1 /* $NetBSD: bt_utils.c,v 1.13 2008/09/10 17:52:35 joerg 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 #ifndef __minix 41 __RCSID("$NetBSD: bt_utils.c,v 1.13 2008/09/10 17:52:35 joerg Exp $"); 42 #endif 43 44 #include <sys/param.h> 45 46 #include <assert.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 51 #include <db.h> 52 #include "btree.h" 53 54 /* 55 * __bt_ret -- 56 * Build return key/data pair. 57 * 58 * Parameters: 59 * t: tree 60 * e: key/data pair to be returned 61 * key: user's key structure (NULL if not to be filled in) 62 * rkey: memory area to hold key 63 * data: user's data structure (NULL if not to be filled in) 64 * rdata: memory area to hold data 65 * copy: always copy the key/data item 66 * 67 * Returns: 68 * RET_SUCCESS, RET_ERROR. 69 */ 70 int 71 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) 72 { 73 BLEAF *bl; 74 void *p; 75 76 bl = GETBLEAF(e->page, e->index); 77 78 /* 79 * We must copy big keys/data to make them contigous. Otherwise, 80 * leave the page pinned and don't copy unless the user specified 81 * concurrent access. 82 */ 83 if (key == NULL) 84 goto dataonly; 85 86 if (bl->flags & P_BIGKEY) { 87 if (__ovfl_get(t, bl->bytes, 88 &key->size, &rkey->data, &rkey->size)) 89 return (RET_ERROR); 90 key->data = rkey->data; 91 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 92 if (bl->ksize > rkey->size) { 93 p = (void *)(rkey->data == NULL ? 94 malloc(bl->ksize) : realloc(rkey->data, bl->ksize)); 95 if (p == NULL) 96 return (RET_ERROR); 97 rkey->data = p; 98 rkey->size = bl->ksize; 99 } 100 memmove(rkey->data, bl->bytes, bl->ksize); 101 key->size = bl->ksize; 102 key->data = rkey->data; 103 } else { 104 key->size = bl->ksize; 105 key->data = bl->bytes; 106 } 107 108 dataonly: 109 if (data == NULL) 110 return (RET_SUCCESS); 111 112 if (bl->flags & P_BIGDATA) { 113 if (__ovfl_get(t, bl->bytes + bl->ksize, 114 &data->size, &rdata->data, &rdata->size)) 115 return (RET_ERROR); 116 data->data = rdata->data; 117 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 118 /* Use +1 in case the first record retrieved is 0 length. */ 119 if (bl->dsize + 1 > rdata->size) { 120 p = (void *)(rdata->data == NULL ? 121 malloc(bl->dsize + 1) : 122 realloc(rdata->data, bl->dsize + 1)); 123 if (p == NULL) 124 return (RET_ERROR); 125 rdata->data = p; 126 rdata->size = bl->dsize + 1; 127 } 128 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 129 data->size = bl->dsize; 130 data->data = rdata->data; 131 } else { 132 data->size = bl->dsize; 133 data->data = bl->bytes + bl->ksize; 134 } 135 136 return (RET_SUCCESS); 137 } 138 139 /* 140 * __BT_CMP -- Compare a key to a given record. 141 * 142 * Parameters: 143 * t: tree 144 * k1: DBT pointer of first arg to comparison 145 * e: pointer to EPG for comparison 146 * 147 * Returns: 148 * < 0 if k1 is < record 149 * = 0 if k1 is = record 150 * > 0 if k1 is > record 151 */ 152 int 153 __bt_cmp(BTREE *t, const DBT *k1, EPG *e) 154 { 155 BINTERNAL *bi; 156 BLEAF *bl; 157 DBT k2; 158 PAGE *h; 159 void *bigkey; 160 161 /* 162 * The left-most key on internal pages, at any level of the tree, is 163 * guaranteed by the following code to be less than any user key. 164 * This saves us from having to update the leftmost key on an internal 165 * page when the user inserts a new key in the tree smaller than 166 * anything we've yet seen. 167 */ 168 h = e->page; 169 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 170 return (1); 171 172 bigkey = NULL; 173 if (h->flags & P_BLEAF) { 174 bl = GETBLEAF(h, e->index); 175 if (bl->flags & P_BIGKEY) 176 bigkey = bl->bytes; 177 else { 178 k2.data = bl->bytes; 179 k2.size = bl->ksize; 180 } 181 } else { 182 bi = GETBINTERNAL(h, e->index); 183 if (bi->flags & P_BIGKEY) 184 bigkey = bi->bytes; 185 else { 186 k2.data = bi->bytes; 187 k2.size = bi->ksize; 188 } 189 } 190 191 if (bigkey) { 192 if (__ovfl_get(t, bigkey, 193 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 194 return (RET_ERROR); 195 k2.data = t->bt_rdata.data; 196 } 197 return ((*t->bt_cmp)(k1, &k2)); 198 } 199 200 /* 201 * __BT_DEFCMP -- Default comparison routine. 202 * 203 * Parameters: 204 * a: DBT #1 205 * b: DBT #2 206 * 207 * Returns: 208 * < 0 if a is < b 209 * = 0 if a is = b 210 * > 0 if a is > b 211 */ 212 int 213 __bt_defcmp(const DBT *a, const DBT *b) 214 { 215 size_t len; 216 uint8_t *p1, *p2; 217 218 /* 219 * XXX 220 * If a size_t doesn't fit in an int, this routine can lose. 221 * What we need is a integral type which is guaranteed to be 222 * larger than a size_t, and there is no such thing. 223 */ 224 len = MIN(a->size, b->size); 225 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 226 if (*p1 != *p2) 227 return ((int)*p1 - (int)*p2); 228 return ((int)a->size - (int)b->size); 229 } 230 231 /* 232 * __BT_DEFPFX -- Default prefix routine. 233 * 234 * Parameters: 235 * a: DBT #1 236 * b: DBT #2 237 * 238 * Returns: 239 * Number of bytes needed to distinguish b from a. 240 */ 241 size_t 242 __bt_defpfx(const DBT *a, const DBT *b) 243 { 244 uint8_t *p1, *p2; 245 size_t cnt, len; 246 247 cnt = 1; 248 len = MIN(a->size, b->size); 249 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 250 if (*p1 != *p2) 251 return (cnt); 252 253 /* a->size must be <= b->size, or they wouldn't be in this order. */ 254 return (a->size < b->size ? a->size + 1 : a->size); 255 } 256