Merge pull request 'Fix: #7: Implement some utilities' (#8) from feat/7 into main

Reviewed-on: #8

lib/nbt/NbtUtils.dart

@@ -0,0 +1,119 @@
+import 'package:libac_flutter/nbt/impl/ByteTag.dart';
+import 'package:libac_flutter/nbt/impl/CompoundTag.dart';
+import 'package:libac_flutter/nbt/impl/DoubleTag.dart';
+import 'package:libac_flutter/nbt/impl/IntArrayTag.dart';
+import 'package:libac_flutter/nbt/impl/IntTag.dart';
+import 'package:libac_flutter/nbt/impl/ListTag.dart';
+import 'package:libac_flutter/utils/Vector3.dart';
+
+import '../utils/Vector2.dart';
+import '../utils/uuid/UUID.dart';
+
+class NbtUtils {
+  static void writeBoolean(CompoundTag tag, String name, bool b) {
+    tag.put(name, ByteTag.valueOf(b ? 1 : 0));
+  }
+
+  static bool readBoolean(CompoundTag tag, String name) {
+    if (tag.contains(name)) {
+      return tag.get(name)!.asByte() == 1 ? true : false;
+    } else {
+      return false;
+    }
+  }
+
+  static void writeVector2d(CompoundTag tag, String name, Vector2d pos) {
+    ListTag posTag = ListTag();
+    posTag.add(DoubleTag.valueOf(pos.X));
+    posTag.add(DoubleTag.valueOf(pos.Z));
+    tag.put(name, posTag);
+  }
+
+  static Vector2d readVector2d(CompoundTag tag, String name) {
+    if (tag.contains(name)) {
+      ListTag lst = tag.get(name)! as ListTag;
+      return Vector2d(X: lst.get(0).asDouble(), Z: lst.get(1).asDouble());
+    } else {
+      return Vector2d.ZERO;
+    }
+  }
+
+  static void writeVector2i(CompoundTag tag, String name, Vector2i pos) {
+    ListTag posTag = ListTag();
+    posTag.add(IntTag.valueOf(pos.X));
+    posTag.add(IntTag.valueOf(pos.Z));
+    tag.put(name, posTag);
+  }
+
+  static Vector2i readVector2i(CompoundTag tag, String name) {
+    if (tag.contains(name)) {
+      ListTag lst = tag.get(name)! as ListTag;
+      return Vector2i(X: lst.get(0).asInt(), Z: lst.get(1).asInt());
+    } else {
+      return Vector2i.ZERO;
+    }
+  }
+
+  static void writeVector3d(CompoundTag tag, String name, Vector3d pos) {
+    ListTag posTag = ListTag();
+    posTag.add(DoubleTag.valueOf(pos.X));
+    posTag.add(DoubleTag.valueOf(pos.Y));
+    posTag.add(DoubleTag.valueOf(pos.Z));
+    tag.put(name, posTag);
+  }
+
+  static Vector3d readVector3d(CompoundTag tag, String name) {
+    if (tag.contains(name)) {
+      ListTag lst = tag.get(name)! as ListTag;
+      return Vector3d(
+          X: lst.get(0).asDouble(),
+          Y: lst.get(1).asDouble(),
+          Z: lst.get(2).asDouble());
+    } else {
+      return Vector3d.ZERO;
+    }
+  }
+
+  static void writeVector3i(CompoundTag tag, String name, Vector3i pos) {
+    ListTag posTag = ListTag();
+    posTag.add(IntTag.valueOf(pos.X));
+    posTag.add(IntTag.valueOf(pos.Y));
+    posTag.add(IntTag.valueOf(pos.Z));
+    tag.put(name, posTag);
+  }
+
+  static Vector3i readVector3i(CompoundTag tag, String name) {
+    if (tag.contains(name)) {
+      ListTag lst = tag.get(name)! as ListTag;
+      return Vector3i(
+          X: lst.get(0).asInt(), Y: lst.get(1).asInt(), Z: lst.get(2).asInt());
+    } else {
+      return Vector3i.ZERO;
+    }
+  }
+
+  static List<int> _msbLsbToIntArray(int msb, int lsb) {
+    return [msb >> 32, msb, lsb >> 32, lsb];
+  }
+
+  static List<int> _uuidToIntArray(UUID ID) {
+    return _msbLsbToIntArray(
+        ID.getMostSignificantBits(), ID.getLeastSignificantBits());
+  }
+
+  static UUID _uuidFromIntArray(List<int> values) {
+    return UUID((values[0] << 32 | values[1] & 4294967295),
+        (values[2] << 32 | values[3] & 4294967295));
+  }
+
+  static void writeUUID(CompoundTag tag, String name, UUID ID) {
+    tag.put(name, IntArrayTag.valueOf(_uuidToIntArray(ID)));
+  }
+
+  static UUID readUUID(CompoundTag tag, String name) {
+    if (!tag.contains(name))
+      return UUID.ZERO;
+    else
+      return _uuidFromIntArray(tag.get(name)!.asIntArray());
+  }
+}

