rename fastnbt -> dynbt. add some NewXXX api

nbt/decode_test.go

@@ -428,6 +428,22 @@ func TestDecoder_Decode_textUnmarshaler(t *testing.T) {
 	if b != true {
 		t.Errorf("b should be true")
 	}
+
+	var s struct {
+		A TextBool
+	}
+	data = []byte{
+		TagCompound, 0, 0,
+		TagString, 0, 1, 'A', 0, 4, 't', 'r', 'u', 'e',
+		TagEnd,
+	}
+	_, err = NewDecoder(bytes.NewReader(data)).Decode(&s)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if s.A != true {
+		t.Errorf("s.A should be true")
+	}
 }
 
 func TestDecoder_Decode_ErrorUnknownField(t *testing.T) {

nbt/dynbt/decode.go

@@ -1,4 +1,4 @@
-package fastnbt
+package dynbt
 
 import (
 	"encoding/binary"

nbt/dynbt/decode_test.go

@@ -1,4 +1,4 @@
-package fastnbt
+package dynbt
 
 import (
 	"bytes"

nbt/dynbt/encode.go

@@ -1,4 +1,4 @@
-package fastnbt
+package dynbt
 
 import (
 	"errors"

nbt/dynbt/encode_test.go

@@ -1,7 +1,9 @@
-package fastnbt
+package dynbt
 
 import (
 	"bytes"
+	"math/rand"
+	"reflect"
 	"testing"
 
 	"github.com/Tnze/go-mc/nbt"
@@ -37,13 +39,29 @@ func TestValue_new(t *testing.T) {
 	}
 
 	byteArray := make([]byte, 1000)
-	for n := 0; n < 1000; n++ {
+	for n := range byteArray {
 		byteArray[n] = byte((n*n*255 + n*7) % 100)
 	}
 	if val := NewByteArray(byteArray); !bytes.Equal(byteArray, val.ByteArray()) {
 		t.Error("encode byteArray error")
 	}
 
+	intArray := make([]int32, 250)
+	for n := range intArray {
+		intArray[n] = rand.Int31()
+	}
+	if val := NewIntArray(intArray); !reflect.DeepEqual(intArray, val.IntArray()) {
+		t.Error("encode intArray error")
+	}
+
+	longArray := make([]int64, 125)
+	for n := range longArray {
+		longArray[n] = rand.Int63()
+	}
+	if val := NewLongArray(longArray); !reflect.DeepEqual(longArray, val.LongArray()) {
+		t.Error("encode longArray error")
+	}
+
 	val := NewCompound()
 	val.Set("a", NewString("tnze"))
 	if val.Get("a").String() != "tnze" || val.Compound().Len() != 1 {

nbt/dynbt/types.go

@@ -1,4 +1,21 @@
-package fastnbt
+// Package dynbt is a library that provides dynamic NBT operation APIs.
+//
+// Dynamically represented NBT value is useful in many cases, for example,
+//   - You want to store custom structural values at runtime.
+//   - You want to query or modify the data later. (Otherwise use the [nbt.RawMessage])
+//   - You don't know what type the data is at compile time. (Otherwise use the [nbt.RawMessage] too)
+//
+// The [*Value] provides a group of APIs on top of the [nbt] package.
+// [*Value] implements [nbt.Marshaler] and [nbt.Unmarshaler] interfaces.
+// It can be used as a field of struct, or element of slice, map, etc.
+// The pointer type should always be used, unless used as fields for structures
+//
+// Notice that querying Tags in Compound use a linear search, so it's not recommended to use it in a large Compound.
+// The better choice is map[string]*Value for dynamic accessing a large Compound.
+//
+// This package tries its best to not copy data if possible.
+// It returns the underlying data in some cases. Don't modify them!
+package dynbt
 
 import (
 	"encoding/binary"
@@ -62,6 +79,24 @@ func NewByteArray(v []byte) *Value {
 	return &Value{tag: nbt.TagByteArray, data: append(data, v...)}
 }
 
+func NewIntArray(v []int32) *Value {
+	data := make([]byte, 4+len(v)*4)
+	binary.BigEndian.PutUint32(data, uint32(len(v)))
+	for i, j := 0, 4; i < len(v); i, j = i+1, j+4 {
+		binary.BigEndian.PutUint32(data[j:], uint32(v[i]))
+	}
+	return &Value{tag: nbt.TagIntArray, data: data}
+}
+
+func NewLongArray(v []int64) *Value {
+	data := make([]byte, 4+len(v)*8)
+	binary.BigEndian.PutUint32(data, uint32(len(v)))
+	for i, j := 0, 4; i < len(v); i, j = i+1, j+8 {
+		binary.BigEndian.PutUint64(data[j:], uint64(v[i]))
+	}
+	return &Value{tag: nbt.TagLongArray, data: data}
+}
+
 func NewString(str string) *Value {
 	data := make([]byte, 2, 2+len(str))
 	binary.BigEndian.PutUint16(data, uint16(len(str)))
@@ -126,10 +161,16 @@ func (v *Value) Double() float64 {
 }
 
 func (v *Value) List() []*Value {
+	if v.tag != nbt.TagList {
+		return nil
+	}
 	return v.list
 }
 
 func (v *Value) Compound() *Compound {
+	if v.tag != nbt.TagCompound {
+		return nil
+	}
 	return &v.comp
 }
 
@@ -141,10 +182,25 @@ func (v *Value) ByteArray() []byte {
 }
 
 func (v *Value) IntArray() []int32 {
+	if v.tag != nbt.TagIntArray {
+		return nil
+	}
 	length := binary.BigEndian.Uint32(v.data)
 	ret := make([]int32, length)
-	for i := uint32(0); i < length; i += 4 {
-		ret[i] = int32(binary.BigEndian.Uint32(v.data[i:]))
+	for i, j := uint32(0), 4; i < length; i, j = i+1, j+4 {
+		ret[i] = int32(binary.BigEndian.Uint32(v.data[j:]))
+	}
+	return ret
+}
+
+func (v *Value) LongArray() []int64 {
+	if v.tag != nbt.TagLongArray {
+		return nil
+	}
+	length := binary.BigEndian.Uint32(v.data)
+	ret := make([]int64, length)
+	for i, j := uint32(0), 4; i < length; i, j = i+1, j+8 {
+		ret[i] = int64(binary.BigEndian.Uint64(v.data[j:]))
 	}
 	return ret
 }

nbt/dynbt/update.go

@@ -1,4 +1,4 @@
-package fastnbt
+package dynbt
 
 import "github.com/Tnze/go-mc/nbt"