add serdes (start) for elkrem

elkrem/serdes.go

@@ -0,0 +1,72 @@
+package elkrem
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+)
+
+//type ElkremNode struct {
+//	i   uint64        // index (ith node)
+//	h   uint8         // height of this node
+//	sha *wire.ShaHash // hash
+//}
+//type ElkremSender struct {
+//	current    uint64        // last sent hash index
+//	treeHeight uint8         // height of tree (size is 2**height -1 )
+//	maxIndex   uint64        // top of the tree
+//	root       *wire.ShaHash // root hash of the tree
+//}
+//type ElkremReceiver struct {
+//	current    uint64       // last received index (actually don't need it?)
+//	treeHeight uint8        // height of tree (size is 2**height -1 )
+//	s          []ElkremNode // store of received hashes, max size = height
+//}
+
+// ToBytes turns an ElkremNode into a 41 byte long byte slice.
+// 8 byte index, 1 byte height, 32 byte hash
+func (e *ElkremNode) ToBytes() ([]byte, error) {
+	var buf bytes.Buffer
+
+	err := binary.Write(&buf, binary.BigEndian, e.i)
+	if err != nil {
+		return nil, err
+	}
+	err = binary.Write(&buf, binary.BigEndian, e.h)
+	if err != nil {
+		return nil, err
+	}
+	n, err := buf.Write(e.sha.Bytes())
+	if err != nil {
+		return nil, err
+	}
+	if n != 32 {
+		return nil, fmt.Errorf("%d byte hash, expect 32", n)
+	}
+
+	return buf.Bytes(), nil
+}
+
+// FromBytes turns an ElkremNode into a 41 byte long byte slice.
+// 8 byte index, 1 byte height, 32 byte hash
+
+func ElkremNodeFromBytes([]byte) (ElkremNode, error) {
+	var e ElkremNode
+	return e, nil
+}
+
+func (e *ElkremSender) ToBytes() ([]byte, error) {
+	return nil, nil
+}
+
+func (e *ElkremSender) FromBytes([]byte) error {
+	return nil
+}
+
+func (e *ElkremReceiver) ToBytes() ([]byte, error) {
+	return nil, nil
+}
+
+func (e *ElkremReceiver) FromBytes([]byte) error {
+	return nil
+}