lib/nbt/Stream.dart

@@ -21,7 +21,7 @@ class ByteLayer {
     final requiredCapacity = _position + additionalBytes;
     if (requiredCapacity > _byteBuffer.length) {
       final newCapacity =
-          _position * 2 + additionalBytes; // Adjust capacity as needed
+          _position + additionalBytes; // Adjust capacity as needed
       final newBuffer = Uint8List(newCapacity);
       newBuffer.setAll(0, _byteBuffer);
       _byteBuffer = newBuffer;
@@ -86,12 +86,24 @@ class ByteLayer {
     _position++;
   }
 
+  void writeUnsignedByte(int value) {
+    _ensureCapacity(1);
+    _byteBuffer.buffer.asByteData().setUint8(_position, value);
+    _position++;
+  }
+
   int readByte() {
     final value = _byteBuffer[_position];
     _position++;
     return value;
   }
 
+  int readUnsignedByte() {
+    final value = _byteBuffer.buffer.asByteData().getUint8(_position);
+    _position++;
+    return value;
+  }
+
   void writeVarInt(int value) {
     while ((value & ~0x7F) != 0) {
       writeByte((value & 0x7F) | 0x80);
@@ -232,6 +244,12 @@ class ByteLayer {
     _position += 8;
   }
 
+  void writeUnsignedLong(int value) {
+    _ensureCapacity(8);
+    _byteBuffer.buffer.asByteData().setUint64(_position, value, Endian.big);
+    _position += 8;
+  }
+
   int readLong() {
     final value =
         _byteBuffer.buffer.asByteData().getInt64(_position, Endian.big);
@@ -239,6 +257,13 @@ class ByteLayer {
     return value;
   }
 
+  int readUnsignedLong() {
+    final value =
+        _byteBuffer.buffer.asByteData().getUint64(_position, Endian.big);
+    _position += 8;
+    return value;
+  }
+
   void writeVarLongNoZigZag(int value) {
     while (true) {
       if ((value & ~0x7F) == 0) {
@@ -283,4 +308,71 @@ class ByteLayer {
     int value = readLong();
     return (value >> 1) ^ (-(value & 1));
   }
+
+  void writeBytes(Iterable<int> bytes) {
+    for (int byte in bytes) {
+      writeUnsignedByte(byte);
+    }
+  }
+
+  List<int> readBytes(int num) {
+    List<int> lst = [];
+    for (int i = 0; i < num; i++) {
+      lst.add(readUnsignedByte());
+    }
+
+    return lst;
+  }
+
+  void setBit(int position, int maskToSet) {
+    if (position < _byteBuffer.length) {
+      // Set the value now
+      seek(position);
+      int current = readUnsignedByte();
+      seek(position);
+      current |= maskToSet;
+      writeUnsignedByte(current);
+    }
+  }
+
+  void clearBit(int position, int maskToClear) {
+    if (position < _byteBuffer.length) {
+      // Lets clear the bit
+      seek(position);
+      int current = readUnsignedByte();
+      current = current & ~maskToClear;
+      seek(position);
+      writeUnsignedByte(current);
+    }
+  }
+
+  bool checkBit(int position, int mask) {
+    if (position < _byteBuffer.length) {
+      seek(position);
+      int current = readUnsignedByte();
+      return (current & mask) == mask;
+    } else
+      return false;
+  }
+
+  int getBit(int position) {
+    if (position < _byteBuffer.length) {
+      seek(position);
+      return readUnsignedByte();
+    } else {
+      return 0;
+    }
+  }
+
+  void seek(int position) {
+    _position = 0;
+    _ensureCapacity(position);
+    _position = position;
+  }
+
+  /// Unsets a mask, then sets a mask
+  void unsetSetBit(int position, int maskToClear, int maskToSet) {
+    clearBit(position, maskToClear);
+    setBit(position, maskToSet);
+  }
 }

