collate.c
3.59 KB
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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*/,
};
/**
* 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;
}