/* vi: set sw=4 ts=4: */
/*
 * dblist.c -- directory block list functions
 *
 * Copyright 1997 by Theodore Ts'o
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 *
 */

#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <string.h>
#include <time.h>

#include "ext2_fs.h"
#include "ext2fsP.h"

static int dir_block_cmp(const void *a, const void *b);

/*
 * Returns the number of directories in the filesystem as reported by
 * the group descriptors.  Of course, the group descriptors could be
 * wrong!
 */
errcode_t ext2fs_get_num_dirs(ext2_filsys fs, ext2_ino_t *ret_num_dirs)
{
        dgrp_t  i;
        ext2_ino_t      num_dirs, max_dirs;

        EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

        num_dirs = 0;
        max_dirs = fs->super->s_inodes_per_group;
        for (i = 0; i < fs->group_desc_count; i++) {
                if (fs->group_desc[i].bg_used_dirs_count > max_dirs)
                        num_dirs += max_dirs / 8;
                else
                        num_dirs += fs->group_desc[i].bg_used_dirs_count;
        }
        if (num_dirs > fs->super->s_inodes_count)
                num_dirs = fs->super->s_inodes_count;

        *ret_num_dirs = num_dirs;

        return 0;
}

/*
 * helper function for making a new directory block list (for
 * initialize and copy).
 */
static errcode_t make_dblist(ext2_filsys fs, ext2_ino_t size, ext2_ino_t count,
                             struct ext2_db_entry *list,
                             ext2_dblist *ret_dblist)
{
        ext2_dblist     dblist;
        errcode_t       retval;
        size_t          len;

        EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

        if ((ret_dblist == 0) && fs->dblist &&
            (fs->dblist->magic == EXT2_ET_MAGIC_DBLIST))
                return 0;

        retval = ext2fs_get_mem(sizeof(struct ext2_struct_dblist), &dblist);
        if (retval)
                return retval;
        memset(dblist, 0, sizeof(struct ext2_struct_dblist));

        dblist->magic = EXT2_ET_MAGIC_DBLIST;
        dblist->fs = fs;
        if (size)
                dblist->size = size;
        else {
                retval = ext2fs_get_num_dirs(fs, &dblist->size);
                if (retval)
                        goto cleanup;
                dblist->size = (dblist->size * 2) + 12;
        }
        len = (size_t) sizeof(struct ext2_db_entry) * dblist->size;
        dblist->count = count;
        retval = ext2fs_get_mem(len, &dblist->list);
        if (retval)
                goto cleanup;

        if (list)
                memcpy(dblist->list, list, len);
        else
                memset(dblist->list, 0, len);
        if (ret_dblist)
                *ret_dblist = dblist;
        else
                fs->dblist = dblist;
        return 0;
cleanup:
        ext2fs_free_mem(&dblist);
        return retval;
}

/*
 * Initialize a directory block list
 */
errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
{
        ext2_dblist     dblist;
        errcode_t       retval;

        retval = make_dblist(fs, 0, 0, 0, &dblist);
        if (retval)
                return retval;

        dblist->sorted = 1;
        if (ret_dblist)
                *ret_dblist = dblist;
        else
                fs->dblist = dblist;

        return 0;
}

/*
 * Copy a directory block list
 */
errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
{
        ext2_dblist     dblist;
        errcode_t       retval;

        retval = make_dblist(src->fs, src->size, src->count, src->list,
                             &dblist);
        if (retval)
                return retval;
        dblist->sorted = src->sorted;
        *dest = dblist;
        return 0;
}

/*
 * Close a directory block list
 *
 * (moved to closefs.c)
 */


/*
 * Add a directory block to the directory block list
 */
errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
                               int blockcnt)
{
        struct ext2_db_entry    *new_entry;
        errcode_t               retval;
        unsigned long           old_size;

        EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);

        if (dblist->count >= dblist->size) {
                old_size = dblist->size * sizeof(struct ext2_db_entry);
                dblist->size += 100;
                retval = ext2fs_resize_mem(old_size, (size_t) dblist->size *
                                           sizeof(struct ext2_db_entry),
                                           &dblist->list);
                if (retval) {
                        dblist->size -= 100;
                        return retval;
                }
        }
        new_entry = dblist->list + ( (int) dblist->count++);
        new_entry->blk = blk;
        new_entry->ino = ino;
        new_entry->blockcnt = blockcnt;

        dblist->sorted = 0;

        return 0;
}

/*
 * Change the directory block to the directory block list
 */
errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
                               int blockcnt)
{
        dgrp_t                  i;

        EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);

        for (i=0; i < dblist->count; i++) {
                if ((dblist->list[i].ino != ino) ||
                    (dblist->list[i].blockcnt != blockcnt))
                        continue;
                dblist->list[i].blk = blk;
                dblist->sorted = 0;
                return 0;
        }
        return EXT2_ET_DB_NOT_FOUND;
}

void ext2fs_dblist_sort(ext2_dblist dblist,
                        int (*sortfunc)(const void *,
                                                    const void *))
{
        if (!sortfunc)
                sortfunc = dir_block_cmp;
        qsort(dblist->list, (size_t) dblist->count,
              sizeof(struct ext2_db_entry), sortfunc);
        dblist->sorted = 1;
}

/*
 * This function iterates over the directory block list
 */
errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
                                int (*func)(ext2_filsys fs,
                                            struct ext2_db_entry *db_info,
                                            void        *priv_data),
                                void *priv_data)
{
        ext2_ino_t      i;
        int             ret;

        EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);

        if (!dblist->sorted)
                ext2fs_dblist_sort(dblist, 0);
        for (i=0; i < dblist->count; i++) {
                ret = (*func)(dblist->fs, &dblist->list[(int)i], priv_data);
                if (ret & DBLIST_ABORT)
                        return 0;
        }
        return 0;
}

static int dir_block_cmp(const void *a, const void *b)
{
        const struct ext2_db_entry *db_a =
                (const struct ext2_db_entry *) a;
        const struct ext2_db_entry *db_b =
                (const struct ext2_db_entry *) b;

        if (db_a->blk != db_b->blk)
                return (int) (db_a->blk - db_b->blk);

        if (db_a->ino != db_b->ino)
                return (int) (db_a->ino - db_b->ino);

        return (int) (db_a->blockcnt - db_b->blockcnt);
}

int ext2fs_dblist_count(ext2_dblist dblist)
{
        return (int) dblist->count;
}