lib/nbt/Tag.dart

@@ -279,10 +279,10 @@ class NBTAccountant {
   static void leaveTag(Tag tag) {
     if (tag is CompoundTag || tag is ListTag) {
       if (tag is CompoundTag) {
-        CompoundTag ct = tag as CompoundTag;
+        CompoundTag ct = tag;
         ct.endPrettyPrint(_prettyIndex);
       } else if (tag is ListTag) {
-        ListTag lt = tag as ListTag;
+        ListTag lt = tag;
         lt.endPrettyPrint(_prettyIndex);
       }
     }

lib/nbt/impl/ByteArrayTag.dart

@@ -39,11 +39,11 @@ class ByteArrayTag extends Tag {
   void prettyPrint(int indent, bool recurse) {
     String array = "";
     for (int b in value) {
-      array += "${b}, ";
+      array += "$b, ";
     }
     array = array.substring(0, array.length - 2);
 
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: [${array}]");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: [$array]");
   }
 }

lib/nbt/impl/ByteTag.dart

@@ -32,6 +32,6 @@ class ByteTag extends Tag {
   @override
   void prettyPrint(int indent, bool recurse) {
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: ${value}");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: $value");
   }
 }

lib/nbt/impl/CompoundTag.dart

@@ -10,24 +10,24 @@ class CompoundTag extends Tag {
   void readValue(ByteLayer data) {
     value.clear();
 
-    NBTAccountant.visitTag();
-    NBTAccountant.printRead(this);
+    //NBTAccountant.visitTag();
+    //NBTAccountant.printRead(this);
 
     while (true) {
       Tag tag = Tag.readNamedTag(data);
       if (tag.getType() == 0) {
-        NBTAccountant.leaveTag(this);
+        //NBTAccountant.leaveTag(this);
         return;
       }
 
       put(tag.getKey(), tag);
-
+/*
       if (tag.getTagType() != TagType.Compound &&
           tag.getTagType() != TagType.List) {
         NBTAccountant.visitTag();
         NBTAccountant.printRead(tag);
         NBTAccountant.leaveTag(tag);
-      }
+      }*/
     }
   }
 

lib/nbt/impl/DoubleTag.dart

@@ -32,6 +32,6 @@ class DoubleTag extends Tag {
   @override
   void prettyPrint(int indent, bool recurse) {
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: ${value}");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: $value");
   }
 }

lib/nbt/impl/FloatTag.dart

@@ -31,6 +31,6 @@ class FloatTag extends Tag {
   @override
   void prettyPrint(int indent, bool recurse) {
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: ${value}");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: $value");
   }
 }

lib/nbt/impl/IntArrayTag.dart

@@ -9,6 +9,10 @@ class IntArrayTag extends Tag {
     this.value.addAll(value);
   }
 
+  static IntArrayTag valueOf(List<int> value) {
+    return IntArrayTag._(value);
+  }
+
   @override
   void readValue(ByteLayer data) {
     int count = data.readInt();
@@ -34,11 +38,11 @@ class IntArrayTag extends Tag {
   void prettyPrint(int indent, bool recurse) {
     String array = "";
     for (int b in value) {
-      array += "${b}, ";
+      array += "$b, ";
     }
     array = array.substring(0, array.length - 2);
 
