feat(head): use uniform head extract & crc64 -> md5

gold/head/raw.go

@@ -0,0 +1,22 @@
+package head
+
+import (
+	"crypto/md5"
+	"encoding/binary"
+)
+
+// CRC64 extract packet header checksum
+func CRC64(data []byte) uint64 {
+	return binary.LittleEndian.Uint64(data[52:PacketHeadLen])
+}
+
+// CalcCRC64 calculate packet header checksum
+func CalcCRC64(data []byte) uint64 {
+	m := md5.Sum(data[:52])
+	return binary.LittleEndian.Uint64(m[:8])
+}
+
+// Hash extract 32 bytes blake2b hash from raw bytes
+func Hash(data []byte) []byte {
+	return data[20:52]
+}