1 #pragma ident "%Z%%M% %I% %E% SMI" 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 static char sccsid[] = "@(#)bt_utils.c 8.8 (Berkeley) 7/20/94"; 41 #endif /* LIBC_SCCS and not lint */ 42 43 #include <sys/param.h> 44 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 49 #include "db-int.h" 50 #include "btree.h" 51 52 /* 53 * __bt_ret -- 54 * Build return key/data pair. 55 * 56 * Parameters: 57 * t: tree 58 * e: key/data pair to be returned 59 * key: user's key structure (NULL if not to be filled in) 60 * rkey: memory area to hold key 61 * data: user's data structure (NULL if not to be filled in) 62 * rdata: memory area to hold data 63 * copy: always copy the key/data item 64 * 65 * Returns: 66 * RET_SUCCESS, RET_ERROR. 67 */ 68 int 69 __bt_ret(t, e, key, rkey, data, rdata, copy) 70 BTREE *t; 71 EPG *e; 72 DBT *key, *rkey, *data, *rdata; 73 int copy; 74 { 75 BLEAF *bl; 76 void *p; 77 78 bl = GETBLEAF(e->page, e->index); 79 80 /* 81 * We must copy big keys/data to make them contigous. Otherwise, 82 * leave the page pinned and don't copy unless the user specified 83 * concurrent access. 84 */ 85 if (key == NULL) 86 goto dataonly; 87 88 if (bl->flags & P_BIGKEY) { 89 if (__ovfl_get(t, bl->bytes, 90 &key->size, &rkey->data, &rkey->size)) 91 return (RET_ERROR); 92 key->data = rkey->data; 93 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 94 if (bl->ksize > rkey->size) { 95 p = (void *)(rkey->data == NULL ? 96 malloc(bl->ksize) : realloc(rkey->data, bl->ksize)); 97 if (p == NULL) 98 return (RET_ERROR); 99 rkey->data = p; 100 rkey->size = bl->ksize; 101 } 102 memmove(rkey->data, bl->bytes, bl->ksize); 103 key->size = bl->ksize; 104 key->data = rkey->data; 105 } else { 106 key->size = bl->ksize; 107 key->data = bl->bytes; 108 } 109 110 dataonly: 111 if (data == NULL) 112 return (RET_SUCCESS); 113 114 if (bl->flags & P_BIGDATA) { 115 if (__ovfl_get(t, bl->bytes + bl->ksize, 116 &data->size, &rdata->data, &rdata->size)) 117 return (RET_ERROR); 118 data->data = rdata->data; 119 } else if (copy || F_ISSET(t, B_DB_LOCK)) { 120 /* Use +1 in case the first record retrieved is 0 length. */ 121 if (bl->dsize + 1 > rdata->size) { 122 p = (void *)(rdata->data == NULL ? 123 malloc(bl->dsize + 1) : 124 realloc(rdata->data, bl->dsize + 1)); 125 if (p == NULL) 126 return (RET_ERROR); 127 rdata->data = p; 128 rdata->size = bl->dsize + 1; 129 } 130 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize); 131 data->size = bl->dsize; 132 data->data = rdata->data; 133 } else { 134 data->size = bl->dsize; 135 data->data = bl->bytes + bl->ksize; 136 } 137 138 return (RET_SUCCESS); 139 } 140 141 /* 142 * __BT_CMP -- Compare a key to a given record. 143 * 144 * Parameters: 145 * t: tree 146 * k1: DBT pointer of first arg to comparison 147 * e: pointer to EPG for comparison 148 * 149 * Returns: 150 * < 0 if k1 is < record 151 * = 0 if k1 is = record 152 * > 0 if k1 is > record 153 */ 154 int 155 __bt_cmp(t, k1, e) 156 BTREE *t; 157 const DBT *k1; 158 EPG *e; 159 { 160 BINTERNAL *bi; 161 BLEAF *bl; 162 DBT k2; 163 PAGE *h; 164 void *bigkey; 165 166 /* 167 * The left-most key on internal pages, at any level of the tree, is 168 * guaranteed by the following code to be less than any user key. 169 * This saves us from having to update the leftmost key on an internal 170 * page when the user inserts a new key in the tree smaller than 171 * anything we've yet seen. 172 */ 173 h = e->page; 174 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF)) 175 return (1); 176 177 bigkey = NULL; 178 if (h->flags & P_BLEAF) { 179 bl = GETBLEAF(h, e->index); 180 if (bl->flags & P_BIGKEY) 181 bigkey = bl->bytes; 182 else { 183 k2.data = bl->bytes; 184 k2.size = bl->ksize; 185 } 186 } else { 187 bi = GETBINTERNAL(h, e->index); 188 if (bi->flags & P_BIGKEY) 189 bigkey = bi->bytes; 190 else { 191 k2.data = bi->bytes; 192 k2.size = bi->ksize; 193 } 194 } 195 196 if (bigkey) { 197 if (__ovfl_get(t, bigkey, 198 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size)) 199 return (RET_ERROR); 200 k2.data = t->bt_rdata.data; 201 } 202 return ((*t->bt_cmp)(k1, &k2)); 203 } 204 205 /* 206 * __BT_DEFCMP -- Default comparison routine. 207 * 208 * Parameters: 209 * a: DBT #1 210 * b: DBT #2 211 * 212 * Returns: 213 * < 0 if a is < b 214 * = 0 if a is = b 215 * > 0 if a is > b 216 */ 217 int 218 __bt_defcmp(a, b) 219 const DBT *a, *b; 220 { 221 register size_t len; 222 register u_char *p1, *p2; 223 224 /* 225 * XXX 226 * If a size_t doesn't fit in an int, this routine can lose. 227 * What we need is a integral type which is guaranteed to be 228 * larger than a size_t, and there is no such thing. 229 */ 230 len = MIN(a->size, b->size); 231 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2) 232 if (*p1 != *p2) 233 return ((int)*p1 - (int)*p2); 234 return ((int)a->size - (int)b->size); 235 } 236 237 /* 238 * __BT_DEFPFX -- Default prefix routine. 239 * 240 * Parameters: 241 * a: DBT #1 242 * b: DBT #2 243 * 244 * Returns: 245 * Number of bytes needed to distinguish b from a. 246 */ 247 size_t 248 __bt_defpfx(a, b) 249 const DBT *a, *b; 250 { 251 register u_char *p1, *p2; 252 register size_t cnt, len; 253 254 cnt = 1; 255 len = MIN(a->size, b->size); 256 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt) 257 if (*p1 != *p2) 258 return (cnt); 259 260 /* a->size must be <= b->size, or they wouldn't be in this order. */ 261 return (a->size < b->size ? a->size + 1 : a->size); 262 } 263