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: [${array}]");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: [$array]");
   }
 }

lib/nbt/impl/IntTag.dart

@@ -31,6 +31,6 @@ class IntTag extends Tag {
   @override
   void prettyPrint(int indent, bool recurse) {
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: ${value}");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: $value");
   }
 }

lib/nbt/impl/ListTag.dart

@@ -1,6 +1,8 @@
 import 'package:libac_flutter/nbt/Stream.dart';
 import 'package:libac_flutter/nbt/Tag.dart';
 
+import 'EndTag.dart';
+
 class ListTag extends Tag {
   List<Tag> value = [];
 
@@ -42,6 +44,14 @@ class ListTag extends Tag {
     }
   }
 
+  Tag get(int index) {
+    if (size() > index) {
+      return value[index];
+    } else {
+      return EndTag();
+    }
+  }
+
   void remove(Tag tag) {
     value.remove(tag);
   }

lib/nbt/impl/LongArrayTag.dart

@@ -42,11 +42,11 @@ class LongArrayTag extends Tag {
   void prettyPrint(int indent, bool recurse) {
     String array = "";
     for (int b in value) {
-      array += "${b}, ";
+      array += "$b, ";
     }
     array = array.substring(0, array.length - 2);
 
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: [${array}]");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: [$array]");
   }
 }

lib/nbt/impl/LongTag.dart

@@ -31,6 +31,6 @@ class LongTag extends Tag {
   @override
   void prettyPrint(int indent, bool recurse) {
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: ${value}");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: $value");
   }
 }

lib/nbt/impl/ShortTag.dart

@@ -31,6 +31,6 @@ class ShortTag extends Tag {
   @override
   void prettyPrint(int indent, bool recurse) {
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: ${value}");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: $value");
   }
 }

lib/nbt/impl/StringTag.dart

@@ -31,6 +31,6 @@ class StringTag extends Tag {
   @override
   void prettyPrint(int indent, bool recurse) {
     print(
-        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: ${value}");
+        "${"".padLeft(indent, '\t')}${Tag.getCanonicalName(getTagType())}: $value");
   }
 }

lib/utils/Vector2.dart

@@ -0,0 +1,151 @@
+class Vector2d {
+  static final Vector2d ZERO = Vector2d(X: 0, Z: 0);
+  double X = 0.0;
+  double Z = 0.0;
+
+  Vector2d({this.X = 0.0, this.Z = 0.0});
+
+  @override
+  bool operator ==(Object otherz) {
+    if (otherz is Vector2d) {
+      Vector2d other = otherz;
+      return X == other.X && Z == other.Z;
+    }
+    return false;
+  }
+
+  Vector2d operator +(Vector2d other) {
+    Vector2d n = Clone();
+    n.X += other.X;
+    n.Z += other.Z;
+
+    return n;
+  }
+
+  Vector2d operator -(Vector2d other) {
+    Vector2d n = Clone();
+    n.X -= other.X;
+    n.Z -= other.Z;
+
+    return n;
+  }
+
+  Vector2d operator *(Vector2d other) {
+    Vector2d n = Clone();
+    n.X *= other.X;
+    n.Z *= other.Z;
+
+    return n;
+  }
+
+  Vector2d operator /(Vector2d other) {
+    Vector2d n = Clone();
+    n.X /= other.X;
+    n.Z /= other.Z;
+
+    return n;
+  }
+
+  bool operator >(Vector2d other) {
+    return (X > other.X) || (X > other.Z);
+  }
+
+  bool operator <(Vector2d other) {
+    return (X < other.X) || (X < other.Z);
+  }
+
+  Vector2d Clone() {
+    return Vector2d(X: X, Z: Z);
+  }
+
+  @override
+  String toString() {
+    return "<$X, $Z>";
+  }
+
+  bool inside(Vector2d min, Vector2d max) {
+    if (min.X <= X && max.X >= X) {
+      if (min.Z <= Z && max.Z >= Z) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+}
+
+class Vector2i {
+  static final Vector2i ZERO = Vector2i(X: 0, Z: 0);
+  int X = 0;
+  int Z = 0;
+
+  Vector2i({this.X = 0, this.Z = 0});
+
+  @override
+  bool operator ==(Object otherz) {
+    if (otherz is Vector2i) {
+      Vector2i other = otherz;
+      return X == other.X && Z == other.Z;
+    }
+    return false;
+  }
+
+  Vector2i operator +(Vector2i other) {
+    Vector2i n = Clone();
+    n.X += other.X;
+    n.Z += other.Z;
+
+    return n;
+  }
+
+  Vector2i operator -(Vector2i other) {
+    Vector2i n = Clone();
+    n.X -= other.X;
+    n.Z -= other.Z;
+
+    return n;
+  }
+
+  Vector2i operator *(Vector2i other) {
+    Vector2i n = Clone();
+    n.X *= other.X;
+    n.Z *= other.Z;
+
+    return n;
+  }
+
+  Vector2i operator /(Vector2i other) {
+    Vector2i n = Clone();
+    n.X = (n.X / other.X).round();
+    n.Z = (n.Z / other.Z).round();
+
+    return n;
+  }
+
+  bool operator >(Vector2i other) {
+    return (X > other.X) || (X > other.Z);
+  }
+
+  bool operator <(Vector2i other) {
+    return (X < other.X) || (X < other.Z);
+  }
+
+  Vector2i Clone() {
+    return Vector2i(X: X, Z: Z);
+  }
+
+  @override
+  String toString() {
+    return "<$X, $Z>";
+  }
+
+  bool inside(Vector2i min, Vector2i max) {
+    if (min.X <= X && max.X >= X) {
+      if (min.Z <= Z && max.Z >= Z) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+}

