collate.c

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/*
 * 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*/,
};

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;
}