125 lines
3.6 KiB
C
125 lines
3.6 KiB
C
/*
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* collate.c - NTFS kernel collation handling. Part of the Linux-NTFS project.
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*
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* Copyright (c) 2004 Anton Altaparmakov
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*
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* This program/include file is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as published
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* by the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program/include file is distributed in the hope that it will be
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* useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program (in the main directory of the Linux-NTFS
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* distribution in the file COPYING); if not, write to the Free Software
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* Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "collate.h"
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#include "debug.h"
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#include "ntfs.h"
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static int ntfs_collate_binary(ntfs_volume *vol,
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const void *data1, const int data1_len,
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const void *data2, const int data2_len)
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{
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int rc;
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ntfs_debug("Entering.");
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rc = memcmp(data1, data2, min(data1_len, data2_len));
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if (!rc && (data1_len != data2_len)) {
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if (data1_len < data2_len)
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rc = -1;
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else
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rc = 1;
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}
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ntfs_debug("Done, returning %i", rc);
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return rc;
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}
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static int ntfs_collate_ntofs_ulong(ntfs_volume *vol,
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const void *data1, const int data1_len,
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const void *data2, const int data2_len)
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{
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int rc;
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u32 d1, d2;
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ntfs_debug("Entering.");
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// FIXME: We don't really want to bug here.
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BUG_ON(data1_len != data2_len);
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BUG_ON(data1_len != 4);
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d1 = le32_to_cpup(data1);
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d2 = le32_to_cpup(data2);
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if (d1 < d2)
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rc = -1;
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else {
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if (d1 == d2)
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rc = 0;
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else
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rc = 1;
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}
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ntfs_debug("Done, returning %i", rc);
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return rc;
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}
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typedef int (*ntfs_collate_func_t)(ntfs_volume *, const void *, const int,
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const void *, const int);
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static ntfs_collate_func_t ntfs_do_collate0x0[3] = {
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ntfs_collate_binary,
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NULL/*ntfs_collate_file_name*/,
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NULL/*ntfs_collate_unicode_string*/,
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};
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static ntfs_collate_func_t ntfs_do_collate0x1[4] = {
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ntfs_collate_ntofs_ulong,
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NULL/*ntfs_collate_ntofs_sid*/,
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NULL/*ntfs_collate_ntofs_security_hash*/,
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NULL/*ntfs_collate_ntofs_ulongs*/,
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};
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/**
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* ntfs_collate - collate two data items using a specified collation rule
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* @vol: ntfs volume to which the data items belong
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* @cr: collation rule to use when comparing the items
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* @data1: first data item to collate
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* @data1_len: length in bytes of @data1
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* @data2: second data item to collate
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* @data2_len: length in bytes of @data2
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*
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* Collate the two data items @data1 and @data2 using the collation rule @cr
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* and return -1, 0, ir 1 if @data1 is found, respectively, to collate before,
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* to match, or to collate after @data2.
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*
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* For speed we use the collation rule @cr as an index into two tables of
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* function pointers to call the appropriate collation function.
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*/
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int ntfs_collate(ntfs_volume *vol, COLLATION_RULE cr,
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const void *data1, const int data1_len,
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const void *data2, const int data2_len) {
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int i;
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ntfs_debug("Entering.");
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/*
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* FIXME: At the moment we only support COLLATION_BINARY and
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* COLLATION_NTOFS_ULONG, so we BUG() for everything else for now.
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*/
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BUG_ON(cr != COLLATION_BINARY && cr != COLLATION_NTOFS_ULONG);
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i = le32_to_cpu(cr);
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BUG_ON(i < 0);
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if (i <= 0x02)
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return ntfs_do_collate0x0[i](vol, data1, data1_len,
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data2, data2_len);
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BUG_ON(i < 0x10);
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i -= 0x10;
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if (likely(i <= 3))
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return ntfs_do_collate0x1[i](vol, data1, data1_len,
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data2, data2_len);
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BUG();
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return 0;
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}
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