/*-
 * 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 "dcmtk/config/osconfig.h"
#include "citrus_db.h"

#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "citrus_bcs.h"
#include "citrus_region.h"
#include "citrus_memstream.h"
#include "citrus_mmap.h"
#include "citrus_db_factory.h"
#include "citrus_db_file.h"

struct _citrus_db {
    struct _citrus_region       db_region;
    _citrus_db_hash_func_t   db_hashfunc;
    void            *db_hashfunc_closure;
};

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

    _citrus_memory_stream_bind(&ms, r);

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

    if (be32toh(dhx->dhx_num_entries)*_CITRUS_DB_ENTRY_SIZE >
        _citrus_memory_stream_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)
{
    struct _citrus_db_entry_x *dex;
    struct _citrus_db_header_x *dhx;
    struct _citrus_region r;
    struct _citrus_memory_stream ms;
    uint32_t hashval, num_entries;
    size_t offset;

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

    dhx = _citrus_memory_stream_getregion(&ms, NULL, sizeof(*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 >= _citrus_region_size(&db->db_region))
            return (ENOENT);
    } else {
        hashval = db->db_hashfunc(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 = _citrus_memory_stream_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 = _citrus_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) == _citrus_region_size(key)) {
            /* seek to the head of the key. */
            if (_citrus_memory_stream_seek(&ms, be32toh(dex->dex_key_offset),
                SEEK_SET))
                return (EFTYPE);
            /* get the region of the key */
            if (_citrus_memory_stream_getregion(&ms, &r,
                _citrus_region_size(key)) == NULL)
                return (EFTYPE);
            /* compare key byte stream */
            if (memcmp(_citrus_region_head(&r), _citrus_region_head(key),
                _citrus_region_size(key)) == 0) {
                /* match */
                if (_citrus_memory_stream_seek(
                    &ms, be32toh(dex->dex_data_offset),
                    SEEK_SET))
                    return (EFTYPE);
                if (_citrus_memory_stream_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 _citrus_region r;

    _citrus_region_init(&r, CITRUS_DECONST(void *, 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)
{
    struct _citrus_region r;
    int ret;

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

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

    if (rval)
        memcpy(rval, _citrus_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)
{
    struct _citrus_region r;
    int ret;
    uint16_t val;

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

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

    if (rval) {
        memcpy(&val, _citrus_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)
{
    struct _citrus_region r;
    uint32_t val;
    int ret;

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

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

    if (rval) {
        memcpy(&val, _citrus_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)
{
    struct _citrus_region r;
    int ret;

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

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

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

    return (0);
}

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

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

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

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

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

    dhx = _citrus_memory_stream_getregion(&ms, NULL, sizeof(*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 = _citrus_memory_stream_getregion(&ms, NULL, _CITRUS_DB_ENTRY_SIZE);
    if (dex == NULL)
        return (EFTYPE);
    /* seek to the head of the key. */
    if (_citrus_memory_stream_seek(&ms, be32toh(dex->dex_key_offset), SEEK_SET))
        return (EFTYPE);
    /* get the region of the key. */
    if (_citrus_memory_stream_getregion(&ms, key, be32toh(dex->dex_key_size))==NULL)
        return (EFTYPE);
    /* seek to the head of the data. */
    if (_citrus_memory_stream_seek(&ms, be32toh(dex->dex_data_offset), SEEK_SET))
        return (EFTYPE);
    /* get the region of the data. */
    if (_citrus_memory_stream_getregion(&ms, data, be32toh(dex->dex_data_size))==NULL)
        return (EFTYPE);

    return (0);
}
