wernermisc/qpkg/jrb.h

/*
Libraries for fields, doubly-linked lists and red-black trees.
Copyright (C) 2001 James S. Plank

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

---------------------------------------------------------------------------
Please see http://www.cs.utk.edu/~plank/plank/classes/cs360/360/notes/Libfdr/
for instruction on how to use this library.

Jim Plank
plank@cs.utk.edu
http://www.cs.utk.edu/~plank

Associate Professor
Department of Computer Science
University of Tennessee
203 Claxton Complex
1122 Volunteer Blvd.
Knoxville, TN 37996-3450

     865-974-4397
Fax: 865-974-4404
 */

/* Heavily edited and reformatted to K&R style 2010 by Werner Almesberger */


#ifndef	_JRB_H_
#define	_JRB_H_

/* Main jrb_node.  You only ever use the fields
   flink
   blink
   k.key or k.ikey
   v.val
*/


struct jrb {
	unsigned char red;
	unsigned char internal;
	unsigned char left;
	unsigned char roothead;  /* (bit 1 is root, bit 2 is head) */
	struct jrb *flink;
	struct jrb *blink;
	struct jrb *parent;
	void *key;
	void *val;
};


struct jrb *make_jrb(void);   /* Creates a new rb-tree */


/* Creates a node with key key and val val and inserts it into the tree.
   jrb_insert uses strcmp() as comparison funcion.  jrb_inserti uses <>=,
   jrb_insertg uses func() */

struct jrb *jrb_insert(struct jrb *tree, void *key, void *val,
    int (*func)(const void *a, const void *b));

/* If the key already exists, return the node (without altering it).
   Otherwise, insert a new node. */

struct jrb *jrb_find_or_insert(struct jrb *tree, void *key, void *val,
    int (*func)(const void *a, const void *b));

/* returns an external node in t whose value is equal k. Returns NULL if
   there is no such node in the tree */

struct jrb *jrb_find(struct jrb *root, const void *key,
    int (*func)(const void *a, const void *b));

/* returns an external node in t whose value is equal
  k or whose value is the smallest value greater than k. Sets found to
  1 if the key was found, and 0 otherwise.  */

struct jrb *jrb_find_gte(struct jrb *root, const void *key,
    int (*func)(const void *a, const void *b), int *found);


/* Creates a node with key key and val val and inserts it into the
   tree before/after node nd.  Does not check to ensure that you are
   keeping the correct order */

void jrb_delete_node(struct jrb *node);  /* Deletes and frees a node (but
                                            not the key or val) */
void jrb_free_tree(struct jrb *root);  /* Deletes and frees an entire tree */

void *jrb_val(struct jrb *node);  /* Returns node->v.val -- this is to shut
                                     lint up */

int jrb_nblack(struct jrb *n); /* returns # of black nodes in path from
                                  n to the root */
int jrb_plength(struct jrb *n); /* returns the # of nodes in path from
				   n to the root */

#define jrb_first(n) ((n)->flink)
#define jrb_last(n) ((n)->blink)
#define jrb_next(n) ((n)->flink)
#define jrb_prev(n) ((n)->blink)
#define jrb_empty(t) ((t)->flink == (t))
#ifndef jrb_nil
#define jrb_nil(t) (t)
#endif

#define jrb_traverse(ptr, lst) \
    for (ptr = jrb_first(lst); ptr != jrb_nil(lst); ptr = jrb_next(ptr))

#define jrb_rtraverse(ptr, lst) \
    for (ptr = jrb_last(lst); ptr != jrb_nil(lst); ptr = jrb_prev(ptr))

#endif