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