xref: /freebsd/lib/libc/db/btree/bt_conv.c (revision 5f4c09dd85bff675e0ca63c55ea3c517e0fddfcc)
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_conv.c	8.5 (Berkeley) 8/17/94";
37 #endif /* LIBC_SCCS and not lint */
38 #include <sys/param.h>
39 
40 #include <stdio.h>
41 
42 #include <db.h>
43 #include "btree.h"
44 
45 static void mswap(PAGE *);
46 
47 /*
48  * __BT_BPGIN, __BT_BPGOUT --
49  *	Convert host-specific number layout to/from the host-independent
50  *	format stored on disk.
51  *
52  * Parameters:
53  *	t:	tree
54  *	pg:	page number
55  *	h:	page to convert
56  */
57 void
58 __bt_pgin(void *t, pgno_t pg, void *pp)
59 {
60 	PAGE *h;
61 	indx_t i, top;
62 	u_char flags;
63 	char *p;
64 
65 	if (!F_ISSET(((BTREE *)t), B_NEEDSWAP))
66 		return;
67 	if (pg == P_META) {
68 		mswap(pp);
69 		return;
70 	}
71 
72 	h = pp;
73 	M_32_SWAP(h->pgno);
74 	M_32_SWAP(h->prevpg);
75 	M_32_SWAP(h->nextpg);
76 	M_32_SWAP(h->flags);
77 	M_16_SWAP(h->lower);
78 	M_16_SWAP(h->upper);
79 
80 	top = NEXTINDEX(h);
81 	if ((h->flags & P_TYPE) == P_BINTERNAL)
82 		for (i = 0; i < top; i++) {
83 			M_16_SWAP(h->linp[i]);
84 			p = (char *)GETBINTERNAL(h, i);
85 			P_32_SWAP(p);
86 			p += sizeof(u_int32_t);
87 			P_32_SWAP(p);
88 			p += sizeof(pgno_t);
89 			if (*(u_char *)p & P_BIGKEY) {
90 				p += sizeof(u_char);
91 				P_32_SWAP(p);
92 				p += sizeof(pgno_t);
93 				P_32_SWAP(p);
94 			}
95 		}
96 	else if ((h->flags & P_TYPE) == P_BLEAF)
97 		for (i = 0; i < top; i++) {
98 			M_16_SWAP(h->linp[i]);
99 			p = (char *)GETBLEAF(h, i);
100 			P_32_SWAP(p);
101 			p += sizeof(u_int32_t);
102 			P_32_SWAP(p);
103 			p += sizeof(u_int32_t);
104 			flags = *(u_char *)p;
105 			if (flags & (P_BIGKEY | P_BIGDATA)) {
106 				p += sizeof(u_char);
107 				if (flags & P_BIGKEY) {
108 					P_32_SWAP(p);
109 					p += sizeof(pgno_t);
110 					P_32_SWAP(p);
111 				}
112 				if (flags & P_BIGDATA) {
113 					p += sizeof(u_int32_t);
114 					P_32_SWAP(p);
115 					p += sizeof(pgno_t);
116 					P_32_SWAP(p);
117 				}
118 			}
119 		}
120 }
121 
122 void
123 __bt_pgout(void *t, pgno_t pg, void *pp)
124 {
125 	PAGE *h;
126 	indx_t i, top;
127 	u_char flags;
128 	char *p;
129 
130 	if (!F_ISSET(((BTREE *)t), B_NEEDSWAP))
131 		return;
132 	if (pg == P_META) {
133 		mswap(pp);
134 		return;
135 	}
136 
137 	h = pp;
138 	top = NEXTINDEX(h);
139 	if ((h->flags & P_TYPE) == P_BINTERNAL)
140 		for (i = 0; i < top; i++) {
141 			p = (char *)GETBINTERNAL(h, i);
142 			P_32_SWAP(p);
143 			p += sizeof(u_int32_t);
144 			P_32_SWAP(p);
145 			p += sizeof(pgno_t);
146 			if (*(u_char *)p & P_BIGKEY) {
147 				p += sizeof(u_char);
148 				P_32_SWAP(p);
149 				p += sizeof(pgno_t);
150 				P_32_SWAP(p);
151 			}
152 			M_16_SWAP(h->linp[i]);
153 		}
154 	else if ((h->flags & P_TYPE) == P_BLEAF)
155 		for (i = 0; i < top; i++) {
156 			p = (char *)GETBLEAF(h, i);
157 			P_32_SWAP(p);
158 			p += sizeof(u_int32_t);
159 			P_32_SWAP(p);
160 			p += sizeof(u_int32_t);
161 			flags = *(u_char *)p;
162 			if (flags & (P_BIGKEY | P_BIGDATA)) {
163 				p += sizeof(u_char);
164 				if (flags & P_BIGKEY) {
165 					P_32_SWAP(p);
166 					p += sizeof(pgno_t);
167 					P_32_SWAP(p);
168 				}
169 				if (flags & P_BIGDATA) {
170 					p += sizeof(u_int32_t);
171 					P_32_SWAP(p);
172 					p += sizeof(pgno_t);
173 					P_32_SWAP(p);
174 				}
175 			}
176 			M_16_SWAP(h->linp[i]);
177 		}
178 
179 	M_32_SWAP(h->pgno);
180 	M_32_SWAP(h->prevpg);
181 	M_32_SWAP(h->nextpg);
182 	M_32_SWAP(h->flags);
183 	M_16_SWAP(h->lower);
184 	M_16_SWAP(h->upper);
185 }
186 
187 /*
188  * MSWAP -- Actually swap the bytes on the meta page.
189  *
190  * Parameters:
191  *	p:	page to convert
192  */
193 static void
194 mswap(PAGE *pg)
195 {
196 	char *p;
197 
198 	p = (char *)pg;
199 	P_32_SWAP(p);		/* magic */
200 	p += sizeof(u_int32_t);
201 	P_32_SWAP(p);		/* version */
202 	p += sizeof(u_int32_t);
203 	P_32_SWAP(p);		/* psize */
204 	p += sizeof(u_int32_t);
205 	P_32_SWAP(p);		/* free */
206 	p += sizeof(u_int32_t);
207 	P_32_SWAP(p);		/* nrecs */
208 	p += sizeof(u_int32_t);
209 	P_32_SWAP(p);		/* flags */
210 	p += sizeof(u_int32_t);
211 }
212