fnv.h

/*
 * fnv - Fowler/Noll/Vo- hash code
 *
 * @(#) $Revision: 5.4 $
 * @(#) $Id: fnv.h,v 5.4 2009/07/30 22:49:13 chongo Exp $
 * @(#) $Source: /usr/local/src/cmd/fnv/RCS/fnv.h,v $
 *
 ***
 *
 * Fowler/Noll/Vo- hash
 *
 * The basis of this hash algorithm was taken from an idea sent
 * as reviewer comments to the IEEE POSIX P1003.2 committee by:
 *
 *      Phong Vo (http://www.research.att.com/info/kpv/)
 *      Glenn Fowler (http://www.research.att.com/~gsf/)
 *
 * In a subsequent ballot round:
 *
 *      Landon Curt Noll (http://www.isthe.com/chongo/)
 *
 * improved on their algorithm.  Some people tried this hash
 * and found that it worked rather well.  In an EMail message
 * to Landon, they named it the ``Fowler/Noll/Vo'' or FNV hash.
 *
 * FNV hashes are designed to be fast while maintaining a low
 * collision rate. The FNV speed allows one to quickly hash lots
 * of data while maintaining a reasonable collision rate.  See:
 *
 *      http://www.isthe.com/chongo/tech/comp/fnv/index.html
 *
 * for more details as well as other forms of the FNV hash.
 *
 ***
 *
 * NOTE: The FNV-0 historic hash is not recommended.  One should use
 *	 the FNV-1 hash instead.
 *
 * To use the 32 bit FNV-0 historic hash, pass FNV0_32_INIT as the
 * Fnv32_t hashval argument to fnv_32_buf() or fnv_32_str().
 *
 * To use the 64 bit FNV-0 historic hash, pass FNV0_64_INIT as the
 * Fnv64_t hashval argument to fnv_64_buf() or fnv_64_str().
 *
 * To use the recommended 32 bit FNV-1 hash, pass FNV1_32_INIT as the
 * Fnv32_t hashval argument to fnv_32_buf() or fnv_32_str().
 *
 * To use the recommended 64 bit FNV-1 hash, pass FNV1_64_INIT as the
 * Fnv64_t hashval argument to fnv_64_buf() or fnv_64_str().
 *
 * To use the recommended 32 bit FNV-1a hash, pass FNV1_32A_INIT as the
 * Fnv32_t hashval argument to fnv_32a_buf() or fnv_32a_str().
 *
 * To use the recommended 64 bit FNV-1a hash, pass FNV1A_64_INIT as the
 * Fnv64_t hashval argument to fnv_64a_buf() or fnv_64a_str().
 *
 ***
 *
 * Please do not copyright this code.  This code is in the public domain.
 *
 * LANDON CURT NOLL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO
 * EVENT SHALL LANDON CURT NOLL BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 *
 * By:
 *	chongo <Landon Curt Noll> /\oo/\
 *      http://www.isthe.com/chongo/
 *
 * Share and Enjoy!	:-)
 */

#if !defined(__FNV_H__)
#define __FNV_H__

#include <sys/types.h>

#define FNV_VERSION "5.0.2"	/* @(#) FNV Version */


/*
 * 32 bit FNV-0 hash type
 */
typedef u_int32_t Fnv32_t;


/*
 * 32 bit FNV-0 zero initial basis
 *
 * This historic hash is not recommended.  One should use
 * the FNV-1 hash and initial basis instead.
 */
#define FNV0_32_INIT ((Fnv32_t)0)


/*
 * 32 bit FNV-1 and FNV-1a non-zero initial basis
 *
 * The FNV-1 initial basis is the FNV-0 hash of the following 32 octets:
 *
 *              chongo <Landon Curt Noll> /\../\
 *
 * NOTE: The \'s above are not back-slashing escape characters.
 * They are literal ASCII  backslash 0x5c characters.
 *
 * NOTE: The FNV-1a initial basis is the same value as FNV-1 by definition.
 */
#define FNV1_32_INIT ((Fnv32_t)0x811c9dc5)
#define FNV1_32A_INIT FNV1_32_INIT


/*
 * determine how 64 bit unsigned values are represented
 */
#include "longlong.h"


/*
 * 64 bit FNV-0 hash
 */
#if defined(HAVE_64BIT_LONG_LONG)
typedef u_int64_t Fnv64_t;
#else /* HAVE_64BIT_LONG_LONG */
typedef struct {
    u_int32_t w32[2]; /* w32[0] is low order, w32[1] is high order word */
} Fnv64_t;
#endif /* HAVE_64BIT_LONG_LONG */


