46e16b347f
This is similar to string_hash_ops but operates one file system paths specifically. It will ensure that "/foo//bar" and "///foo/bar" are considered to be the same path for hashmap purposes. This makes use of the existing path_compare() API, and adds a matching hashing function for it. Note that relative and absolute paths will hash to different values, however whether the path is suffixed with a slash or not is not detected. This matches the existing path_compare() behaviour, and follows the logic that on Linux there can't be two different objects at path /foo/bar and /foo/bar/ either.
66 lines
2.5 KiB
C
66 lines
2.5 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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Copyright 2014 Michal Schmidt
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include "macro.h"
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#include "siphash24.h"
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typedef void (*hash_func_t)(const void *p, struct siphash *state);
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typedef int (*compare_func_t)(const void *a, const void *b);
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struct hash_ops {
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hash_func_t hash;
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compare_func_t compare;
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};
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void string_hash_func(const void *p, struct siphash *state);
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int string_compare_func(const void *a, const void *b) _pure_;
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extern const struct hash_ops string_hash_ops;
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void path_hash_func(const void *p, struct siphash *state);
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int path_compare_func(const void *a, const void *b) _pure_;
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extern const struct hash_ops path_hash_ops;
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/* This will compare the passed pointers directly, and will not dereference them. This is hence not useful for strings
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* or suchlike. */
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void trivial_hash_func(const void *p, struct siphash *state);
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int trivial_compare_func(const void *a, const void *b) _const_;
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extern const struct hash_ops trivial_hash_ops;
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/* 32bit values we can always just embed in the pointer itself, but in order to support 32bit archs we need store 64bit
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* values indirectly, since they don't fit in a pointer. */
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void uint64_hash_func(const void *p, struct siphash *state);
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int uint64_compare_func(const void *a, const void *b) _pure_;
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extern const struct hash_ops uint64_hash_ops;
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/* On some archs dev_t is 32bit, and on others 64bit. And sometimes it's 64bit on 32bit archs, and sometimes 32bit on
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* 64bit archs. Yuck! */
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#if SIZEOF_DEV_T != 8
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void devt_hash_func(const void *p, struct siphash *state) _pure_;
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int devt_compare_func(const void *a, const void *b) _pure_;
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extern const struct hash_ops devt_hash_ops;
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#else
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#define devt_hash_func uint64_hash_func
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#define devt_compare_func uint64_compare_func
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#define devt_hash_ops uint64_hash_ops
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#endif
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