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