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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)bt_utils.c 8.8 (Berkeley) 7/20/94 33 * $DragonFly: src/lib/libc/db/btree/bt_utils.c,v 1.5 2005/11/12 23:01:54 swildner Exp $ 34 */ 35 36 #include <sys/param.h> 37 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 42 #include <db.h> 43 #include "btree.h" 44 45 /* 46 * __bt_ret -- 47 * Build return key/data pair. 48 * 49 * Parameters: 50 * t: tree 51 * e: key/data pair to be returned 52 * key: user's key structure (NULL if not to be filled in) 53 * rkey: memory area to hold key 54 * data: user's data structure (NULL if not to be filled in) 55 * rdata: memory area to hold data 56 * copy: always copy the key/data item 57 * 58 * Returns: 59 * RET_SUCCESS, RET_ERROR. 60 */ 61 int 62 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy) 63 { 64 BLEAF *bl; 65 void *p; 66 67 bl = GETBLEAF(e->page, e->index); 68 69 /* 70 * We must copy big keys/data to make them contigous. Otherwise, 71 * leave the page pinned and don't copy unless the user specified 72 * concurrent access. 73 */ 74 if (key == NULL) 75 goto dataonly; 76 77 if (bl->flags & P_BIGKEY) { 78 if (__ovfl_get(t, bl->bytes, 79 &key->size, &rkey->data, &rkey->size)) 80 return (RET_ERROR); 81 key->data = rkey->data; 82 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 83 if (bl->ksize > rkey->size) { 84 p = (void *)(rkey->data == NULL ? 85 malloc(bl->ksize) : realloc(rkey->data, bl->ksize)); 86 if (p == NULL) 87 return (RET_ERROR); 88 rkey->data = p; 89 rkey->size = bl->ksize; 90 } 91 memmove(rkey->data, bl->bytes, bl->ksize); 92 key->size = bl->ksize; 93 key->data = rkey->data; 94 } else { 95 key->size = bl->ksize; 96 key->data = bl->bytes; 97 } 98 99 dataonly: 100 if (data == NULL) 101 return (RET_SUCCESS); 102 103 if (bl->flags & P_BIGDATA) { 104 if (__ovfl_get(t, bl->bytes + bl->ksize, 105 &data->size, &rdata->data, &rdata->size)) 106 return (RET_ERROR); 107 data->data = rdata->data; 108 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 109 /* Use +1 in case the first record retrieved is 0 length. */ 110 if (bl->dsize + 1 > rdata->size) { 111 p = (void *)(rdata->data == NULL ? 112 malloc(bl->dsize + 1) : 113 realloc(rdata->data, bl->dsize + 1)); 114 if (p == NULL) 115 return (RET_ERROR); 116 rdata->data = p; 117 rdata->size = bl->dsize + 1; 118 } 119 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 120 data->size = bl->dsize; 121 data->data = rdata->data; 122 } else { 123 data->size = bl->dsize; 124 data->data = bl->bytes + bl->ksize; 125 } 126 127 return (RET_SUCCESS); 128 } 129 130 /* 131 * __BT_CMP -- Compare a key to a given record. 132 * 133 * Parameters: 134 * t: tree 135 * k1: DBT pointer of first arg to comparison 136 * e: pointer to EPG for comparison 137 * 138 * Returns: 139 * < 0 if k1 is < record 140 * = 0 if k1 is = record 141 * > 0 if k1 is > record 142 */ 143 int 144 __bt_cmp(BTREE *t, const DBT *k1, EPG *e) 145 { 146 BINTERNAL *bi; 147 BLEAF *bl; 148 DBT k2; 149 PAGE *h; 150 void *bigkey; 151 152 /* 153 * The left-most key on internal pages, at any level of the tree, is 154 * guaranteed by the following code to be less than any user key. 155 * This saves us from having to update the leftmost key on an internal 156 * page when the user inserts a new key in the tree smaller than 157 * anything we've yet seen. 158 */ 159 h = e->page; 160 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 161 return (1); 162 163 bigkey = NULL; 164 if (h->flags & P_BLEAF) { 165 bl = GETBLEAF(h, e->index); 166 if (bl->flags & P_BIGKEY) 167 bigkey = bl->bytes; 168 else { 169 k2.data = bl->bytes; 170 k2.size = bl->ksize; 171 } 172 } else { 173 bi = GETBINTERNAL(h, e->index); 174 if (bi->flags & P_BIGKEY) 175 bigkey = bi->bytes; 176 else { 177 k2.data = bi->bytes; 178 k2.size = bi->ksize; 179 } 180 } 181 182 if (bigkey) { 183 if (__ovfl_get(t, bigkey, 184 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 185 return (RET_ERROR); 186 k2.data = t->bt_rdata.data; 187 } 188 return ((*t->bt_cmp)(k1, &k2)); 189 } 190 191 /* 192 * __BT_DEFCMP -- Default comparison routine. 193 * 194 * Parameters: 195 * a: DBT #1 196 * b: DBT #2 197 * 198 * Returns: 199 * < 0 if a is < b 200 * = 0 if a is = b 201 * > 0 if a is > b 202 */ 203 int 204 __bt_defcmp(const DBT *a, const DBT *b) 205 { 206 size_t len; 207 u_char *p1, *p2; 208 209 /* 210 * XXX 211 * If a size_t doesn't fit in an int, this routine can lose. 212 * What we need is a integral type which is guaranteed to be 213 * larger than a size_t, and there is no such thing. 214 */ 215 len = MIN(a->size, b->size); 216 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 217 if (*p1 != *p2) 218 return ((int)*p1 - (int)*p2); 219 return ((int)a->size - (int)b->size); 220 } 221 222 /* 223 * __BT_DEFPFX -- Default prefix routine. 224 * 225 * Parameters: 226 * a: DBT #1 227 * b: DBT #2 228 * 229 * Returns: 230 * Number of bytes needed to distinguish b from a. 231 */ 232 size_t 233 __bt_defpfx(const DBT *a, const DBT *b) 234 { 235 u_char *p1, *p2; 236 size_t cnt, len; 237 238 cnt = 1; 239 len = MIN(a->size, b->size); 240 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 241 if (*p1 != *p2) 242 return (cnt); 243 244 /* a->size must be <= b->size, or they wouldn't be in this order. */ 245 return (a->size < b->size ? a->size + 1 : a->size); 246 } 247