/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _SYS_MODHASH_IMPL_H
#define _SYS_MODHASH_IMPL_H

/*
 * Internal details for the kernel's generic hash implementation.
 */

#ifdef __cplusplus
extern "C" {
#endif

#ifdef _KERNEL

#include <sys/ksynch.h>
#include <sys/modhash.h>

struct mod_hash_entry {
        mod_hash_key_t mhe_key;                 /* stored hash key      */
        mod_hash_val_t mhe_val;                 /* stored hash value    */
        struct mod_hash_entry *mhe_next;        /* next item in chain   */
};

struct mod_hash_stat {
        ulong_t mhs_hit;        /* tried a 'find' and it succeeded */
        ulong_t mhs_miss;       /* tried a 'find' but it failed */
        ulong_t mhs_coll;       /* occur when insert fails because of dup's */
        ulong_t mhs_nelems;     /* total number of stored key/value pairs */
        ulong_t mhs_nomem;      /* number of times kmem_alloc failed */
};

struct mod_hash {
        krwlock_t       mh_contents;    /* lock protecting contents */
        char            *mh_name;       /* hash name */
        int             mh_sleep;       /* kmem_alloc flag */
        size_t          mh_nchains;     /* # of elements in mh_entries */

        /* key and val destructor */
        void    (*mh_kdtor)(mod_hash_key_t);
        void    (*mh_vdtor)(mod_hash_val_t);

        /* key comparator */
        int     (*mh_keycmp)(mod_hash_key_t, mod_hash_key_t);

        /* hash algorithm, and algorithm-private data */
        uint_t  (*mh_hashalg)(void *, mod_hash_key_t);
        void    *mh_hashalg_data;

        struct mod_hash *mh_next;       /* next hash in list */

        struct mod_hash_stat mh_stat;

        struct mod_hash_entry *mh_entries[1];
};

/*
 * MH_SIZE()
 *      Compute the size of a mod_hash_t, in bytes, given the number of
 *      elements it contains.
 */
#define MH_SIZE(n) \
        (sizeof (mod_hash_t) + ((n) - 1) * (sizeof (struct mod_hash_entry *)))

/*
 * Module initialization; called once.
 */
void mod_hash_init(void);

/*
 * Internal routines.  Use directly with care.
 */
uint_t i_mod_hash(mod_hash_t *, mod_hash_key_t);
int i_mod_hash_insert_nosync(mod_hash_t *, mod_hash_key_t, mod_hash_val_t,
    mod_hash_hndl_t);
int i_mod_hash_remove_nosync(mod_hash_t *, mod_hash_key_t, mod_hash_val_t *);
int i_mod_hash_find_nosync(mod_hash_t *, mod_hash_key_t, mod_hash_val_t *);
void i_mod_hash_walk_nosync(mod_hash_t *, uint_t (*)(mod_hash_key_t,
    mod_hash_val_t *, void *), void *);
void i_mod_hash_clear_nosync(mod_hash_t *hash);

#endif /* _KERNEL */

#ifdef __cplusplus
}
#endif

#endif /* _SYS_MODHASH_IMPL_H */