1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Mike Olson. 7 * 8 * %sccs.include.redist.c% 9 */ 10 11 #if defined(LIBC_SCCS) && !defined(lint) 12 static char sccsid[] = "@(#)bt_put.c 5.11 (Berkeley) 01/10/93"; 13 #endif /* LIBC_SCCS and not lint */ 14 15 #include <sys/types.h> 16 17 #include <db.h> 18 #include <errno.h> 19 #include <stdio.h> 20 #include <stdlib.h> 21 #include <string.h> 22 23 #include "btree.h" 24 25 static EPG *bt_fast __P((BTREE *, const DBT *, const DBT *, int *)); 26 27 /* 28 * __BT_PUT -- Add a btree item to the tree. 29 * 30 * Parameters: 31 * dbp: pointer to access method 32 * key: key 33 * data: data 34 * flag: R_NOOVERWRITE 35 * 36 * Returns: 37 * RET_ERROR, RET_SUCCESS and RET_SPECIAL if the key is already in the 38 * tree and R_NOOVERWRITE specified. 39 */ 40 int 41 __bt_put(dbp, key, data, flags) 42 const DB *dbp; 43 DBT *key; 44 const DBT *data; 45 u_int flags; 46 { 47 BTREE *t; 48 DBT tkey, tdata; 49 EPG *e; 50 PAGE *h; 51 index_t index, nxtindex; 52 pgno_t pg; 53 size_t nbytes; 54 int dflags, exact, status; 55 char *dest, db[NOVFLSIZE], kb[NOVFLSIZE]; 56 57 t = dbp->internal; 58 59 switch (flags) { 60 case R_CURSOR: 61 if (!ISSET(t, BTF_SEQINIT)) 62 goto einval; 63 if (ISSET(t, BTF_DELCRSR)) 64 goto einval; 65 break; 66 case 0: 67 case R_NOOVERWRITE: 68 break; 69 default: 70 einval: errno = EINVAL; 71 return (RET_ERROR); 72 } 73 74 if (ISSET(t, BTF_RDONLY)) { 75 errno = EPERM; 76 return (RET_ERROR); 77 } 78 79 /* 80 * If the key/data won't fit on a page, store it on indirect pages. 81 * Only store the key on the overflow page if it's too big after the 82 * data is on an overflow page. 83 * 84 * XXX 85 * If the insert fails later on, these pages aren't recovered. 86 */ 87 dflags = 0; 88 if (key->size + data->size > t->bt_ovflsize) { 89 if (key->size > t->bt_ovflsize) { 90 storekey: if (__ovfl_put(t, key, &pg) == RET_ERROR) 91 return (RET_ERROR); 92 tkey.data = kb; 93 tkey.size = NOVFLSIZE; 94 bcopy(&pg, kb, sizeof(pgno_t)); 95 bcopy(&key->size, kb + sizeof(pgno_t), sizeof(size_t)); 96 dflags |= P_BIGKEY; 97 key = &tkey; 98 } 99 if (key->size + data->size > t->bt_ovflsize) { 100 if (__ovfl_put(t, data, &pg) == RET_ERROR) 101 return (RET_ERROR); 102 tdata.data = db; 103 tdata.size = NOVFLSIZE; 104 bcopy(&pg, db, sizeof(pgno_t)); 105 bcopy(&data->size, db + sizeof(pgno_t), sizeof(size_t)); 106 dflags |= P_BIGDATA; 107 data = &tdata; 108 } 109 if (key->size + data->size > t->bt_ovflsize) 110 goto storekey; 111 } 112 113 /* Replace the cursor. */ 114 if (flags == R_CURSOR) { 115 if ((h = mpool_get(t->bt_mp, t->bt_bcursor.pgno, 0)) == NULL) 116 return (RET_ERROR); 117 index = t->bt_bcursor.index; 118 goto delete; 119 } 120 121 /* 122 * Find the key to delete, or, the location at which to insert. Bt_fast 123 * and __bt_search pin the returned page. 124 */ 125 if (t->bt_order == NOT || (e = bt_fast(t, key, data, &exact)) == NULL) 126 if ((e = __bt_search(t, key, &exact)) == NULL) 127 return (RET_ERROR); 128 h = e->page; 129 index = e->index; 130 131 /* 132 * Add the specified key/data pair to the tree. If an identical key 133 * is already in the tree, and R_NOOVERWRITE is set, an error is 134 * returned. If R_NOOVERWRITE is not set, the key is either added (if 135 * duplicates are permitted) or an error is returned. 136 * 137 * Pages are split as required. 