Asterisk - The Open Source Telephony Project  GIT-master-09303e8
rec_search.c
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1 /*-
2  * Copyright (c) 1990, 1993
3  * The Regents of the University of California. All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  * notice, this list of conditions and the following disclaimer in the
12  * documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  * must display the following acknowledgement:
15  * This product includes software developed by the University of
16  * California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  * may be used to endorse or promote products derived from this software
19  * without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)rec_search.c 8.4 (Berkeley) 7/14/94";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <sys/types.h>
39 
40 #include <errno.h>
41 #include <stdio.h>
42 
43 #include "../include/db.h"
44 #include "recno.h"
45 
46 /*
47  * __REC_SEARCH -- Search a btree for a key.
48  *
49  * Parameters:
50  * t: tree to search
51  * recno: key to find
52  * op: search operation
53  *
54  * Returns:
55  * EPG for matching record, if any, or the EPG for the location of the
56  * key, if it were inserted into the tree.
57  *
58  * Returns:
59  * The EPG for matching record, if any, or the EPG for the location
60  * of the key, if it were inserted into the tree, is entered into
61  * the bt_cur field of the tree. A pointer to the field is returned.
62  */
63 EPG *
64 __rec_search(t, recno, op)
65  BTREE *t;
66  recno_t recno;
67  enum SRCHOP op;
68 {
69  register indx_t index;
70  register PAGE *h;
71  EPGNO *parent;
72  RINTERNAL *r;
73  pgno_t pg;
74  indx_t top;
75  recno_t total;
76  int sverrno;
77 
78  BT_CLR(t);
79  for (pg = P_ROOT, total = 0;;) {
80  if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
81  goto err;
82  if (h->flags & P_RLEAF) {
83  t->bt_cur.page = h;
84  t->bt_cur.index = recno - total;
85  return (&t->bt_cur);
86  }
87  for (index = 0, top = NEXTINDEX(h);;) {
88  r = GETRINTERNAL(h, index);
89  if (++index == top || total + r->nrecs > recno)
90  break;
91  total += r->nrecs;
92  }
93 
94  BT_PUSH(t, pg, index - 1);
95 
96  pg = r->pgno;
97  switch (op) {
98  case SDELETE:
99  --GETRINTERNAL(h, (index - 1))->nrecs;
100  mpool_put(t->bt_mp, h, MPOOL_DIRTY);
101  break;
102  case SINSERT:
103  ++GETRINTERNAL(h, (index - 1))->nrecs;
104  mpool_put(t->bt_mp, h, MPOOL_DIRTY);
105  break;
106  case SEARCH:
107  mpool_put(t->bt_mp, h, 0);
108  break;
109  }
110 
111  }
112  /* Try and recover the tree. */
113 err: sverrno = errno;
114  if (op != SEARCH)
115  while ((parent = BT_POP(t)) != NULL) {
116  if ((h = mpool_get(t->bt_mp, parent->pgno, 0)) == NULL)
117  break;
118  if (op == SINSERT)
119  --GETRINTERNAL(h, parent->index)->nrecs;
120  else
121  ++GETRINTERNAL(h, parent->index)->nrecs;
122  mpool_put(t->bt_mp, h, MPOOL_DIRTY);
123  }
124  errno = sverrno;
125  return (NULL);
126 }
Definition: btree.h:75
#define NEXTINDEX(p)
Definition: btree.h:98
recno_t nrecs
Definition: btree.h:160
#define BT_PUSH(t, p, i)
Definition: btree.h:322
Definition: recno.h:36
EPG bt_cur
Definition: btree.h:317
int mpool_put(MPOOL *mp, void *page, u_int flags)
Definition: mpool.c:251
Definition: btree.h:254
indx_t index
Definition: btree.h:251
#define BT_POP(t)
Definition: btree.h:327
#define NULL
Definition: resample.c:96
u_int16_t indx_t
Definition: db.h:80
EPG * __rec_search(BTREE *t, recno_t recno, enum SRCHOP op)
Definition: rec_search.c:64
Definition: btree.h:249
#define GETRINTERNAL(pg, indx)
Definition: btree.h:165
Definition: btree.h:312
#define P_RLEAF
Definition: btree.h:84
#define MPOOL_DIRTY
Definition: mpool.h:61
SRCHOP
Definition: recno.h:36
void * mpool_get(MPOOL *mp, pgno_t pgno, u_int flags)
Definition: mpool.c:165
u_int32_t flags
Definition: btree.h:87
pgno_t pgno
Definition: btree.h:161
PAGE * page
Definition: btree.h:255
MPOOL * bt_mp
Definition: btree.h:313
u_int32_t pgno_t
Definition: db.h:78
indx_t index
Definition: btree.h:256
int errno
#define P_ROOT
Definition: btree.h:65
Definition: recno.h:36
pgno_t pgno
Definition: btree.h:250
Definition: recno.h:36
#define BT_CLR(t)
Definition: btree.h:328
static int total
Definition: res_adsi.c:968
u_int32_t recno_t
Definition: db.h:82