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)
38static 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 <db.h>
49#include "btree.h"
50
51static 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 */
66int
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 = NULL;
76 PAGE *h;
77 indx_t index, 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) {
127storekey: 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 index = 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 index = 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 */
190delete: if (__bt_dleaf(t, key, h, index) == 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 (h->upper - h->lower < nbytes + sizeof(indx_t)) {
205 if ((status = __bt_split(t, h, key,
206 data, dflags, nbytes, index)) != RET_SUCCESS)
207 return (status);
208 goto success;
209 }
210
211 if (index < (nxtindex = NEXTINDEX(h)))
212 memmove(h->linp + index + 1, h->linp + index,
213 (nxtindex - index) * sizeof(indx_t));
214 h->lower += sizeof(indx_t);
215
216 h->linp[index] = 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 >= index)
224 ++t->bt_cursor.pg.index;
225
226 if (t->bt_order == NOT) {
227 if (h->nextpg == P_INVALID) {
228 if (index == NEXTINDEX(h) - 1) {
229 t->bt_order = FORWARD;
230 t->bt_last.index = index;
231 t->bt_last.pgno = h->pgno;
232 }
233 } else if (h->prevpg == P_INVALID) {
234 if (index == 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
244success:
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
253u_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 */
266static EPG *
267bt_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 (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
314miss:
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}
322