Asterisk - The Open Source Telephony Project  21.4.1
bt_put.c
1 /*-
2  * Copyright (c) 1990, 1993, 1994
3  * The Regents of the University of California. All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Mike Olson.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  * notice, this list of conditions and the following disclaimer in the
15  * documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  * must display the following acknowledgement:
18  * This product includes software developed by the University of
19  * California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  * may be used to endorse or promote products derived from this software
22  * without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)bt_put.c 8.8 (Berkeley) 7/26/94";
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include <sys/types.h>
42 
43 #include <errno.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 
48 #include "../include/db.h"
49 #include "btree.h"
50 
51 static EPG *bt_fast __P((BTREE *, const DBT *, const DBT *, int *));
52 
53 /*
54  * __BT_PUT -- Add a btree item to the tree.
55  *
56  * Parameters:
57  * dbp: pointer to access method
58  * key: key
59  * data: data
60  * flag: R_NOOVERWRITE
61  *
62  * Returns:
63  * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the
64  * tree and R_NOOVERWRITE specified.
65  */
66 int
67 __bt_put(dbp, key, data, flags)
68  const DB *dbp;
69  DBT *key;
70  const DBT *data;
71  u_int flags;
72 {
73  BTREE *t;
74  DBT tkey, tdata;
75  EPG *e = 0;
76  PAGE *h;
77  indx_t idx, nxtindex;
78  pgno_t pg;
79  u_int32_t nbytes;
80  int dflags, exact, status;
81  char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
82 
83  t = dbp->internal;
84 
85  /* Toss any page pinned across calls. */
86  if (t->bt_pinned != NULL) {
87  mpool_put(t->bt_mp, t->bt_pinned, 0);
88  t->bt_pinned = NULL;
89  }
90 
91  /* Check for change to a read-only tree. */
92  if (F_ISSET(t, B_RDONLY)) {
93  errno = EPERM;
94  return (RET_ERROR);
95  }
96 
97  switch (flags) {
98  case 0:
99  case R_NOOVERWRITE:
100  break;
101  case R_CURSOR:
102  /*
103  * If flags is R_CURSOR, put the cursor. Must already
104  * have started a scan and not have already deleted it.
105  */
106  if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
107  !F_ISSET(&t->bt_cursor,
108  CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
109  break;
110  /* FALLTHROUGH */
111  default:
112  errno = EINVAL;
113  return (RET_ERROR);
114  }
115 
116  /*
117  * If the key/data pair won't fit on a page, store it on overflow
118  * pages. Only put the key on the overflow page if the pair are
119  * still too big after moving the data to an overflow page.
120  *
121  * XXX
122  * If the insert fails later on, the overflow pages aren't recovered.
123  */
124  dflags = 0;
125  if (key->size + data->size > t->bt_ovflsize) {
126  if (key->size > t->bt_ovflsize) {
127 storekey: if (__ovfl_put(t, key, &pg) == RET_ERROR)
128  return (RET_ERROR);
129  tkey.data = kb;
130  tkey.size = NOVFLSIZE;
131  memmove(kb, &pg, sizeof(pgno_t));
132  memmove(kb + sizeof(pgno_t),
133  &key->size, sizeof(u_int32_t));
134  dflags |= P_BIGKEY;
135  key = &tkey;
136  }
137  if (key->size + data->size > t->bt_ovflsize) {
138  if (__ovfl_put(t, data, &pg) == RET_ERROR)
139  return (RET_ERROR);
140  tdata.data = db;
141  tdata.size = NOVFLSIZE;
142  memmove(db, &pg, sizeof(pgno_t));
143  memmove(db + sizeof(pgno_t),
144  &data->size, sizeof(u_int32_t));
145  dflags |= P_BIGDATA;
146  data = &tdata;
147  }
148  if (key->size + data->size > t->bt_ovflsize)
149  goto storekey;
150  }
151 
152  /* Replace the cursor. */
153  if (flags == R_CURSOR) {
154  if ((h = mpool_get(t->bt_mp, t->bt_cursor.pg.pgno, 0)) == NULL)
155  return (RET_ERROR);
156  idx = t->bt_cursor.pg.index;
157  goto delete;
158  }
159 
160  /*
161  * Find the key to delete, or, the location at which to insert.
162  * Bt_fast and __bt_search both pin the returned page.
163  */
164  if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
165  if ((e = __bt_search(t, key, &exact)) == NULL)
166  return (RET_ERROR);
167  h = e->page;
168  idx = e->index;
169 
170  /*
171  * Add the key/data pair to the tree. If an identical key is already
172  * in the tree, and R_NOOVERWRITE is set, an error is returned. If
173  * R_NOOVERWRITE is not set, the key is either added (if duplicates are
174  * permitted) or an error is returned.
