1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 Copyright 2014 Michal Schmidt
8 #include "hash-funcs.h"
11 void string_hash_func(const void *p, struct siphash *state) {
12 siphash24_compress(p, strlen(p) + 1, state);
15 int string_compare_func(const void *a, const void *b) {
19 const struct hash_ops string_hash_ops = {
20 .hash = string_hash_func,
21 .compare = string_compare_func
24 void path_hash_func(const void *p, struct siphash *state) {
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. */
37 if (n > 0) { /* Eat up initial slashes, and add one "/" to the hash for all of them */
38 siphash24_compress(q, 1, state);
43 /* Determine length of next component */
45 if (n == 0) /* Reached the end? */
48 /* Add this component to the hash and skip over it */
49 siphash24_compress(q, n, state);
52 /* How many slashes follow this component? */
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 */
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);
63 int path_compare_func(const void *a, const void *b) {
64 return path_compare(a, b);
67 const struct hash_ops path_hash_ops = {
68 .hash = path_hash_func,
69 .compare = path_compare_func
72 void trivial_hash_func(const void *p, struct siphash *state) {
73 siphash24_compress(&p, sizeof(p), state);
76 int trivial_compare_func(const void *a, const void *b) {
77 return a < b ? -1 : (a > b ? 1 : 0);
80 const struct hash_ops trivial_hash_ops = {
81 .hash = trivial_hash_func,
82 .compare = trivial_compare_func
85 void uint64_hash_func(const void *p, struct siphash *state) {
86 siphash24_compress(p, sizeof(uint64_t), state);
89 int uint64_compare_func(const void *_a, const void *_b) {
91 a = *(const uint64_t*) _a;
92 b = *(const uint64_t*) _b;
93 return a < b ? -1 : (a > b ? 1 : 0);
96 const struct hash_ops uint64_hash_ops = {
97 .hash = uint64_hash_func,
98 .compare = uint64_compare_func
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);
106 int devt_compare_func(const void *_a, const void *_b) {
108 a = *(const dev_t*) _a;
109 b = *(const dev_t*) _b;
110 return a < b ? -1 : (a > b ? 1 : 0);
113 const struct hash_ops devt_hash_ops = {
114 .hash = devt_hash_func,
115 .compare = devt_compare_func