1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * |
4 | * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved. |
5 | * |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/types.h> |
10 | |
11 | #include "ntfs_fs.h" |
12 | |
13 | static inline u16 upcase_unicode_char(const u16 *upcase, u16 chr) |
14 | { |
15 | if (chr < 'a') |
16 | return chr; |
17 | |
18 | if (chr <= 'z') |
19 | return chr - ('a' - 'A'); |
20 | |
21 | return upcase[chr]; |
22 | } |
23 | |
24 | /* |
25 | * ntfs_cmp_names |
26 | * |
27 | * Thanks Kari Argillander <kari.argillander@gmail.com> for idea and implementation 'bothcase' |
28 | * |
29 | * Straight way to compare names: |
30 | * - Case insensitive |
31 | * - If name equals and 'bothcases' then |
32 | * - Case sensitive |
33 | * 'Straight way' code scans input names twice in worst case. |
34 | * Optimized code scans input names only once. |
35 | */ |
36 | int ntfs_cmp_names(const __le16 *s1, size_t l1, const __le16 *s2, size_t l2, |
37 | const u16 *upcase, bool bothcase) |
38 | { |
39 | int diff1 = 0; |
40 | int diff2; |
41 | size_t len = min(l1, l2); |
42 | |
43 | if (!bothcase && upcase) |
44 | goto case_insentive; |
45 | |
46 | for (; len; s1++, s2++, len--) { |
47 | diff1 = le16_to_cpu(*s1) - le16_to_cpu(*s2); |
48 | if (diff1) { |
49 | if (bothcase && upcase) |
50 | goto case_insentive; |
51 | |
52 | return diff1; |
53 | } |
54 | } |
55 | return l1 - l2; |
56 | |
57 | case_insentive: |
58 | for (; len; s1++, s2++, len--) { |
59 | diff2 = upcase_unicode_char(upcase, le16_to_cpu(*s1)) - |
60 | upcase_unicode_char(upcase, le16_to_cpu(*s2)); |
61 | if (diff2) |
62 | return diff2; |
63 | } |
64 | |
65 | diff2 = l1 - l2; |
66 | return diff2 ? diff2 : diff1; |
67 | } |
68 | |
69 | int ntfs_cmp_names_cpu(const struct cpu_str *uni1, const struct le_str *uni2, |
70 | const u16 *upcase, bool bothcase) |
71 | { |
72 | const u16 *s1 = uni1->name; |
73 | const __le16 *s2 = uni2->name; |
74 | size_t l1 = uni1->len; |
75 | size_t l2 = uni2->len; |
76 | size_t len = min(l1, l2); |
77 | int diff1 = 0; |
78 | int diff2; |
79 | |
80 | if (!bothcase && upcase) |
81 | goto case_insentive; |
82 | |
83 | for (; len; s1++, s2++, len--) { |
84 | diff1 = *s1 - le16_to_cpu(*s2); |
85 | if (diff1) { |
86 | if (bothcase && upcase) |
87 | goto case_insentive; |
88 | |
89 | return diff1; |
90 | } |
91 | } |
92 | return l1 - l2; |
93 | |
94 | case_insentive: |
95 | for (; len; s1++, s2++, len--) { |
96 | diff2 = upcase_unicode_char(upcase, chr: *s1) - |
97 | upcase_unicode_char(upcase, le16_to_cpu(*s2)); |
98 | if (diff2) |
99 | return diff2; |
100 | } |
101 | |
102 | diff2 = l1 - l2; |
103 | return diff2 ? diff2 : diff1; |
104 | } |
105 | |
106 | /* Helper function for ntfs_d_hash. */ |
107 | unsigned long ntfs_names_hash(const u16 *name, size_t len, const u16 *upcase, |
108 | unsigned long hash) |
109 | { |
110 | while (len--) { |
111 | unsigned int c = upcase_unicode_char(upcase, chr: *name++); |
112 | hash = partial_name_hash(c, prevhash: hash); |
113 | } |
114 | |
115 | return hash; |
116 | } |
117 | |