source: rtems-libbsd/freebsd/lib/libc/db/btree/bt_overflow.c @ 2404264

4.1155-freebsd-126-freebsd-12freebsd-9.3
Last change on this file since 2404264 was 2404264, checked in by Sebastian Huber <sebastian.huber@…>, on 10/30/13 at 12:23:59

Revert superfluous changes

  • Property mode set to 100644
File size: 5.5 KB
Line 
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 * 4. 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
33#if defined(LIBC_SCCS) && !defined(lint)
34static char sccsid[] = "@(#)bt_overflow.c       8.5 (Berkeley) 7/16/94";
35#endif /* LIBC_SCCS and not lint */
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD$");
38
39#include <rtems/bsd/sys/param.h>
40
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44
45#include <db.h>
46#include "btree.h"
47
48/*
49 * Big key/data code.
50 *
51 * Big key and data entries are stored on linked lists of pages.  The initial
52 * reference is byte string stored with the key or data and is the page number
53 * and size.  The actual record is stored in a chain of pages linked by the
54 * nextpg field of the PAGE header.
55 *
56 * The first page of the chain has a special property.  If the record is used
57 * by an internal page, it cannot be deleted and the P_PRESERVE bit will be set
58 * in the header.
59 *
60 * XXX
61 * A single DBT is written to each chain, so a lot of space on the last page
62 * is wasted.  This is a fairly major bug for some data sets.
63 */
64
65/*
66 * __OVFL_GET -- Get an overflow key/data item.
67 *
68 * Parameters:
69 *      t:      tree
70 *      p:      pointer to { pgno_t, u_int32_t }
71 *      buf:    storage address
72 *      bufsz:  storage size
73 *
74 * Returns:
75 *      RET_ERROR, RET_SUCCESS
76 */
77int
78__ovfl_get(BTREE *t, void *p, size_t *ssz, void **buf, size_t *bufsz)
79{
80        PAGE *h;
81        pgno_t pg;
82        size_t nb, plen;
83        u_int32_t sz;
84
85        memmove(&pg, p, sizeof(pgno_t));
86        memmove(&sz, (char *)p + sizeof(pgno_t), sizeof(u_int32_t));
87        *ssz = sz;
88
89#ifdef DEBUG
90        if (pg == P_INVALID || sz == 0)
91                abort();
92#endif
93        /* Make the buffer bigger as necessary. */
94        if (*bufsz < sz) {
95                *buf = reallocf(*buf, sz);
96                if (*buf == NULL)
97                        return (RET_ERROR);
98                *bufsz = sz;
99        }
100
101        /*
102         * Step through the linked list of pages, copying the data on each one
103         * into the buffer.  Never copy more than the data's length.
104         */
105        plen = t->bt_psize - BTDATAOFF;
106        for (p = *buf;; p = (char *)p + nb, pg = h->nextpg) {
107                if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
108                        return (RET_ERROR);
109
110                nb = MIN(sz, plen);
111                memmove(p, (char *)h + BTDATAOFF, nb);
112                mpool_put(t->bt_mp, h, 0);
113
114                if ((sz -= nb) == 0)
115                        break;
116        }
117        return (RET_SUCCESS);
118}
119
120/*
121 * __OVFL_PUT -- Store an overflow key/data item.
122 *
123 * Parameters:
124 *      t:      tree
125 *      data:   DBT to store
126 *      pgno:   storage page number
127 *
128 * Returns:
129 *      RET_ERROR, RET_SUCCESS
130 */
131int
132__ovfl_put(BTREE *t, const DBT *dbt, pgno_t *pg)
133{
134        PAGE *h, *last;
135        void *p;
136        pgno_t npg;
137        size_t nb, plen;
138        u_int32_t sz;
139
140        /*
141         * Allocate pages and copy the key/data record into them.  Store the
142         * number of the first page in the chain.
143         */
144        plen = t->bt_psize - BTDATAOFF;
145        for (last = NULL, p = dbt->data, sz = dbt->size;;
146            p = (char *)p + plen, last = h) {
147                if ((h = __bt_new(t, &npg)) == NULL)
148                        return (RET_ERROR);
149
150                h->pgno = npg;
151                h->nextpg = h->prevpg = P_INVALID;
152                h->flags = P_OVERFLOW;
153                h->lower = h->upper = 0;
154
155                nb = MIN(sz, plen);
156                memmove((char *)h + BTDATAOFF, p, nb);
157
158                if (last) {
159                        last->nextpg = h->pgno;
160                        mpool_put(t->bt_mp, last, MPOOL_DIRTY);
161                } else
162                        *pg = h->pgno;
163
164                if ((sz -= nb) == 0) {
165                        mpool_put(t->bt_mp, h, MPOOL_DIRTY);
166                        break;
167                }
168        }
169        return (RET_SUCCESS);
170}
171
172/*
173 * __OVFL_DELETE -- Delete an overflow chain.
174 *
175 * Parameters:
176 *      t:      tree
177 *      p:      pointer to { pgno_t, u_int32_t }
178 *
179 * Returns:
180 *      RET_ERROR, RET_SUCCESS
181 */
182int
183__ovfl_delete(BTREE *t, void *p)
184{
185        PAGE *h;
186        pgno_t pg;
187        size_t plen;
188        u_int32_t sz;
189
190        memmove(&pg, p, sizeof(pgno_t));
191        memmove(&sz, (char *)p + sizeof(pgno_t), sizeof(u_int32_t));
192
193#ifdef DEBUG
194        if (pg == P_INVALID || sz == 0)
195                abort();
196#endif
197        if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
198                return (RET_ERROR);
199
200        /* Don't delete chains used by internal pages. */
201        if (h->flags & P_PRESERVE) {
202                mpool_put(t->bt_mp, h, 0);
203                return (RET_SUCCESS);
204        }
205
206        /* Step through the chain, calling the free routine for each page. */
207        for (plen = t->bt_psize - BTDATAOFF;; sz -= plen) {
208                pg = h->nextpg;
209                __bt_free(t, h);
210                if (sz <= plen)
211                        break;
212                if ((h = mpool_get(t->bt_mp, pg, 0)) == NULL)
213                        return (RET_ERROR);
214        }
215        return (RET_SUCCESS);
216}
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