77 lines
2.9 KiB
C
77 lines
2.9 KiB
C
// This file contains the definitions of the public functions used by the shash-hashtable library and is part of the shash library
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// Copyright (C) 2023 theboring_XOR
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// This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
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// This program 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 General Public License for more details.
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// You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.
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#ifndef _SHASH_H
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#define _SHASH_H
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#include <assert.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include <time.h>
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#include <stdbool.h>
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#define WORD 32
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#define TRANSFORM_TABLE_MAX_RAND 4294967296
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#define DELTA 1
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// If set to 1, all strings will be hashed to SIMULATED_COLLISON_HASH
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#define SIMULATE_COLLISIONS 0
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#define SIMULATED_COLLISION_HASH 20
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#ifdef __clang__
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#include <builtins.h>
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#define rot32_left(x, y) __builtin_rotateleft32(x, y)
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#else
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#define rot32_left(x, y) (x << y) | (x >> 32 - y)
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#endif
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typedef struct
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{
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char *key;
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unsigned int keylen;
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void *data;
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// gets set to 1 if another key, collides with this elemnts location
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u_int8_t encountered_collision;
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// On collision, this field stores where in the hash table array the second key (with the same hash) is located
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int next_key_location;
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} shash_table_element_t;
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// Contains everything the functions for the hashtables need, to work with, including the hash table itself
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typedef struct
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{
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// stores a transformation table used by the shash_hash function
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unsigned int *transformation_table;
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shash_table_element_t *hash_table;
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unsigned int table_size;
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} shash_hashtable_t;
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// Initialize an empty hastable in hashtable with a size of table_size. Returns -1 on failure
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int shash_init_hashtable(shash_hashtable_t *hashtable, unsigned int table_size);
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// Hash the key key of length len so that it fits in hashtable. Returns the calculated hash
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unsigned int shash_hash(char *key, unsigned int len, shash_hashtable_t *hashtable);
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/* Store the pointer data in hashtable at the key key of length len.
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Returns EXIT_FAILURE when the hashtable is full */
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int shash_set(char *key, unsigned int len, void *data, shash_hashtable_t *hashtable);
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/* Returns the pointer stored at the key key of length len in hashtable.
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Returns ptr to NULL when the key is not found */
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void *shash_get(char *key, unsigned int len, shash_hashtable_t *hashtable);
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// Free up the space allocated for hashtable. Data inside the hastable is NOT freed
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void shash_destroy_hashtable(shash_hashtable_t *hashtable);
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#endif
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