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