1 files changed, 26 insertions, 12 deletions

diff --git a/rrdformat/rrdbinary/unmarshal.go b/rrdformat/rrdbinary/decode.go
index 00f1222..f3ae80e 100644
--- a/rrdformat/rrdbinary/unmarshal.go
+++ b/rrdformat/rrdbinary/decode.go
@@ -15,21 +15,27 @@ type Decoder struct {
 	data []byte
 }
 
+func NewDecoder(arch Architecture, data []byte) *Decoder {
+	return &Decoder{
+		arch: arch,
+		pos:  0,
+		data: data,
+	}
+}
+
 type unmarshaler interface {
 	unmarshalRRD(d *Decoder, tag string) error
 }
 
 func Unmarshal(arch Architecture, data []byte, ptr interface{}) error {
-	ptrValue := reflect.ValueOf(ptr)
-	if ptrValue.Kind() != reflect.Ptr {
-		return typeErrorf("ptr is a %v, not a pointer", ptrValue.Kind())
+	decoder := NewDecoder(arch, data)
+	if err := decoder.Decode(ptr, ""); err != nil {
+		return err
 	}
-	decoder := &Decoder{
-		arch: arch,
-		pos:  0,
-		data: data,
+	if err := decoder.Decode(&EOF{}, ""); err != nil {
+		return err
 	}
-	return decoder.Decode(ptrValue, "")
+	return nil
 }
 
 func (d *Decoder) binError(ctxLen int, msg string) error {
@@ -40,7 +46,15 @@ func (d *Decoder) binErrorf(ctxLen int, format string, a ...interface{}) error {
 	return d.binError(ctxLen, fmt.Sprintf(format, a...))
 }
 
-func (d *Decoder) Decode(v reflect.Value, tag string) error {
+func (d *Decoder) Decode(ptr interface{}, tag string) error {
+	ptrValue := reflect.ValueOf(ptr)
+	if ptrValue.Kind() != reflect.Ptr {
+		return typeErrorf("ptr is a %v, not a pointer", ptrValue.Kind())
+	}
+	return d.decode(ptrValue, tag)
+}
+
+func (d *Decoder) decode(v reflect.Value, tag string) error {
 	if v.CanInterface() {
 		if u, ok := v.Interface().(unmarshaler); ok {
 			return u.unmarshalRRD(d, tag)
@@ -52,7 +66,7 @@ func (d *Decoder) Decode(v reflect.Value, tag string) error {
 	case reflect.Array, reflect.Slice:
 		return d.decodeList(v, tag)
 	default:
-		return typeErrorf("invalid type for rrdbinary.Decoder.Decode: %v", v.Type())
+		return typeErrorf("invalid type for rrdbinary.Decoder: %v", v.Type())
 	}
 }
 
@@ -70,7 +84,7 @@ func (d *Decoder) decodeStruct(v reflect.Value, tag string) error {
 		if tag == "-" {
 			continue
 		}
-		if err := d.Decode(v.Field(i), tag); err != nil {
+		if err := d.decode(v.Field(i), tag); err != nil {
 			return fmt.Errorf("field %s: %w", fieldInfo.Name, err)
 		}
 	}
@@ -82,7 +96,7 @@ func (d *Decoder) decodeList(v reflect.Value, tag string) error {
 	panicUnless(v.CanSet())
 
 	for i := 0; i < v.Len(); i++ {
-		if err := d.Decode(v.Index(i), tag); err != nil {
+		if err := d.decode(v.Index(i), tag); err != nil {
 			return fmt.Errorf("index %d: %w", i, err)
 		}
 	}