1 files changed, 140 insertions, 0 deletions
diff --git a/types/item.go b/types/item.go
new file mode 100644
index 0000000..5e8836e
--- /dev/null
+++ b/types/item.go
@@ -0,0 +1,140 @@
+package types
+
+import (
+	"fmt"
+
+	"github.com/google/certificate-transparency-go/tls"
+)
+
+// StFormat defines a particular StItem type that is versioned
+type StFormat tls.Enum
+
+const (
+	StFormatReserved           StFormat = 0
+	StFormatSignedTreeHeadV1   StFormat = 1
+	StFormatCosignedTreeHeadV1 StFormat = 2
+	StFormatConsistencyProofV1 StFormat = 3
+	StFormatInclusionProofV1   StFormat = 4
+	StFormatSignedChecksumV1   StFormat = 5
+)
+
+// StItem references a versioned item based on a given format specifier
+type StItem struct {
+	Format             StFormat            `tls:"maxval:65535"`
+	SignedTreeHeadV1   *SignedTreeHeadV1   `tls:"selector:Format,val:1"`
+	CosignedTreeHeadV1 *CosignedTreeHeadV1 `tls:"selector:Format,val:2"`
+	ConsistencyProofV1 *ConsistencyProofV1 `tls:"selector:Format,val:3"`
+	InclusionProofV1   *InclusionProofV1   `tls:"selector:Format,val:4"`
+	SignedChecksumV1   *SignedChecksumV1   `tls:"selector:Format,val:5"`
+}
+
+// TODO: StItemList
+
+type SignedTreeHeadV1 struct {
+	TreeHead  TreeHeadV1
+	Signature SignatureV1
+}
+
+type CosignedTreeHeadV1 struct {
+	SignedTreeHead SignedTreeHeadV1
+	Cosignatures   []SignatureV1 `tls:"minlen:0,maxlen:4294967295"`
+}
+
+type ConsistencyProofV1 struct {
+	LogId           Namespace
+	TreeSize1       uint64
+	TreeSize2       uint64
+	ConsistencyPath []NodeHash `tls:"minlen:0,maxlen:65535"`
+}
+
+type InclusionProofV1 struct {
+	LogId         Namespace
+	TreeSize      uint64
+	LeafIndex     uint64
+	InclusionPath []NodeHash `tls:"minlen:0,maxlen:65535"`
+}
+
+type SignedChecksumV1 struct {
+	Data      ChecksumV1
+	Signature SignatureV1
+}
+
+type ChecksumV1 struct {
+	Identifier []byte `tls:"minlen:1,maxlen:128"`
+	Checksum   []byte `tls:"minlen:1,maxlen:64"`
+}
+
+type TreeHeadV1 struct {
+	Timestamp uint64
+	TreeSize  uint64
+	RootHash  NodeHash
+	Extension []byte `tls:"minlen:0,maxlen:65535"`
+}
+
+type NodeHash struct {
+	Data []byte `tls:"minlen:32,maxlen:255"`
+}
+
+type SignatureV1 struct {
+	Namespace Namespace
+	Signature []byte `tls:"minlen:1,maxlen:65535"`
+}
+
+func (f StFormat) String() string {
+	switch f {
+	case StFormatReserved:
+		return "reserved"
+	case StFormatSignedTreeHeadV1:
+		return "signed_tree_head_v1"
+	case StFormatCosignedTreeHeadV1:
+		return "cosigned_tree_head_v1"
+	case StFormatConsistencyProofV1:
+		return "consistency_proof_v1"
+	case StFormatInclusionProofV1:
+		return "inclusion_proof_v1"
+	case StFormatSignedChecksumV1:
+		return "signed_checksum_v1"
+	default:
+		return fmt.Sprintf("unknown StFormat: %d", f)
+	}
+}
+
+func (i StItem) String() string {
+	switch i.Format {
+	case StFormatReserved:
+		return fmt.Sprintf("Format(%s)", i.Format)
+	case StFormatSignedTreeHeadV1:
+		return fmt.Sprintf("Format(%s): %+v", i.Format, i.SignedTreeHeadV1)
+	case StFormatCosignedTreeHeadV1:
+		return fmt.Sprintf("Format(%s): %+v", i.Format, i.CosignedTreeHeadV1)
+	case StFormatConsistencyProofV1:
+		return fmt.Sprintf("Format(%s): %+v", i.Format, i.ConsistencyProofV1)
+	case StFormatInclusionProofV1:
+		return fmt.Sprintf("Format(%s): %+v", i.Format, i.InclusionProofV1)
+	case StFormatSignedChecksumV1:
+		return fmt.Sprintf("Format(%s): %+v", i.Format, i.SignedChecksumV1)
+	default:
+		return fmt.Sprintf("unknown StItem: %v", i.Format)
+	}
+}
+
+// Marshal marshals a TLS-encodable item
+func Marshal(item interface{}) ([]byte, error) {
+	serialized, err := tls.Marshal(item)
+	if err != nil {
+		return nil, fmt.Errorf("tls.Marshal: %v", err)
+	}
+	return serialized, nil
+}
+
+// Unmarshal unmarshals a TLS-encoded item
+func Unmarshal(serialized []byte, out interface{}) error {
+	extra, err := tls.Unmarshal(serialized, out)
+	if err != nil {
+		return fmt.Errorf("tls.Unmarshal: %v", err)
+	}
+	if len(extra) > 0 {
+		return fmt.Errorf("tls.Unmarshal: extra data: %X", extra)
+	}
+	return nil
+}