diff options
Diffstat (limited to 'include/fnv_hash.h')
-rw-r--r-- | include/fnv_hash.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/include/fnv_hash.h b/include/fnv_hash.h new file mode 100644 index 00000000..9d8851bd --- /dev/null +++ b/include/fnv_hash.h @@ -0,0 +1,107 @@ +/* + * Fowler / Noll / Vo Hash (FNV Hash) + * http://www.isthe.com/chongo/tech/comp/fnv/ + * + * This is an implementation of the algorithms posted above. + * This file is placed in the public domain by Peter Wemm. + * + * $FreeBSD: src/sys/sys/fnv_hash.h,v 1.2 2001/03/20 02:10:18 peter Exp $ + */ + +typedef unsigned int Fnv32_t; +typedef unsigned long long Fnv64_t; + +#define FNV1_32_INIT ((Fnv32_t) 33554467UL) +#define FNV1_64_INIT ((Fnv64_t) 0xcbf29ce484222325ULL) + +#define FNV_32_PRIME ((Fnv32_t) 0x01000193UL) +#define FNV_64_PRIME ((Fnv64_t) 0x100000001b3ULL) + +static __inline Fnv32_t +fnv_32_buf(const void *buf, size_t len, Fnv32_t hval) +{ + const unsigned char *s = (const unsigned char *)buf; + + while (len-- != 0) { + hval *= FNV_32_PRIME; + hval ^= *s++; + } + return hval; +} + +static __inline Fnv32_t +fnv_32_str(const char *str, Fnv32_t hval) +{ + const unsigned char *s = (const unsigned char *)str; + Fnv32_t c; + + while ((c = *s++) != 0) { + hval *= FNV_32_PRIME; + hval ^= c; + } + return hval; +} + +static __inline Fnv32_t +fnv1a_32_str(const char *str, Fnv32_t hval) +{ + const unsigned char *s = (const unsigned char *)str; + Fnv32_t c; + + while ((c = *s++) != 0) { + hval ^= c; + hval *= FNV_32_PRIME; + } + return hval; +} + +static __inline Fnv32_t +fnv1a_32_strcase(const char *str, Fnv32_t hval) +{ + const unsigned char *s = (const unsigned char *)str; + Fnv32_t c; + + while ((c = *s++) != 0) { + hval ^= toupper(c); + hval *= FNV_32_PRIME; + } + return hval; +} + +static __inline Fnv64_t +fnv_64_buf(const void *buf, size_t len, Fnv64_t hval) +{ + const unsigned char *s = (const unsigned char *)buf; + + while (len-- != 0) { + hval *= FNV_64_PRIME; + hval ^= *s++; + } + return hval; +} + +static __inline Fnv64_t +fnv_64_str(const char *str, Fnv64_t hval) +{ + const unsigned char *s = (const unsigned char *)str; + Fnv64_t c; + + while ((c = *s++) != 0) { + hval *= FNV_64_PRIME; + hval ^= c; + } + return hval; +} + +static __inline Fnv64_t +fnv1a_64_strcase(const char *str, Fnv64_t hval) +{ + const unsigned char *s = (const unsigned char *)str; + Fnv64_t c; + + while ((c = *s++) != 0) { + hval ^= toupper(c); + hval *= FNV_64_PRIME; + } + return hval; +} |