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Diffstat (limited to 'lib/fnv/fnv.h')
| -rw-r--r-- | lib/fnv/fnv.h | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/lib/fnv/fnv.h b/lib/fnv/fnv.h new file mode 100644 index 0000000000..5249366731 --- /dev/null +++ b/lib/fnv/fnv.h @@ -0,0 +1,250 @@ +/* + * 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 <stdlib.h> +#include <stdint.h> + +#define FNV_VERSION "5.0.2" /* @(#) FNV Version */ + + +/* + * 32 bit FNV-0 hash type + */ +typedef uint32_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 uint64_t Fnv64_t; +#else /* HAVE_64BIT_LONG_LONG */ +typedef struct { + uint32_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__ */ |