/*      $NetBSD: citrus_db.c,v 1.6 2025/12/16 12:39:01 nia Exp $        */

/*-
 * Copyright (c)2003 Citrus Project,
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
__RCSID("$NetBSD: citrus_db.c,v 1.6 2025/12/16 12:39:01 nia Exp $");
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/endian.h>

#include "citrus_namespace.h"
#include "citrus_bcs.h"
#include "citrus_region.h"
#include "citrus_memstream.h"
#include "citrus_mmap.h"
#include "citrus_db.h"
#include "citrus_db_file.h"

struct _citrus_db {
        /* private */
        struct _region db_region;
        uint32_t (*db_hashfunc)(void *, struct _citrus_region *);
        void *db_hashfunc_closure;
};

int
_citrus_db_open(struct _citrus_db **rdb, struct _region *r, const char *magic,
                uint32_t (*hashfunc)(void *, struct _citrus_region *),
                void *hashfunc_closure)
{
        struct _memstream ms;
        struct _citrus_db *db;
        struct _citrus_db_header_x *dhx;

        _memstream_bind(&ms, r);

        /* sanity check */
        dhx = _memstream_getregion(&ms, NULL, sizeof(*dhx));
        if (dhx == NULL)
                return EFTYPE;
        if (strncmp(dhx->dhx_magic, magic, _CITRUS_DB_MAGIC_SIZE) != 0)
                return EFTYPE;
        if (_memstream_seek(&ms, be32toh(dhx->dhx_entry_offset), SEEK_SET))
                return EFTYPE;

        if (be32toh(dhx->dhx_num_entries)*_CITRUS_DB_ENTRY_SIZE >
            _memstream_remainder(&ms))
                return EFTYPE;

        db = malloc(sizeof(*db));
        if (db==NULL)
                return errno;
        db->db_region = *r;
        db->db_hashfunc = hashfunc;
        db->db_hashfunc_closure = hashfunc_closure;
        *rdb = db;

        return 0;
}

void
_citrus_db_close(struct _citrus_db *db)
{
        free(db);
}

int
_citrus_db_lookup(struct _citrus_db *db, struct _citrus_region *key,
                  struct _citrus_region *data, struct _citrus_db_locator *dl)
{
        uint32_t hashval, num_entries;
        size_t offset;
        struct _memstream ms;
        struct _citrus_db_header_x *dhx;
        struct _citrus_db_entry_x *dex;
        struct _citrus_region r;

        _memstream_bind(&ms, &db->db_region);

        dhx = _memstream_getregion(&ms, NULL, sizeof(*dhx));
        _DIAGASSERT(dhx);
        num_entries = be32toh(dhx->dhx_num_entries);
        if (num_entries == 0)
                return ENOENT;

        if (dl != NULL && dl->dl_offset>0) {
                hashval = dl->dl_hashval;
                offset = dl->dl_offset;
                if (offset >= _region_size(&db->db_region))
                        return ENOENT;
        } else {
                hashval =
                    db->db_hashfunc(db->db_hashfunc_closure, key)%num_entries;
                offset =
                    be32toh(dhx->dhx_entry_offset) +
                    hashval * _CITRUS_DB_ENTRY_SIZE;
                if (dl)
                        dl->dl_hashval = hashval;
        }
        do {
                /* seek to the next entry */
                if (_citrus_memory_stream_seek(&ms, offset, SEEK_SET))
                        return EFTYPE;
                /* get the entry record */
                dex = _memstream_getregion(&ms, NULL, _CITRUS_DB_ENTRY_SIZE);
                if (dex == NULL)
                        return EFTYPE;

                /* jump to next entry having the same hash value. */
                offset = be32toh(dex->dex_next_offset);

                /* save the current position */
                if (dl) {
                        dl->dl_offset = offset;
                        if (offset==0)
                                dl->dl_offset = _region_size(&db->db_region);
                }

                /* compare hash value. */
                if (be32toh(dex->dex_hash_value) != hashval)
                        /* not found */
                        break;
                /* compare key length */
                if (be32toh(dex->dex_key_size) == _region_size(key)) {
                        /* seek to the head of the key. */
                        if (_memstream_seek(&ms, be32toh(dex->dex_key_offset),
                                            SEEK_SET))
                                return EFTYPE;
                        /* get the region of the key */
                        if (_memstream_getregion(&ms, &r,
                                                 _region_size(key)) == NULL)
                                return EFTYPE;
                        /* compare key byte stream */
                        if (memcmp(_region_head(&r), _region_head(key),
                                   _region_size(key)) == 0) {
                                /* match */
                                if (_memstream_seek(
                                        &ms, be32toh(dex->dex_data_offset),
                                        SEEK_SET))
                                        return EFTYPE;
                                if (_memstream_getregion(
                                        &ms, data,
                                        be32toh(dex->dex_data_size)) == NULL)
                                        return EFTYPE;
                                return 0;
                        }
                }
        } while (offset != 0);

        return ENOENT;
}

int
_citrus_db_lookup_by_string(struct _citrus_db *db, const char *key,
                            struct _citrus_region *data,
                            struct _citrus_db_locator *dl)
{
        struct _region r;

