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This source file includes following definitions.
- __bt_put
- bt_fast
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. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)bt_put.c 8.8 (Berkeley) 7/26/94";
35 #endif /* LIBC_SCCS and not lint */
36
37 #ifdef HAVE_CONFIG_H
38 #include <config.h>
39 #endif
40 #include <sys/types.h>
41
42 #include <errno.h>
43 #include <stdio.h>
44 #ifdef STDC_HEADERS
45 #include <stdlib.h>
46 #endif
47 #ifdef HAVE_STRING_H
48 #include <string.h>
49 #else
50 #include <strings.h>
51 #endif
52
53 #include "db.h"
54 #include "btree.h"
55
56 static EPG *bt_fast(BTREE *, const DBT *, const DBT *, int *);
57
58 /**
59 * __BT_PUT -- Add a btree item to the tree.
60 *
61 * @param dbp pointer to access method
62 * @param key key
63 * @param data data
64 * @param flags #R_NOOVERWRITE
65 *
66 * @return
67 * #RET_ERROR, #RET_SUCCESS and #RET_SPECIAL if the key is already in the
68 * tree and #R_NOOVERWRITE specified.
69 */
70 int
71 __bt_put(dbp, key, data, flags)
72 const DB *dbp;
73 DBT *key;
74 const DBT *data;
75 u_int flags;
76 {
77 BTREE *t;
78 DBT tkey, tdata;
79 EPG *e = NULL;
80 PAGE *h;
81 indx_t index, nxtindex;
82 pgno_t pg;
83 u_int32_t nbytes;
84 int dflags, exact, status;
85 char *dest, db[NOVFLSIZE], kb[NOVFLSIZE];
86
87 t = dbp->internal;
88
89 /* Toss any page pinned across calls. */
90 if (t->bt_pinned != NULL) {
91 mpool_put(t->bt_mp, t->bt_pinned, 0);
92 t->bt_pinned = NULL;
93 }
94
95 /* Check for change to a read-only tree. */
96 if (F_ISSET(t, B_RDONLY)) {
97 errno = EPERM;
98 return (RET_ERROR);
99 }
100
101 switch (flags) {
102 case 0:
103 case R_NOOVERWRITE:
104 break;
105 case R_CURSOR:
106 /*
107 * If flags is R_CURSOR, put the cursor. Must already
108 * have started a scan and not have already deleted it.
109 */
110 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
111 !F_ISSET(&t->bt_cursor,
112 CURS_ACQUIRE | CURS_AFTER | CURS_BEFORE))
113 break;
114 /* FALLTHROUGH */
115 default:
116 errno = EINVAL;
117 return (RET_ERROR);
118 }
119
120 /*
121 * If the key/data pair won't fit on a page, store it on overflow
122 * pages. Only put the key on the overflow page if the pair are
123 * still too big after moving the data to an overflow page.
124 *
125 * XXX
126 * If the insert fails later on, the overflow pages aren't recovered.
127 */
128 dflags = 0;
129 if (key->size + data->size > t->bt_ovflsize) {
130 if (key->size > t->bt_ovflsize) {
131 storekey: if (__ovfl_put(t, key, &pg) == RET_ERROR)
132 return (RET_ERROR);
133 tkey.data = kb;
134 tkey.size = NOVFLSIZE;
135 memmove(kb, &pg, sizeof(pgno_t));
136 memmove(kb + sizeof(pgno_t),
137 &key->size, sizeof(u_int32_t));
138 dflags |= P_BIGKEY;
139 key = &tkey;
140 }
141 if (key->size + data->size > t->bt_ovflsize) {
142 if (__ovfl_put(t, data, &pg) == RET_ERROR)
143 return (RET_ERROR);
144 tdata.data = db;
145 tdata.size = NOVFLSIZE;
146 memmove(db, &pg, sizeof(pgno_t));
147 memmove(db + sizeof(pgno_t),
148 &data->size, sizeof(u_int32_t));
149 dflags |= P_BIGDATA;
150 data = &tdata;
151 }
152 if (key->size + data->size > t->bt_ovflsize)
153 goto storekey;
154 }
155
156 /* Replace the cursor. */
157 if (flags == R_CURSOR) {
158 if ((h = mpool_get(t->bt_mp, t->bt_cursor.pg.pgno, 0)) == NULL)
159 return (RET_ERROR);
160 index = t->bt_cursor.pg.index;
161 goto delete;
162 }
163
164 /*
165 * Find the key to delete, or, the location at which to insert.
166 * Bt_fast and __bt_search both pin the returned page.
167 */
168 if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL)
169 if ((e = __bt_search(t, key, &exact)) == NULL)
170 return (RET_ERROR);
171 h = e->page;
172 index = e->index;
173
174 /*
175 * Add the key/data pair to the tree. If an identical key is already
176 * in the tree, and R_NOOVERWRITE is set, an error is returned. If
177 * R_NOOVERWRITE is not set, the key is either added (if duplicates are
178 * permitted) or an error is returned.
