1 /* $NetBSD: bt_utils.c,v 1.11 2007/02/03 23:46:09 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 #if defined(LIBC_SCCS) && !defined(lint) 41 #if 0 42 static char sccsid[] = "@(#)bt_utils.c 8.8 (Berkeley) 7/20/94"; 43 #else 44 __RCSID("$NetBSD: bt_utils.c,v 1.11 2007/02/03 23:46:09 christos Exp $"); 45 #endif 46 #endif /* LIBC_SCCS and not lint */ 47 48 #include <sys/param.h> 49 50 #include <assert.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 55 #include <db.h> 56 #include "btree.h" 57 58 /* 59 * __bt_ret -- 60 * Build return key/data pair. 61 * 62 * Parameters: 63 * t: tree 64 * e: key/data pair to be returned 65 * key: user's key structure (NULL if not to be filled in) 66 * rkey: memory area to hold key 67 * data: user's data structure (NULL if not to be filled in) 68 * rdata: memory area to hold data 69 * copy: always copy the key/data item 70 * 71 * Returns: 72 * RET_SUCCESS, RET_ERROR. 73 */ 74 int 75 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) 76 { 77 BLEAF *bl; 78 void *p; 79 80 bl = GETBLEAF(e->page, e->index); 81 82 /* 83 * We must copy big keys/data to make them contigous. Otherwise, 84 * leave the page pinned and don't copy unless the user specified 85 * concurrent access. 86 */ 87 if (key == NULL) 88 goto dataonly; 89 90 if (bl->flags & P_BIGKEY) { 91 if (__ovfl_get(t, bl->bytes, 92 &key->size, &rkey->data, &rkey->size)) 93 return (RET_ERROR); 94 key->data = rkey->data; 95 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 96 if (bl->ksize > rkey->size) { 97 p = (void *)(rkey->data == NULL ? 98 malloc(bl->ksize) : realloc(rkey->data, bl->ksize)); 99 if (p == NULL) 100 return (RET_ERROR); 101 rkey->data = p; 102 rkey->size = bl->ksize; 103 } 104 memmove(rkey->data, bl->bytes, bl->ksize); 105 key->size = bl->ksize; 106 key->data = rkey->data; 107 } else { 108 key->size = bl->ksize; 109 key->data = bl->bytes; 110 } 111 112 dataonly: 113 if (data == NULL) 114 return (RET_SUCCESS); 115 116 if (bl->flags & P_BIGDATA) { 117 if (__ovfl_get(t, bl->bytes + bl->ksize, 118 &data->size, &rdata->data, &rdata->size)) 119 return (RET_ERROR); 120 data->data = rdata->data; 121 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 122 /* Use +1 in case the first record retrieved is 0 length. */ 123 if (bl->dsize + 1 > rdata->size) { 124 p = (void *)(rdata->data == NULL ? 125 malloc(bl->dsize + 1) : 126 realloc(rdata->data, bl->dsize + 1)); 127 if (p == NULL) 128 return (RET_ERROR); 129 rdata->data = p; 130 rdata->size = bl->dsize + 1; 131 } 132 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 133 data->size = bl->dsize; 134 data->data = rdata->data; 135 } else { 136 data->size = bl->dsize; 137 data->data = bl->bytes + bl->ksize; 138 } 139 140 return (RET_SUCCESS); 141 } 142 143 /* 144 * __BT_CMP -- Compare a key to a given record. 145 * 146 * Parameters: 147 * t: tree 148 * k1: DBT pointer of first arg to comparison 149 * e: pointer to EPG for comparison 150 * 151 * Returns: 152 * < 0 if k1 is < record 153 * = 0 if k1 is = record 154 * > 0 if k1 is > record 155 */ 156 int 157 __bt_cmp(BTREE *t, const DBT *k1, EPG *e) 158 { 159 BINTERNAL *bi; 160 BLEAF *bl; 161 DBT k2; 162 PAGE *h; 163 void *bigkey; 164 165 /* 166 * The left-most key on internal pages, at any level of the tree, is 167 * guaranteed by the following code to be less than any user key. 168 * This saves us from having to update the leftmost key on an internal 169 * page when the user inserts a new key in the tree smaller than 170 * anything we've yet seen. 171 */ 172 h = e->page; 173 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 174 return (1); 175 176 bigkey = NULL; 177 if (h->flags & P_BLEAF) { 178 bl = GETBLEAF(h, e->index); 179 if (bl->flags & P_BIGKEY) 180 bigkey = bl->bytes; 181 else { 182 k2.data = bl->bytes; 183 k2.size = bl->ksize; 184 } 185 } else { 186 bi = GETBINTERNAL(h, e->index); 187 if (bi->flags & P_BIGKEY) 188 bigkey = bi->bytes; 189 else { 190 k2.data = bi->bytes; 191 k2.size = bi->ksize; 192 } 193 } 194 195 if (bigkey) { 196 if (__ovfl_get(t, bigkey, 197 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 198 return (RET_ERROR); 199 k2.data = t->bt_rdata.data; 200 } 201 return ((*t->bt_cmp)(k1, &k2)); 202 } 203 204 /* 205 * __BT_DEFCMP -- Default comparison routine. 206 * 207 * Parameters: 208 * a: DBT #1 209 * b: DBT #2 210 * 211 * Returns: 212 * < 0 if a is < b 213 * = 0 if a is = b 214 * > 0 if a is > b 215 */ 216 int 217 __bt_defcmp(const DBT *a, const DBT *b) 218 { 219 size_t len; 220 u_char *p1, *p2; 221 222 /* 223 * XXX 224 * If a size_t doesn't fit in an int, this routine can lose. 225 * What we need is a integral type which is guaranteed to be 226 * larger than a size_t, and there is no such thing. 227 */ 228 len = MIN(a->size, b->size); 229 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 230 if (*p1 != *p2) 231 return ((int)*p1 - (int)*p2); 232 return ((int)a->size - (int)b->size); 233 } 234 235 /* 236 * __BT_DEFPFX -- Default prefix routine. 237 * 238 * Parameters: 239 * a: DBT #1 240 * b: DBT #2 241 * 242 * Returns: 243 * Number of bytes needed to distinguish b from a. 244 */ 245 size_t 246 __bt_defpfx(const DBT *a, const DBT *b) 247 { 248 u_char *p1, *p2; 249 size_t cnt, len; 250 251 cnt = 1; 252 len = MIN(a->size, b->size); 253 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 254 if (*p1 != *p2) 255 return (cnt); 256 257 /* a->size must be <= b->size, or they wouldn't be in this order. */ 258 return (a->size < b->size ? a->size + 1 : a->size); 259 } 260