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 /*static char sccsid[] = "from: @(#)bt_utils.c 8.1 (Berkeley) 6/4/93";*/ 39 static char rcsid[] = "$Id: bt_utils.c,v 1.2 1993/08/01 18:43:46 mycroft 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 if (bl->flags & P_BIGDATA) { 75 if (__ovfl_get(t, bl->bytes + bl->ksize, 76 &data->size, &t->bt_dbuf, &t->bt_dbufsz)) 77 return (RET_ERROR); 78 } else { 79 /* Use +1 in case the first record retrieved is 0 length. */ 80 if (bl->dsize + 1 > t->bt_dbufsz) { 81 if ((p = realloc(t->bt_dbuf, bl->dsize + 1)) == NULL) 82 return (RET_ERROR); 83 t->bt_dbuf = p; 84 t->bt_dbufsz = bl->dsize + 1; 85 } 86 memmove(t->bt_dbuf, bl->bytes + bl->ksize, bl->dsize); 87 data->size = bl->dsize; 88 } 89 data->data = t->bt_dbuf; 90 91 if (key == NULL) 92 return (RET_SUCCESS); 93 94 if (bl->flags & P_BIGKEY) { 95 if (__ovfl_get(t, bl->bytes, 96 &key->size, &t->bt_kbuf, &t->bt_kbufsz)) 97 return (RET_ERROR); 98 } else { 99 if (bl->ksize > t->bt_kbufsz) { 100 if ((p = realloc(t->bt_kbuf, bl->ksize)) == NULL) 101 return (RET_ERROR); 102 t->bt_kbuf = p; 103 t->bt_kbufsz = bl->ksize; 104 } 105 memmove(t->bt_kbuf, bl->bytes, bl->ksize); 106 key->size = bl->ksize; 107 } 108 key->data = t->bt_kbuf; 109 return (RET_SUCCESS); 110 } 111 112 /* 113 * __BT_CMP -- Compare a key to a given record. 114 * 115 * Parameters: 116 * t: tree 117 * k1: DBT pointer of first arg to comparison 118 * e: pointer to EPG for comparison 119 * 120 * Returns: 121 * < 0 if k1 is < record 122 * = 0 if k1 is = record 123 * > 0 if k1 is > record 124 */ 125 int 126 __bt_cmp(t, k1, e) 127 BTREE *t; 128 const DBT *k1; 129 EPG *e; 130 { 131 BINTERNAL *bi; 132 BLEAF *bl; 133 DBT k2; 134 PAGE *h; 135 void *bigkey; 136 137 /* 138 * The left-most key on internal pages, at any level of the tree, is 139 * guaranteed by the following code to be less than any user key. 140 * This saves us from having to update the leftmost key on an internal 141 * page when the user inserts a new key in the tree smaller than 142 * anything we've yet seen. 143 */ 144 h = e->page; 145 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 146 return (1); 147 148 bigkey = NULL; 149 if (h->flags & P_BLEAF) { 150 bl = GETBLEAF(h, e->index); 151 if (bl->flags & P_BIGKEY) 152 bigkey = bl->bytes; 153 else { 154 k2.data = bl->bytes; 155 k2.size = bl->ksize; 156 } 157 } else { 158 bi = GETBINTERNAL(h, e->index); 159 if (bi->flags & P_BIGKEY) 160 bigkey = bi->bytes; 161 else { 162 k2.data = bi->bytes; 163 k2.size = bi->ksize; 164 } 165 } 166 167 if (bigkey) { 168 if (__ovfl_get(t, bigkey, 169 &k2.size, &t->bt_dbuf, &t->bt_dbufsz)) 170 return (RET_ERROR); 171 k2.data = t->bt_dbuf; 172 } 173 return ((*t->bt_cmp)(k1, &k2)); 174 } 175 176 /* 177 * __BT_DEFCMP -- Default comparison routine. 178 * 179 * Parameters: 180 * a: DBT #1 181 * b: DBT #2 182 * 183 * Returns: 184 * < 0 if a is < b 185 * = 0 if a is = b 186 * > 0 if a is > b 187 */ 188 int 189 __bt_defcmp(a, b) 190 const DBT *a, *b; 191 { 192 register u_char *p1, *p2; 193 register int diff, len; 194 195 len = MIN(a->size, b->size); 196 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 197 if (diff = *p1 - *p2) 198 return (diff); 199 return (a->size - b->size); 200 } 201 202 /* 203 * __BT_DEFPFX -- Default prefix routine. 204 * 205 * Parameters: 206 * a: DBT #1 207 * b: DBT #2 208 * 209 * Returns: 210 * Number of bytes needed to distinguish b from a. 211 */ 212 int 213 __bt_defpfx(a, b) 214 const DBT *a, *b; 215 { 216 register u_char *p1, *p2; 217 register int len; 218 int cnt; 219 220 cnt = 1; 221 len = MIN(a->size, b->size); 222 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 223 if (*p1 != *p2) 224 return (cnt); 225 226 /* a->size must be <= b->size, or they wouldn't be in this order. */ 227 return (a->size < b->size ? a->size + 1 : a->size); 228 } 229