/*-------------------------------------------------------------------------
 * Copyright (C) 1997	National Center for Supercomputing Applications.
 *			All rights reserved.
 *
 *-------------------------------------------------------------------------
 *
 * Created:		H5ACprivate.h
 *			Jul  9 1997
 *			Robb Matzke <matzke@llnl.gov>
 *
 * Purpose:		Constants and typedefs available to the rest of the
 *			library.
 *
 * Modifications:
 *
 *-------------------------------------------------------------------------
 */
#ifndef _H5ACprivate_H
#define _H5ACprivate_H

#include <H5ACpublic.h>		/*public prototypes			     */

/* Pivate headers needed by this header */
#include <H5private.h>
#include <H5Fprivate.h>

/*
 * Feature: Define H5AC_DEBUG on the compiler command line if you want to
 *	    debug H5AC_protect() and H5AC_unprotect() by insuring that
 *	    nothing  accesses protected objects.  NDEBUG must not be defined
 *	    in order for this to have any effect.
 */
#ifdef NDEBUG
#  undef H5AC_DEBUG
#endif

/*
 * Class methods pertaining to caching.	 Each type of cached object will
 * have a constant variable with permanent life-span that describes how
 * to cache the object.	 That variable will be of type H5AC_class_t and
 * have the following required fields...
 *
 * LOAD:	Loads an object from disk to memory.  The function
 *		should allocate some data structure and return it.
 *
 * FLUSH:	Writes some data structure back to disk.  It would be
 *		wise for the data structure to include dirty flags to
 *		indicate whether it really needs to be written.	 This
 *		function is also responsible for freeing memory allocated
 *		by the LOAD method if the DEST argument is non-zero.
 */
typedef enum H5AC_subid_t {
    H5AC_BT_ID		= 0,	/*B-tree nodes				     */
    H5AC_SNODE_ID	= 1,	/*symbol table nodes			     */
    H5AC_LHEAP_ID	= 2,	/*local heap				     */
    H5AC_GHEAP_ID	= 3,	/*global heap				     */
    H5AC_OHDR_ID	= 4,	/*object header				     */
    H5AC_NTYPES		= 5	/*THIS MUST BE LAST!			     */
} H5AC_subid_t;

typedef struct H5AC_class_t {
    H5AC_subid_t	id;
    void		*(*load)(H5F_t *, const haddr_t *addr,
				 const void *udata1, void *udata2);
    herr_t		(*flush)(H5F_t *, hbool_t dest,
				 const haddr_t *addr, void *thing);
} H5AC_class_t;

/*
 * A cache has a certain number of entries.  Objects are mapped into a
 * cache entry by hashing the object's file address.  Each file has its
 * own cache, an array of slots.
 */
#define H5AC_NSLOTS	10330		/*prime number tend to work best     */
#define H5AC_HASH(F,ADDR_P) H5F_addr_hash(ADDR_P,(F)->shared->cache->nslots)

typedef struct H5AC_prot_t {
    const H5AC_class_t	*type;		/*type of protected thing	     */
    haddr_t		addr;		/*address of protected thing	     */
    void		*thing;		/*(possible) protected thing	     */
} H5AC_prot_t;

typedef struct H5AC_slot_t {
    const H5AC_class_t	*type;		/*type of object stored here	     */
    haddr_t		addr;		/*file address for object	     */
    void		*thing;		/*the thing which is cached	     */
#ifdef H5AC_DEBUG
    intn		nprots;		/*number of things protected	     */
    intn		aprots;		/*nelmts of `prot' array	     */
    H5AC_prot_t		*prot;		/*array of protected things	     */
#endif
} H5AC_slot_t;

typedef struct H5AC_t {
    uintn	nslots;			/*number of cache slots		     */
    H5AC_slot_t *slot;			/*the cache slots		     */
    intn	nprots;			/*number of protected objects	     */
    struct {
	uintn	nhits;			/*number of cache hits		     */
	uintn	nmisses;		/*number of cache misses	     */
	uintn	ninits;			/*number of cache inits		     */
	uintn	nflushes;		/*number of flushes to disk	     */
    } diagnostics[H5AC_NTYPES];		/*diagnostics for each type of object*/
} H5AC_t;

/*
 * Library prototypes.
 */
herr_t H5AC_dest (H5F_t *f);
void *H5AC_find_f (H5F_t *f, const H5AC_class_t *type, const haddr_t *addr,
		   const void *udata1, void *udata2);
void *H5AC_protect (H5F_t *f, const H5AC_class_t *type, const haddr_t *addr,
		    const void *udata1, void *udata2);
herr_t H5AC_unprotect (H5F_t *f, const H5AC_class_t *type,
		       const haddr_t *addr, void *thing);
herr_t H5AC_flush (H5F_t *f, const H5AC_class_t *type, const haddr_t *addr,
		   hbool_t destroy);
herr_t H5AC_create (H5F_t *f, intn size_hint);
herr_t H5AC_rename (H5F_t *f, const H5AC_class_t *type,
		    const haddr_t *old_addr, const haddr_t *new_addr);
herr_t H5AC_set (H5F_t *f, const H5AC_class_t *type, const haddr_t *addr,
		 void *thing);
herr_t H5AC_debug (H5F_t *f);

#define H5AC_find(F,TYPE,ADDR_P,UDATA1,UDATA2)				      \
   (((F)->shared->cache->slot[H5AC_HASH(F,ADDR_P)].type==(TYPE) &&	      \
     H5F_addr_eq (&((F)->shared->cache->slot[H5AC_HASH(F,ADDR_P)].addr),      \
		  ADDR_P)) ?						      \
    ((F)->shared->cache->diagnostics[(TYPE)->id].nhits++,		      \
     (F)->shared->cache->slot[H5AC_HASH(F,ADDR_P)].thing) :		      \
    H5AC_find_f (F, TYPE, ADDR_P, UDATA1, UDATA2))
     
#endif /* !_H5ACprivate_H */
