1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1990, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Mike Olson. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)bt_utils.c 8.8 (Berkeley) 7/20/94"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 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 -- 52 * Build return key/data pair. 53 * 54 * Parameters: 55 * t: tree 56 * e: key/data pair to be returned 57 * key: user's key structure (NULL if not to be filled in) 58 * rkey: memory area to hold key 59 * data: user's data structure (NULL if not to be filled in) 60 * rdata: memory area to hold data 61 * copy: always copy the key/data item 62 * 63 * Returns: 64 * RET_SUCCESS, RET_ERROR. 65 */ 66 int 67 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) 68 { 69 BLEAF *bl; 70 void *p; 71 72 bl = GETBLEAF(e->page, e->index); 73 74 /* 75 * We must copy big keys/data to make them contigous. Otherwise, 76 * leave the page pinned and don't copy unless the user specified 77 * concurrent access. 78 */ 79 if (key == NULL) 80 goto dataonly; 81 82 if (bl->flags & P_BIGKEY) { 83 if (__ovfl_get(t, bl->bytes, 84 &key->size, &rkey->data, &rkey->size)) 85 return (RET_ERROR); 86 key->data = rkey->data; 87 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 88 if (bl->ksize > rkey->size) { 89 p = realloc(rkey->data, bl->ksize); 90 if (p == NULL) 91 return (RET_ERROR); 92 rkey->data = p; 93 rkey->size = bl->ksize; 94 } 95 memmove(rkey->data, bl->bytes, bl->ksize); 96 key->size = bl->ksize; 97 key->data = rkey->data; 98 } else { 99 key->size = bl->ksize; 100 key->data = bl->bytes; 101 } 102 103 dataonly: 104 if (data == NULL) 105 return (RET_SUCCESS); 106 107 if (bl->flags & P_BIGDATA) { 108 if (__ovfl_get(t, bl->bytes + bl->ksize, 109 &data->size, &rdata->data, &rdata->size)) 110 return (RET_ERROR); 111 data->data = rdata->data; 112 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 113 /* Use +1 in case the first record retrieved is 0 length. */ 114 if (bl->dsize + 1 > rdata->size) { 115 p = realloc(rdata->data, bl->dsize + 1); 116 if (p == NULL) 117 return (RET_ERROR); 118 rdata->data = p; 119 rdata->size = bl->dsize + 1; 120 } 121 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 122 data->size = bl->dsize; 123 data->data = rdata->data; 124 } else { 125 data->size = bl->dsize; 126 data->data = bl->bytes + bl->ksize; 127 } 128 129 return (RET_SUCCESS); 130 } 131 132 /* 133 * __BT_CMP -- Compare a key to a given record. 134 * 135 * Parameters: 136 * t: tree 137 * k1: DBT pointer of first arg to comparison 138 * e: pointer to EPG for comparison 139 * 140 * Returns: 141 * < 0 if k1 is < record 142 * = 0 if k1 is = record 143 * > 0 if k1 is > record 144 */ 145 int 146 __bt_cmp(BTREE *t, const DBT *k1, 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_rdata.data, &t->bt_rdata.size)) 187 return (RET_ERROR); 188 k2.data = t->bt_rdata.data; 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(const DBT *a, const DBT *b) 207 { 208 size_t len; 209 u_char *p1, *p2; 210 211 /* 212 * XXX 213 * If a size_t doesn't fit in an int, this routine can lose. 214 * What we need is an integral type which is guaranteed to be 215 * larger than a size_t, and there is no such thing. 216 */ 217 len = MIN(a->size, b->size); 218 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 219 if (*p1 != *p2) 220 return ((int)*p1 - (int)*p2); 221 return ((int)a->size - (int)b->size); 222 } 223 224 /* 225 * __BT_DEFPFX -- Default prefix routine. 226 * 227 * Parameters: 228 * a: DBT #1 229 * b: DBT #2 230 * 231 * Returns: 232 * Number of bytes needed to distinguish b from a. 233 */ 234 size_t 235 __bt_defpfx(const DBT *a, const DBT *b) 236 { 237 u_char *p1, *p2; 238 size_t cnt, len; 239 240 cnt = 1; 241 len = MIN(a->size, b->size); 242 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 243 if (*p1 != *p2) 244 return (cnt); 245 246 /* a->size must be <= b->size, or they wouldn't be in this order. */ 247 return (a->size < b->size ? a->size + 1 : a->size); 248 } 249