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+/*
+ * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
+ * 
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * 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.
+ *
+ *	@(#)mpool.h	8.1 (Berkeley) 6/2/93
+ */
+
+/*
+ * The memory pool scheme is a simple one.  Each in memory page is referenced
+ * by a bucket which is threaded in three ways.  All active pages are threaded
+ * on a hash chain (hashed by the page number) and an lru chain.  Inactive
+ * pages are threaded on a free chain.  Each reference to a memory pool is
+ * handed an MPOOL which is the opaque cookie passed to all of the memory
+ * routines.
+ */
+#define	HASHSIZE	128
+#define	HASHKEY(pgno)	((pgno - 1) % HASHSIZE)
+
+/* The BKT structures are the elements of the lists. */
+typedef struct BKT {
+	struct BKT	*hnext;		/* next hash bucket */
+	struct BKT	*hprev;		/* previous hash bucket */
+	struct BKT	*cnext;		/* next free/lru bucket */
+	struct BKT	*cprev;		/* previous free/lru bucket */
+	void		*page;		/* page */
+	pgno_t		pgno;		/* page number */
+
+#define	MPOOL_DIRTY	0x01		/* page needs to be written */
+#define	MPOOL_PINNED	0x02		/* page is pinned into memory */
+	unsigned long	flags;		/* flags */
+} BKT;
+
+/* The BKTHDR structures are the heads of the lists. */
+typedef struct BKTHDR {
+	struct BKT	*hnext;		/* next hash bucket */
+	struct BKT	*hprev;		/* previous hash bucket */
+	struct BKT	*cnext;		/* next free/lru bucket */
+	struct BKT	*cprev;		/* previous free/lru bucket */
+} BKTHDR;
+
+typedef struct MPOOL {
+	BKTHDR	free;			/* The free list. */
+	BKTHDR	lru;			/* The LRU list. */
+	BKTHDR	hashtable[HASHSIZE];	/* Hashed list by page number. */
+	pgno_t	curcache;		/* Current number of cached pages. */
+	pgno_t	maxcache;		/* Max number of cached pages. */
+	pgno_t	npages;			/* Number of pages in the file. */
+	u_long	pagesize;		/* File page size. */
+	int	fd;			/* File descriptor. */
+					/* Page in conversion routine. */
+	void    (*pgin) __P((void *, pgno_t, void *));
+					/* Page out conversion routine. */
+	void    (*pgout) __P((void *, pgno_t, void *));
+	void	*pgcookie;		/* Cookie for page in/out routines. */
+#ifdef STATISTICS
+	unsigned long	cachehit;
+	unsigned long	cachemiss;
+	unsigned long	pagealloc;
+	unsigned long	pageflush;
+	unsigned long	pageget;
+	unsigned long	pagenew;
+	unsigned long	pageput;
+	unsigned long	pageread;
+	unsigned long	pagewrite;
+#endif
+} MPOOL;
+
+#ifdef __MPOOLINTERFACE_PRIVATE
+/* Macros to insert/delete into/from hash chain. */
+#define rmhash(bp) { \
+        (bp)->hprev->hnext = (bp)->hnext; \
+        (bp)->hnext->hprev = (bp)->hprev; \
+}
+#define inshash(bp, pg) { \
+	hp = &mp->hashtable[HASHKEY(pg)]; \
+        (bp)->hnext = hp->hnext; \
+        (bp)->hprev = (struct BKT *)hp; \
+        hp->hnext->hprev = (bp); \
+        hp->hnext = (bp); \
+}
+
+/* Macros to insert/delete into/from lru and free chains. */
+#define	rmchain(bp) { \
+        (bp)->cprev->cnext = (bp)->cnext; \
+        (bp)->cnext->cprev = (bp)->cprev; \
+}
+#define inschain(bp, dp) { \
+        (bp)->cnext = (dp)->cnext; \
+        (bp)->cprev = (struct BKT *)(dp); \
+        (dp)->cnext->cprev = (bp); \
+        (dp)->cnext = (bp); \
+}
+#endif
+
+__BEGIN_DECLS
+MPOOL	*mpool_open __P((DBT *, int, pgno_t, pgno_t));
+void	 mpool_filter __P((MPOOL *, void (*)(void *, pgno_t, void *),
+	    void (*)(void *, pgno_t, void *), void *));
+void	*mpool_new __P((MPOOL *, pgno_t *));
+void	*mpool_get __P((MPOOL *, pgno_t, u_int));
+int	 mpool_put __P((MPOOL *, void *, u_int));
+int	 mpool_sync __P((MPOOL *));
+int	 mpool_close __P((MPOOL *));
+#ifdef STATISTICS
+void	 mpool_stat __P((MPOOL *));
+#endif
+__END_DECLS