path: root/libibex/diskarray.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
 *
 * Copyright (C) 2000 Ximian, Inc.
 *
 * Authors: Michael Zucchi <notzed@ximian.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public License
 * as published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 * 
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with the Gnome Library; see the file COPYING.LIB.  If not,
 * write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/* a disk based array storage class */


#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#include <glib.h>

#include "block.h"
#include "index.h"

#define d(x)
/*#define DEBUG*/

static struct _IBEXStore *disk_create(struct _memcache *bc);
static int disk_sync(struct _IBEXStore *store);
static int disk_close(struct _IBEXStore *store);

static blockid_t disk_add(struct _IBEXStore *store, blockid_t head, nameid_t data);
static blockid_t disk_add_list(struct _IBEXStore *store, blockid_t head, GArray *data);
static blockid_t disk_remove(struct _IBEXStore *store, blockid_t head, nameid_t data);
static void disk_free(struct _IBEXStore *store, blockid_t head);

static gboolean disk_find(struct _IBEXStore *store, blockid_t head, nameid_t data);
static GArray *disk_get(struct _IBEXStore *store, blockid_t head);

struct _IBEXStoreClass ibex_diskarray_class = {
    disk_create, disk_sync, disk_close,
    disk_add, disk_add_list,
    disk_remove, disk_free,
    disk_find, disk_get
};

static struct _IBEXStore *disk_create(struct _memcache *bc)
{
    struct _IBEXStore *store;

    store = g_malloc0(sizeof(*store));
    store->klass = &ibex_diskarray_class;
    store->blocks = bc;

    return store;
}

static int disk_sync(struct _IBEXStore *store)
{
    /* no cache, nop */
    return 0;
}

static int disk_close(struct _IBEXStore *store)
{
    g_free(store);
    return 0;
}

static blockid_t
disk_add(struct _IBEXStore *store, blockid_t head, nameid_t data)
{
    struct _block *block;
    struct _block *newblock;
    blockid_t new;

    if (head == 0) {
        head = ibex_block_get(store->blocks);
    }
    block = ibex_block_read(store->blocks, head);

    d(printf("adding record %d to block %d (next = %d)\n", data, head, block->next));

    if (block->used < sizeof(block->bl_data)/sizeof(block->bl_data[0])) {
        d(printf("adding record into block %d  %d\n", head, data));
        block->bl_data[block->used] = data;
        block->used++;
        ibex_block_dirty(block);
        return head;
    } else {
        new = ibex_block_get(store->blocks);
        newblock = ibex_block_read(store->blocks, new);
        newblock->next = head;
        newblock->bl_data[0] = data;
        newblock->used = 1;
        d(printf("adding record into new %d  %d, next =%d\n", new, data, newblock->next));
        ibex_block_dirty(newblock);
        return new;
    }
}

static blockid_t
disk_add_list(struct _IBEXStore *store, blockid_t head, GArray *data)
{
    struct _block *block;
    struct _block *newblock;
    blockid_t new;
    int copied = 0;
    int left, space, tocopy;

    if (head == 0) {
        head = ibex_block_get(store->blocks);
    }
    block = ibex_block_read(store->blocks, head);

    while (copied < data->len) {
        left = data->len - copied;
        space = sizeof(block->bl_data)/sizeof(block->bl_data[0]) - block->used;
        if (space) {
            tocopy = MIN(left, space);
            memcpy(block->bl_data+block->used, &g_array_index(data, blockid_t, copied), tocopy*sizeof(blockid_t));
            block->used += tocopy;
            ibex_block_dirty(block);
        } else {
            new = ibex_block_get(store->blocks);
            newblock = ibex_block_read(store->blocks, new);
            newblock->next = head;
            tocopy = MIN(left, sizeof(block->bl_data)/sizeof(block->bl_data[0]));
            memcpy(newblock->bl_data, &g_array_index(data, blockid_t, copied), tocopy*sizeof(blockid_t));
            newblock->used = tocopy;
            block = newblock;
            head = new;
            ibex_block_dirty(newblock);
        }
        copied += tocopy;
    }
    return head;
}

static blockid_t
disk_remove(struct _IBEXStore *store, blockid_t head, nameid_t data)
{
    blockid_t node = head;

    d(printf("removing %d from %d\n", data, head));
    while (node) {
        struct _block *block = ibex_block_read(store->blocks, node);
        int i;

        for (i=0;i<block->used;i++) {
            if (block->bl_data[i] == data) {
                struct _block *start = ibex_block_read(store->blocks, head);

                start->used--;
                block->bl_data[i] = start->bl_data[start->used];
                if (start->used == 0) {
                    struct _root *root = (struct _root *)ibex_block_read(store->blocks, 0);
                    blockid_t new;

                    d(printf("dropping block %d, new head = %d\n", head, start->next));
                    new = start->next;
                    start->next = root->free;
                    root->free = head;
                    head = new;
                    ibex_block_dirty((struct _block *)root);
                }
                ibex_block_dirty(block);
                ibex_block_dirty(start);
                return head;
            }
        }
        node = block->next;
    }
    return head;
}

static void disk_free(struct _IBEXStore *store, blockid_t head)
{
    blockid_t next;
    struct _block *block;

    while (head) {
        block = ibex_block_read(store->blocks, head);
        next = block->next;
        ibex_block_free(store->blocks, head);
        head = next;
    }
}

static gboolean
disk_find(struct _IBEXStore *store, blockid_t head, nameid_t data)
{
    blockid_t node = head;

    d(printf("finding %d from %d\n", data, head));
    while (node) {
        struct _block *block = ibex_block_read(store->blocks, node);
        int i;

        for (i=0;i<block->used;i++) {
            if (block->bl_data[i] == data) {
                return TRUE;
            }
        }
        node = block->next;
    }
    return FALSE;
}

static GArray *
disk_get(struct _IBEXStore *store, blockid_t head)
{
    GArray *result = g_array_new(0, 0, sizeof(nameid_t));

    while (head) {
        struct _block *block = ibex_block_read(store->blocks, head);

        d(printf("getting data from block %d\n", head));

        g_array_append_vals(result, block->bl_data, block->used);
        head = block->next;
        d(printf("next = %d\n", head));
    }
    return result;
}

void
ibex_diskarray_dump(struct _memcache *blocks, blockid_t head)
{
    blockid_t node = head;

    printf("dumping list %d\n", node);
    while (node) {
        struct _block *block = ibex_block_read(blocks, node);
        int i;

        printf(" block %d used %d\n ", node, block->used);
        for (i=0;i<block->used;i++) {
            printf(" %d", block->bl_data[i]);
        }
        printf("\n");
        node = block->next;
    }
}