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
__bt_ret(t,e,key,rkey,data,rdata,copy)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
__bt_cmp(t,k1,e)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
__bt_defcmp(a,b)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
__bt_defpfx(a,b)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