1 /* $NetBSD: bt_utils.c,v 1.16 2013/12/14 18:04:56 christos Exp $ */ 2 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 HAVE_NBTOOL_CONFIG_H 36 #include "nbtool_config.h" 37 #endif 38 39 #include <sys/cdefs.h> 40 __RCSID("$NetBSD: bt_utils.c,v 1.16 2013/12/14 18:04:56 christos Exp $"); 41 42 #include <sys/param.h> 43 44 #include <assert.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 49 #include <db.h> 50 #include "btree.h" 51 52 /* 53 * __bt_ret -- 54 * Build return key/data pair. 55 * 56 * Parameters: 57 * t: tree 58 * e: key/data pair to be returned 59 * key: user's key structure (NULL if not to be filled in) 60 * rkey: memory area to hold key 61 * data: user's data structure (NULL if not to be filled in) 62 * rdata: memory area to hold data 63 * copy: always copy the key/data item 64 * 65 * Returns: 66 * RET_SUCCESS, RET_ERROR. 67 */ 68 int 69 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) 70 { 71 BLEAF *bl; 72 void *p; 73 74 bl = GETBLEAF(e->page, e->index); 75 76 /* 77 * We must copy big keys/data to make them contiguous. Otherwise, 78 * leave the page pinned and don't copy unless the user specified 79 * concurrent access. 80 */ 81 if (key == NULL) 82 goto dataonly; 83 84 if (bl->flags & P_BIGKEY) { 85 if (__ovfl_get(t, bl->bytes, 86 &key->size, &rkey->data, &rkey->size)) 87 return (RET_ERROR); 88 key->data = rkey->data; 89 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 90 if (bl->ksize > rkey->size) { 91 p = realloc(rkey->data, bl->ksize); 92 if (p == NULL) 93 return (RET_ERROR); 94 rkey->data = p; 95 rkey->size = bl->ksize; 96 } 97 memmove(rkey->data, bl->bytes, bl->ksize); 98 key->size = bl->ksize; 99 key->data = rkey->data; 100 } else { 101 key->size = bl->ksize; 102 key->data = bl->bytes; 103 } 104 105 dataonly: 106 if (data == NULL) 107 return (RET_SUCCESS); 108 109 if (bl->flags & P_BIGDATA) { 110 if (__ovfl_get(t, bl->bytes + bl->ksize, 111 &data->size, &rdata->data, &rdata->size)) 112 return (RET_ERROR); 113 data->data = rdata->data; 114 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 115 /* Use +1 in case the first record retrieved is 0 length. */ 116 if (bl->dsize + 1 > rdata->size) { 117 p = realloc(rdata->data, bl->dsize + 1); 118 if (p == NULL) 119 return (RET_ERROR); 120 rdata->data = p; 121 rdata->size = bl->dsize + 1; 122 } 123 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 124 data->size = bl->dsize; 125 data->data = rdata->data; 126 } else { 127 data->size = bl->dsize; 128 data->data = bl->bytes + bl->ksize; 129 } 130 131 return (RET_SUCCESS); 132 } 133 134 /* 135 * __BT_CMP -- Compare a key to a given record. 136 * 137 * Parameters: 138 * t: tree 139 * k1: DBT pointer of first arg to comparison 140 * e: pointer to EPG for comparison 141 * 142 * Returns: 143 * < 0 if k1 is < record 144 * = 0 if k1 is = record 145 * > 0 if k1 is > record 146 */ 147 int 148 __bt_cmp(BTREE *t, const DBT *k1, EPG *e) 149 { 150 BINTERNAL *bi; 151 BLEAF *bl; 152 DBT k2; 153 PAGE *h; 154 void *bigkey; 155 156 /* 157 * The left-most key on internal pages, at any level of the tree, is 158 * guaranteed by the following code to be less than any user key. 159 * This saves us from having to update the leftmost key on an internal 160 * page when the user inserts a new key in the tree smaller than 161 * anything we've yet seen. 162 */ 163 h = e->page; 164 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 165 return (1); 166 167 bigkey = NULL; 168 if (h->flags & P_BLEAF) { 169 bl = GETBLEAF(h, e->index); 170 if (bl->flags & P_BIGKEY) 171 bigkey = bl->bytes; 172 else { 173 k2.data = bl->bytes; 174 k2.size = bl->ksize; 175 } 176 } else { 177 bi = GETBINTERNAL(h, e->index); 178 if (bi->flags & P_BIGKEY) 179 bigkey = bi->bytes; 180 else { 181 k2.data = bi->bytes; 182 k2.size = bi->ksize; 183 } 184 } 185 186 if (bigkey) { 187 if (__ovfl_get(t, bigkey, 188 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 189 return (RET_ERROR); 190 k2.data = t->bt_rdata.data; 191 } 192 return ((*t->bt_cmp)(k1, &k2)); 193 } 194 195 /* 196 * __BT_DEFCMP -- Default comparison routine. 197 * 198 * Parameters: 199 * a: DBT #1 200 * b: DBT #2 201 * 202 * Returns: 203 * < 0 if a is < b 204 * = 0 if a is = b 205 * > 0 if a is > b 206 */ 207 int 208 __bt_defcmp(const DBT *a, const DBT *b) 209 { 210 size_t len; 211 uint8_t *p1, *p2; 212 213 /* 214 * XXX 215 * If a size_t doesn't fit in an int, this routine can lose. 216 * What we need is a integral type which is guaranteed to be 217 * larger than a size_t, and there is no such thing. 218 */ 219 len = MIN(a->size, b->size); 220 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 221 if (*p1 != *p2) 222 return ((int)*p1 - (int)*p2); 223 return ((int)a->size - (int)b->size); 224 } 225 226 /* 227 * __BT_DEFPFX -- Default prefix routine. 228 * 229 * Parameters: 230 * a: DBT #1 231 * b: DBT #2 232 * 233 * Returns: 234 * Number of bytes needed to distinguish b from a. 235 */ 236 size_t 237 __bt_defpfx(const DBT *a, const DBT *b) 238 { 239 uint8_t *p1, *p2; 240 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
Indexes created Sat Sep 20 22:09:52 GMT 2025