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26 * \brief Implementation of a generic, opaque hash table data type.
28 * \author Ian Romanick <ian.d.romanick@intel.com>
36 typedef unsigned (*hash_func_t)(const void *key);
37 typedef int (*hash_compare_func_t)(const void *key1, const void *key2);
44 * Hash table constructor
46 * Creates a hash table with the specified number of buckets. The supplied
47 * \c hash and \c compare routines are used when adding elements to the table
48 * and when searching for elements in the table.
50 * \param num_buckets Number of buckets (bins) in the hash table.
51 * \param hash Function used to compute hash value of input keys.
52 * \param compare Function used to compare keys.
54 extern struct hash_table *hash_table_ctor(unsigned num_buckets,
55 hash_func_t hash, hash_compare_func_t compare);
59 * Release all memory associated with a hash table
62 * This function cannot release memory occupied either by keys or data.
64 extern void hash_table_dtor(struct hash_table *ht);
68 * Flush all entries from a hash table
70 * \param ht Table to be cleared of its entries.
72 extern void hash_table_clear(struct hash_table *ht);
76 * Search a hash table for a specific element
78 * \param ht Table to be searched
79 * \param key Key of the desired element
82 * The \c data value supplied to \c hash_table_insert when the element with
83 * the matching key was added. If no matching key exists in the table,
84 * \c NULL is returned.
86 extern void *hash_table_find(struct hash_table *ht, const void *key);
90 * Add an element to a hash table
92 extern void hash_table_insert(struct hash_table *ht, void *data,
96 * Remove a specific element from a hash table.
98 extern void hash_table_remove(struct hash_table *ht, const void *key);
101 * Compute hash value of a string
103 * Computes the hash value of a string using the DJB2 algorithm developed by
104 * Professor Daniel J. Bernstein. It was published on comp.lang.c once upon
105 * a time. I was unable to find the original posting in the archives.
107 * \param key Pointer to a NUL terminated string to be hashed.
109 * \sa hash_table_string_compare
111 extern unsigned hash_table_string_hash(const void *key);
115 * Compare two strings used as keys
117 * This is just a macro wrapper around \c strcmp.
119 * \sa hash_table_string_hash
121 #define hash_table_string_compare ((hash_compare_func_t) strcmp)
125 * Compute hash value of a pointer
127 * \param key Pointer to be used as a hash key
130 * The memory pointed to by \c key is \b never accessed. The value of \c key
131 * itself is used as the hash key
133 * \sa hash_table_pointer_compare
136 hash_table_pointer_hash(const void *key);
140 * Compare two pointers used as keys
142 * \sa hash_table_pointer_hash
145 hash_table_pointer_compare(const void *key1, const void *key2);
148 hash_table_call_foreach(struct hash_table *ht,
149 void (*callback)(const void *key,
157 #endif /* HASH_TABLE_H */