tape: Implement encoding for "any" values

tape/dynamic.go

@@ -13,8 +13,43 @@ import "reflect"
 //   - string
 //   - []<supported type>
 //   - map[uint16]<supported type>
-func EncodeAny(encoder *Encoder, value any) (Tag, error) {
+func EncodeAny(encoder *Encoder, value any, tag Tag) (n int, err error) {
-	// TODO
+	// primitives
+	switch value := value.(type) {
+	case int:    return encoder.WriteInt32(int32(value))
+	case uint:   return encoder.WriteUint32(uint32(value))
+	case int8:   return encoder.WriteInt8(value)
+	case uint8:  return encoder.WriteUint8(value)
+	case int16:  return encoder.WriteInt16(value)
+	case uint16: return encoder.WriteUint16(value)
+	case int32:  return encoder.WriteInt32(value)
+	case uint32: return encoder.WriteUint32(value)
+	case int64:  return encoder.WriteInt64(value)
+	case uint64: return encoder.WriteUint64(value)
+	case string: return EncodeAny(encoder, []byte(value), tag)
+	case []byte:
+		if tag.Is(LBA) {
+			nn, err := encoder.WriteUintN(uint64(len(value)), tag.CN() + 1)
+			n += nn; if err != nil { return n, err }
+		}
+		nn, err := encoder.Write(value)
+		n += nn; if err != nil { return n, err }
+	}
+
+	// aggregates
+	reflectType := reflect.TypeOf(value)
+	switch reflectType.Kind() {
+	case reflect.Slice:
+		return encodeAnySlice(encoder, value, tag)
+	case reflect.Array:
+		return encodeAnySlice(encoder, reflect.ValueOf(value).Slice(0, reflectType.Len()).Interface(), tag)
+	case reflect.Map:
+		if reflectType.Key() == reflect.TypeOf(uint16(0)) {
+			return encodeAnyMap(encoder, value, tag)
+		}
+		return 0, fmt.Errorf("cannot encode map key %T, key must be uint16", value)
+	}
+	return 0, fmt.Errorf("cannot encode type %T", value)
 }
 
 // TagAny returns the correct tag for an "any" value. Returns an error if the
@@ -27,7 +62,7 @@ func TagAny(value any) (Tag, error) {
 	case int8,  uint8:  return LI.WithCN(0), nil
 	case int16, uint16: return LI.WithCN(1), nil
 	case int32, uint32: return LI.WithCN(3), nil
-	case int64, uint64: return LI.WithCN(8), nil
+	case int64, uint64: return LI.WithCN(7), nil
 	case string:        return bufferLenTag(len(value)), nil
 	case []byte:        return bufferLenTag(len(value)), nil
 	}
@@ -43,5 +78,51 @@ func TagAny(value any) (Tag, error) {
 		}
 		return 0, fmt.Errorf("cannot encode map key %T, key must be uint16", value)
 	}
-	return 0, fmt.Errorf("cannot encode type %T", value)
+	return 0, fmt.Errorf("cannot get tag of type %T", value)
+}
+
+func encodeAnySlice(encoder *Encoder, value any, tag Tag) (n int, err error) {
+	// OTA: <length: UN> <elementTag: tape.Tag> <values>*
+	reflectValue := reflect.ValueOf(value)
+	nn, err := encoder.WriteUintN(uint64(reflectValue.Len()), tag.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	reflectType := reflect.TypeOf(value)
+	oneTag, err := TagAny(reflect.Zero(reflectType.Elem()).Interface())
+	if err != nil { return n, err }
+	for index := 0; index <= reflectValue.Len(); index += 1 {
+		item := reflectValue.Index(index).Interface()
+		itemTag, err := TagAny(item)
+		if err != nil { return n, err }
+		if itemTag.CN() > oneTag.CN() { oneTag = itemTag }
+	}
+	if oneTag.Is(SBA) { oneTag += 1 << 5 }
+	nn, err = encoder.WriteUint8(uint8(oneTag))
+	n += nn; if err != nil { return n, err }
+	for index := 0; index <= reflectValue.Len(); index += 1 {
+		item := reflectValue.Index(index).Interface()
+		nn, err = EncodeAny(encoder, item, oneTag)
+		n += nn; if err != nil { return n, err }
+	}
+	return n, err
+}
+
+func encodeAnyMap(encoder *Encoder, value any, tag Tag) (n int, err error) {
+	// KTV: <length: UN> (<key: U16> <tag: Tag> <value>)*
+	reflectValue := reflect.ValueOf(value)
+	nn, err := encoder.WriteUintN(uint64(reflectValue.Len()), tag.CN() + 1)
+	n += nn; if err != nil { return n, err }
+	iter := reflectValue.MapRange()
+	for iter.Next() {
+		key   := iter.Key().Interface().(uint16)
+		value := iter.Value().Interface()
+		nn, err = encoder.WriteUint16(key)
+		n += nn; if err != nil { return n, err }
+		itemTag, err := TagAny(value)
+		n += nn; if err != nil { return n, err }
+		nn, err = encoder.WriteUint8(uint8(itemTag))
+		n += nn; if err != nil { return n, err }
+		nn, err = EncodeAny(encoder, value, itemTag)
+		n += nn; if err != nil { return n, err }
+	}
+	return n, nil
 }