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 #ifndef _SYS_FNV_HASH_H_ 9 #define _SYS_FNV_HASH_H_ 10 11 typedef u_int32_t Fnv32_t; 12 typedef u_int64_t Fnv64_t; 13 14 #define FNV1_32_INIT ((Fnv32_t) 33554467UL) 15 #define FNV1_64_INIT ((Fnv64_t) 0xcbf29ce484222325ULL) 16 17 #define FNV_32_PRIME ((Fnv32_t) 0x01000193UL) 18 #define FNV_64_PRIME ((Fnv64_t) 0x100000001b3ULL) 19 20 static __inline Fnv32_t 21 fnv_32_buf(const void *buf, size_t len, Fnv32_t hval) 22 { 23 const u_int8_t *s = (const u_int8_t *)buf; 24 25 while (len-- != 0) { 26 hval *= FNV_32_PRIME; 27 hval ^= *s++; 28 } 29 return hval; 30 } 31 32 static __inline Fnv32_t 33 fnv_32_str(const char *str, Fnv32_t hval) 34 { 35 const u_int8_t *s = (const u_int8_t *)str; 36 Fnv32_t c; 37 38 while ((c = *s++) != 0) { 39 hval *= FNV_32_PRIME; 40 hval ^= c; 41 } 42 return hval; 43 } 44 45 static __inline Fnv64_t 46 fnv_64_buf(const void *buf, size_t len, Fnv64_t hval) 47 { 48 const u_int8_t *s = (const u_int8_t *)buf; 49 50 while (len-- != 0) { 51 hval *= FNV_64_PRIME; 52 hval ^= *s++; 53 } 54 return hval; 55 } 56 57 static __inline Fnv64_t 58 fnv_64_str(const char *str, Fnv64_t hval) 59 { 60 const u_int8_t *s = (const u_int8_t *)str; 61 u_register_t c; /* 32 bit on i386, 64 bit on alpha */ 62 63 while ((c = *s++) != 0) { 64 hval *= FNV_64_PRIME; 65 hval ^= c; 66 } 67 return hval; 68 } 69 #endif /* _SYS_FNV_HASH_H_ */ 70