bind9/lib/isc/include/isc/hash.h
2019-05-21 10:23:17 +00:00

62 lines
1.6 KiB
C

/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
#ifndef ISC_HASH_H
#define ISC_HASH_H 1
#include <inttypes.h>
#include <stdbool.h>
#include "isc/lang.h"
#include "isc/types.h"
/***
*** Functions
***/
ISC_LANG_BEGINDECLS
const void *
isc_hash_get_initializer(void);
void
isc_hash_set_initializer(const void *initializer);
uint64_t
isc_hash_function(const void *data, const size_t length,
const bool case_sensitive);
/*!<
* \brief Calculate a hash over data.
*
* This hash function is useful for hashtables. The hash function is
* opaque and not important to the caller. The returned hash values are
* non-deterministic and will have different mapping every time a
* process using this library is run, but will have uniform
* distribution.
*
* isc_hash_function() calculates the hash from start to end over the
* input data.
*
* 'data' is the data to be hashed.
*
* 'length' is the size of the data to be hashed.
*
* 'case_sensitive' specifies whether the hash key should be treated as
* case_sensitive values. It should typically be false if the hash key
* is a DNS name.
*
* WARNING: In case of case insensitive input, the input buffer cannot
* be longer than 1024, which should be fine, as it is only used for
* DNS names.
*/
ISC_LANG_ENDDECLS
#endif /* ISC_HASH_H */