// Blake2b returns the 64-byte BLAKE2b cryptographic
// hash of the Frame. This is useful for hashing and
// de-duplicating a stream of Frames.
//
// reference: https://godoc.org/github.com/codahale/blake2
// reference: https://blake2.net/
// reference: https://tools.ietf.org/html/rfc7693
//
func (f *Frame) Blake2b() []byte {
h, err := blake2b.New(nil)
panicOn(err)
n := f.NumBytes()
var m [24]byte
binary.LittleEndian.PutUint64(m[:8], uint64(f.Prim))
switch {
case n == 8:
h.Write(m[:8])
default:
pti := f.GetPTI()
switch pti {
case PtiOneInt64:
binary.LittleEndian.PutUint64(m[8:16], uint64(f.Ude))
h.Write(m[:16])
case PtiOneFloat64:
binary.LittleEndian.PutUint64(m[8:16], math.Float64bits(f.V0))
h.Write(m[:16])
case PtiTwo64:
binary.LittleEndian.PutUint64(m[8:16], math.Float64bits(f.V0))
binary.LittleEndian.PutUint64(m[16:24], uint64(f.Ude))
h.Write(m[:24])
case PtiUDE:
binary.LittleEndian.PutUint64(m[8:16], uint64(f.Ude))
h.Write(m[:16])
h.Write(f.Data)
}
}
return []byte(h.Sum(nil))
}
// Blake2bUint64 returns an 8 byte BLAKE2b cryptographic
// hash of the raw.
//
// we're using the pure go: https://github.com/dchest/blake2b
//
// but the C-wrapped refence may be helpful as well --
//
// reference: https://godoc.org/github.com/codahale/blake2
// reference: https://blake2.net/
// reference: https://tools.ietf.org/html/rfc7693
//
func Blake2bUint64(raw []byte) uint64 {
cfg := &blake2b.Config{Size: 8}
h, err := blake2b.New(cfg)
panicOn(err)
h.Write(raw)
by := h.Sum(nil)
return binary.LittleEndian.Uint64(by[:8])
}