// HashE returns a hash code for an object.
// Uses iseq.Hashable.Hash if the interface is implemented.
// It special cases Go numbers and strings.
// Returns an error if the object is not covered by these cases.
func HashE(v interface{}) (uint32, error) {
if h, ok := v.(iseq.Hashable); ok {
return h.Hash(), nil
}
switch v := v.(type) {
case bool, int, int8, int32, int64:
return murmur3.HashUInt64(uint64(reflect.ValueOf(v).Int())), nil
case uint, uint8, uint32, uint64:
return murmur3.HashUInt64(uint64(reflect.ValueOf(v).Uint())), nil
case float32, float64:
return murmur3.HashUInt64(math.Float64bits(reflect.ValueOf(v).Float())), nil
case nil:
return murmur3.HashUInt64(0), nil
case string:
return murmur3.HashString(v), nil
case complex64, complex128:
return HashComplex128(v.(complex128)), nil
}
return 0, errors.New("don't know how to hash")
}
// HashComplex128 computes a hash for a complex128
func HashComplex128(c complex128) uint32 {
hash := murmur3.MixHash(
murmur3.HashUInt64(math.Float64bits(real(c))),
murmur3.HashUInt64(math.Float64bits(imag(c))))
return murmur3.Finalize(hash, 2)
}
