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 * $DragonFly: src/sys/sys/fnv_hash.h,v 1.3 2006/05/20 02:42:13 dillon Exp $ 10 */ 11 12 #ifndef _SYS_FNV_HASH_H_ 13 #define _SYS_FNV_HASH_H_ 14 15 #ifndef _SYS_TYPES_H_ 16 #include <sys/types.h> 17 #endif 18 19 typedef u_int32_t Fnv32_t; 20 typedef u_int64_t Fnv64_t; 21 22 #define FNV1_32_INIT ((Fnv32_t) 33554467UL) 23 #define FNV1_64_INIT ((Fnv64_t) 0xcbf29ce484222325ULL) 24 25 #define FNV_32_PRIME ((Fnv32_t) 0x01000193UL) 26 #define FNV_64_PRIME ((Fnv64_t) 0x100000001b3ULL) 27 28 static __inline Fnv32_t 29 fnv_32_buf(const void *buf, size_t len, Fnv32_t hval) 30 { 31 const u_int8_t *s = (const u_int8_t *)buf; 32 33 while (len-- != 0) { 34 hval *= FNV_32_PRIME; 35 hval ^= *s++; 36 } 37 return hval; 38 } 39 40 static __inline Fnv32_t 41 fnv_32_str(const char *str, Fnv32_t hval) 42 { 43 const u_int8_t *s = (const u_int8_t *)str; 44 Fnv32_t c; 45 46 while ((c = *s++) != 0) { 47 hval *= FNV_32_PRIME; 48 hval ^= c; 49 } 50 return hval; 51 } 52 53 static __inline Fnv64_t 54 fnv_64_buf(const void *buf, size_t len, Fnv64_t hval) 55 { 56 const u_int8_t *s = (const u_int8_t *)buf; 57 58 while (len-- != 0) { 59 hval *= FNV_64_PRIME; 60 hval ^= *s++; 61 } 62 return hval; 63 } 64 65 static __inline Fnv64_t 66 fnv_64_str(const char *str, Fnv64_t hval) 67 { 68 const u_int8_t *s = (const u_int8_t *)str; 69 u_register_t c; /* 32 bit on i386, 64 bit on alpha,ia64 */ 70 71 while ((c = *s++) != 0) { 72 hval *= FNV_64_PRIME; 73 hval ^= c; 74 } 75 return hval; 76 } 77 78 #endif 79