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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #if defined(LIBC_SCCS) && !defined(lint) 34 static char sccsid[] = "@(#)bt_utils.c 8.8 (Berkeley) 7/20/94"; 35 #endif /* LIBC_SCCS and not lint */ 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include <sys/param.h> 40 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 45 #include <db.h> 46 #include "btree.h" 47 48 /* 49 * __bt_ret -- 50 * Build return key/data pair. 51 * 52 * Parameters: 53 * t: tree 54 * e: key/data pair to be returned 55 * key: user's key structure (NULL if not to be filled in) 56 * rkey: memory area to hold key 57 * data: user's data structure (NULL if not to be filled in) 58 * rdata: memory area to hold data 59 * copy: always copy the key/data item 60 * 61 * Returns: 62 * RET_SUCCESS, RET_ERROR. 63 */ 64 int 65 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) 66 { 67 BLEAF *bl; 68 void *p; 69 70 bl = GETBLEAF(e->page, e->index); 71 72 /* 73 * We must copy big keys/data to make them contigous. Otherwise, 74 * leave the page pinned and don't copy unless the user specified 75 * concurrent access. 76 */ 77 if (key == NULL) 78 goto dataonly; 79 80 if (bl->flags & P_BIGKEY) { 81 if (__ovfl_get(t, bl->bytes, 82 &key->size, &rkey->data, &rkey->size)) 83 return (RET_ERROR); 84 key->data = rkey->data; 85 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 86 if (bl->ksize > rkey->size) { 87 p = (void *)(rkey->data == NULL ? 88 malloc(bl->ksize) : realloc(rkey->data, bl->ksize)); 89 if (p == NULL) 90 return (RET_ERROR); 91 rkey->data = p; 92 rkey->size = bl->ksize; 93 } 94 memmove(rkey->data, bl->bytes, bl->ksize); 95 key->size = bl->ksize; 96 key->data = rkey->data; 97 } else { 98 key->size = bl->ksize; 99 key->data = bl->bytes; 100 } 101 102 dataonly: 103 if (data == NULL) 104 return (RET_SUCCESS); 105 106 if (bl->flags & P_BIGDATA) { 107 if (__ovfl_get(t, bl->bytes + bl->ksize, 108 &data->size, &rdata->data, &rdata->size)) 109 return (RET_ERROR); 110 data->data = rdata->data; 111 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 112 /* Use +1 in case the first record retrieved is 0 length. */ 113 if (bl->dsize + 1 > rdata->size) { 114 p = (void *)(rdata->data == NULL ? 115 malloc(bl->dsize + 1) : 116 realloc(rdata->data, bl->dsize + 1)); 117 if (p == NULL) 118 return (RET_ERROR); 119 rdata->data = p; 120 rdata->size = bl->dsize + 1; 121 } 122 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 123 data->size = bl->dsize; 124 data->data = rdata->data; 125 } else { 126 data->size = bl->dsize; 127 data->data = bl->bytes + bl->ksize; 128 } 129 130 return (RET_SUCCESS); 131 } 132 133 /* 134 * __BT_CMP -- Compare a key to a given record. 135 * 136 * Parameters: 137 * t: tree 138 * k1: DBT pointer of first arg to comparison 139 * e: pointer to EPG for comparison 140 * 141 * Returns: 142 * < 0 if k1 is < record 143 * = 0 if k1 is = record 144 * > 0 if k1 is > record 145 */ 146 int 147 __bt_cmp(BTREE *t, const DBT *k1, EPG *e) 148 { 149 BINTERNAL *bi; 150 BLEAF *bl; 151 DBT k2; 152 PAGE *h; 153 void *bigkey; 154 155 /* 156 * The left-most key on internal pages, at any level of the tree, is 157 * guaranteed by the following code to be less than any user key. 158 * This saves us from having to update the leftmost key on an internal 159 * page when the user inserts a new key in the tree smaller than 160 * anything we've yet seen. 161 */ 162 h = e->page; 163 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 164 return (1); 165 166 bigkey = NULL; 167 if (h->flags & P_BLEAF) { 168 bl = GETBLEAF(h, e->index); 169 if (bl->flags & P_BIGKEY) 170 bigkey = bl->bytes; 171 else { 172 k2.data = bl->bytes; 173 k2.size = bl->ksize; 174 } 175 } else { 176 bi = GETBINTERNAL(h, e->index); 177 if (bi->flags & P_BIGKEY) 178 bigkey = bi->bytes; 179 else { 180 k2.data = bi->bytes; 181 k2.size = bi->ksize; 182 } 183 } 184 185 if (bigkey) { 186 if (__ovfl_get(t, bigkey, 187 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 188 return (RET_ERROR); 189 k2.data = t->bt_rdata.data; 190 } 191 return ((*t->bt_cmp)(k1, &k2)); 192 } 193 194 /* 195 * __BT_DEFCMP -- Default comparison routine. 196 * 197 * Parameters: 198 * a: DBT #1 199 * b: DBT #2 200 * 201 * Returns: 202 * < 0 if a is < b 203 * = 0 if a is = b 204 * > 0 if a is > b 205 */ 206 int 207 __bt_defcmp(const DBT *a, const DBT *b) 208 { 209 size_t len; 210 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 an 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(const DBT *a, const DBT *b) 237 { 238 u_char *p1, *p2; 239 size_t cnt, len; 240 241 cnt = 1; 242 len = MIN(a->size, b->size); 243 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 244 if (*p1 != *p2) 245 return (cnt); 246 247 /* a->size must be <= b->size, or they wouldn't be in this order. */ 248 return (a->size < b->size ? a->size + 1 : a->size); 249 } 250