status-go/vendor/github.com/allegro/bigcache/fnv.go

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2018-12-19 10:02:07 +00:00
package bigcache
// newDefaultHasher returns a new 64-bit FNV-1a Hasher which makes no memory allocations.
// Its Sum64 method will lay the value out in big-endian byte order.
// See https://en.wikipedia.org/wiki/FowlerNollVo_hash_function
func newDefaultHasher() Hasher {
return fnv64a{}
}
type fnv64a struct{}
const (
// offset64 FNVa offset basis. See https://en.wikipedia.org/wiki/FowlerNollVo_hash_function#FNV-1a_hash
offset64 = 14695981039346656037
// prime64 FNVa prime value. See https://en.wikipedia.org/wiki/FowlerNollVo_hash_function#FNV-1a_hash
prime64 = 1099511628211
)
// Sum64 gets the string and returns its uint64 hash value.
func (f fnv64a) Sum64(key string) uint64 {
var hash uint64 = offset64
for i := 0; i < len(key); i++ {
hash ^= uint64(key[i])
hash *= prime64
}
return hash
}