1 /* 2 * Fowler / Noll / Vo Hash (FNV Hash) 3 * http://www.isthe.com/chongo/tech/comp/fnv/ 4 * 5 * This is an implementation of the algorithms posted above. 6 * This file is placed in the public domain by Peter Wemm. 7 * 8 * $FreeBSD: src/sys/sys/fnv_hash.h,v 1.2.2.1 2001/03/21 10:50:59 peter Exp $ 9 */ 10 11 #ifndef _SYS_FNV_HASH_H_ 12 #define _SYS_FNV_HASH_H_ 13 14 #ifndef _SYS_TYPES_H_ 15 #include <sys/types.h> 16 #endif 17 18 typedef u_int32_t Fnv32_t; 19 typedef u_int64_t Fnv64_t; 20 21 #define FNV1_32_INIT ((Fnv32_t) 33554467UL) 22 #define FNV1_64_INIT ((Fnv64_t) 0xcbf29ce484222325ULL) 23 24 #define FNV_32_PRIME ((Fnv32_t) 0x01000193UL) 25 #define FNV_64_PRIME ((Fnv64_t) 0x100000001b3ULL) 26 27 static __inline Fnv32_t 28 fnv_32_buf(const void *buf, size_t len, Fnv32_t hval) 29 { 30 const u_int8_t *s = (const u_int8_t *)buf; 31 32 while (len-- != 0) { 33 hval *= FNV_32_PRIME; 34 hval ^= *s++; 35 } 36 return hval; 37 } 38 39 static __inline Fnv32_t 40 fnv_32_str(const char *str, Fnv32_t hval) 41 { 42 const u_int8_t *s = (const u_int8_t *)str; 43 Fnv32_t c; 44 45 while ((c = *s++) != 0) { 46 hval *= FNV_32_PRIME; 47 hval ^= c; 48 } 49 return hval; 50 } 51 52 static __inline Fnv64_t 53 fnv_64_buf(const void *buf, size_t len, Fnv64_t hval) 54 { 55 const u_int8_t *s = (const u_int8_t *)buf; 56 57 while (len-- != 0) { 58 hval *= FNV_64_PRIME; 59 hval ^= *s++; 60 } 61 return hval; 62 } 63 64 static __inline Fnv64_t 65 fnv_64_str(const char *str, Fnv64_t hval) 66 { 67 const u_int8_t *s = (const u_int8_t *)str; 68 u_register_t c; /* 64 bit on x86_64 */ 69 70 while ((c = *s++) != 0) { 71 hval *= FNV_64_PRIME; 72 hval ^= c; 73 } 74 return hval; 75 } 76 77 #endif 78