)) {
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fprintf(stderr,
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"ERROR: jrb_plength called on a non-external node %p\n", n);
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exit(1);
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}
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pl = 0;
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while (!ishead(n)) {
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pl++;
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n = n->parent;
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}
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return pl;
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}
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void jrb_free_tree(struct jrb *n)
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{
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if (!ishead(n)) {
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fprintf(stderr,
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"ERROR: Rb_free_tree called on a non-head node\n");
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exit(1);
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}
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while (jrb_first(n) != jrb_nil(n))
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jrb_delete_node(jrb_first(n));
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free(n);
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}
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void *jrb_val(struct jrb *n)
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{
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return n->val;
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}
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struct jrb *jrb_insert(struct jrb *tree, void *key, void *val,
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int (*func)(const void *a, const void *b))
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{
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int fnd;
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return jrb_insert_b(jrb_find_gte(tree, key, func, &fnd), key, val);
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}
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struct jrb *jrb_find_or_insert(struct jrb *tree, void *key, void *val,
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int (*func)(const void *a, const void *b))
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{
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struct jrb *n;
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int fnd;
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n = jrb_find_gte(tree, key, func, &fnd);
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return fnd ? n : jrb_insert_b(n, key, val);
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}
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