138 */ 139 switch (flags) { 140 case R_NOOVERWRITE: 141 if (!exact) 142 break; 143 /* 144 * One special case is if the cursor references the record and 145 * it's been flagged for deletion. Then, we delete the record, 146 * leaving the cursor there -- this means that the inserted 147 * record will not be seen in a cursor scan. 148 */ 149 if (ISSET(t, BTF_DELCRSR) && t->bt_bcursor.pgno == h->pgno && 150 t->bt_bcursor.index == index) { 151 CLR(t, BTF_DELCRSR); 152 goto delete; 153 } 154 mpool_put(t->bt_mp, h, 0); 155 return (RET_SPECIAL); 156 default: 157 if (!exact || !ISSET(t, BTF_NODUPS)) 158 break; 159 delete: if (__bt_dleaf(t, h, index) == RET_ERROR) { 160 mpool_put(t->bt_mp, h, 0); 161 return (RET_ERROR); 162 } 163 break; 164 } 165 166 /* 167 * If not enough room, or the user has put a ceiling on the number of 168 * keys permitted in the page, split the page. The split code will 169 * insert the key and data and unpin the current page. If inserting 170 * into the offset array, shift the pointers up. 171 */ 172 nbytes = NBLEAFDBT(key->size, data->size); 173 if (h->upper - h->lower < nbytes + sizeof(index_t)) { 174 if ((status = __bt_split(t, h, key, 175 data, dflags, nbytes, index)) != RET_SUCCESS) 176 return (status); 177 goto success; 178 } 179 180 if (index < (nxtindex = NEXTINDEX(h))) 181 bcopy(h->linp + index, h->linp + index + 1, 182 (nxtindex - index) * sizeof(index_t)); 183 h->lower += sizeof(index_t); 184 185 h->linp[index] = h->upper -= nbytes; 186 dest = (char *)h + h->upper; 187 WR_BLEAF(dest, key, data, dflags); 188 189 if (t->bt_order == NOT) 190 if (h->nextpg == P_INVALID) { 191 if (index == NEXTINDEX(h) - 1) { 192 t->bt_order = FORWARD; 193 t->bt_last.index = index; 194 t->bt_last.pgno = h->pgno; 195 } 196 } else if (h->prevpg == P_INVALID) { 197 if (index == 0) { 198 t->bt_order = BACK; 199 t->bt_last.index = 0; 200 t->bt_last.pgno = h->pgno; 201 } 202 } 203 204 mpool_put(t->bt_mp, h, MPOOL_DIRTY); 205 206 success: 207 if (flags == R_SETCURSOR) { 208 t->bt_bcursor.pgno = e->page->pgno; 209 t->bt_bcursor.index = e->index; 210 } 211 SET(t, BTF_MODIFIED); 212 return (RET_SUCCESS); 213 } 214 215 #ifdef STATISTICS 216 u_long bt_cache_hit, bt_cache_miss; 217 #endif 218 219 /* 220 * BT_FAST -- Do a quick check for sorted data. 221 * 222 * Parameters: 223 * t: tree 224 * key: key to insert 225 * 226 * Returns: 227 * EPG for new record or NULL if not found. 228 */ 229 static EPG * 230 bt_fast(t, key, data, exactp) 231 BTREE *t; 232 const DBT *key, *data; 233 int *exactp; 234 { 235 EPG e; 236 PAGE *h; 237 size_t nbytes; 238 int cmp; 239 240 if ((h = mpool_get(t->bt_mp, t->bt_last.pgno, 0)) == NULL) { 241 t->bt_order = NOT; 242 return (NULL); 243 } 244 e.page = h; 245 e.index = t->bt_last.index; 246 247 /* 248 * If won't fit in this page or have too many keys in this page, have 249 * to search to get split stack. 250 */ 251 nbytes = NBLEAFDBT(key->size, data->size); 252 if (h->upper - h->lower < nbytes + sizeof(index_t)) 253 goto miss; 254 255 if (t->bt_order == FORWARD) { 256 if (e.page->nextpg != P_INVALID) 257 goto miss; 258 if (e.index != NEXTINDEX(h) - 1) 259 goto miss; 260 if ((cmp = __bt_cmp(t, key, &e)) < 0) 261 goto miss; 262 t->bt_last.index = cmp ? ++e.index : e.index; 263 } else { 264 if (e.page->prevpg != P_INVALID) 265 goto miss; 266 if (e.index != 0) 267 goto miss; 268 if ((cmp = __bt_cmp(t, key, &e)) > 0) 269 goto miss; 270 t->bt_last.index = 0; 271 } 272 *exactp = cmp == 0; 273 #ifdef STATISTICS 274 ++bt_cache_hit; 275 #endif 276 return (&e); 277 278 miss: 279 #ifdef STATISTICS 280 ++bt_cache_miss; 281 #endif 282 t->bt_order = NOT; 283 mpool_put(t->bt_mp, h, 0); 284 return (NULL); 285 } 286