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 #include <sys/param.h> 36 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <string.h> 40 41 #include <db.h> 42 #include "btree.h" 43 44 /* 45 * __bt_ret -- 46 * Build return key/data pair. 47 * 48 * Parameters: 49 * t: tree 50 * e: key/data pair to be returned 51 * key: user's key structure (NULL if not to be filled in) 52 * rkey: memory area to hold key 53 * data: user's data structure (NULL if not to be filled in) 54 * rdata: memory area to hold data 55 * copy: always copy the key/data item 56 * 57 * Returns: 58 * RET_SUCCESS, RET_ERROR. 59 */ 60 int 61 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) 62 { 63 BLEAF *bl; 64 void *p; 65 66 bl = GETBLEAF(e->page, e->index); 67 68 /* 69 * We must copy big keys/data to make them contigous. Otherwise, 70 * leave the page pinned and don't copy unless the user specified 71 * concurrent access. 72 */ 73 if (key == NULL) 74 goto dataonly; 75 76 if (bl->flags & P_BIGKEY) { 77 if (__ovfl_get(t, bl->bytes, 78 &key->size, &rkey->data, &rkey->size)) 79 return (RET_ERROR); 80 key->data = rkey->data; 81 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 82 if (bl->ksize > rkey->size) { 83 p = realloc(rkey->data, bl->ksize); 84 if (p == NULL) 85 return (RET_ERROR); 86 rkey->data = p; 87 rkey->size = bl->ksize; 88 } 89 memmove(rkey->data, bl->bytes, bl->ksize); 90 key->size = bl->ksize; 91 key->data = rkey->data; 92 } else { 93 key->size = bl->ksize; 94 key->data = bl->bytes; 95 } 96 97 dataonly: 98 if (data == NULL) 99 return (RET_SUCCESS); 100 101 if (bl->flags & P_BIGDATA) { 102 if (__ovfl_get(t, bl->bytes + bl->ksize, 103 &data->size, &rdata->data, &rdata->size)) 104 return (RET_ERROR); 105 data->data = rdata->data; 106 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 107 /* Use +1 in case the first record retrieved is 0 length. */ 108 if (bl->dsize + 1 > rdata->size) { 109 p = realloc(rdata->data, bl->dsize + 1); 110 if (p == NULL) 111 return (RET_ERROR); 112 rdata->data = p; 113 rdata->size = bl->dsize + 1; 114 } 115 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 116 data->size = bl->dsize; 117 data->data = rdata->data; 118 } else { 119 data->size = bl->dsize; 120 data->data = bl->bytes + bl->ksize; 121 } 122 123 return (RET_SUCCESS); 124 } 125 126 /* 127 * __BT_CMP -- Compare a key to a given record. 128 * 129 * Parameters: 130 * t: tree 131 * k1: DBT pointer of first arg to comparison 132 * e: pointer to EPG for comparison 133 * 134 * Returns: 135 * < 0 if k1 is < record 136 * = 0 if k1 is = record 137 * > 0 if k1 is > record 138 */ 139 int 140 __bt_cmp(BTREE *t, const DBT *k1, EPG *e) 141 { 142 BINTERNAL *bi; 143 BLEAF *bl; 144 DBT k2; 145 PAGE *h; 146 void *bigkey; 147 148 /* 149 * The left-most key on internal pages, at any level of the tree, is 150 * guaranteed by the following code to be less than any user key. 151 * This saves us from having to update the leftmost key on an internal 152 * page when the user inserts a new key in the tree smaller than 153 * anything we've yet seen. 154 */ 155 h = e->page; 156 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 157 return (1); 158 159 bigkey = NULL; 160 if (h->flags & P_BLEAF) { 161 bl = GETBLEAF(h, e->index); 162 if (bl->flags & P_BIGKEY) 163 bigkey = bl->bytes; 164 else { 165 k2.data = bl->bytes; 166 k2.size = bl->ksize; 167 } 168 } else { 169 bi = GETBINTERNAL(h, e->index); 170 if (bi->flags & P_BIGKEY) 171 bigkey = bi->bytes; 172 else { 173 k2.data = bi->bytes; 174 k2.size = bi->ksize; 175 } 176 } 177 178 if (bigkey) { 179 if (__ovfl_get(t, bigkey, 180 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 181 return (RET_ERROR); 182 k2.data = t->bt_rdata.data; 183 } 184 return ((*t->bt_cmp)(k1, &k2)); 185 } 186 187 /* 188 * __BT_DEFCMP -- Default comparison routine. 189 * 190 * Parameters: 191 * a: DBT #1 192 * b: DBT #2 193 * 194 * Returns: 195 * < 0 if a is < b 196 * = 0 if a is = b 197 * > 0 if a is > b 198 */ 199 int 200 __bt_defcmp(const DBT *a, const DBT *b) 201 { 202 size_t len; 203 u_char *p1, *p2; 204 205 /* 206 * XXX 207 * If a size_t doesn't fit in an int, this routine can lose. 208 * What we need is an integral type which is guaranteed to be 209 * larger than a size_t, and there is no such thing. 210 */ 211 len = MIN(a->size, b->size); 212 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 213 if (*p1 != *p2) 214 return ((int)*p1 - (int)*p2); 215 return ((int)a->size - (int)b->size); 216 } 217 218 /* 219 * __BT_DEFPFX -- Default prefix routine. 220 * 221 * Parameters: 222 * a: DBT #1 223 * b: DBT #2 224 * 225 * Returns: 226 * Number of bytes needed to distinguish b from a. 227 */ 228 size_t 229 __bt_defpfx(const DBT *a, const DBT *b) 230 { 231 u_char *p1, *p2; 232 size_t cnt, len; 233 234 cnt = 1; 235 len = MIN(a->size, b->size); 236 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 237 if (*p1 != *p2) 238 return (cnt); 239 240 /* a->size must be <= b->size, or they wouldn't be in this order. */ 241 return (a->size < b->size ? a->size + 1 : a->size); 242 } 243