Import FNV-1a
This commit is contained in:
Chris Young
parent
c659e11585
commit
4c2d40b35e
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/*
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* fnv - Fowler/Noll/Vo- hash code
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*
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* @(#) $Revision: 5.4 $
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* @(#) $Id: fnv.h,v 5.4 2009/07/30 22:49:13 chongo Exp $
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* @(#) $Source: /usr/local/src/cmd/fnv/RCS/fnv.h,v $
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*
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***
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*
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* Fowler/Noll/Vo- hash
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*
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* The basis of this hash algorithm was taken from an idea sent
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* as reviewer comments to the IEEE POSIX P1003.2 committee by:
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*
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* Phong Vo (http://www.research.att.com/info/kpv/)
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* Glenn Fowler (http://www.research.att.com/~gsf/)
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*
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* In a subsequent ballot round:
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*
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* Landon Curt Noll (http://www.isthe.com/chongo/)
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*
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* improved on their algorithm. Some people tried this hash
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* and found that it worked rather well. In an EMail message
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* to Landon, they named it the ``Fowler/Noll/Vo'' or FNV hash.
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*
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* FNV hashes are designed to be fast while maintaining a low
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* collision rate. The FNV speed allows one to quickly hash lots
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* of data while maintaining a reasonable collision rate. See:
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*
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* http://www.isthe.com/chongo/tech/comp/fnv/index.html
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*
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* for more details as well as other forms of the FNV hash.
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*
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***
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*
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* NOTE: The FNV-0 historic hash is not recommended. One should use
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* the FNV-1 hash instead.
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*
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* To use the 32 bit FNV-0 historic hash, pass FNV0_32_INIT as the
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* Fnv32_t hashval argument to fnv_32_buf() or fnv_32_str().
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*
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* To use the 64 bit FNV-0 historic hash, pass FNV0_64_INIT as the
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* Fnv64_t hashval argument to fnv_64_buf() or fnv_64_str().
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*
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* To use the recommended 32 bit FNV-1 hash, pass FNV1_32_INIT as the
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* Fnv32_t hashval argument to fnv_32_buf() or fnv_32_str().
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*
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* To use the recommended 64 bit FNV-1 hash, pass FNV1_64_INIT as the
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* Fnv64_t hashval argument to fnv_64_buf() or fnv_64_str().
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*
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* To use the recommended 32 bit FNV-1a hash, pass FNV1_32A_INIT as the
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* Fnv32_t hashval argument to fnv_32a_buf() or fnv_32a_str().
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*
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* To use the recommended 64 bit FNV-1a hash, pass FNV1A_64_INIT as the
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* Fnv64_t hashval argument to fnv_64a_buf() or fnv_64a_str().
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*
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***
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*
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* Please do not copyright this code. This code is in the public domain.
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*
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* LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
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* EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
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* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*
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* By:
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* chongo <Landon Curt Noll> /\oo/\
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* http://www.isthe.com/chongo/
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*
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* Share and Enjoy! :-)
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*/
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#if !defined(__FNV_H__)
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#define __FNV_H__
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#include <sys/types.h>
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#define FNV_VERSION "5.0.2" /* @(#) FNV Version */
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/*
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* 32 bit FNV-0 hash type
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*/
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typedef u_int32_t Fnv32_t;
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/*
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* 32 bit FNV-0 zero initial basis
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*
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* This historic hash is not recommended. One should use
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* the FNV-1 hash and initial basis instead.
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*/
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#define FNV0_32_INIT ((Fnv32_t)0)
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/*
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* 32 bit FNV-1 and FNV-1a non-zero initial basis
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*
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* The FNV-1 initial basis is the FNV-0 hash of the following 32 octets:
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*
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* chongo <Landon Curt Noll> /\../\
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*
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* NOTE: The \'s above are not back-slashing escape characters.
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* They are literal ASCII backslash 0x5c characters.
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*
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* NOTE: The FNV-1a initial basis is the same value as FNV-1 by definition.
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*/
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#define FNV1_32_INIT ((Fnv32_t)0x811c9dc5)
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#define FNV1_32A_INIT FNV1_32_INIT
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/*
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* determine how 64 bit unsigned values are represented
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*/
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#include "longlong.h"
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/*
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* 64 bit FNV-0 hash
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*/
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#if defined(HAVE_64BIT_LONG_LONG)
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typedef u_int64_t Fnv64_t;
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#else /* HAVE_64BIT_LONG_LONG */
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typedef struct {
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u_int32_t w32[2]; /* w32[0] is low order, w32[1] is high order word */
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} Fnv64_t;
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#endif /* HAVE_64BIT_LONG_LONG */
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/*
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* 64 bit FNV-0 zero initial basis
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*
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* This historic hash is not recommended. One should use
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* the FNV-1 hash and initial basis instead.
