dtrenew.c revision 7c2fbfb345896881c631598ee3852ce9ce33fb07
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2008 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"
/* Renew the object at the current finger.
**
** Written by Kiem-Phong Vo (5/25/96)
*/
#if __STD_C
Void_t* dtrenew(Dt_t* dt, reg Void_t* obj)
#else
Void_t* dtrenew(dt, obj)
Dt_t* dt;
reg Void_t* obj;
#endif
{
reg Void_t* key;
reg Dtlink_t *e, *t, **s;
reg Dtdisc_t* disc = dt->disc;
UNFLATTEN(dt);
if(!(e = dt->data->here) || _DTOBJ(e,disc->link) != obj)
return NIL(Void_t*);
if(dt->data->type&(DT_STACK|DT_QUEUE|DT_LIST))
return obj;
else if(dt->data->type&(DT_OSET|DT_OBAG) )
{ if(!e->right ) /* make left child the new root */
dt->data->here = e->left;
else /* make right child the new root */
{ dt->data->here = e->right;
/* merge left subtree to right subtree */
if(e->left)
{ for(t = e->right; t->left; t = t->left)
;
t->left = e->left;
}
}
}
else /*if(dt->data->type&(DT_SET|DT_BAG))*/
{ s = dt->data->htab + HINDEX(dt->data->ntab,e->hash);
if((t = *s) == e)
*s = e->right;
else
{ for(; t->right != e; t = t->right)
;
t->right = e->right;
}
key = _DTKEY(obj,disc->key,disc->size);
e->hash = _DTHSH(dt,key,disc,disc->size);
dt->data->here = NIL(Dtlink_t*);
}
dt->data->size -= 1;
return (*dt->meth->searchf)(dt,(Void_t*)e,DT_RENEW) ? obj : NIL(Void_t*);
}