/*
 * 64 bit FNV-0 zero initial basis
 *
 * This historic hash is not recommended.  One should use
 * the FNV-1 hash and initial basis instead.
 */
#if defined(HAVE_64BIT_LONG_LONG)
#define FNV0_64_INIT ((Fnv64_t)0)
#else /* HAVE_64BIT_LONG_LONG */
extern const Fnv64_t fnv0_64_init;
#define FNV0_64_INIT (fnv0_64_init)
#endif /* HAVE_64BIT_LONG_LONG */


/*
 * 64 bit FNV-1 non-zero initial basis
 *
 * The FNV-1 initial basis is the FNV-0 hash of the following 32 octets:
 *
 *              chongo <Landon Curt Noll> /\../\
 *
 * NOTE: The \'s above are not back-slashing escape characters.
 * They are literal ASCII  backslash 0x5c characters.
 *
 * NOTE: The FNV-1a initial basis is the same value as FNV-1 by definition.
 */
#if defined(HAVE_64BIT_LONG_LONG)
#define FNV1_64_INIT ((Fnv64_t)0xcbf29ce484222325ULL)
#define FNV1A_64_INIT FNV1_64_INIT
#else /* HAVE_64BIT_LONG_LONG */
extern const fnv1_64_init;
extern const Fnv64_t fnv1a_64_init;
#define FNV1_64_INIT (fnv1_64_init)
#define FNV1A_64_INIT (fnv1a_64_init)
#endif /* HAVE_64BIT_LONG_LONG */


/*
 * hash types
 */
enum fnv_type {
    FNV_NONE = 0,	/* invalid FNV hash type */
    FNV0_32 = 1,	/* FNV-0 32 bit hash */
    FNV1_32 = 2,	/* FNV-1 32 bit hash */
    FNV1a_32 = 3,	/* FNV-1a 32 bit hash */
    FNV0_64 = 4,	/* FNV-0 64 bit hash */
    FNV1_64 = 5,	/* FNV-1 64 bit hash */
    FNV1a_64 = 6,	/* FNV-1a 64 bit hash */
};


/*
 * these test vectors are used as part o the FNV test suite
 */
struct test_vector {
    void *buf;		/* start of test vector buffer */
    int len;		/* length of test vector */
};
struct fnv0_32_test_vector {
    struct test_vector *test;	/* test vector buffer to hash */
    Fnv32_t fnv0_32;		/* expected FNV-0 32 bit hash value */
};
struct fnv1_32_test_vector {
    struct test_vector *test;	/* test vector buffer to hash */
    Fnv32_t fnv1_32;		/* expected FNV-1 32 bit hash value */
};
struct fnv1a_32_test_vector {
    struct test_vector *test;	/* test vector buffer to hash */
    Fnv32_t fnv1a_32;		/* expected FNV-1a 32 bit hash value */
};
struct fnv0_64_test_vector {
    struct test_vector *test;	/* test vector buffer to hash */
    Fnv64_t fnv0_64;		/* expected FNV-0 64 bit hash value */
};
struct fnv1_64_test_vector {
    struct test_vector *test;	/* test vector buffer to hash */
    Fnv64_t fnv1_64;		/* expected FNV-1 64 bit hash value */
};
struct fnv1a_64_test_vector {
    struct test_vector *test;	/* test vector buffer to hash */
    Fnv64_t fnv1a_64;		/* expected FNV-1a 64 bit hash value */
};


/*
 * external functions
 */
/* hash_32.c */
extern Fnv32_t fnv_32_buf(void *buf, size_t len, Fnv32_t hashval);
extern Fnv32_t fnv_32_str(char *buf, Fnv32_t hashval);

/* hash_32a.c */
extern Fnv32_t fnv_32a_buf(void *buf, size_t len, Fnv32_t hashval);
extern Fnv32_t fnv_32a_str(char *buf, Fnv32_t hashval);

/* hash_64.c */
extern Fnv64_t fnv_64_buf(void *buf, size_t len, Fnv64_t hashval);
extern Fnv64_t fnv_64_str(char *buf, Fnv64_t hashval);

/* hash_64a.c */
extern Fnv64_t fnv_64a_buf(void *buf, size_t len, Fnv64_t hashval);
extern Fnv64_t fnv_64a_str(char *buf, Fnv64_t hashval);

/* test_fnv.c */
extern struct test_vector fnv_test_str[];
extern struct fnv0_32_test_vector fnv0_32_vector[];
extern struct fnv1_32_test_vector fnv1_32_vector[];
extern struct fnv1a_32_test_vector fnv1a_32_vector[];
extern struct fnv0_64_test_vector fnv0_64_vector[];
extern struct fnv1_64_test_vector fnv1_64_vector[];
extern struct fnv1a_64_test_vector fnv1a_64_vector[];
extern void unknown_hash_type(char *prog, enum fnv_type type, int code);
extern void print_fnv32(Fnv32_t hval, Fnv32_t mask, int verbose, char *arg);
extern void print_fnv64(Fnv64_t hval, Fnv64_t mask, int verbose, char *arg);


#endif /* __FNV_H__ */