/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef _SYS_ZAP_LEAF_H
#define _SYS_ZAP_LEAF_H

#define ZAP_LEAF_MAGIC 0x2AB1EAF

/* chunk size = 24 bytes */
#define ZAP_LEAF_CHUNKSIZE 24

/*
 * The amount of space within the chunk available for the array is:
 * chunk size - space for type (1) - space for next pointer (2)
 */
#define ZAP_LEAF_ARRAY_BYTES (ZAP_LEAF_CHUNKSIZE - 3)

typedef enum zap_chunk_type {
        ZAP_CHUNK_FREE = 253,
        ZAP_CHUNK_ENTRY = 252,
        ZAP_CHUNK_ARRAY = 251,
        ZAP_CHUNK_TYPE_MAX = 250
} zap_chunk_type_t;

/*
 * TAKE NOTE:
 * If zap_leaf_phys_t is modified, zap_leaf_byteswap() must be modified.
 */
typedef struct zap_leaf_phys {
        struct zap_leaf_header {
                uint64_t lh_block_type;         /* ZBT_LEAF */
                uint64_t lh_pad1;
                uint64_t lh_prefix;             /* hash prefix of this leaf */
                uint32_t lh_magic;              /* ZAP_LEAF_MAGIC */
                uint16_t lh_nfree;              /* number free chunks */
                uint16_t lh_nentries;           /* number of entries */
                uint16_t lh_prefix_len;         /* num bits used to id this */

/* above is accessable to zap, below is zap_leaf private */

                uint16_t lh_freelist;           /* chunk head of free list */
                uint8_t lh_pad2[12];
        } l_hdr; /* 2 24-byte chunks */

        /*
         * The header is followed by a hash table with
         * ZAP_LEAF_HASH_NUMENTRIES(zap) entries.  The hash table is
         * followed by an array of ZAP_LEAF_NUMCHUNKS(zap)
         * zap_leaf_chunk structures.  These structures are accessed
         * with the ZAP_LEAF_CHUNK() macro.
         */

        uint16_t l_hash[1];
} zap_leaf_phys_t;

typedef union zap_leaf_chunk {
        struct zap_leaf_entry {
                uint8_t le_type;                /* always ZAP_CHUNK_ENTRY */
                uint8_t le_int_size;            /* size of ints */
                uint16_t le_next;               /* next entry in hash chain */
                uint16_t le_name_chunk;         /* first chunk of the name */
                uint16_t le_name_length;        /* bytes in name, incl null */
                uint16_t le_value_chunk;        /* first chunk of the value */
                uint16_t le_value_length;       /* value length in ints */
                uint32_t le_cd;                 /* collision differentiator */
                uint64_t le_hash;               /* hash value of the name */
        } l_entry;
        struct zap_leaf_array {
                uint8_t la_type;                /* always ZAP_CHUNK_ARRAY */
                uint8_t la_array[ZAP_LEAF_ARRAY_BYTES];
                uint16_t la_next;               /* next blk or CHAIN_END */
        } l_array;
        struct zap_leaf_free {
                uint8_t lf_type;                /* always ZAP_CHUNK_FREE */
                uint8_t lf_pad[ZAP_LEAF_ARRAY_BYTES];
                uint16_t lf_next;       /* next in free list, or CHAIN_END */
        } l_free;
} zap_leaf_chunk_t;

#endif /* _SYS_ZAP_LEAF_H */