1 /* $OpenBSD: bt_utils.c,v 1.5 2003/05/01 20:23:40 avsm 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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #if defined(LIBC_SCCS) && !defined(lint) 40 #if 0 41 static char sccsid[] = "@(#)bt_utils.c 8.8 (Berkeley) 7/20/94"; 42 #else 43 static const char rcsid[] = "$OpenBSD: bt_utils.c,v 1.5 2003/05/01 20:23:40 avsm Exp $"; 44 #endif 45 #endif /* LIBC_SCCS and not lint */ 46 47 #include <sys/param.h> 48 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 53 #include <db.h> 54 #include "btree.h" 55 56 /* 57 * __bt_ret -- 58 * Build return key/data pair. 59 * 60 * Parameters: 61 * t: tree 62 * e: key/data pair to be returned 63 * key: user's key structure (NULL if not to be filled in) 64 * rkey: memory area to hold key 65 * data: user's data structure (NULL if not to be filled in) 66 * rdata: memory area to hold data 67 * copy: always copy the key/data item 68 * 69 * Returns: 70 * RET_SUCCESS, RET_ERROR. 71 */ 72 int 73 __bt_ret(t, e, key, rkey, data, rdata, copy) 74 BTREE *t; 75 EPG *e; 76 DBT *key, *rkey, *data, *rdata; 77 int copy; 78 { 79 BLEAF *bl; 80 void *p; 81 82 bl = GETBLEAF(e->page, e->index); 83 84 /* 85 * We must copy big keys/data to make them contigous. Otherwise, 86 * leave the page pinned and don't copy unless the user specified 87 * concurrent access. 88 */ 89 if (key == NULL) 90 goto dataonly; 91 92 if (bl->flags & P_BIGKEY) { 93 if (__ovfl_get(t, bl->bytes, 94 &key->size, &rkey->data, &rkey->size)) 95 return (RET_ERROR); 96 key->data = rkey->data; 97 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 98 if (bl->ksize > rkey->size) { 99 p = (void *)(rkey->data == NULL ? 100 malloc(bl->ksize) : realloc(rkey->data, bl->ksize)); 101 if (p == NULL) 102 return (RET_ERROR); 103 rkey->data = p; 104 rkey->size = bl->ksize; 105 } 106 memmove(rkey->data, bl->bytes, bl->ksize); 107 key->size = bl->ksize; 108 key->data = rkey->data; 109 } else { 110 key->size = bl->ksize; 111 key->data = bl->bytes; 112 } 113 114 dataonly: 115 if (data == NULL) 116 return (RET_SUCCESS); 117 118 if (bl->flags & P_BIGDATA) { 119 if (__ovfl_get(t, bl->bytes + bl->ksize, 120 &data->size, &rdata->data, &rdata->size)) 121 return (RET_ERROR); 122 data->data = rdata->data; 123 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 124 /* Use +1 in case the first record retrieved is 0 length. */ 125 if (bl->dsize + 1 > rdata->size) { 126 p = (void *)(rdata->data == NULL ? 127 malloc(bl->dsize + 1) : 128 realloc(rdata->data, bl->dsize + 1)); 129 if (p == NULL) 130 return (RET_ERROR); 131 rdata->data = p; 132 rdata->size = bl->dsize + 1; 133 } 134 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 135 data->size = bl->dsize; 136 data->data = rdata->data; 137 } else { 138 data->size = bl->dsize; 139 data->data = bl->bytes + bl->ksize; 140 } 141 142 return (RET_SUCCESS); 143 } 144 145 /* 146 * __BT_CMP -- Compare a key to a given record. 147 * 148 * Parameters: 149 * t: tree 150 * k1: DBT pointer of first arg to comparison 151 * e: pointer to EPG for comparison 152 * 153 * Returns: 154 * < 0 if k1 is < record 155 * = 0 if k1 is = record 156 * > 0 if k1 is > record 157 */ 158 int 159 __bt_cmp(t, k1, e) 160 BTREE *t; 161 const DBT *k1; 162 EPG *e; 163 { 164 BINTERNAL *bi; 165 BLEAF *bl; 166 DBT k2; 167 PAGE *h; 168 void *bigkey; 169 170 /* 171 * The left-most key on internal pages, at any level of the tree, is 172 * guaranteed by the following code to be less than any user key. 173 * This saves us from having to update the leftmost key on an internal 174 * page when the user inserts a new key in the tree smaller than 175 * anything we've yet seen. 176 */ 177 h = e->page; 178 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 179 return (1); 180 181 bigkey = NULL; 182 if (h->flags & P_BLEAF) { 183 bl = GETBLEAF(h, e->index); 184 if (bl->flags & P_BIGKEY) 185 bigkey = bl->bytes; 186 else { 187 k2.data = bl->bytes; 188 k2.size = bl->ksize; 189 } 190 } else { 191 bi = GETBINTERNAL(h, e->index); 192 if (bi->flags & P_BIGKEY) 193 bigkey = bi->bytes; 194 else { 195 k2.data = bi->bytes; 196 k2.size = bi->ksize; 197 } 198 } 199 200 if (bigkey) { 201 if (__ovfl_get(t, bigkey, 202 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 203 return (RET_ERROR); 204 k2.data = t->bt_rdata.data; 205 } 206 return ((*t->bt_cmp)(k1, &k2)); 207 } 208 209 /* 210 * __BT_DEFCMP -- Default comparison routine. 211 * 212 * Parameters: 213 * a: DBT #1 214 * b: DBT #2 215 * 216 * Returns: 217 * < 0 if a is < b 218 * = 0 if a is = b 219 * > 0 if a is > b 220 */ 221 int 222 __bt_defcmp(a, b) 223 const DBT *a, *b; 224 { 225 register size_t len; 226 register u_char *p1, *p2; 227 228 /* 229 * XXX 230 * If a size_t doesn't fit in an int, this routine can lose. 231 * What we need is a integral type which is guaranteed to be 232 * larger than a size_t, and there is no such thing. 233 */ 234 len = MIN(a->size, b->size); 235 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 236 if (*p1 != *p2) 237 return ((int)*p1 - (int)*p2); 238 return ((int)a->size - (int)b->size); 239 } 240 241 /* 242 * __BT_DEFPFX -- Default prefix routine. 243 * 244 * Parameters: 245 * a: DBT #1 246 * b: DBT #2 247 * 248 * Returns: 249 * Number of bytes needed to distinguish b from a. 250 */ 251 size_t 252 __bt_defpfx(a, b) 253 const DBT *a, *b; 254 { 255 register u_char *p1, *p2; 256 register size_t cnt, len; 257 258 cnt = 1; 259 len = MIN(a->size, b->size); 260 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 261 if (*p1 != *p2) 262 return (cnt); 263 264 /* a->size must be <= b->size, or they wouldn't be in this order. */ 265 return (a->size < b->size ? a->size + 1 : a->size); 266 } 267