        _region_init(&r, __UNCONST(key), strlen(key));

        return _citrus_db_lookup(db, &r, data, dl);
}

int
_citrus_db_lookup8_by_string(struct _citrus_db *db, const char *key,
                             uint8_t *rval, struct _citrus_db_locator *dl)
{
        int ret;
        struct _region r;

        ret = _citrus_db_lookup_by_string(db, key, &r, dl);
        if (ret)
                return ret;

        if (_region_size(&r) != 1)
                return EFTYPE;

        if (rval)
                memcpy(rval, _region_head(&r), 1);

        return 0;
}

int
_citrus_db_lookup16_by_string(struct _citrus_db *db, const char *key,
                              uint16_t *rval, struct _citrus_db_locator *dl)
{
        int ret;
        struct _region r;
        uint16_t val;

        ret = _citrus_db_lookup_by_string(db, key, &r, dl);
        if (ret)
                return ret;

        if (_region_size(&r) != 2)
                return EFTYPE;

        if (rval) {
                memcpy(&val, _region_head(&r), 2);
                *rval = be16toh(val);
        }

        return 0;
}

int
_citrus_db_lookup32_by_string(struct _citrus_db *db, const char *key,
                              uint32_t *rval, struct _citrus_db_locator *dl)
{
        int ret;
        struct _region r;
        uint32_t val;

        ret = _citrus_db_lookup_by_string(db, key, &r, dl);
        if (ret)
                return ret;

        if (_region_size(&r) != 4)
                return EFTYPE;

        if (rval) {
                memcpy(&val, _region_head(&r), 4);
                *rval = be32toh(val);
        }

        return 0;
}

int
_citrus_db_lookup_string_by_string(struct _citrus_db *db, const char *key,
                                   const char **rdata,
                                   struct _citrus_db_locator *dl)
{
        int ret;
        struct _region r;

        ret = _citrus_db_lookup_by_string(db, key, &r, dl);
        if (ret)
                return ret;

        /* check whether the string is null terminated */
        if (_region_size(&r) == 0)
                return EFTYPE;
        if (*((const char*)_region_head(&r)+_region_size(&r)-1) != '\0')
                return EFTYPE;

        if (rdata)
                *rdata = _region_head(&r);

        return 0;
}

int
_citrus_db_get_number_of_entries(struct _citrus_db *db)
{
        struct _memstream ms;
        struct _citrus_db_header_x *dhx;

        _memstream_bind(&ms, &db->db_region);

        dhx = _memstream_getregion(&ms, NULL, sizeof(*dhx));
        _DIAGASSERT(dhx);
        return (int)be32toh(dhx->dhx_num_entries);
}

int
_citrus_db_get_entry(struct _citrus_db *db, int idx,
                     struct _region *key, struct _region *data)
{
        uint32_t num_entries;
        size_t offset;
        struct _memstream ms;
        struct _citrus_db_header_x *dhx;
        struct _citrus_db_entry_x *dex;

        _memstream_bind(&ms, &db->db_region);

        dhx = _memstream_getregion(&ms, NULL, sizeof(*dhx));
        _DIAGASSERT(dhx);
        num_entries = be32toh(dhx->dhx_num_entries);
        if (idx < 0 || (uint32_t)idx >= num_entries)
                return EINVAL;

        /* seek to the next entry */
        offset = be32toh(dhx->dhx_entry_offset) + idx * _CITRUS_DB_ENTRY_SIZE;
        if (_citrus_memory_stream_seek(&ms, offset, SEEK_SET))
                return EFTYPE;
        /* get the entry record */
        dex = _memstream_getregion(&ms, NULL, _CITRUS_DB_ENTRY_SIZE);
        if (dex == NULL)
                return EFTYPE;
        /* seek to the head of the key. */
        if (_memstream_seek(&ms, be32toh(dex->dex_key_offset), SEEK_SET))
                return EFTYPE;
        /* get the region of the key. */
        if (_memstream_getregion(&ms, key, be32toh(dex->dex_key_size))==NULL)
                return EFTYPE;
        /* seek to the head of the data. */
        if (_memstream_seek(&ms, be32toh(dex->dex_data_offset), SEEK_SET))
                return EFTYPE;
        /* get the region of the data. */
        if (_memstream_getregion(&ms, data, be32toh(dex->dex_data_size))==NULL)
                return EFTYPE;

        return 0;
}