Merge branch 'design' of github.com:system-transparency/stfe into design

1 files changed, 57 insertions, 0 deletions

diff --git a/types/trunnel.go b/types/trunnel.go
new file mode 100644
index 0000000..72ae68d
--- /dev/null
+++ b/types/trunnel.go
@@ -0,0 +1,57 @@
+package types
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+const (
+	// MessageSize is the number of bytes in a Trunnel-encoded leaf message
+	MessageSize = 8 + HashSize
+	// LeafSize is the number of bytes in a Trunnel-encoded leaf
+	LeafSize = MessageSize + SignatureSize + HashSize
+)
+
+// Marshal returns a Trunnel-encoded message
+func (m *Message) Marshal() []byte {
+	buf := make([]byte, MessageSize)
+	binary.BigEndian.PutUint64(buf, m.ShardHint)
+	copy(buf[8:], m.Checksum[:])
+	return buf
+}
+
+// Marshal returns a Trunnel-encoded leaf
+func (l *Leaf) Marshal() []byte {
+	buf := l.Message.Marshal()
+	buf = append(buf, l.SigIdent.Signature[:]...)
+	buf = append(buf, l.SigIdent.KeyHash[:]...)
+	return buf
+}
+
+// Marshal returns a Trunnel-encoded tree head
+func (th *TreeHead) Marshal() []byte {
+	buf := make([]byte, 8+8+HashSize)
+	binary.BigEndian.PutUint64(buf[0:8], th.Timestamp)
+	binary.BigEndian.PutUint64(buf[8:16], th.TreeSize)
+	copy(buf[16:], th.RootHash[:])
+	return buf
+}
+
+// Unmarshal parses the Trunnel-encoded buffer as a leaf
+func (l *Leaf) Unmarshal(buf []byte) error {
+	if len(buf) != LeafSize {
+		return fmt.Errorf("invalid leaf size: %v", len(buf))
+	}
+	// Shard hint
+	l.ShardHint = binary.BigEndian.Uint64(buf)
+	offset := 8
+	// Checksum
+	copy(l.Checksum[:], buf[offset:offset+HashSize])
+	offset += HashSize
+	// Signature
+	copy(l.Signature[:], buf[offset:offset+SignatureSize])
+	offset += SignatureSize
+	// KeyHash
+	copy(l.KeyHash[:], buf[offset:])
+	return nil
+}