lib/utils/Vector3.dart

@@ -0,0 +1,165 @@
+class Vector3d {
+  static final Vector3d ZERO = Vector3d(X: 0, Y: 0, Z: 0);
+  double X = 0.0;
+  double Y = 0.0;
+  double Z = 0.0;
+
+  Vector3d({this.X = 0.0, this.Y = 0.0, this.Z = 0.0});
+
+  @override
+  bool operator ==(Object otherz) {
+    if (otherz is Vector3d) {
+      Vector3d other = otherz;
+      return X == other.X && Y == other.Y && Z == other.Z;
+    }
+    return false;
+  }
+
+  Vector3d operator +(Vector3d other) {
+    Vector3d n = Clone();
+    n.X += other.X;
+    n.Y += other.Y;
+    n.Z += other.Z;
+
+    return n;
+  }
+
+  Vector3d operator -(Vector3d other) {
+    Vector3d n = Clone();
+    n.X -= other.X;
+    n.Y -= other.Y;
+    n.Z -= other.Z;
+
+    return n;
+  }
+
+  Vector3d operator *(Vector3d other) {
+    Vector3d n = Clone();
+    n.X *= other.X;
+    n.Y *= other.Y;
+    n.Z *= other.Z;
+
+    return n;
+  }
+
+  Vector3d operator /(Vector3d other) {
+    Vector3d n = Clone();
+    n.X /= other.X;
+    n.Y /= other.Y;
+    n.Z /= other.Z;
+
+    return n;
+  }
+
+  bool operator >(Vector3d other) {
+    return (X > other.X) || (Y > other.Y) || (X > other.Z);
+  }
+
+  bool operator <(Vector3d other) {
+    return (X < other.X) || (Y < other.Y) || (X < other.Z);
+  }
+
+  Vector3d Clone() {
+    return Vector3d(X: X, Y: Y, Z: Z);
+  }
+
+  @override
+  String toString() {
+    return "<$X, $Y, $Z>";
+  }
+
+  bool inside(Vector3d min, Vector3d max) {
+    if (min.X <= X && max.X >= X) {
+      if (min.Y <= Y && max.Y >= Y) {
+        if (min.Z <= Z && max.Z >= Z) {
+          return true;
+        }
+      }
+    }
+
+    return false;
+  }
+}
+
+class Vector3i {
+  static final Vector3i ZERO = Vector3i(X: 0, Y: 0, Z: 0);
+  int X = 0;
+  int Y = 0;
+  int Z = 0;
+
+  Vector3i({this.X = 0, this.Y = 0, this.Z = 0});
+
+  @override
+  bool operator ==(Object otherz) {
+    if (otherz is Vector3i) {
+      Vector3i other = otherz;
+      return X == other.X && Y == other.Y && Z == other.Z;
+    }
+    return false;
+  }
+
+  Vector3i operator +(Vector3i other) {
+    Vector3i n = Clone();
+    n.X += other.X;
+    n.Y += other.Y;
+    n.Z += other.Z;
+
+    return n;
+  }
+
+  Vector3i operator -(Vector3i other) {
+    Vector3i n = Clone();
+    n.X -= other.X;
+    n.Y -= other.Y;
+    n.Z -= other.Z;
+
+    return n;
+  }
+
+  Vector3i operator *(Vector3i other) {
+    Vector3i n = Clone();
+    n.X *= other.X;
+    n.Y *= other.Y;
+    n.Z *= other.Z;
+
+    return n;
+  }
+
+  Vector3i operator /(Vector3i other) {
+    Vector3i n = Clone();
+    n.X = (n.X / other.X).round();
+    n.Y = (n.Y / other.Y).round();
+    n.Z = (n.Z / other.Z).round();
+
+    return n;
+  }
+
+  bool operator >(Vector3i other) {
+    return (X > other.X) || (Y > other.Y) || (X > other.Z);
+  }
+
+  bool operator <(Vector3i other) {
+    return (X < other.X) || (Y < other.Y) || (X < other.Z);
+  }
+
+  Vector3i Clone() {
+    return Vector3i(X: X, Y: Y, Z: Z);
+  }
+
+  @override
+  String toString() {
+    return "<$X, $Y, $Z>";
+  }
+
+  bool inside(Vector3i min, Vector3i max) {
+    if (min.X <= X && max.X >= X) {
+      if (min.Y <= Y && max.Y >= Y) {
+        if (min.Z <= Z && max.Z >= Z) {
+          return true;
+        }
+      }
+    }
+
+    return false;
+  }
+}