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*/
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#if defined(HAVE_64BIT_LONG_LONG)
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#define FNV0_64_INIT ((Fnv64_t)0)
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#else /* HAVE_64BIT_LONG_LONG */
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extern const Fnv64_t fnv0_64_init;
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#define FNV0_64_INIT (fnv0_64_init)
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#endif /* HAVE_64BIT_LONG_LONG */
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/*
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* 64 bit FNV-1 non-zero initial basis
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*
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* The FNV-1 initial basis is the FNV-0 hash of the following 32 octets:
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*
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* chongo <Landon Curt Noll> /\../\
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*
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* NOTE: The \'s above are not back-slashing escape characters.
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* They are literal ASCII backslash 0x5c characters.
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*
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* NOTE: The FNV-1a initial basis is the same value as FNV-1 by definition.
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*/
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#if defined(HAVE_64BIT_LONG_LONG)
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#define FNV1_64_INIT ((Fnv64_t)0xcbf29ce484222325ULL)
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#define FNV1A_64_INIT FNV1_64_INIT
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#else /* HAVE_64BIT_LONG_LONG */
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extern const fnv1_64_init;
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extern const Fnv64_t fnv1a_64_init;
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#define FNV1_64_INIT (fnv1_64_init)
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#define FNV1A_64_INIT (fnv1a_64_init)
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#endif /* HAVE_64BIT_LONG_LONG */
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/*
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* hash types
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*/
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enum fnv_type {
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FNV_NONE = 0, /* invalid FNV hash type */
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FNV0_32 = 1, /* FNV-0 32 bit hash */
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FNV1_32 = 2, /* FNV-1 32 bit hash */
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FNV1a_32 = 3, /* FNV-1a 32 bit hash */
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FNV0_64 = 4, /* FNV-0 64 bit hash */
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FNV1_64 = 5, /* FNV-1 64 bit hash */
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FNV1a_64 = 6, /* FNV-1a 64 bit hash */
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};
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/*
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* these test vectors are used as part o the FNV test suite
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*/
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struct test_vector {
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void *buf; /* start of test vector buffer */
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int len; /* length of test vector */
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};
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struct fnv0_32_test_vector {
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struct test_vector *test; /* test vector buffer to hash */
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Fnv32_t fnv0_32; /* expected FNV-0 32 bit hash value */
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};
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struct fnv1_32_test_vector {
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struct test_vector *test; /* test vector buffer to hash */
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Fnv32_t fnv1_32; /* expected FNV-1 32 bit hash value */
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};
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struct fnv1a_32_test_vector {
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struct test_vector *test; /* test vector buffer to hash */
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Fnv32_t fnv1a_32; /* expected FNV-1a 32 bit hash value */
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};
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struct fnv0_64_test_vector {
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struct test_vector *test; /* test vector buffer to hash */
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Fnv64_t fnv0_64; /* expected FNV-0 64 bit hash value */
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};
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struct fnv1_64_test_vector {
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struct test_vector *test; /* test vector buffer to hash */
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Fnv64_t fnv1_64; /* expected FNV-1 64 bit hash value */
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};
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struct fnv1a_64_test_vector {
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struct test_vector *test; /* test vector buffer to hash */
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Fnv64_t fnv1a_64; /* expected FNV-1a 64 bit hash value */
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};
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/*
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* external functions
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*/
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/* hash_32.c */
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extern Fnv32_t fnv_32_buf(void *buf, size_t len, Fnv32_t hashval);
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extern Fnv32_t fnv_32_str(char *buf, Fnv32_t hashval);
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/* hash_32a.c */
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extern Fnv32_t fnv_32a_buf(void *buf, size_t len, Fnv32_t hashval);
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extern Fnv32_t fnv_32a_str(char *buf, Fnv32_t hashval);
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/* hash_64.c */
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extern Fnv64_t fnv_64_buf(void *buf, size_t len, Fnv64_t hashval);
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extern Fnv64_t fnv_64_str(char *buf, Fnv64_t hashval);
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/* hash_64a.c */
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extern Fnv64_t fnv_64a_buf(void *buf, size_t len, Fnv64_t hashval);
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extern Fnv64_t fnv_64a_str(char *buf, Fnv64_t hashval);
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/* test_fnv.c */
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extern struct test_vector fnv_test_str[];
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extern struct fnv0_32_test_vector fnv0_32_vector[];
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extern struct fnv1_32_test_vector fnv1_32_vector[];
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extern struct fnv1a_32_test_vector fnv1a_32_vector[];
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extern struct fnv0_64_test_vector fnv0_64_vector[];
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extern struct fnv1_64_test_vector fnv1_64_vector[];
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extern struct fnv1a_64_test_vector fnv1a_64_vector[];
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extern void unknown_hash_type(char *prog, enum fnv_type type, int code);
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extern void print_fnv32(Fnv32_t hval, Fnv32_t mask, int verbose, char *arg);
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extern void print_fnv64(Fnv64_t hval, Fnv64_t mask, int verbose, char *arg);
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#endif /* __FNV_H__ */
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/*
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* hash_32 - 32 bit Fowler/Noll/Vo FNV-1a hash code
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*
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* @(#) $Revision: 5.1 $
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* @(#) $Id: hash_32a.c,v 5.1 2009/06/30 09:13:32 chongo Exp $
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* @(#) $Source: /usr/local/src/cmd/fnv/RCS/hash_32a.c,v $
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*
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***
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*
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* Fowler/Noll/Vo hash
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*
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* The basis of this hash algorithm was taken from an idea sent
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* as reviewer comments to the IEEE POSIX P1003.2 committee by:
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*
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* Phong Vo (http://www.research.att.com/info/kpv/)
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* Glenn Fowler (http://www.research.att.com/~gsf/)
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*
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* In a subsequent ballot round:
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*
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* Landon Curt Noll (http://www.isthe.com/chongo/)
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*
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* improved on their algorithm. Some people tried this hash
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* and found that it worked rather well. In an EMail message
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* to Landon, they named it the ``Fowler/Noll/Vo'' or FNV hash.
