Add PlaintextSize method to Enclaves

core/enclave.go

@@ -113,3 +113,10 @@ func Open(e *Enclave) (*Buffer, error) {
 	// Return the contents of the Enclave inside a Buffer.
 	return b, nil
 }
+
+/*
+EnclaveSize returns the number of bytes of plaintext data stored inside an Enclave.
+*/
+func EnclaveSize(e *Enclave) int {
+	return len(e.ciphertext) - Overhead
+}

core/enclave_test.go

@@ -135,3 +135,9 @@ func TestOpen(t *testing.T) {
 		t.Error("expected nil buffer in error case")
 	}
 }
+
+func TestEnclaveSize(t *testing.T) {
+	if EnclaveSize(&Enclave{make([]byte, 1234)}) != 1234-Overhead {
+		t.Error("invalid enclave size")
+	}
+}

enclave.go

@@ -50,3 +50,10 @@ func (e *Enclave) Open() (*LockedBuffer, error) {
 	b.Freeze()
 	return newBuffer(b), nil
 }
+
+/*
+Size returns the number of bytes of data stored within an Enclave.
+*/
+func (e *Enclave) Size() int {
+	return core.EnclaveSize(e.Enclave)
+}

enclave_test.go

@@ -60,6 +60,9 @@ func TestOpen(t *testing.T) {
 	if b == nil {
 		t.Error("buffer should not be nil")
 	}
+	if e.Size() != b.Size() {
+		t.Error("sizes don't match")
+	}
 	if !bytes.Equal(b.Bytes(), []byte("yellow submarine")) {
 		t.Error("data does not match")
 	}