lib/utils/uuid/UUID.dart

@@ -0,0 +1,179 @@
+import 'dart:convert';
+import 'dart:math';
+
+import 'package:crypto/crypto.dart';
+import 'package:libac_flutter/nbt/Stream.dart';
+
+class UUID {
+  late final int LSB;
+  late final int MSB;
+  late final List<int> _bytes;
+
+  UUID(int msb, int lsb) {
+    MSB = msb;
+    LSB = lsb;
+
+    ByteLayer layer = ByteLayer();
+    layer.writeLong(MSB);
+    layer.writeLong(LSB);
+    layer.resetPosition();
+
+    _bytes = layer.readBytes(16);
+  }
+
+  static final UUID ZERO = UUID.generate(0);
+
+  /// Validates whether the given [uuid] is a valid UUID.
+  static bool validate(String uuid) {
+    if (uuid.length == ((16 * 2) + 4)) {
+      return true; // Likely is true. This is just a surface level check
+    } else
+      return false;
+  }
+
+  /// Parses the given [uuid] string and returns a UUID object.
+  static UUID parse(String uuid) {
+    if (validate(uuid)) {
+      final segments = uuid.split('-');
+      if (segments.length != 5) {
+        throw const FormatException('Invalid UUID format');
+      }
+
+      final msbString = segments.sublist(0, 3).join('');
+      final lsbString = segments.sublist(3, 5).join('');
+
+      int msb = 0;
+      int lsb = 0;
+
+      int i = 0;
+      ByteLayer layer = ByteLayer();
+      for (i = 0; i < msbString.length; i += 2) {
+        String hex = "${msbString.substring(i, i + 2)}";
+        int byte = int.parse(hex, radix: 16);
+        layer.writeByte(byte);
+      }
+
+      for (i = 0; i < lsbString.length; i += 2) {
+        String hex = "${lsbString.substring(i, i + 2)}";
+        int byte = int.parse(hex, radix: 16);
+        layer.writeByte(byte);
+      }
+
+      layer.resetPosition();
+      msb = layer.readLong();
+      lsb = layer.readLong();
+
+      return UUID(msb, lsb);
+    } else
+      return UUID.ZERO;
+  }
+
+  @override
+  String toString() {
+    String hexBuilder = "";
+    for (int byte in _bytes) {
+      hexBuilder += byte.toRadixString(16).padLeft(2, '0');
+    }
+    return '${hexBuilder.substring(0, 8)}-${hexBuilder.substring(8, 12)}-${hexBuilder.substring(12, 16)}-${hexBuilder.substring(16, 20)}-${hexBuilder.substring(20, 32)}';
+  }
+
+  /// Returns the Most Significant Bits (MSB) long value of the UUID.
+  int getMostSignificantBits() => MSB;
+
+  /// Returns the Least Significant Bits (LSB) long value of the UUID.
+  int getLeastSignificantBits() => LSB;
+
+  /// Factory method to generate UUID of the specific version.
+  factory UUID.generate(int version, {List<Object>? parameters}) {
+    List<Object> params = [];
+    if (parameters == null) {
+      if (version != 4) {
+        return UUID.generate(4);
+      }
+    } else
+      params = parameters!;
+    switch (version) {
