1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)bt_utils.c 8.8 (Berkeley) 7/20/94";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40
41 #include <sys/param.h>
42
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46
47 #include <db.h>
48 #include "btree.h"
49
50 /*
51 * __bt_ret --
52 * Build return key/data pair.
53 *
54 * Parameters:
55 * t: tree
56 * e: key/data pair to be returned
57 * key: user's key structure (NULL if not to be filled in)
58 * rkey: memory area to hold key
59 * data: user's data structure (NULL if not to be filled in)
60 * rdata: memory area to hold data
61 * copy: always copy the key/data item
62 *
63 * Returns:
64 * RET_SUCCESS, RET_ERROR.
65 */
66 int
__bt_ret(BTREE * t,EPG * e,DBT * key,DBT * rkey,DBT * data,DBT * rdata,int copy)67 __bt_ret(BTREE *t, EPG *e, DBT *key, DBT *rkey, DBT *data, DBT *rdata, int copy)
68 {
69 BLEAF *bl;
70 void *p;
71
72 bl = GETBLEAF(e->page, e->index);
73
74 /*
75 * We must copy big keys/data to make them contigous. Otherwise,
76 * leave the page pinned and don't copy unless the user specified
77 * concurrent access.
78 */
79 if (key == NULL)
80 goto dataonly;
81
82 if (bl->flags & P_BIGKEY) {
83 if (__ovfl_get(t, bl->bytes,
84 &key->size, &rkey->data, &rkey->size))
85 return (RET_ERROR);
86 key->data = rkey->data;
87 } else if (copy || F_ISSET(t, B_DB_LOCK)) {
88 if (bl->ksize > rkey->size) {
89 p = realloc(rkey->data, bl->ksize);
90 if (p == NULL)
91 return (RET_ERROR);
92 rkey->data = p;
93 rkey->size = bl->ksize;
94 }
95 memmove(rkey->data, bl->bytes, bl->ksize);
96 key->size = bl->ksize;
97 key->data = rkey->data;
98 } else {
99 key->size = bl->ksize;
100 key->data = bl->bytes;
101 }
102
103 dataonly:
104 if (data == NULL)
105 return (RET_SUCCESS);
106
107 if (bl->flags & P_BIGDATA) {
108 if (__ovfl_get(t, bl->bytes + bl->ksize,
109 &data->size, &rdata->data, &rdata->size))
110 return (RET_ERROR);
111 data->data = rdata->data;
112 } else if (copy || F_ISSET(t, B_DB_LOCK)) {
113 /* Use +1 in case the first record retrieved is 0 length. */
114 if (bl->dsize + 1 > rdata->size) {
115 p = realloc(rdata->data, bl->dsize + 1);
116 if (p == NULL)
117 return (RET_ERROR);
118 rdata->data = p;
119 rdata->size = bl->dsize + 1;
120 }
121 memmove(rdata->data, bl->bytes + bl->ksize, bl->dsize);
122 data->size = bl->dsize;
123 data->data = rdata->data;
124 } else {
125 data->size = bl->dsize;
126 data->data = bl->bytes + bl->ksize;
127 }
128
129 return (RET_SUCCESS);
130 }
131
132 /*
133 * __BT_CMP -- Compare a key to a given record.
134 *
135 * Parameters:
136 * t: tree
137 * k1: DBT pointer of first arg to comparison
138 * e: pointer to EPG for comparison
139 *
140 * Returns:
141 * < 0 if k1 is < record
142 * = 0 if k1 is = record
143 * > 0 if k1 is > record
144 */
145 int
__bt_cmp(BTREE * t,const DBT * k1,EPG * e)146 __bt_cmp(BTREE *t, const DBT *k1, EPG *e)
147 {
148 BINTERNAL *bi;
149 BLEAF *bl;
150 DBT k2;
151 PAGE *h;
152 void *bigkey;
153
154 /*
155 * The left-most key on internal pages, at any level of the tree, is
156 * guaranteed by the following code to be less than any user key.
157 * This saves us from having to update the leftmost key on an internal
158 * page when the user inserts a new key in the tree smaller than
159 * anything we've yet seen.
160 */
161 h = e->page;
162 if (e->index == 0 && h->prevpg == P_INVALID && !(h->flags & P_BLEAF))
163 return (1);
164
165 bigkey = NULL;
166 if (h->flags & P_BLEAF) {
167 bl = GETBLEAF(h, e->index);
168 if (bl->flags & P_BIGKEY)
169 bigkey = bl->bytes;
170 else {
171 k2.data = bl->bytes;
172 k2.size = bl->ksize;
173 }
174 } else {
175 bi = GETBINTERNAL(h, e->index);
176 if (bi->flags & P_BIGKEY)
177 bigkey = bi->bytes;
178 else {
179 k2.data = bi->bytes;
180 k2.size = bi->ksize;
181 }
182 }
183
184 if (bigkey) {
185 if (__ovfl_get(t, bigkey,
186 &k2.size, &t->bt_rdata.data, &t->bt_rdata.size))
187 return (RET_ERROR);
188 k2.data = t->bt_rdata.data;
189 }
190 return ((*t->bt_cmp)(k1, &k2));
191 }
192
193 /*
194 * __BT_DEFCMP -- Default comparison routine.
195 *
196 * Parameters:
197 * a: DBT #1
198 * b: DBT #2
199 *
200 * Returns:
201 * < 0 if a is < b
202 * = 0 if a is = b
203 * > 0 if a is > b
204 */
205 int
__bt_defcmp(const DBT * a,const DBT * b)206 __bt_defcmp(const DBT *a, const DBT *b)
207 {
208 size_t len;
209 u_char *p1, *p2;
210
211 /*
212 * XXX
213 * If a size_t doesn't fit in an int, this routine can lose.
214 * What we need is an integral type which is guaranteed to be
215 * larger than a size_t, and there is no such thing.
216 */
217 len = MIN(a->size, b->size);
218 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2)
219 if (*p1 != *p2)
220 return ((int)*p1 - (int)*p2);
221 return ((int)a->size - (int)b->size);
222 }
223
224 /*
225 * __BT_DEFPFX -- Default prefix routine.
226 *
227 * Parameters:
228 * a: DBT #1
229 * b: DBT #2
230 *
231 * Returns:
232 * Number of bytes needed to distinguish b from a.
233 */
234 size_t
__bt_defpfx(const DBT * a,const DBT * b)235 __bt_defpfx(const DBT *a, const DBT *b)
236 {
237 u_char *p1, *p2;
238 size_t cnt, len;
239
240 cnt = 1;
241 len = MIN(a->size, b->size);
242 for (p1 = a->data, p2 = b->data; len--; ++p1, ++p2, ++cnt)
243 if (*p1 != *p2)
244 return (cnt);
245
246 /* a->size must be <= b->size, or they wouldn't be in this order. */
247 return (a->size < b->size ? a->size + 1 : a->size);
248 }
249