bt_conv.c

asterisk 一个模拟IPPBX的源代码

/*-
 * Copyright (c) 1990, 1993, 1994
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Mike Olson.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)bt_conv.c	8.5 (Berkeley) 8/17/94";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>

#include <stdio.h>

#include "../include/db.h"
#include "btree.h"

static void mswap __P((PAGE *));

/*
 * __BT_BPGIN, __BT_BPGOUT --
 *	Convert host-specific number layout to/from the host-independent
 *	format stored on disk.
 *
 * Parameters:
 *	t:	tree
 *	pg:	page number
 *	h:	page to convert
 */
void
__bt_pgin(t, pg, pp)
	void *t;
	pgno_t pg;
	void *pp;
{
	PAGE *h;
	indx_t i, top;
	u_char flags;
	char *p;

	if (!F_ISSET(((BTREE *)t), B_NEEDSWAP))
		return;
	if (pg == P_META) {
		mswap(pp);
		return;
	}

	h = pp;
	M_32_SWAP(h->pgno);
	M_32_SWAP(h->prevpg);
	M_32_SWAP(h->nextpg);
	M_32_SWAP(h->flags);
	M_16_SWAP(h->lower);
	M_16_SWAP(h->upper);

	top = NEXTINDEX(h);
	if ((h->flags & P_TYPE) == P_BINTERNAL)
		for (i = 0; i < top; i++) {
			M_16_SWAP(h->linp[i]);
			p = (char *)GETBINTERNAL(h, i);
			P_32_SWAP(p);
			p += sizeof(u_int32_t);
			P_32_SWAP(p);
			p += sizeof(pgno_t);
			if (*(u_char *)p & P_BIGKEY) {
				p += sizeof(u_char);
				P_32_SWAP(p);
				p += sizeof(pgno_t);
				P_32_SWAP(p);
			}
		}
	else if ((h->flags & P_TYPE) == P_BLEAF)
		for (i = 0; i < top; i++) {
			M_16_SWAP(h->linp[i]);
			p = (char *)GETBLEAF(h, i);
			P_32_SWAP(p);
			p += sizeof(u_int32_t);
			P_32_SWAP(p);
			p += sizeof(u_int32_t);
			flags = *(u_char *)p;
			if (flags & (P_BIGKEY | P_BIGDATA)) {
				p += sizeof(u_char);
				if (flags & P_BIGKEY) {
					P_32_SWAP(p);
					p += sizeof(pgno_t);
					P_32_SWAP(p);
				}
				if (flags & P_BIGDATA) {
					p += sizeof(u_int32_t);
					P_32_SWAP(p);
					p += sizeof(pgno_t);
					P_32_SWAP(p);
				}
			}
		}
}

void
__bt_pgout(t, pg, pp)
	void *t;
	pgno_t pg;
	void *pp;
{
	PAGE *h;
	indx_t i, top;
	u_char flags;
	char *p;

	if (!F_ISSET(((BTREE *)t), B_NEEDSWAP))
		return;
	if (pg == P_META) {
		mswap(pp);
		return;
	}

	h = pp;
	top = NEXTINDEX(h);
	if ((h->flags & P_TYPE) == P_BINTERNAL)
		for (i = 0; i < top; i++) {
			p = (char *)GETBINTERNAL(h, i);
			P_32_SWAP(p);
			p += sizeof(u_int32_t);
			P_32_SWAP(p);
			p += sizeof(pgno_t);
			if (*(u_char *)p & P_BIGKEY) {
				p += sizeof(u_char);
				P_32_SWAP(p);
				p += sizeof(pgno_t);
				P_32_SWAP(p);
			}
			M_16_SWAP(h->linp[i]);
		}
	else if ((h->flags & P_TYPE) == P_BLEAF)
		for (i = 0; i < top; i++) {
			p = (char *)GETBLEAF(h, i);
			P_32_SWAP(p);
			p += sizeof(u_int32_t);
			P_32_SWAP(p);
			p += sizeof(u_int32_t);
			flags = *(u_char *)p;
			if (flags & (P_BIGKEY | P_BIGDATA)) {
				p += sizeof(u_char);
				if (flags & P_BIGKEY) {
					P_32_SWAP(p);
					p += sizeof(pgno_t);
					P_32_SWAP(p);
				}
				if (flags & P_BIGDATA) {
					p += sizeof(u_int32_t);
					P_32_SWAP(p);
					p += sizeof(pgno_t);
					P_32_SWAP(p);
				}
			}
			M_16_SWAP(h->linp[i]);
		}

	M_32_SWAP(h->pgno);
	M_32_SWAP(h->prevpg);
	M_32_SWAP(h->nextpg);
	M_32_SWAP(h->flags);
	M_16_SWAP(h->lower);
	M_16_SWAP(h->upper);
}

/*
 * MSWAP -- Actually swap the bytes on the meta page.
 *
 * Parameters:
 *	p:	page to convert
 */
static void
mswap(pg)
	PAGE *pg;
{
	char *p;

	p = (char *)pg;
	P_32_SWAP(p);		/* magic */
	p += sizeof(u_int32_t);
	P_32_SWAP(p);		/* version */
	p += sizeof(u_int32_t);
	P_32_SWAP(p);		/* psize */
	p += sizeof(u_int32_t);
	P_32_SWAP(p);		/* free */
	p += sizeof(u_int32_t);
	P_32_SWAP(p);		/* nrecs */
	p += sizeof(u_int32_t);
	P_32_SWAP(p);		/* flags */
	p += sizeof(u_int32_t);
}