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26 * \brief Implementation of a generic, opaque hash table data type.
28 * \author Ian Romanick <ian.d.romanick@intel.com>
38 typedef unsigned (*hash_func_t
)(const void *key
);
39 typedef int (*hash_compare_func_t
)(const void *key1
, const void *key2
);
42 * Hash table constructor
44 * Creates a hash table with the specified number of buckets. The supplied
45 * \c hash and \c compare routines are used when adding elements to the table
46 * and when searching for elements in the table.
48 * \param num_buckets Number of buckets (bins) in the hash table.
49 * \param hash Function used to compute hash value of input keys.
50 * \param compare Function used to compare keys.
52 extern struct hash_table
*hash_table_ctor(unsigned num_buckets
,
53 hash_func_t hash
, hash_compare_func_t compare
);
57 * Release all memory associated with a hash table
60 * This function cannot release memory occupied either by keys or data.
62 extern void hash_table_dtor(struct hash_table
*ht
);
66 * Flush all entries from a hash table
68 * \param ht Table to be cleared of its entries.
70 extern void hash_table_clear(struct hash_table
*ht
);
74 * Search a hash table for a specific element
76 * \param ht Table to be searched
77 * \param key Key of the desired element
80 * The \c data value supplied to \c hash_table_insert when the element with
81 * the matching key was added. If no matching key exists in the table,
82 * \c NULL is returned.
84 extern void *hash_table_find(struct hash_table
*ht
, const void *key
);
88 * Add an element to a hash table
90 extern void hash_table_insert(struct hash_table
*ht
, void *data
,
95 * Compute hash value of a string
97 * Computes the hash value of a string using the DJB2 algorithm developed by
98 * Professor Daniel J. Bernstein. It was published on comp.lang.c once upon
99 * a time. I was unable to find the original posting in the archives.
101 * \param key Pointer to a NUL terminated string to be hashed.
103 * \sa hash_table_string_compare
105 extern unsigned hash_table_string_hash(const void *key
);
109 * Compare two strings used as keys
111 * This is just a macro wrapper around \c strcmp.
113 * \sa hash_table_string_hash
115 #define hash_table_string_compare ((hash_compare_func_t) strcmp)
117 #endif /* HASH_TABLE_H */