+      case 0:
+        return UUID(0, 0);
+      case 3:
+        {
+          if (params.length != 2)
+            throw Exception(
+                "UUID v3 requires two parameters, [namespace,name]");
+          String namespace = params[0] as String;
+          String name = params[1] as String;
+
+          ByteLayer layer = ByteLayer();
+
+          final namespaceBytes = utf8.encode(namespace);
+          layer.writeBytes(namespaceBytes);
+          final nameBytes = utf8.encode(name);
+          layer.writeBytes(nameBytes);
+
+          var bytes = md5.convert(List.from(layer.bytes)).bytes;
+          layer.clear();
+          layer.writeBytes(bytes);
+
+          layer.unsetSetBit(6, 0xF0, 0x30);
+          layer.unsetSetBit(8, 0xC0, 0x80);
+
+          layer.resetPosition();
+
+          var msb = layer.readUnsignedLong();
+          var lsb = layer.readUnsignedLong();
+
+          layer.resetPosition();
+          return UUID(msb, lsb);
+        }
+      case 4:
+        {
+          ByteLayer layer = ByteLayer();
+          final random = Random.secure();
+
+          layer.writeLong(
+              (random.nextInt(0xFFFFFFFF) << 32) | random.nextInt(0xFFFFFFFF));
+          layer.writeLong(
+              (random.nextInt(0xFFFFFFFF) << 32) | random.nextInt(0xFFFFFFFF));
+
+          layer.unsetSetBit(6, 0xF0, 0x40);
+          layer.unsetSetBit(8, 0xC0, 0x80);
+
+          layer.resetPosition();
+
+          return UUID(layer.readUnsignedLong(), layer.readUnsignedLong());
+        }
+      case 5:
+        {
+          ByteLayer layer = ByteLayer();
+          if (params.length != 2)
+            throw Exception(
+                "UUID v5 requires two parameters, [namespace,name]");
+          String namespace = params[0] as String;
+          String name = params[1] as String;
+
+          if (!namespace.isEmpty) {
+            final namespaceBytes = utf8.encode(namespace);
+            layer.writeBytes(namespaceBytes);
+          }
+
+          if (!name.isEmpty) {
+            final nameBytes = utf8.encode(name);
+            layer.writeBytes(nameBytes);
+          }
+
+          final hashBytes = sha1.convert(List.from(layer.bytes)).bytes;
+          layer.clear();
+          layer.writeBytes(hashBytes);
+
+          layer.unsetSetBit(6, 0xF0, 0x50);
+          layer.unsetSetBit(8, 0xC0, 0x80);
+
+          layer.resetPosition();
+
+          return UUID(layer.readUnsignedLong(), layer.readUnsignedLong());
+        }
+      default:
+        throw ArgumentError('Unsupported UUID version: $version');
+    }
+  }
+}

pubspec.yaml

@@ -8,6 +8,7 @@ environment:
   flutter: ">=1.17.0"
 
 dependencies:
+  crypto: ^3.0.3
   flutter:
     sdk: flutter
 

test/nbt_test.dart

@@ -2,8 +2,10 @@ import 'dart:io';
 
