-/*-
- * 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
- * Margo Seltzer.
- *
- * 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.
- *
- * @(#)page.h 8.2 (Berkeley) 5/31/94
- * $FreeBSD: src/lib/libc/db/hash/page.h,v 1.2 2002/03/22 23:41:40 obrien Exp $
- */
-
-/*
- * Definitions for hashing page file format.
- */
-
-/*
- * routines dealing with a data page
- *
- * page format:
- * +------------------------------+
- * p | n | keyoff | datoff | keyoff |
- * +------------+--------+--------+
- * | datoff | free | ptr | --> |
- * +--------+---------------------+
- * | F R E E A R E A |
- * +--------------+---------------+
- * | <---- - - - | data |
- * +--------+-----+----+----------+
- * | key | data | key |
- * +--------+----------+----------+
- *
- * Pointer to the free space is always: p[p[0] + 2]
- * Amount of free space on the page is: p[p[0] + 1]
- */
-
-/*
- * How many bytes required for this pair?
- * 2 shorts in the table at the top of the page + room for the
- * key and room for the data
- *
- * We prohibit entering a pair on a page unless there is also room to append
- * an overflow page. The reason for this it that you can get in a situation
- * where a single key/data pair fits on a page, but you can't append an
- * overflow page and later you'd have to split the key/data and handle like
- * a big pair.
- * You might as well do this up front.
- */
-
-#define PAIRSIZE(K,D) (2*sizeof(u_int16_t) + (K)->size + (D)->size)
-#define BIGOVERHEAD (4*sizeof(u_int16_t))
-#define KEYSIZE(K) (4*sizeof(u_int16_t) + (K)->size);
-#define OVFLSIZE (2*sizeof(u_int16_t))
-#define FREESPACE(P) ((P)[(P)[0]+1])
-#define OFFSET(P) ((P)[(P)[0]+2])
-#define PAIRFITS(P,K,D) \
- (((P)[2] >= REAL_KEY) && \
- (PAIRSIZE((K),(D)) + OVFLSIZE) <= FREESPACE((P)))
-#define PAGE_META(N) (((N)+3) * sizeof(u_int16_t))
-
-typedef struct {
- BUFHEAD *newp;
- BUFHEAD *oldp;
- BUFHEAD *nextp;
- u_int16_t next_addr;
-} SPLIT_RETURN;
projects / apple / libc.git / blobdiff