182 lines
5.2 KiB
C
182 lines
5.2 KiB
C
/*
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* Copyright (C) 2008-2012 Tobias Brunner
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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/**
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* @defgroup hashtable hashtable
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* @{ @ingroup collections
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*/
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#ifndef HASHTABLE_H_
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#define HASHTABLE_H_
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#include <collections/enumerator.h>
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typedef struct hashtable_t hashtable_t;
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/**
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* Prototype for a function that computes the hash code from the given key.
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*
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* @param key key to hash
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* @return hash code
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*/
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typedef u_int (*hashtable_hash_t)(const void *key);
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/**
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* Hashtable hash function calculation the hash solely based on the key pointer.
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*
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* @param key key to hash
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* @return hash of key
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*/
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u_int hashtable_hash_ptr(const void *key);
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/**
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* Hashtable hash function calculation the hash for char* keys.
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*
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* @param key key to hash, a char*
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* @return hash of key
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*/
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u_int hashtable_hash_str(const void *key);
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/**
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* Prototype for a function that compares the two keys for equality.
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*
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* @param key first key (the one we are looking for)
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* @param other_key second key
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* @return TRUE if the keys are equal
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*/
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typedef bool (*hashtable_equals_t)(const void *key, const void *other_key);
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/**
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* Hashtable equals function comparing pointers.
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*
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* @param key key to compare
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* @param other_key other key to compare
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* @return TRUE if key == other_key
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*/
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bool hashtable_equals_ptr(const void *key, const void *other_key);
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/**
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* Hashtable equals function comparing char* keys.
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*
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* @param key key to compare
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* @param other_key other key to compare
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* @return TRUE if streq(key, other_key)
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*/
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bool hashtable_equals_str(const void *key, const void *other_key);
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/**
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* Class implementing a hash table.
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*
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* General purpose hash table. This hash table is not synchronized.
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*/
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struct hashtable_t {
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/**
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* Create an enumerator over the hash table key/value pairs.
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*
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* @return enumerator over (void *key, void *value)
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*/
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enumerator_t *(*create_enumerator) (hashtable_t *this);
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/**
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* Adds the given value with the given key to the hash table, if there
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* exists no entry with that key. NULL is returned in this case.
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* Otherwise the existing value is replaced and the function returns the
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* old value.
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*
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* @param key the key to store
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* @param value the value to store
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* @return NULL if no item was replaced, the old value otherwise
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*/
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void *(*put) (hashtable_t *this, const void *key, void *value);
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/**
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* Returns the value with the given key, if the hash table contains such an
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* entry, otherwise NULL is returned.
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*
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* @param key the key of the requested value
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* @return the value, NULL if not found
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*/
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void *(*get) (hashtable_t *this, const void *key);
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/**
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* Returns the value with a matching key, if the hash table contains such an
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* entry, otherwise NULL is returned.
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*
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* Compared to get() the given match function is used to compare the keys
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* for equality. The hash function does have to be deviced properly in
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* order to make this work if the match function compares keys differently
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* than the equals function provided to the constructor. This basically
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* allows to enumerate all entries with the same hash value.
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*
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* @param key the key to match against
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* @param match match function to be used when comparing keys
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* @return the value, NULL if not found
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*/
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void *(*get_match) (hashtable_t *this, const void *key,
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hashtable_equals_t match);
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/**
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* Removes the value with the given key from the hash table and returns the
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* removed value (or NULL if no such value existed).
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*
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* @param key the key of the value to remove
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* @return the removed value, NULL if not found
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*/
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void *(*remove) (hashtable_t *this, const void *key);
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/**
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* Removes the key and value pair from the hash table at which the given
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* enumerator currently points.
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*
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* @param enumerator enumerator, from create_enumerator
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*/
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void (*remove_at) (hashtable_t *this, enumerator_t *enumerator);
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/**
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* Gets the number of items in the hash table.
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*
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* @return number of items
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*/
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u_int (*get_count) (hashtable_t *this);
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/**
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* Destroys a hash table object.
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*/
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void (*destroy) (hashtable_t *this);
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/**
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* Destroys a hash table object and calls the given function for each
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* item and its key in the hash table.
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*
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* @param function function to call on each item and key
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*/
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void (*destroy_function)(hashtable_t *this,
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void (*)(void *val, const void *key));
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};
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/**
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* Creates an empty hash table object.
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*
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* @param hash hash function
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* @param equals equals function
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* @param capacity initial capacity
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* @return hashtable_t object.
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*/
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hashtable_t *hashtable_create(hashtable_hash_t hash, hashtable_equals_t equals,
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u_int capacity);
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#endif /** HASHTABLE_H_ @}*/
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