1 /*- 2 * Copyright (c) 1990, 1993 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 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #if defined(LIBC_SCCS) && !defined(lint) 38 /* from: static char sccsid[] = "@(#)bt_utils.c 8.2 (Berkeley) 9/7/93"; */ 39 static char *rcsid = "$Id: bt_utils.c,v 1.4 1993/09/09 02:41:32 cgd Exp $"; 40 #endif /* LIBC_SCCS and not lint */ 41 42 #include <sys/param.h> 43 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 48 #include <db.h> 49 #include "btree.h" 50 51 /* 52 * __BT_RET -- Build return key/data pair as a result of search or scan. 53 * 54 * Parameters: 55 * t: tree 56 * d: LEAF to be returned to the user. 57 * key: user's key structure (NULL if not to be filled in) 58 * data: user's data structure 59 * 60 * Returns: 61 * RET_SUCCESS, RET_ERROR. 62 */ 63 int 64 __bt_ret(t, e, key, data) 65 BTREE *t; 66 EPG *e; 67 DBT *key, *data; 68 { 69 register BLEAF *bl; 70 register void *p; 71 72 bl = GETBLEAF(e->page, e->index); 73 74 /* 75 * We always copy big keys/data to make them contigous. Otherwise, 76 * we leave the page pinned and don't copy unless the user specified 77 * concurrent access. 78 */ 79 if (bl->flags & P_BIGDATA) { 80 if (__ovfl_get(t, bl->bytes + bl->ksize, 81 &data->size, &t->bt_dbuf, &t->bt_dbufsz)) 82 return (RET_ERROR); 83 data->data = t->bt_dbuf; 84 } else if (ISSET(t, B_DB_LOCK)) { 85 /* Use +1 in case the first record retrieved is 0 length. */ 86 if (bl->dsize + 1 > t->bt_dbufsz) { 87 if ((p = realloc(t->bt_dbuf, bl->dsize + 1)) == NULL) 88 return (RET_ERROR); 89 t->bt_dbuf = p; 90 t->bt_dbufsz = bl->dsize + 1; 91 } 92 memmove(t->bt_dbuf, bl->bytes + bl->ksize, bl->dsize); 93 data->size = bl->dsize; 94 data->data = t->bt_dbuf; 95 } else { 96 data->size = bl->dsize; 97 data->data = bl->bytes + bl->ksize; 98 } 99 100 if (key == NULL) 101 return (RET_SUCCESS); 102 103 if (bl->flags & P_BIGKEY) { 104 if (__ovfl_get(t, bl->bytes, 105 &key->size, &t->bt_kbuf, &t->bt_kbufsz)) 106 return (RET_ERROR); 107 key->data = t->bt_kbuf; 108 } else if (ISSET(t, B_DB_LOCK)) { 109 if (bl->ksize > t->bt_kbufsz) { 110 if ((p = realloc(t->bt_kbuf, bl->ksize)) == NULL) 111 return (RET_ERROR); 112 t->bt_kbuf = p; 113 t->bt_kbufsz = bl->ksize; 114 } 115 memmove(t->bt_kbuf, bl->bytes, bl->ksize); 116 key->size = bl->ksize; 117 key->data = t->bt_kbuf; 118 } else { 119 key->size = bl->ksize; 120 key->data = bl->bytes; 121 } 122 return (RET_SUCCESS); 123 } 124 125 /* 126 * __BT_CMP -- Compare a key to a given record. 127 * 128 * Parameters: 129 * t: tree 130 * k1: DBT pointer of first arg to comparison 131 * e: pointer to EPG for comparison 132 * 133 * Returns: 134 * < 0 if k1 is < record 135 * = 0 if k1 is = record 136 * > 0 if k1 is > record 137 */ 138 int 139 __bt_cmp(t, k1, e) 140 BTREE *t; 141 const DBT *k1; 142 EPG *e; 143 { 144 BINTERNAL *bi; 145 BLEAF *bl; 146 DBT k2; 147 PAGE *h; 148 void *bigkey; 149 150 /* 151 * The left-most key on internal pages, at any level of the tree, is 152 * guaranteed by the following code to be less than any user key. 153 * This saves us from having to update the leftmost key on an internal 154 * page when the user inserts a new key in the tree smaller than 155 * anything we've yet seen. 156 */ 157 h = e->page; 158 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 159 return (1); 160 161 bigkey = NULL; 162 if (h->flags & P_BLEAF) { 163 bl = GETBLEAF(h, e->index); 164 if (bl->flags & P_BIGKEY) 165 bigkey = bl->bytes; 166 else { 167 k2.data = bl->bytes; 168 k2.size = bl->ksize; 169 } 170 } else { 171 bi = GETBINTERNAL(h, e->index); 172 if (bi->flags & P_BIGKEY) 173 bigkey = bi->bytes; 174 else { 175 k2.data = bi->bytes; 176 k2.size = bi->ksize; 177 } 178 } 179 180 if (bigkey) { 181 if (__ovfl_get(t, bigkey, 182 &k2.size, &t->bt_dbuf, &t->bt_dbufsz)) 183 return (RET_ERROR); 184 k2.data = t->bt_dbuf; 185 } 186 return ((*t->bt_cmp)(k1, &k2)); 187 } 188 189 /* 190 * __BT_DEFCMP -- Default comparison routine. 191 * 192 * Parameters: 193 * a: DBT #1 194 * b: DBT #2 195 * 196 * Returns: 197 * < 0 if a is < b 198 * = 0 if a is = b 199 * > 0 if a is > b 200 */ 201 int 202 __bt_defcmp(a, b) 203 const DBT *a, *b; 204 { 205 register u_char *p1, *p2; 206 register int diff, len; 207 208 len = MIN(a->size, b->size); 209 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 210 if (diff = *p1 - *p2) 211 return (diff); 212 return (a->size - b->size); 213 } 214 215 /* 216 * __BT_DEFPFX -- Default prefix routine. 217 * 218 * Parameters: 219 * a: DBT #1 220 * b: DBT #2 221 * 222 * Returns: 223 * Number of bytes needed to distinguish b from a. 224 */ 225 int 226 __bt_defpfx(a, b) 227 const DBT *a, *b; 228 { 229 register u_char *p1, *p2; 230 register int len; 231 int cnt; 232 233 cnt = 1; 234 len = MIN(a->size, b->size); 235 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 236 if (*p1 != *p2) 237 return (cnt); 238 239 /* a->size must be <= b->size, or they wouldn't be in this order. */ 240 return (a->size < b->size ? a->size + 1 : a->size); 241 } 242