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 #define MAX(a, b) ((a) > (b) ? (a) : (b)) 55 #define MIN(a, b) ((a) < (b) ? (a) : (b)) 56 57 /* 58 * __bt_ret -- 59 * Build return key/data pair. 60 * 61 * Parameters: 62 * t: tree 63 * e: key/data pair to be returned 64 * key: user's key structure (NULL if not to be filled in) 65 * rkey: memory area to hold key 66 * data: user's data structure (NULL if not to be filled in) 67 * rdata: memory area to hold data 68 * copy: always copy the key/data item 69 * 70 * Returns: 71 * RET_SUCCESS, RET_ERROR. 72 */ 73 int 74 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) 75 { 76 BLEAF *bl; 77 void *p; 78 79 bl = GETBLEAF(e->page, e->index); 80 81 /* 82 * We must copy big keys/data to make them contigous. Otherwise, 83 * leave the page pinned and don't copy unless the user specified 84 * concurrent access. 85 */ 86 if (key == NULL) 87 goto dataonly; 88 89 if (bl->flags & P_BIGKEY) { 90 if (__ovfl_get(t, bl->bytes, 91 &key->size, &rkey->data, &rkey->size)) 92 return (RET_ERROR); 93 key->data = rkey->data; 94 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 95 if (bl->ksize > rkey->size) { 96 p = (void *)(rkey->data == NULL ? 97 malloc(bl->ksize) : realloc(rkey->data, bl->ksize)); 98 if (p == NULL) 99 return (RET_ERROR); 100 rkey->data = p; 101 rkey->size = bl->ksize; 102 } 103 memmove(rkey->data, bl->bytes, bl->ksize); 104 key->size = bl->ksize; 105 key->data = rkey->data; 106 } else { 107 key->size = bl->ksize; 108 key->data = bl->bytes; 109 } 110 111 dataonly: 112 if (data == NULL) 113 return (RET_SUCCESS); 114 115 if (bl->flags & P_BIGDATA) { 116 if (__ovfl_get(t, bl->bytes + bl->ksize, 117 &data->size, &rdata->data, &rdata->size)) 118 return (RET_ERROR); 119 data->data = rdata->data; 120 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 121 /* Use +1 in case the first record retrieved is 0 length. */ 122 if (bl->dsize + 1 > rdata->size) { 123 p = (void *)(rdata->data == NULL ? 124 malloc(bl->dsize + 1) : 125 realloc(rdata->data, bl->dsize + 1)); 126 if (p == NULL) 127 return (RET_ERROR); 128 rdata->data = p; 129 rdata->size = bl->dsize + 1; 130 } 131 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 132 data->size = bl->dsize; 133 data->data = rdata->data; 134 } else { 135 data->size = bl->dsize; 136 data->data = bl->bytes + bl->ksize; 137 } 138 139 return (RET_SUCCESS); 140 } 141 142 /* 143 * __BT_CMP -- Compare a key to a given record. 144 * 145 * Parameters: 146 * t: tree 147 * k1: DBT pointer of first arg to comparison 148 * e: pointer to EPG for comparison 149 * 150 * Returns: 151 * < 0 if k1 is < record 152 * = 0 if k1 is = record 153 * > 0 if k1 is > record 154 */ 155 int 156 __bt_cmp(BTREE *t, const DBT *k1, EPG *e) 157 { 158 BINTERNAL *bi; 159 BLEAF *bl; 160 DBT k2; 161 PAGE *h; 162 void *bigkey; 163 164 /* 165 * The left-most key on internal pages, at any level of the tree, is 166 * guaranteed by the following code to be less than any user key. 167 * This saves us from having to update the leftmost key on an internal 168 * page when the user inserts a new key in the tree smaller than 169 * anything we've yet seen. 170 */ 171 h = e->page; 172 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 173 return (1); 174 175 bigkey = NULL; 176 if (h->flags & P_BLEAF) { 177 bl = GETBLEAF(h, e->index); 178 if (bl->flags & P_BIGKEY) 179 bigkey = bl->bytes; 180 else { 181 k2.data = bl->bytes; 182 k2.size = bl->ksize; 183 } 184 } else { 185 bi = GETBINTERNAL(h, e->index); 186 if (bi->flags & P_BIGKEY) 187 bigkey = bi->bytes; 188 else { 189 k2.data = bi->bytes; 190 k2.size = bi->ksize; 191 } 192 } 193 194 if (bigkey) { 195 if (__ovfl_get(t, bigkey, 196 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 197 return (RET_ERROR); 198 k2.data = t->bt_rdata.data; 199 } 200 return ((*t->bt_cmp)(k1, &k2)); 201 } 202 203 /* 204 * __BT_DEFCMP -- Default comparison routine. 205 * 206 * Parameters: 207 * a: DBT #1 208 * b: DBT #2 209 * 210 * Returns: 211 * < 0 if a is < b 212 * = 0 if a is = b 213 * > 0 if a is > b 214 */ 215 int 216 __bt_defcmp(const DBT *a, const DBT *b) 217 { 218 size_t len; 219 uint8_t *p1, *p2; 220 221 /* 222 * XXX 223 * If a size_t doesn't fit in an int, this routine can lose. 224 * What we need is a integral type which is guaranteed to be 225 * larger than a size_t, and there is no such thing. 226 */ 227 len = MIN(a->size, b->size); 228 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 229 if (*p1 != *p2) 230 return ((int)*p1 - (int)*p2); 231 return ((int)a->size - (int)b->size); 232 } 233 234 /* 235 * __BT_DEFPFX -- Default prefix routine. 236 * 237 * Parameters: 238 * a: DBT #1 239 * b: DBT #2 240 * 241 * Returns: 242 * Number of bytes needed to distinguish b from a. 243 */ 244 size_t 245 __bt_defpfx(const DBT *a, const DBT *b) 246 { 247 uint8_t *p1, *p2; 248 size_t cnt, len; 249 250 cnt = 1; 251 len = MIN(a->size, b->size); 252 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 253 if (*p1 != *p2) 254 return (cnt); 255 256 /* a->size must be <= b->size, or they wouldn't be in this order. */ 257 return (a->size < b->size ? a->size + 1 : a->size); 258 } 259