can parse TAG_String

nbt/read.go

@@ -0,0 +1,81 @@
+package nbt
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+func Unmarshal(data []byte, v interface{}) error {
+	return NewDecoder(bytes.NewReader(data)).Decode(v)
+}
+
+func (d *Decoder) Decode(v interface{}) error {
+	val := reflect.ValueOf(v)
+	if val.Kind() != reflect.Ptr {
+		return errors.New("non-pointer passed to Unmarshal")
+	}
+	return d.unmarshal(val.Elem())
+}
+
+// func (d *Decoder) unmarshalInt(val reflect.Value) error {
+
+// }
+
+func (d *Decoder) unmarshal(val reflect.Value) error {
+	tagType, err := d.r.ReadByte()
+	if err != nil {
+		return err
+	}
+
+	var tagName string
+	if !d.nameless { //Read Tag
+		if tagName, err = d.readString(); err != nil {
+			return err
+		}
+	}
+
+	switch tagType {
+	default:
+		return fmt.Errorf("unknown tag 0x%2x", tagType)
+	case TagString:
+		if val.Kind() != reflect.String {
+			return errors.New("cannot unmarshal TAG_String into " + val.Kind().String())
+		}
+
+		s, err := d.readString()
+		if err != nil {
+			return err
+		}
+
+		val.SetString(s)
+	case TagCompound:
+		if val.Kind() != reflect.Struct {
+			return errors.New("cannot unmarshal TAG_Compound into " + val.Kind().String())
+		}
+		fmt.Println("TagName:", tagName)
+	}
+
+	return nil
+}
+
+func (d *Decoder) readNByte(n int) (buf []byte, err error) {
+	buf = make([]byte, n)
+	_, err = d.r.Read(buf) //what happend if (returned n) != (argument n) ?
+	return
+}
+
+func (d *Decoder) readInt16() (int16, error) {
+	data, err := d.readNByte(2)
+	return int16(data[0])<<4 | int16(data[1]), err
+}
+
+func (d *Decoder) readString() (string, error) {
+	length, err := d.readInt16()
+	if err != nil {
+		return "", err
+	}
+	buf, err := d.readNByte(int(length))
+	return string(buf), err
+}