1 /*- 2 * Copyright (c) 1990, 1993 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 /* from: static char sccsid[] = "@(#)bt_put.c 8.3 (Berkeley) 9/16/93"; */ 39 static char *rcsid = "$Id: bt_put.c,v 1.5 1993/09/17 01:06:26 cgd Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 41 42 #include <sys/types.h> 43 44 #include <errno.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 49 #include <db.h> 50 #include "btree.h" 51 52 static EPG *bt_fast __P((BTREE *, const DBT *, const DBT *, int *)); 53 54 /* 55 * __BT_PUT -- Add a btree item to the tree. 56 * 57 * Parameters: 58 * dbp: pointer to access method 59 * key: key 60 * data: data 61 * flag: R_NOOVERWRITE 62 * 63 * Returns: 64 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the 65 * tree and R_NOOVERWRITE specified. 66 */ 67 int 68 __bt_put(dbp, key, data, flags) 69 const DB *dbp; 70 DBT *key; 71 const DBT *data; 72 u_int flags; 73 { 74 BTREE *t; 75 DBT tkey, tdata; 76 EPG *e; 77 PAGE *h; 78 indx_t index, nxtindex; 79 pgno_t pg; 80 size_t nbytes; 81 int dflags, exact, status; 82 char *dest, db[NOVFLSIZE], kb[NOVFLSIZE]; 83 84 t = dbp->internal; 85 86 /* Toss any page pinned across calls. */ 87 if (t->bt_pinned != NULL) { 88 mpool_put(t->bt_mp, t->bt_pinned, 0); 89 t->bt_pinned = NULL; 90 } 91 92 switch (flags) { 93 case R_CURSOR: 94 if (!ISSET(t, B_SEQINIT)) 95 goto einval; 96 if (ISSET(t, B_DELCRSR)) 97 goto einval; 98 break; 99 case 0: 100 case R_NOOVERWRITE: 101 break; 102 default: 103 einval: errno = EINVAL; 104 return (RET_ERROR); 105 } 106 107 if (ISSET(t, B_RDONLY)) { 108 errno = EPERM; 109 return (RET_ERROR); 110 } 111 112 /* 113 * If the key/data won't fit on a page, store it on indirect pages. 114 * Only store the key on the overflow page if it's too big after the 115 * data is on an overflow page. 116 * 117 * XXX 118 * If the insert fails later on, these pages aren't recovered. 119 */ 120 dflags = 0; 121 if (key->size + data->size > t->bt_ovflsize) { 122 if (key->size > t->bt_ovflsize) { 123 storekey: if (__ovfl_put(t, key, &pg) == RET_ERROR) 124 return (RET_ERROR); 125 tkey.data = kb; 126 tkey.size = NOVFLSIZE; 127 memmove(kb, &pg, sizeof(pgno_t)); 128 memmove(kb + sizeof(pgno_t), 129 &key->size, sizeof(size_t)); 130 dflags |= P_BIGKEY; 131 key = &tkey; 132 } 133 if (key->size + data->size > t->bt_ovflsize) { 134 if (__ovfl_put(t, data, &pg) == RET_ERROR) 135 return (RET_ERROR); 136 tdata.data = db; 137 tdata.size = NOVFLSIZE; 138 memmove(db, &pg, sizeof(pgno_t)); 139 memmove(db + sizeof(pgno_t), 140 &data->size, sizeof(size_t)); 141 dflags |= P_BIGDATA; 142 data = &tdata; 143 } 144 if (key->size + data->size > t->bt_ovflsize) 145 goto storekey; 146 } 147 148 /* Replace the cursor. */ 149 if (flags == R_CURSOR) { 150 if ((h = mpool_get(t->bt_mp, t->bt_bcursor.pgno, 0)) == NULL) 151 return (RET_ERROR); 152 index = t->bt_bcursor.index; 153 goto delete; 154 } 155 156 /* 157 * Find the key to delete, or, the location at which to insert. Bt_fast 158 * and __bt_search pin the returned page. 159 */ 160 if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL) 161 if ((e = __bt_search(t, key, &exact)) == NULL) 162 return (RET_ERROR); 163 h = e->page; 164 index = e->index; 165 166 /* 167 * Add the specified key/data pair to the tree. If an identical key 168 * is already in the tree, and R_NOOVERWRITE is set, an error is 169 * returned. If R_NOOVERWRITE is not set, the key is either added (if 170 * duplicates are permitted) or an error is returned. 