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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
Copyright 2014 Michal Schmidt
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <string.h>
#include "hash-funcs.h"
#include "path-util.h"
void string_hash_func(const void *p, struct siphash *state) {
siphash24_compress(p, strlen(p) + 1, state);
}
int string_compare_func(const void *a, const void *b) {
return strcmp(a, b);
}
const struct hash_ops string_hash_ops = {
.hash = string_hash_func,
.compare = string_compare_func
};
void path_hash_func(const void *p, struct siphash *state) {
const char *q = p;
size_t n;
assert(q);
assert(state);
/* Calculates a hash for a path in a way this duplicate inner slashes don't make a differences, and also
* whether there's a trailing slash or not. This fits well with the semantics of path_compare(), which does
* similar checks and also doesn't care for trailing slashes. Note that relative and absolute paths (i.e. those
* which begin in a slash or not) will hash differently though. */
n = strspn(q, "/");
if (n > 0) { /* Eat up initial slashes, and add one "/" to the hash for all of them */
siphash24_compress(q, 1, state);
q += n;
}
for (;;) {
/* Determine length of next component */
n = strcspn(q, "/");
if (n == 0) /* Reached the end? */
break;
/* Add this component to the hash and skip over it */
siphash24_compress(q, n, state);
q += n;
/* How many slashes follow this component? */
n = strspn(q, "/");
if (q[n] == 0) /* Is this a trailing slash? If so, we are at the end, and don't care about the slashes anymore */
break;
/* We are not add the end yet. Hash exactly one slash for all of the ones we just encountered. */
siphash24_compress(q, 1, state);
q += n;
}
}
int path_compare_func(const void *a, const void *b) {
return path_compare(a, b);
}
const struct hash_ops path_hash_ops = {
.hash = path_hash_func,
.compare = path_compare_func
};
void trivial_hash_func(const void *p, struct siphash *state) {
siphash24_compress(&p, sizeof(p), state);
}
int trivial_compare_func(const void *a, const void *b) {
return a < b ? -1 : (a > b ? 1 : 0);
}
const struct hash_ops trivial_hash_ops = {
.hash = trivial_hash_func,
.compare = trivial_compare_func
};
void uint64_hash_func(const void *p, struct siphash *state) {
siphash24_compress(p, sizeof(uint64_t), state);
}
int uint64_compare_func(const void *_a, const void *_b) {
uint64_t a, b;
a = *(const uint64_t*) _a;
b = *(const uint64_t*) _b;
return a < b ? -1 : (a > b ? 1 : 0);
}
const struct hash_ops uint64_hash_ops = {
.hash = uint64_hash_func,
.compare = uint64_compare_func
};
#if SIZEOF_DEV_T != 8
void devt_hash_func(const void *p, struct siphash *state) {
siphash24_compress(p, sizeof(dev_t), state);
}
int devt_compare_func(const void *_a, const void *_b) {
dev_t a, b;
a = *(const dev_t*) _a;
b = *(const dev_t*) _b;
return a < b ? -1 : (a > b ? 1 : 0);
}
const struct hash_ops devt_hash_ops = {
.hash = devt_hash_func,
.compare = devt_compare_func
};
#endif
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