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Diffstat (limited to 'src/libknot/hash/hash-functions.h')
| -rw-r--r-- | src/libknot/hash/hash-functions.h | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/src/libknot/hash/hash-functions.h b/src/libknot/hash/hash-functions.h new file mode 100644 index 0000000..f23730b --- /dev/null +++ b/src/libknot/hash/hash-functions.h @@ -0,0 +1,85 @@ +/*! + * \file hash-functions.h + * + * \author Lubos Slovak <lubos.slovak@nic.cz> + * + * \brief Various hash functions. + * + * All of the hash functions are downloaded from various sources. + * + * \todo Add references to sources. + * + * \addtogroup hashing + * @{ + */ +/* Copyright (C) 2011 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz> + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef _KNOT_HASH_FUNCTIONS_H_ +#define _KNOT_HASH_FUNCTIONS_H_ + +#include <stdint.h> +#include <string.h> + +/* + * Fowler / Noll / Vo Hash (FNV Hash) + * http://www.isthe.com/chongo/tech/comp/fnv/ + * + * This is an implementation of the algorithms posted above. + * This file is placed in the public domain by Peter Wemm. + * + * $FreeBSD: src/sys/sys/fnv_hash.h,v 1.2.2.1 2001/03/21 10:50:59 peter Exp $ + */ + +typedef uint32_t Fnv32_t; + +#define FNV1_32_INIT ((Fnv32_t) 33554467UL) + +#define FNV_32_PRIME ((Fnv32_t) 0x01000193UL) + +static __inline Fnv32_t +fnv_32_buf(const void *buf, size_t len, Fnv32_t hval) +{ + const uint8_t *s = (const uint8_t *)buf; + + while (len-- != 0) { + hval *= FNV_32_PRIME; + hval ^= *s++; + } + return hval; +} + +/*! + * \brief Jenkins hash function. + * + * Downloaded from http://burtleburtle.net/bob/hash/evahash.html + * + * \param k Data to hash + * \param length Size of the data in bytes. + * \param initval The previous hash or an arbitrary value. + * + * \return Hash of the data. + * + * \todo Add source. + */ +typedef unsigned long int ub4; /* unsigned 4-byte quantities */ +typedef unsigned char ub1; /* unsigned 1-byte quantities */ + +ub4 jhash(register ub1 *k, register ub4 length, register ub4 initval); + +#endif /* _KNOT_HASH_FUNCTIONS_H_ */ + +/*! @} */ |