1 /***********************************************************************
2 * *
3 * This software is part of the ast package *
4 * Copyright (c) 1985-2010 AT&T Intellectual Property *
5 * and is licensed under the *
6 * Common Public License, Version 1.0 *
7 * by AT&T Intellectual Property *
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
dtmethod(Dt_t * dt,Dtmethod_t * meth)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