1 /*
2 * collate.c - NTFS kernel collation handling. Part of the Linux-NTFS project.
3 *
4 * Copyright (c) 2004 Anton Altaparmakov
5 *
6 * This program/include file is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as published
8 * by the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program/include file is distributed in the hope that it will be
12 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program (in the main directory of the Linux-NTFS
18 * distribution in the file COPYING); if not, write to the Free Software
19 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22 #include "collate.h"
23 #include "debug.h"
24 #include "ntfs.h"
25
ntfs_collate_binary(ntfs_volume * vol,const void * data1,const int data1_len,const void * data2,const int data2_len)26 static int ntfs_collate_binary(ntfs_volume *vol,
27 const void *data1, const int data1_len,
28 const void *data2, const int data2_len)
29 {
30 int rc;
31
32 ntfs_debug("Entering.");
33 rc = memcmp(data1, data2, min(data1_len, data2_len));
34 if (!rc && (data1_len != data2_len)) {
35 if (data1_len < data2_len)
36 rc = -1;
37 else
38 rc = 1;
39 }
40 ntfs_debug("Done, returning %i", rc);
41 return rc;
42 }
43
ntfs_collate_ntofs_ulong(ntfs_volume * vol,const void * data1,const int data1_len,const void * data2,const int data2_len)44 static int ntfs_collate_ntofs_ulong(ntfs_volume *vol,
45 const void *data1, const int data1_len,
46 const void *data2, const int data2_len)
47 {
48 int rc;
49 u32 d1, d2;
50
51 ntfs_debug("Entering.");
52 // FIXME: We don't really want to bug here.
53 BUG_ON(data1_len != data2_len);
54 BUG_ON(data1_len != 4);
55 d1 = le32_to_cpup(data1);
56 d2 = le32_to_cpup(data2);
57 if (d1 < d2)
58 rc = -1;
59 else {
60 if (d1 == d2)
61 rc = 0;
62 else
63 rc = 1;
64 }
65 ntfs_debug("Done, returning %i", rc);
66 return rc;
67 }
68
69 typedef int (*ntfs_collate_func_t)(ntfs_volume *, const void *, const int,
70 const void *, const int);
71
72 static ntfs_collate_func_t ntfs_do_collate0x0[3] = {
73 ntfs_collate_binary,
74 NULL/*ntfs_collate_file_name*/,
75 NULL/*ntfs_collate_unicode_string*/,
76 };
77
78 static ntfs_collate_func_t ntfs_do_collate0x1[4] = {
79 ntfs_collate_ntofs_ulong,
80 NULL/*ntfs_collate_ntofs_sid*/,
81 NULL/*ntfs_collate_ntofs_security_hash*/,
82 NULL/*ntfs_collate_ntofs_ulongs*/,
83 };
84
85 /**
86 * ntfs_collate - collate two data items using a specified collation rule
87 * @vol: ntfs volume to which the data items belong
88 * @cr: collation rule to use when comparing the items
89 * @data1: first data item to collate
90 * @data1_len: length in bytes of @data1
91 * @data2: second data item to collate
92 * @data2_len: length in bytes of @data2
93 *
94 * Collate the two data items @data1 and @data2 using the collation rule @cr
95 * and return -1, 0, ir 1 if @data1 is found, respectively, to collate before,
96 * to match, or to collate after @data2.
97 *
98 * For speed we use the collation rule @cr as an index into two tables of
99 * function pointers to call the appropriate collation function.
100 */
ntfs_collate(ntfs_volume * vol,COLLATION_RULE cr,const void * data1,const int data1_len,const void * data2,const int data2_len)101 int ntfs_collate(ntfs_volume *vol, COLLATION_RULE cr,
102 const void *data1, const int data1_len,
103 const void *data2, const int data2_len) {
104 int i;
105
106 ntfs_debug("Entering.");
107 /*
108 * FIXME: At the moment we only support COLLATION_BINARY and
109 * COLLATION_NTOFS_ULONG, so we BUG() for everything else for now.
110 */
111 BUG_ON(cr != COLLATION_BINARY && cr != COLLATION_NTOFS_ULONG);
112 i = le32_to_cpu(cr);
113 BUG_ON(i < 0);
114 if (i <= 0x02)
115 return ntfs_do_collate0x0[i](vol, data1, data1_len,
116 data2, data2_len);
117 BUG_ON(i < 0x10);
118 i -= 0x10;
119 if (likely(i <= 3))
120 return ntfs_do_collate0x1[i](vol, data1, data1_len,
121 data2, data2_len);
122 BUG();
123 return 0;
124 }
125