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/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2011 AT&T Intellectual Property *
* and is licensed under the *
* Eclipse Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.eclipse.org/org/documents/epl-v10.html *
* (with md5 checksum b35adb5213ca9657e911e9befb180842) *
* *
* 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"
/* Change search method.
**
** Written by Kiem-Phong Vo (05/25/96)
*/
#if __STD_C
Dtmethod_t* dtmethod(Dt_t* dt, Dtmethod_t* meth)
#else
Dtmethod_t* dtmethod(dt, meth)
Dt_t* dt;
Dtmethod_t* meth;
#endif
{
Dtlink_t *list;
Dtdisc_t *disc = dt->disc;
Dtmethod_t *oldmt = dt->meth;
Dtdata_t *newdt, *olddt = dt->data;
if(!meth || meth == oldmt)
return oldmt;
/* ask discipline if switching to new method is ok */
if(disc->eventf && (*disc->eventf)(dt,DT_METH,(Void_t*)meth,disc) < 0)
return NIL(Dtmethod_t*);
list = dtextract(dt); /* extract elements out of dictionary */
/* try to create internal structure for new method */
if(dt->searchf == oldmt->searchf) /* ie, not viewpathing */
dt->searchf = meth->searchf;
dt->meth = meth;
dt->data = NIL(Dtdata_t*);
if((*dt->meth->eventf)(dt, DT_OPEN, NIL(Void_t*)) < 0 )
newdt = NIL(Dtdata_t*);
else newdt = dt->data;
/* see what need to be done to data of the old method */
if(dt->searchf == meth->searchf)
dt->searchf = oldmt->searchf;
dt->meth = oldmt;
dt->data = olddt;
if(newdt) /* switch was successful, remove old data */
{ (void)(*dt->meth->eventf)(dt, DT_CLOSE, NIL(Void_t*));
if(dt->searchf == oldmt->searchf)
dt->searchf = meth->searchf;
dt->meth = meth;
dt->data = newdt;
dtrestore(dt, list);
return oldmt;
}
else /* switch failed, restore dictionary to previous states */
{ dtrestore(dt, list);
return NIL(Dtmethod_t*);
}
}
/* customize certain actions in a container data structure */
int dtcustomize(Dt_t* dt, int type, int action)
{
int done = 0;
if((type&DT_SHARE) &&
(!dt->meth->eventf || (*dt->meth->eventf)(dt, DT_SHARE, (Void_t*)((long)action)) >= 0) )
{ if(action <= 0 )
dt->data->type &= ~DT_SHARE;
else dt->data->type |= DT_SHARE;
done |= DT_SHARE;
}
if((type&DT_ANNOUNCE) &&
(!dt->meth->eventf || (*dt->meth->eventf)(dt, DT_ANNOUNCE, (Void_t*)((long)action)) >= 0) )
{ if(action <= 0 )
dt->data->type &= ~DT_ANNOUNCE;
else dt->data->type |= DT_ANNOUNCE;
done |= DT_ANNOUNCE;
}
if((type&DT_OPTIMIZE) &&
(!dt->meth->eventf || (*dt->meth->eventf)(dt, DT_OPTIMIZE, (Void_t*)((long)action)) >= 0) )
done |= DT_OPTIMIZE;
return done;
}
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