/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2010 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#include "dthdr.h"
/* Set attributes of a tree.
**
** Written by Kiem-Phong Vo (09/17/2001)
*/
#if __STD_C
static Dtlink_t* treebalance(Dtlink_t* list, int size)
#else
static Dtlink_t* treebalance(list, size)
Dtlink_t* list;
int size;
#endif
{
int n;
Dtlink_t *l, *mid;
if(size <= 2)
return list;
for(l = list, n = size/2 - 1; n > 0; n -= 1)
l = l->right;
mid = l->right; l->right = NIL(Dtlink_t*);
mid->left = treebalance(list, (n = size/2) );
mid->right = treebalance(mid->right, size - (n + 1));
return mid;
}
#if __STD_C
int dttreeset(Dt_t* dt, int minp, int balance)
#else
int dttreeset(dt, minp, balance)
Dt_t* dt;
int minp;
int balance;
#endif
{
int size;
if(dt->meth->type != DT_OSET)
return -1;
size = dtsize(dt);
if(minp < 0)
{ for(minp = 0; minp < DT_MINP; ++minp)
if((1 << minp) >= size)
break;
if(minp <= DT_MINP-4) /* use log(size) + 4 */
minp += 4;
}
if((dt->data->minp = minp + (minp%2)) > DT_MINP)
dt->data->minp = DT_MINP;
if(balance)
dt->data->here = treebalance(dtflatten(dt), size);
return 0;
}