 import 'package:flutter_test/flutter_test.dart';
 import 'package:libac_flutter/nbt/NbtIo.dart';
+import 'package:libac_flutter/nbt/NbtUtils.dart';
 import 'package:libac_flutter/nbt/impl/CompoundTag.dart';
 import 'package:libac_flutter/nbt/impl/StringTag.dart';
+import 'package:libac_flutter/utils/uuid/UUID.dart';
 
 void main() {
   test('read non-compressed helloworld NBT', () async {
@@ -44,4 +46,13 @@ void main() {
     expect(tag.get("doubleTest")!.asDouble(), 0.4931287132182315);
     expect(tag.get("floatTest")!.asFloat(), 0.49823147);
   });
+
+  test("Generate a UUID v4, save to NBT, and read it back again", () async {
+    var id = UUID.generate(4);
+    CompoundTag tag = CompoundTag();
+    NbtUtils.writeUUID(tag, "test", id);
+
+    var newID = NbtUtils.readUUID(tag, "test");
+    expect(id.toString(), newID.toString());
+  });
 }

test/uuid_test.dart

@@ -0,0 +1,78 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:libac_flutter/nbt/Stream.dart';
+import 'package:libac_flutter/utils/uuid/UUID.dart';
+
+void main() {
+  test("Store a 64bit value in int", () {
+    int X = 9223372036854775807;
+    expect(X.toString(), "9223372036854775807");
+  });
+
+  test("Generate a UUID v4", () {
+    var ID = UUID.generate(4);
+    expect(UUID.validate(ID.toString()), true);
+  });
+
+  test("Generate 10 UUIDv4", () {
+    List<UUID> ID = [];
+    for (int i = 0; i < 10; i++) {
+      ID.add(UUID.generate(4));
+    }
+
+    for (UUID sID in ID) {
+      print("ID : ${sID}}");
+    }
+  });
+
+  test("Check UUIDv4 for validity", () {
+    var ID = UUID.generate(4);
+    ByteLayer layer = ByteLayer();
+    layer.writeLong(ID.getMostSignificantBits().toInt());
+    layer.writeLong(ID.getLeastSignificantBits().toInt());
+
+    print(
+        "Checking version bit: ${layer.checkBit(6, 0x40)} - ${layer.getBit(6)}");
+    expect(layer.checkBit(6, 0x40), true);
+  });
+
+  test("Generate and check a UUIDv3", () {
+    var ID3 = UUID.generate(3, parameters: ["Test", "Test2"]);
+    ByteLayer layer = ByteLayer();
+    layer.writeLong(ID3.getMostSignificantBits().toInt());
+    layer.writeLong(ID3.getLeastSignificantBits().toInt());
+
+    print(
+        "Checking version bit: ${layer.checkBit(6, 0x30)} - ${layer.getBit(6)}");
+    expect(layer.checkBit(6, 0x30), true);
+  });
+
+  test("Test stream bitflipping", () {
+    ByteLayer layer = ByteLayer();
+    layer.writeBytes({0, 255, 80});
+    layer.setBit(0, 0x10);
+    layer.unsetSetBit(1, 0x0F, 0x50);
+
+    expect(layer.checkBit(0, 0x10), true);
+    expect(layer.checkBit(1, 0x50), true);
+    expect(layer.getBit(2), 80);
+  });
+
+  test("Test v3 implementation", () {
+    var expected =
+        "3e1b8c8a-efab-381b-ab57-4764c45b0889"; // Minecraft offline UUID : zontreck
+    var ID3 = UUID.generate(3, parameters: ["OfflinePlayer:zontreck", ""]);
+
+    expect(ID3.toString(), expected);
+  });
+
+  test("Parse a v3 and compare", () {
+    var asString = "3e1b8c8a-efab-381b-ab57-4764c45b0889";
+    var ID3 = UUID.parse(asString);
+    var ID3X = UUID.generate(3, parameters: ["OfflinePlayer:zontreck", ""]);
+
+    expect(ID3.MSB, ID3X.MSB);
+    expect(ID3.LSB, ID3X.LSB);
+
+    expect(ID3.toString(), asString);
+  });
+}