171 * 172 * Pages are split as required. 173 */ 174 switch (flags) { 175 case R_NOOVERWRITE: 176 if (!exact) 177 break; 178 /* 179 * One special case is if the cursor references the record and 180 * it's been flagged for deletion. Then, we delete the record, 181 * leaving the cursor there -- this means that the inserted 182 * record will not be seen in a cursor scan. 183 */ 184 if (ISSET(t, B_DELCRSR) && t->bt_bcursor.pgno == h->pgno && 185 t->bt_bcursor.index == index) { 186 CLR(t, B_DELCRSR); 187 goto delete; 188 } 189 mpool_put(t->bt_mp, h, 0); 190 return (RET_SPECIAL); 191 default: 192 if (!exact || !ISSET(t, B_NODUPS)) 193 break; 194 delete: if (__bt_dleaf(t, 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 (t->bt_order == NOT) 225 if (h->nextpg == P_INVALID) { 226 if (index == NEXTINDEX(h) - 1) { 227 t->bt_order = FORWARD; 228 t->bt_last.index = index; 229 t->bt_last.pgno = h->pgno; 230 } 231 } else if (h->prevpg == P_INVALID) { 232 if (index == 0) { 233 t->bt_order = BACK; 234 t->bt_last.index = 0; 235 t->bt_last.pgno = h->pgno; 236 } 237 } 238 239 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 240 241 success: 242 if (flags == R_SETCURSOR) { 243 t->bt_bcursor.pgno = e->page->pgno; 244 t->bt_bcursor.index = e->index; 245 } 246 SET(t, B_MODIFIED); 247 return (RET_SUCCESS); 248 } 249 250 #ifdef STATISTICS 251 u_long bt_cache_hit, bt_cache_miss; 252 #endif 253 254 /* 255 * BT_FAST -- Do a quick check for sorted data. 256 * 257 * Parameters: 258 * t: tree 259 * key: key to insert 260 * 261 * Returns: 262 * EPG for new record or NULL if not found. 263 */ 264 static EPG * 265 bt_fast(t, key, data, exactp) 266 BTREE *t; 267 const DBT *key, *data; 268 int *exactp; 269 { 270 PAGE *h; 271 size_t nbytes; 272 int cmp; 273 274 if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) { 275 t->bt_order = NOT; 276 return (NULL); 277 } 278 t->bt_cur.page = h; 279 t->bt_cur.index = t->bt_last.index; 280 281 /* 282 * If won't fit in this page or have too many keys in this page, have 283 * to search to get split stack. 284 */ 285 nbytes = NBLEAFDBT(key->size, data->size); 286 if (h->upper - h->lower < nbytes + sizeof(indx_t)) 287 goto miss; 288 289 if (t->bt_order == FORWARD) { 290 if (t->bt_cur.page->nextpg != P_INVALID) 291 goto miss; 292 if (t->bt_cur.index != NEXTINDEX(h) - 1) 293 goto miss; 294 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) < 0) 295 goto miss; 296 t->bt_last.index = cmp ? ++t->bt_cur.index : t->bt_cur.index; 297 } else { 298 if (t->bt_cur.page->prevpg != P_INVALID) 299 goto miss; 300 if (t->bt_cur.index != 0) 301 goto miss; 302 if ((cmp = __bt_cmp(t, key, &t->bt_cur)) > 0) 303 goto miss; 304 t->bt_last.index = 0; 305 } 306 *exactp = cmp == 0; 307 #ifdef STATISTICS 308 ++bt_cache_hit; 309 #endif 310 return (&t->bt_cur); 311 312 miss: 313 #ifdef STATISTICS 314 ++bt_cache_miss; 315 #endif 316 t->bt_order = NOT; 317 mpool_put(t->bt_mp, h, 0); 318 return (NULL); 319 } 320