179 */
180 switch (flags) {
181 case R_NOOVERWRITE:
182 if (!exact)
183 break;
184 mpool_put(t->bt_mp, h, 0);
185 return (RET_SPECIAL);
186 default:
187 if (!exact || !F_ISSET(t, B_NODUPS))
188 break;
189 /*
190 * !!!
191 * Note, the delete may empty the page, so we need to put a
192 * new entry into the page immediately.
193 */
194 delete: if (__bt_dleaf(t, key, h, index) == RET_ERROR) {
195 mpool_put(t->bt_mp, h, 0);
196 return (RET_ERROR);
197 }
198 break;
199 }
200
201 /*
202 * If not enough room, or the user has put a ceiling on the number of
203 * keys permitted in the page, split the page. The split code will
204 * insert the key and data and unpin the current page. If inserting
205 * into the offset array, shift the pointers up.
206 */
207 nbytes = NBLEAFDBT(key->size, data->size);
208 if (h->upper - h->lower < nbytes + sizeof(indx_t)) {
209 if ((status = __bt_split(t, h, key,
210 data, dflags, nbytes, index)) != RET_SUCCESS)
211 return (status);
212 goto success;
213 }
214
215 if (index < (nxtindex = NEXTINDEX(h)))
216 memmove(h->linp + index + 1, h->linp + index,
217 (nxtindex - index) * sizeof(indx_t));
218 h->lower += sizeof(indx_t);
219
220 h->linp[index] = h->upper -= nbytes;
221 dest = (char *)h + h->upper;
222 WR_BLEAF(dest, key, data, dflags);
223
224 /* If the cursor is on this page, adjust it as necessary. */
225 if (F_ISSET(&t->bt_cursor, CURS_INIT) &&
226 !F_ISSET(&t->bt_cursor, CURS_ACQUIRE) &&
227 t->bt_cursor.pg.pgno == h->pgno && t->bt_cursor.pg.index >= index)
228 ++t->bt_cursor.pg.index;
229
230 if (t->bt_order == NOT) {
231 if (h->nextpg == P_INVALID) {
232 if (index == NEXTINDEX(h) - 1) {
233 t->bt_order = FORWARD;
234 t->bt_last.index = index;
235 t->bt_last.pgno = h->pgno;
236 }
237 } else if (h->prevpg == P_INVALID) {
238 if (index == 0) {
239 t->bt_order = BACK;
240 t->bt_last.index = 0;
241 t->bt_last.pgno = h->pgno;
242 }
243 }
244 }
245 mpool_put(t->bt_mp, h, MPOOL_DIRTY);
246
247 success:
248 if (flags == R_SETCURSOR)
249 __bt_setcur(t, e->page->pgno, e->index);
250
251 F_SET(t, B_MODIFIED);
252 return (RET_SUCCESS);
253 }
254
255 u_long bt_cache_hit, bt_cache_miss;
256
257 /**
258 * BT_FAST -- Do a quick check for sorted data.
259 *
260 * @param t tree
261 * @param key key to insert
262 * @param data
263 * @param exactp
264 *
265 * @return #EPG for new record or @CODE{NULL} if not found.
266 */
267 static EPG *
268 bt_fast(t, key, data, exactp)
269 BTREE *t;
270 const DBT *key, *data;
271 int *exactp;
272 {
273 PAGE *h;
274 u_int32_t nbytes;
275 int cmp;
276
277 if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) {
278 t->bt_order = NOT;
279 return (NULL);
280 }
281 t->bt_cur.page = h;
282 t->bt_cur.index = t->bt_last.index;
283
284 /*
285 * If won't fit in this page or have too many keys in this page,
286 * have to search to get split stack.
287 */
288 nbytes = NBLEAFDBT(key->size, data->size);
289 if (h->upper - h->lower < nbytes + sizeof(indx_t))
290 goto miss;
291
292 if (t->bt_order == FORWARD) {
293 if (t->bt_cur.page->nextpg != P_INVALID)
294 goto miss;
295 if (t->bt_cur.index != NEXTINDEX(h) - 1)
296 goto miss;
297 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0)
298 goto miss;
299 t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index;
300 } else {
301 if (t->bt_cur.page->prevpg != P_INVALID)
302 goto miss;
303 if (t->bt_cur.index != 0)
304 goto miss;
305 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0)
306 goto miss;
307 t->bt_last.index = 0;
308 }
309 *exactp = cmp == 0;
310 #ifdef STATISTICS
311 ++bt_cache_hit;
312 #endif
313 return (&t->bt_cur);
314
315 miss:
316 #ifdef STATISTICS
317 ++bt_cache_miss;
318 #endif
319 t->bt_order = NOT;
320 mpool_put(t->bt_mp, h, 0);
321 return (NULL);
322 }
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