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*
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* FNV hashes are designed to be fast while maintaining a low
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* collision rate. The FNV speed allows one to quickly hash lots
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* of data while maintaining a reasonable collision rate. See:
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*
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* http://www.isthe.com/chongo/tech/comp/fnv/index.html
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*
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* for more details as well as other forms of the FNV hash.
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***
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*
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* To use the recommended 32 bit FNV-1a hash, pass FNV1_32A_INIT as the
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* Fnv32_t hashval argument to fnv_32a_buf() or fnv_32a_str().
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*
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***
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*
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* Please do not copyright this code. This code is in the public domain.
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*
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* LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
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* EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
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* USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
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* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*
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* By:
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* chongo <Landon Curt Noll> /\oo/\
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* http://www.isthe.com/chongo/
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*
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* Share and Enjoy! :-)
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*/
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#include <stdlib.h>
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#include "fnv.h"
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/*
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* 32 bit magic FNV-1a prime
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*/
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#define FNV_32_PRIME ((Fnv32_t)0x01000193)
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/*
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* fnv_32a_buf - perform a 32 bit Fowler/Noll/Vo FNV-1a hash on a buffer
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*
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* input:
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* buf - start of buffer to hash
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* len - length of buffer in octets
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* hval - previous hash value or 0 if first call
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*
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* returns:
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* 32 bit hash as a static hash type
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*
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* NOTE: To use the recommended 32 bit FNV-1a hash, use FNV1_32A_INIT as the
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* hval arg on the first call to either fnv_32a_buf() or fnv_32a_str().
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*/
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Fnv32_t
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fnv_32a_buf(void *buf, size_t len, Fnv32_t hval)
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{
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unsigned char *bp = (unsigned char *)buf; /* start of buffer */
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unsigned char *be = bp + len; /* beyond end of buffer */
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/*
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* FNV-1a hash each octet in the buffer
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*/
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while (bp < be) {
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/* xor the bottom with the current octet */
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hval ^= (Fnv32_t)*bp++;
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/* multiply by the 32 bit FNV magic prime mod 2^32 */
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#if defined(NO_FNV_GCC_OPTIMIZATION)
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hval *= FNV_32_PRIME;
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#else
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hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
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#endif
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}
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/* return our new hash value */
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return hval;
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}
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/*
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* fnv_32a_str - perform a 32 bit Fowler/Noll/Vo FNV-1a hash on a string
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*
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* input:
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* str - string to hash
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* hval - previous hash value or 0 if first call
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*
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* returns:
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* 32 bit hash as a static hash type
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*
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* NOTE: To use the recommended 32 bit FNV-1a hash, use FNV1_32A_INIT as the
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* hval arg on the first call to either fnv_32a_buf() or fnv_32a_str().
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*/
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Fnv32_t
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fnv_32a_str(char *str, Fnv32_t hval)
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{
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unsigned char *s = (unsigned char *)str; /* unsigned string */
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/*
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* FNV-1a hash each octet in the buffer
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*/
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while (*s) {
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/* xor the bottom with the current octet */
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hval ^= (Fnv32_t)*s++;
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/* multiply by the 32 bit FNV magic prime mod 2^32 */
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#if defined(NO_FNV_GCC_OPTIMIZATION)
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hval *= FNV_32_PRIME;
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#else
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hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
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#endif
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}
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/* return our new hash value */
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return hval;
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}
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