1 /*********************************************************************** 2 * * 3 * This software is part of the ast package * 4 * Copyright (c) 1985-2007 AT&T Knowledge Ventures * 5 * and is licensed under the * 6 * Common Public License, Version 1.0 * 7 * by AT&T Knowledge Ventures * 8 * * 9 * A copy of the License is available at * 10 * http://www.opensource.org/licenses/cpl1.0.txt * 11 * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * 12 * * 13 * Information and Software Systems Research * 14 * AT&T Research * 15 * Florham Park NJ * 16 * * 17 * Glenn Fowler <gsf@research.att.com> * 18 * David Korn <dgk@research.att.com> * 19 * Phong Vo <kpv@research.att.com> * 20 * * 21 ***********************************************************************/ 22 #include "dthdr.h" 23 24 /* Change search method. 25 ** 26 ** Written by Kiem-Phong Vo (05/25/96) 27 */ 28 29 #if __STD_C 30 Dtmethod_t* dtmethod(Dt_t* dt, Dtmethod_t* meth) 31 #else 32 Dtmethod_t* dtmethod(dt, meth) 33 Dt_t* dt; 34 Dtmethod_t* meth; 35 #endif 36 { 37 reg Dtlink_t *list, *r; 38 reg Dtdisc_t* disc = dt->disc; 39 reg Dtmethod_t* oldmeth = dt->meth; 40 41 if(!meth || meth->type == oldmeth->type) 42 return oldmeth; 43 44 if(disc->eventf && 45 (*disc->eventf)(dt,DT_METH,(Void_t*)meth,disc) < 0) 46 return NIL(Dtmethod_t*); 47 48 dt->data->minp = 0; 49 50 /* get the list of elements */ 51 list = dtflatten(dt); 52 53 if(dt->data->type&(DT_LIST|DT_STACK|DT_QUEUE) ) 54 dt->data->head = NIL(Dtlink_t*); 55 else if(dt->data->type&(DT_SET|DT_BAG) ) 56 { if(dt->data->ntab > 0) 57 (*dt->memoryf)(dt,(Void_t*)dt->data->htab,0,disc); 58 dt->data->ntab = 0; 59 dt->data->htab = NIL(Dtlink_t**); 60 } 61 62 dt->data->here = NIL(Dtlink_t*); 63 dt->data->type = (dt->data->type&~(DT_METHODS|DT_FLATTEN)) | meth->type; 64 dt->meth = meth; 65 if(dt->searchf == oldmeth->searchf) 66 dt->searchf = meth->searchf; 67 68 if(meth->type&(DT_LIST|DT_STACK|DT_QUEUE) ) 69 { if(!(oldmeth->type&(DT_LIST|DT_STACK|DT_QUEUE)) ) 70 { if((r = list) ) 71 { reg Dtlink_t* t; 72 for(t = r->right; t; r = t, t = t->right ) 73 t->left = r; 74 list->left = r; 75 } 76 } 77 dt->data->head = list; 78 } 79 else if(meth->type&(DT_OSET|DT_OBAG)) 80 { dt->data->size = 0; 81 while(list) 82 { r = list->right; 83 (*meth->searchf)(dt,(Void_t*)list,DT_RENEW); 84 list = r; 85 } 86 } 87 else if(!((meth->type&DT_BAG) && (oldmeth->type&DT_SET)) ) 88 { int rehash; 89 if((meth->type&(DT_SET|DT_BAG)) && !(oldmeth->type&(DT_SET|DT_BAG))) 90 rehash = 1; 91 else rehash = 0; 92 93 dt->data->size = dt->data->loop = 0; 94 while(list) 95 { r = list->right; 96 if(rehash) 97 { reg Void_t* key = _DTOBJ(list,disc->link); 98 key = _DTKEY(key,disc->key,disc->size); 99 list->hash = _DTHSH(dt,key,disc,disc->size); 100 } 101 (void)(*meth->searchf)(dt,(Void_t*)list,DT_RENEW); 102 list = r; 103 } 104 } 105 106 return oldmeth; 107 } 108