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_utils.c 8.5 (Berkeley) 6/20/94"; 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <sys/param.h> 42 43 #include <stdio.h> 44 #include <stdlib.h> 45 #include <string.h> 46 47 #include <db.h> 48 #include "btree.h" 49 50 /* 51 * __BT_RET -- Build return key/data pair as a result of search or scan. 52 * 53 * Parameters: 54 * t: tree 55 * d: LEAF to be returned to the user. 56 * key: user's key structure (NULL if not to be filled in) 57 * data: user's data structure 58 * 59 * Returns: 60 * RET_SUCCESS, RET_ERROR. 61 */ 62 int 63 __bt_ret(t, e, key, data) 64 BTREE *t; 65 EPG *e; 66 DBT *key, *data; 67 { 68 register BLEAF *bl; 69 register void *p; 70 71 bl = GETBLEAF(e->page, e->index); 72 73 /* 74 * We always copy big keys/data to make them contigous. Otherwise, 75 * we leave the page pinned and don't copy unless the user specified 76 * concurrent access. 77 */ 78 if (bl->flags & P_BIGDATA) { 79 if (__ovfl_get(t, bl->bytes + bl->ksize, 80 &data->size, &t->bt_dbuf, &t->bt_dbufsz)) 81 return (RET_ERROR); 82 data->data = t->bt_dbuf; 83 } else if (ISSET(t, B_DB_LOCK)) { 84 /* Use +1 in case the first record retrieved is 0 length. */ 85 if (bl->dsize + 1 > t->bt_dbufsz) { 86 p = (void *)(t->bt_dbuf == NULL ? 87 malloc(bl->dsize + 1) : 88 realloc(t->bt_dbuf, bl->dsize + 1)); 89 if (p == NULL) 90 return (RET_ERROR); 91 t->bt_dbuf = p; 92 t->bt_dbufsz = bl->dsize + 1; 93 } 94 memmove(t->bt_dbuf, bl->bytes + bl->ksize, bl->dsize); 95 data->size = bl->dsize; 96 data->data = t->bt_dbuf; 97 } else { 98 data->size = bl->dsize; 99 data->data = bl->bytes + bl->ksize; 100 } 101 102 if (key == NULL) 103 return (RET_SUCCESS); 104 105 if (bl->flags & P_BIGKEY) { 106 if (__ovfl_get(t, bl->bytes, 107 &key->size, &t->bt_kbuf, &t->bt_kbufsz)) 108 return (RET_ERROR); 109 key->data = t->bt_kbuf; 110 } else if (ISSET(t, B_DB_LOCK)) { 111 if (bl->ksize > t->bt_kbufsz) { 112 p = (void *)(t->bt_kbuf == NULL ? 113 malloc(bl->ksize) : realloc(t->bt_kbuf, bl->ksize)); 114 if (p == NULL) 115 return (RET_ERROR); 116 t->bt_kbuf = p; 117 t->bt_kbufsz = bl->ksize; 118 } 119 memmove(t->bt_kbuf, bl->bytes, bl->ksize); 120 key->size = bl->ksize; 121 key->data = t->bt_kbuf; 122 } else { 123 key->size = bl->ksize; 124 key->data = bl->bytes; 125 } 126 return (RET_SUCCESS); 127 } 128 129 /* 130 * __BT_CMP -- Compare a key to a given record. 131 * 132 * Parameters: 133 * t: tree 134 * k1: DBT pointer of first arg to comparison 135 * e: pointer to EPG for comparison 136 * 137 * Returns: 138 * < 0 if k1 is < record 139 * = 0 if k1 is = record 140 * > 0 if k1 is > record 141 */ 142 int 143 __bt_cmp(t, k1, e) 144 BTREE *t; 145 const DBT *k1; 146 EPG *e; 147 { 148 BINTERNAL *bi; 149 BLEAF *bl; 150 DBT k2; 151 PAGE *h; 152 void *bigkey; 153 154 /* 155 * The left-most key on internal pages, at any level of the tree, is 156 * guaranteed by the following code to be less than any user key. 157 * This saves us from having to update the leftmost key on an internal 158 * page when the user inserts a new key in the tree smaller than 159 * anything we've yet seen. 160 */ 161 h = e->page; 162 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 163 return (1); 164 165 bigkey = NULL; 166 if (h->flags & P_BLEAF) { 167 bl = GETBLEAF(h, e->index); 168 if (bl->flags & P_BIGKEY) 169 bigkey = bl->bytes; 170 else { 171 k2.data = bl->bytes; 172 k2.size = bl->ksize; 173 } 174 } else { 175 bi = GETBINTERNAL(h, e->index); 176 if (bi->flags & P_BIGKEY) 177 bigkey = bi->bytes; 178 else { 179 k2.data = bi->bytes; 180 k2.size = bi->ksize; 181 } 182 } 183 184 if (bigkey) { 185 if (__ovfl_get(t, bigkey, 186 &k2.size, &t->bt_dbuf, &t->bt_dbufsz)) 187 return (RET_ERROR); 188 k2.data = t->bt_dbuf; 189 } 190 return ((*t->bt_cmp)(k1, &k2)); 191 } 192 193 /* 194 * __BT_DEFCMP -- Default comparison routine. 195 * 196 * Parameters: 197 * a: DBT #1 198 * b: DBT #2 199 * 200 * Returns: 201 * < 0 if a is < b 202 * = 0 if a is = b 203 * > 0 if a is > b 204 */ 205 int 206 __bt_defcmp(a, b) 207 const DBT *a, *b; 208 { 209 register size_t len; 210 register u_char *p1, *p2; 211 212 /* 213 * XXX 214 * If a size_t doesn't fit in an int, this routine can lose. 215 * What we need is a integral type which is guaranteed to be 216 * larger than a size_t, and there is no such thing. 217 */ 218 len = MIN(a->size, b->size); 219 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 220 if (*p1 != *p2) 221 return ((int)*p1 - (int)*p2); 222 return ((int)a->size - (int)b->size); 223 } 224 225 /* 226 * __BT_DEFPFX -- Default prefix routine. 227 * 228 * Parameters: 229 * a: DBT #1 230 * b: DBT #2 231 * 232 * Returns: 233 * Number of bytes needed to distinguish b from a. 234 */ 235 size_t 236 __bt_defpfx(a, b) 237 const DBT *a, *b; 238 { 239 register u_char *p1, *p2; 240 register size_t cnt, len; 241 242 cnt = 1; 243 len = MIN(a->size, b->size); 244 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 245 if (*p1 != *p2) 246 return (cnt); 247 248 /* a->size must be <= b->size, or they wouldn't be in this order. */ 249 return (a->size < b->size ? a->size + 1 : a->size); 250 } 251