1 /*- 2 * Copyright (c) 1990, 1993, 1994 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 * @(#)bt_utils.c 8.8 (Berkeley) 7/20/94 37 * $DragonFly: src/lib/libc/db/btree/bt_utils.c,v 1.3 2004/10/25 19:38:01 drhodus Exp $ 38 */ 39 40 #include <sys/param.h> 41 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 46 #include <db.h> 47 #include "btree.h" 48 49 /* 50 * __bt_ret -- 51 * Build return key/data pair. 52 * 53 * Parameters: 54 * t: tree 55 * e: key/data pair to be returned 56 * key: user's key structure (NULL if not to be filled in) 57 * rkey: memory area to hold key 58 * data: user's data structure (NULL if not to be filled in) 59 * rdata: memory area to hold data 60 * copy: always copy the key/data item 61 * 62 * Returns: 63 * RET_SUCCESS, RET_ERROR. 64 */ 65 int 66 __bt_ret(t, e, key, rkey, data, rdata, copy) 67 BTREE *t; 68 EPG *e; 69 DBT *key, *rkey, *data, *rdata; 70 int copy; 71 { 72 BLEAF *bl; 73 void *p; 74 75 bl = GETBLEAF(e->page, e->index); 76 77 /* 78 * We must copy big keys/data to make them contigous. Otherwise, 79 * leave the page pinned and don't copy unless the user specified 80 * concurrent access. 81 */ 82 if (key == NULL) 83 goto dataonly; 84 85 if (bl->flags & P_BIGKEY) { 86 if (__ovfl_get(t, bl->bytes, 87 &key->size, &rkey->data, &rkey->size)) 88 return (RET_ERROR); 89 key->data = rkey->data; 90 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 91 if (bl->ksize > rkey->size) { 92 p = (void *)(rkey->data == NULL ? 93 malloc(bl->ksize) : realloc(rkey->data, bl->ksize)); 94 if (p == NULL) 95 return (RET_ERROR); 96 rkey->data = p; 97 rkey->size = bl->ksize; 98 } 99 memmove(rkey->data, bl->bytes, bl->ksize); 100 key->size = bl->ksize; 101 key->data = rkey->data; 102 } else { 103 key->size = bl->ksize; 104 key->data = bl->bytes; 105 } 106 107 dataonly: 108 if (data == NULL) 109 return (RET_SUCCESS); 110 111 if (bl->flags & P_BIGDATA) { 112 if (__ovfl_get(t, bl->bytes + bl->ksize, 113 &data->size, &rdata->data, &rdata->size)) 114 return (RET_ERROR); 115 data->data = rdata->data; 116 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 117 /* Use +1 in case the first record retrieved is 0 length. */ 118 if (bl->dsize + 1 > rdata->size) { 119 p = (void *)(rdata->data == NULL ? 120 malloc(bl->dsize + 1) : 121 realloc(rdata->data, bl->dsize + 1)); 122 if (p == NULL) 123 return (RET_ERROR); 124 rdata->data = p; 125 rdata->size = bl->dsize + 1; 126 } 127 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 128 data->size = bl->dsize; 129 data->data = rdata->data; 130 } else { 131 data->size = bl->dsize; 132 data->data = bl->bytes + bl->ksize; 133 } 134 135 return (RET_SUCCESS); 136 } 137 138 /* 139 * __BT_CMP -- Compare a key to a given record. 140 * 141 * Parameters: 142 * t: tree 143 * k1: DBT pointer of first arg to comparison 144 * e: pointer to EPG for comparison 145 * 146 * Returns: 147 * < 0 if k1 is < record 148 * = 0 if k1 is = record 149 * > 0 if k1 is > record 150 */ 151 int 152 __bt_cmp(t, k1, e) 153 BTREE *t; 154 const DBT *k1; 155 EPG *e; 156 { 157 BINTERNAL *bi; 158 BLEAF *bl; 159 DBT k2; 160 PAGE *h; 161 void *bigkey; 162 163 /* 164 * The left-most key on internal pages, at any level of the tree, is 165 * guaranteed by the following code to be less than any user key. 166 * This saves us from having to update the leftmost key on an internal 167 * page when the user inserts a new key in the tree smaller than 168 * anything we've yet seen. 169 */ 170 h = e->page; 171 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 172 return (1); 173 174 bigkey = NULL; 175 if (h->flags & P_BLEAF) { 176 bl = GETBLEAF(h, e->index); 177 if (bl->flags & P_BIGKEY) 178 bigkey = bl->bytes; 179 else { 180 k2.data = bl->bytes; 181 k2.size = bl->ksize; 182 } 183 } else { 184 bi = GETBINTERNAL(h, e->index); 185 if (bi->flags & P_BIGKEY) 186 bigkey = bi->bytes; 187 else { 188 k2.data = bi->bytes; 189 k2.size = bi->ksize; 190 } 191 } 192 193 if (bigkey) { 194 if (__ovfl_get(t, bigkey, 195 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 196 return (RET_ERROR); 197 k2.data = t->bt_rdata.data; 198 } 199 return ((*t->bt_cmp)(k1, &k2)); 200 } 201 202 /* 203 * __BT_DEFCMP -- Default comparison routine. 204 * 205 * Parameters: 206 * a: DBT #1 207 * b: DBT #2 208 * 209 * Returns: 210 * < 0 if a is < b 211 * = 0 if a is = b 212 * > 0 if a is > b 213 */ 214 int 215 __bt_defcmp(a, b) 216 const DBT *a, *b; 217 { 218 size_t len; 219 u_char *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(a, b) 246 const DBT *a, *b; 247 { 248 u_char *p1, *p2; 249 size_t cnt, len; 250 251 cnt = 1; 252 len = MIN(a->size, b->size); 253 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 254 if (*p1 != *p2) 255 return (cnt); 256 257 /* a->size must be <= b->size, or they wouldn't be in this order. */ 258 return (a->size < b->size ? a->size + 1 : a->size); 259 } 260