root/fs/ntfs/collate.c

DEFINITIONS

1. ntfs_collate_binary
2. ntfs_collate_ntofs_ulong
3. ntfs_collate

/*
 * collate.c - NTFS kernel collation handling.  Part of the Linux-NTFS project.
 *
 * Copyright (c) 2004 Anton Altaparmakov
 *
 * This program/include file 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/include file 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 (in the main directory of the Linux-NTFS
 * distribution in the file COPYING); if not, write to the Free Software
 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "collate.h"
#include "debug.h"
#include "ntfs.h"

static int ntfs_collate_binary(ntfs_volume *vol,
                const void *data1, const int data1_len,
                const void *data2, const int data2_len)
{
        int rc;

        ntfs_debug("Entering.");
        rc = memcmp(data1, data2, min(data1_len, data2_len));
        if (!rc && (data1_len != data2_len)) {
                if (data1_len < data2_len)
                        rc = -1;
                else
                        rc = 1;
        }
        ntfs_debug("Done, returning %i", rc);
        return rc;
}

static int ntfs_collate_ntofs_ulong(ntfs_volume *vol,
                const void *data1, const int data1_len,
                const void *data2, const int data2_len)
{
        int rc;
        u32 d1, d2;

        ntfs_debug("Entering.");
        // FIXME:  We don't really want to bug here.
        BUG_ON(data1_len != data2_len);
        BUG_ON(data1_len != 4);
        d1 = le32_to_cpup(data1);
        d2 = le32_to_cpup(data2);
        if (d1 < d2)
                rc = -1;
        else {
                if (d1 == d2)
                        rc = 0;
                else
                        rc = 1;
        }
        ntfs_debug("Done, returning %i", rc);
        return rc;
}

typedef int (*ntfs_collate_func_t)(ntfs_volume *, const void *, const int,
                const void *, const int);

static ntfs_collate_func_t ntfs_do_collate0x0[3] = {
        ntfs_collate_binary,
        NULL/*ntfs_collate_file_name*/,
        NULL/*ntfs_collate_unicode_string*/,
};

static ntfs_collate_func_t ntfs_do_collate0x1[4] = {
        ntfs_collate_ntofs_ulong,
        NULL/*ntfs_collate_ntofs_sid*/,
        NULL/*ntfs_collate_ntofs_security_hash*/,
        NULL/*ntfs_collate_ntofs_ulongs*/,
};

/**
 * ntfs_collate - collate two data items using a specified collation rule
 * @vol:        ntfs volume to which the data items belong
 * @cr:         collation rule to use when comparing the items
 * @data1:      first data item to collate
 * @data1_len:  length in bytes of @data1
 * @data2:      second data item to collate
 * @data2_len:  length in bytes of @data2
 *
 * Collate the two data items @data1 and @data2 using the collation rule @cr
 * and return -1, 0, ir 1 if @data1 is found, respectively, to collate before,
 * to match, or to collate after @data2.
 *
 * For speed we use the collation rule @cr as an index into two tables of
 * function pointers to call the appropriate collation function.
 */
int ntfs_collate(ntfs_volume *vol, COLLATION_RULE cr,
                const void *data1, const int data1_len,
                const void *data2, const int data2_len) {
        int i;

        ntfs_debug("Entering.");
        /*
         * FIXME:  At the moment we only support COLLATION_BINARY and
         * COLLATION_NTOFS_ULONG, so we BUG() for everything else for now.
         */
        BUG_ON(cr != COLLATION_BINARY && cr != COLLATION_NTOFS_ULONG);
        i = le32_to_cpu(cr);
        BUG_ON(i < 0);
        if (i <= 0x02)
                return ntfs_do_collate0x0[i](vol, data1, data1_len,
                                data2, data2_len);
        BUG_ON(i < 0x10);
        i -= 0x10;
        if (likely(i <= 3))
                return ntfs_do_collate0x1[i](vol, data1, data1_len,
                                data2, data2_len);
        BUG();
        return 0;
}