/*
Generic C code for red-black trees.
Copyright (C) 2000 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
 */

/* Revision 1.2.  Jim Plank */

/* Original code by Jim Plank (plank@cs.utk.edu) */
/* modified for THINK C 6.0 for Macintosh by Chris Bartley */
 
typedef struct {
  unsigned red : 1 ;
  unsigned internal : 1 ;
  unsigned left : 1 ;
  unsigned root : 1 ;
  unsigned head : 1 ;
} status;
 
/* Main rb_node.  You only ever use the fields

   c.list.flink
   c.list.blink

   k.key or k.ikey
   v.val
*/


typedef struct rb_node {
  union {
    struct {
      struct rb_node *flink;
      struct rb_node *blink;
    } list;
    struct {
      struct rb_node *left;
      struct rb_node *right;
    } child;
  } c;
  union {
    struct rb_node *parent;
    struct rb_node *root;
  } p;
  status s;
  union {
    int ikey;
    char *key;
    struct rb_node *lext;
  } k;
  union {
    char *val;
    struct rb_node *rext;
  } v;
} *Rb_node;


extern Rb_node make_rb();   /* Creates a new rb-tree */



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

extern Rb_node rb_insert(/* Rb_node tree, char *key, char *val */);
extern Rb_node rb_inserti(/* Rb_node tree, int ikey, char *val */);
extern Rb_node rb_insertg(/* Rb_node tree, char *key, char *val,
                          int (/* *func)(char *, char *) */);


/* returns an external node in t whose value is equal
  k or whose value is the smallest value greater than k. */

extern Rb_node rb_find_key(/* Rb_node root, char *key */);
extern Rb_node rb_find_ikey(/* Rb_node root, int ikey */);
extern Rb_node rb_find_gkey(/* Rb_node root, char *key, int (*func)() */);


/* Works just like the find_key versions only it returns whether or not
   it found the key in the integer variable found */

extern Rb_node rb_find_key_n(/* Rb_node root, char *key, int *found */);
extern Rb_node rb_find_ikey_n(/* Rb_node root, int ikey, int *found */);
extern Rb_node rb_find_gkey_n(/* Rb_node root, char *key, int (*func)(), 
                                 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 */

extern Rb_node rb_insert_b(/* Rb_node nd, char *key, char *val */);
extern Rb_node rb_insert_a(/* Rb_node nd, char *key, char *val */);


extern void rb_delete_node(/* Rb_node node */);  /* Deletes and frees a node (but 
                                              not the key or val) */
extern void rb_free_tree(/* Rb_node root */);  /* Deletes and frees an entire tree */

extern char *rb_val(/* Rb_node node */);  /* Returns node->v.val -- this is to shut
                                       lint up */

extern int rb_nblack(/* Rb_node n */); /* returns # of black nodes in path from
                                    n to the root */
int rb_plength(/* Rb_node n */);       /* returns the # of nodes in path from
				    n to the root */
 
#define rb_first(n) (n->c.list.flink)
#define rb_last(n) (n->c.list.blink)
#define rb_next(n) (n->c.list.flink)
#define rb_prev(n) (n->c.list.blink)
#define rb_empty(t) (t->c.list.flink == t)
#ifndef rb_nil
#define rb_nil(t) (t)
#endif
 
#define rb_traverse(ptr, lst) \
  for(ptr = rb_first(lst); ptr != rb_nil(lst); ptr = rb_next(ptr))