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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
758dd67e | 2 | /*** |
96b2fb93 | 3 | Copyright © 2014 Michal Schmidt |
758dd67e LP |
4 | ***/ |
5 | ||
dccca82b LP |
6 | #include <string.h> |
7 | ||
758dd67e | 8 | #include "hash-funcs.h" |
46e16b34 | 9 | #include "path-util.h" |
758dd67e LP |
10 | |
11 | void string_hash_func(const void *p, struct siphash *state) { | |
12 | siphash24_compress(p, strlen(p) + 1, state); | |
13 | } | |
14 | ||
15 | int string_compare_func(const void *a, const void *b) { | |
16 | return strcmp(a, b); | |
17 | } | |
18 | ||
19 | const struct hash_ops string_hash_ops = { | |
20 | .hash = string_hash_func, | |
21 | .compare = string_compare_func | |
22 | }; | |
23 | ||
46e16b34 LP |
24 | void path_hash_func(const void *p, struct siphash *state) { |
25 | const char *q = p; | |
26 | size_t n; | |
27 | ||
28 | assert(q); | |
29 | assert(state); | |
30 | ||
31 | /* Calculates a hash for a path in a way this duplicate inner slashes don't make a differences, and also | |
32 | * whether there's a trailing slash or not. This fits well with the semantics of path_compare(), which does | |
33 | * similar checks and also doesn't care for trailing slashes. Note that relative and absolute paths (i.e. those | |
34 | * which begin in a slash or not) will hash differently though. */ | |
35 | ||
36 | n = strspn(q, "/"); | |
37 | if (n > 0) { /* Eat up initial slashes, and add one "/" to the hash for all of them */ | |
38 | siphash24_compress(q, 1, state); | |
39 | q += n; | |
40 | } | |
41 | ||
42 | for (;;) { | |
43 | /* Determine length of next component */ | |
44 | n = strcspn(q, "/"); | |
45 | if (n == 0) /* Reached the end? */ | |
46 | break; | |
47 | ||
48 | /* Add this component to the hash and skip over it */ | |
49 | siphash24_compress(q, n, state); | |
50 | q += n; | |
51 | ||
52 | /* How many slashes follow this component? */ | |
53 | n = strspn(q, "/"); | |
54 | if (q[n] == 0) /* Is this a trailing slash? If so, we are at the end, and don't care about the slashes anymore */ | |
55 | break; | |
56 | ||
57 | /* We are not add the end yet. Hash exactly one slash for all of the ones we just encountered. */ | |
58 | siphash24_compress(q, 1, state); | |
59 | q += n; | |
60 | } | |
61 | } | |
62 | ||
63 | int path_compare_func(const void *a, const void *b) { | |
64 | return path_compare(a, b); | |
65 | } | |
66 | ||
67 | const struct hash_ops path_hash_ops = { | |
68 | .hash = path_hash_func, | |
69 | .compare = path_compare_func | |
70 | }; | |
71 | ||
758dd67e LP |
72 | void trivial_hash_func(const void *p, struct siphash *state) { |
73 | siphash24_compress(&p, sizeof(p), state); | |
74 | } | |
75 | ||
76 | int trivial_compare_func(const void *a, const void *b) { | |
77 | return a < b ? -1 : (a > b ? 1 : 0); | |
78 | } | |
79 | ||
80 | const struct hash_ops trivial_hash_ops = { | |
81 | .hash = trivial_hash_func, | |
82 | .compare = trivial_compare_func | |
83 | }; | |
84 | ||
85 | void uint64_hash_func(const void *p, struct siphash *state) { | |
86 | siphash24_compress(p, sizeof(uint64_t), state); | |
87 | } | |
88 | ||
89 | int uint64_compare_func(const void *_a, const void *_b) { | |
90 | uint64_t a, b; | |
91 | a = *(const uint64_t*) _a; | |
92 | b = *(const uint64_t*) _b; | |
93 | return a < b ? -1 : (a > b ? 1 : 0); | |
94 | } | |
95 | ||
96 | const struct hash_ops uint64_hash_ops = { | |
97 | .hash = uint64_hash_func, | |
98 | .compare = uint64_compare_func | |
99 | }; | |
100 | ||
101 | #if SIZEOF_DEV_T != 8 | |
102 | void devt_hash_func(const void *p, struct siphash *state) { | |
103 | siphash24_compress(p, sizeof(dev_t), state); | |
104 | } | |
105 | ||
106 | int devt_compare_func(const void *_a, const void *_b) { | |
107 | dev_t a, b; | |
108 | a = *(const dev_t*) _a; | |
109 | b = *(const dev_t*) _b; | |
110 | return a < b ? -1 : (a > b ? 1 : 0); | |
111 | } | |
112 | ||
113 | const struct hash_ops devt_hash_ops = { | |
114 | .hash = devt_hash_func, | |
115 | .compare = devt_compare_func | |
116 | }; | |
117 | #endif |