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eeff
73 lines
2.7 KiB
C
73 lines
2.7 KiB
C
/**
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* NEURON IIoT System for Industry 4.0
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* Copyright (C) 2020-2021 EMQ Technologies Co., Ltd All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 3 of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but 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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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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**/
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#ifndef __NEU_HASH_TABLE_H__
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#define __NEU_HASH_TABLE_H__
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stdint.h>
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#include <string.h>
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// Open addressing hash table, but we use a better probe ( taken from Python)
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// to avoid hitting the same positions. Our hash algorithm is just the low
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// order bits, and we use table sizes that are powers of two.
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typedef struct neu_hash_table neu_hash_table;
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typedef struct neu_hash_table_entry neu_hash_table_entry;
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typedef size_t (*neu_hash_table_hash_cb)(const char *);
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typedef void (*neu_hash_table_free_cb)(void *);
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// NB: These details are entirely private to the hash implementation.
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// They are provided here to facilitate inlining in structures.
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struct neu_hash_table {
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size_t cap;
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size_t count;
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size_t load;
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size_t min_load; // considers placeholders
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size_t max_load;
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neu_hash_table_entry * entries;
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neu_hash_table_hash_cb hash_cb;
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neu_hash_table_free_cb free_cb;
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};
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// The provided `free_cb` could be NULL, so that you manage memory yourself.
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extern void neu_hash_table_init(neu_hash_table * m,
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neu_hash_table_hash_cb hash_cb,
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neu_hash_table_free_cb free_cb);
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extern void neu_hash_table_fini(neu_hash_table *m);
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extern void *neu_hash_table_get(neu_hash_table *m, const char *key);
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// The hash table take ownership of the value but not the key.
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// Returns 0 on success, NEU_ERR_EINVAL if val is NULL, NEU_ERR_ENOMEM if not
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// sufficient memory.
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extern int neu_hash_table_set(neu_hash_table *m, const char *key, void *val);
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// Returns 0 on success, NEU_ERR_ENOENT if the key does not exist.
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extern int neu_hash_table_remove(neu_hash_table *m, const char *key);
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extern size_t neu_hash_cstr(const char *cstr);
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#ifdef __cplusplus
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}
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#endif
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#endif // __NEU_HASH_TABLE_H__
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