/*      $NetBSD: ttree.c,v 1.1.1.1 2008/12/22 00:18:37 haad Exp $       */

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
*
* This file is part of the device-mapper userspace tools.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "dmlib.h"
#include "ttree.h"

struct node {
       unsigned k;
       struct node *l, *m, *r;
       void *data;
};

struct ttree {
       int klen;
       struct dm_pool *mem;
       struct node *root;
};

static struct node **_lookup_single(struct node **c, unsigned int k)
{
       while (*c) {
               if (k < (*c)->k)
                       c = &((*c)->l);

               else if (k > (*c)->k)
                       c = &((*c)->r);

               else {
                       c = &((*c)->m);
                       break;
               }
       }

       return c;
}

void *ttree_lookup(struct ttree *tt, unsigned *key)
{
       struct node **c = &tt->root;
       int count = tt->klen;

       while (*c && count) {
               c = _lookup_single(c, *key++);
               count--;
       }

       return *c ? (*c)->data : NULL;
}

static struct node *_tree_node(struct dm_pool *mem, unsigned int k)
{
       struct node *n = dm_pool_zalloc(mem, sizeof(*n));

       if (n)
               n->k = k;

       return n;
}

int ttree_insert(struct ttree *tt, unsigned int *key, void *data)
{
       struct node **c = &tt->root;
       int count = tt->klen;
       unsigned int k;

       do {
               k = *key++;
               c = _lookup_single(c, k);
               count--;

       } while (*c && count);

       if (!*c) {
               count++;

               while (count--) {
                       if (!(*c = _tree_node(tt->mem, k))) {
                               stack;
                               return 0;
                       }

                       k = *key++;

                       if (count)
                               c = &((*c)->m);
               }
       }
       (*c)->data = data;

       return 1;
}

struct ttree *ttree_create(struct dm_pool *mem, unsigned int klen)
{
       struct ttree *tt;

       if (!(tt = dm_pool_zalloc(mem, sizeof(*tt)))) {
               stack;
               return NULL;
       }

       tt->klen = klen;
       tt->mem = mem;
       return tt;
}