Packer Unpacker: generate length prefix with encoded data

moov-io · Dec 6, 2024 · 83e9046 · 83e9046
1 parent 9183e0c
commit 83e9046
Show file tree

Hide file tree

Showing 2 changed files with 22 additions and 1 deletion.
diff --git a/field/packer_unpacker.go b/field/packer_unpacker.go
@@ -20,7 +20,7 @@ func (p defaultPacker) Pack(value []byte, spec *Spec) ([]byte, error) {
 	}
 
 	// encode the length
-	lengthPrefix, err := spec.Pref.EncodeLength(spec.Length, len(value))
+	lengthPrefix, err := spec.Pref.EncodeLength(spec.Length, len(encodedValue))
 	if err != nil {
 		return nil, fmt.Errorf("failed to encode length: %w", err)
 	}

diff --git a/field/packer_unpacker_test.go b/field/packer_unpacker_test.go
@@ -184,3 +184,24 @@ func TestTrack2Packer(t *testing.T) {
 		})
 	}
 }
+
+func TestPackerandUnpackerWithVariantDataLength(t *testing.T) {
+	spec := &field.Spec{
+		Length:      5,
+		Description: "Field",
+		Enc:         encoding.EBCDIC1047,
+		Pref:        prefix.EBCDIC1047.L,
+	}
+
+	data := []byte{0xc2, 0xa0, 0x31}
+	str := field.NewString(spec)
+	str.SetBytes(data)
+
+	packed, err := str.Pack()
+	require.NoError(t, err)
+	require.Equal(t, 0xf2, packed[0])
+
+	_, err = str.Unpack(packed)
+	require.NoError(t, err)
+	require.Equal(t, data, str.Bytes())
+}