Files
go-mc/nbt/read.go
2019-05-18 01:08:32 +08:00

82 lines
1.6 KiB
Go

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
}