175  */
176  switch (flags) {
177  case R_NOOVERWRITE:
178  if (!exact)
179  break;
180  mpool_put(t->bt_mp, h, 0);
181  return (RET_SPECIAL);
182  default:
183  if (!exact || !F_ISSET(t, B_NODUPS))
184  break;
185  /*
186  * !!!
187  * Note, the delete may empty the page, so we need to put a
188  * new entry into the page immediately.
189  */
190 delete: if (__bt_dleaf(t, key, h, idx) == RET_ERROR) {
191  mpool_put(t->bt_mp, h, 0);
192  return (RET_ERROR);
193  }
194  break;
195  }
196 
197  /*
198  * If not enough room, or the user has put a ceiling on the number of
199  * keys permitted in the page, split the page. The split code will
200  * insert the key and data and unpin the current page. If inserting
201  * into the offset array, shift the pointers up.
202  */
203  nbytes = NBLEAFDBT(key->size, data->size);
204  if ((u_int32_t) (h->upper - h->lower) < nbytes + sizeof(indx_t)) {
205  if ((status = __bt_split(t, h, key,
206  data, dflags, nbytes, idx)) != RET_SUCCESS)
207  return (status);
208  goto success;
209  }
210 
211  if (idx < (nxtindex = NEXTINDEX(h)))
212  memmove(h->linp + idx + 1, h->linp + idx,
213  (nxtindex - idx) * sizeof(indx_t));
214  h->lower += sizeof(indx_t);
215 
216  h->linp[idx] = h->upper -= nbytes;
217  dest = (char *)h + h->upper;
218  WR_BLEAF(dest, key, data, dflags);
219 
220  /* If the cursor is on this page, adjust it as necessary. */
221  if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
222  !F_ISSET(&t->bt_cursor, CURS_ACQUIRE) &&
223  t->bt_cursor.pg.pgno == h->pgno && t->bt_cursor.pg.index >= idx)
224  ++t->bt_cursor.pg.index;
225 
226  if (t->bt_order == NOT) {
227  if (h->nextpg == P_INVALID) {
228  if (idx == NEXTINDEX(h) - 1) {
229  t->bt_order = FORWARD;
230  t->bt_last.index = idx;
231  t->bt_last.pgno = h->pgno;
232  }
233  } else if (h->prevpg == P_INVALID) {
234  if (idx == 0) {
235  t->bt_order = BACK;
236  t->bt_last.index = 0;
237  t->bt_last.pgno = h->pgno;
238  }
239  }
240  }
241 
242  mpool_put(t->bt_mp, h, MPOOL_DIRTY);
243 
244 success:
245  if (flags == R_SETCURSOR)
246  __bt_setcur(t, e->page->pgno, e->index);
247 
248  F_SET(t, B_MODIFIED);
249  return (RET_SUCCESS);
250 }
251 
252 #ifdef STATISTICS
253 u_long bt_cache_hit, bt_cache_miss;
254 #endif
255 
256 /*
257  * BT_FAST -- Do a quick check for sorted data.
258  *
259  * Parameters:
260  * t: tree
261  * key: key to insert
262  *
263  * Returns:
264  * EPG for new record or NULL if not found.
265  */
266 static EPG *
267 bt_fast(t, key, data, exactp)
268  BTREE *t;
269  const DBT *key, *data;
270  int *exactp;
271 {
272  PAGE *h;
273  u_int32_t nbytes;
274  int cmp;
275 
276  if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
277  t->bt_order = NOT;
278  return (NULL);
279  }
280  t->bt_cur.page = h;
281  t->bt_cur.index = t->bt_last.index;
282 
283  /*
284  * If won't fit in this page or have too many keys in this page,
285  * have to search to get split stack.
286  */
287  nbytes = NBLEAFDBT(key->size, data->size);
288  if ((u_int32_t) (h->upper - h->lower) < nbytes + sizeof(indx_t))
289  goto miss;
290 
291  if (t->bt_order == FORWARD) {
292  if (t->bt_cur.page->nextpg != P_INVALID)
293  goto miss;
294  if (t->bt_cur.index != NEXTINDEX(h) - 1)
295  goto miss;
296  if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
297  goto miss;
298  t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
299  } else {
300  if (t->bt_cur.page->prevpg != P_INVALID)
301  goto miss;
302  if (t->bt_cur.index != 0)
303  goto miss;
304  if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
305  goto miss;
306  t->bt_last.index = 0;
307  }
308  *exactp = cmp == 0;
309 #ifdef STATISTICS
310  ++bt_cache_hit;
311 #endif
312  return (&t->bt_cur);
313 
314 miss:
315 #ifdef STATISTICS
316  ++bt_cache_miss;
317 #endif
318  t->bt_order = NOT;
319  mpool_put(t->bt_mp, h, 0);
320  return (NULL);
321 }
Definition: btree.h:75
Definition: btree.h:254
Definition: db.h:85
Definition: btree.h:312
Definition: db.h:129