refac: переосмысление

src/main/java/mc/nbt/ByteArrayTag.java

@@ -0,0 +1,41 @@
+package mc.nbt;
+
+import java.util.Arrays;
+import java.util.Objects;
+
+public class ByteArrayTag extends TagValue {
+    private final byte[] value;
+
+    public ByteArrayTag(byte[] value) {
+        this.value = Objects.requireNonNull(value);
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.BYTE_ARRAY;
+    }
+
+    public byte[] getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ByteArrayTag that = (ByteArrayTag) o;
+        return Arrays.equals(getValue(), that.getValue());
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "ByteArrayTag{" +
+                "value.length=" + value.length +
+                '}';
+    }
+}

src/main/java/mc/nbt/ByteTag.java

@@ -0,0 +1,40 @@
+package mc.nbt;
+
+import java.util.Objects;
+
+public class ByteTag extends TagValue {
+    private final byte value;
+
+    public ByteTag(byte value) {
+        this.value = value;
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.BYTE;
+    }
+
+    public byte getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ByteTag byteTag = (ByteTag) o;
+        return getValue() == byteTag.getValue();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "ByteTag{" +
+                "value=" + value +
+                '}';
+    }
+}

src/main/java/mc/nbt/CompoundTag.java

@@ -0,0 +1,113 @@
+package mc.nbt;
+
+import java.io.Serializable;
+import java.util.*;
+
+public class CompoundTag extends TagValue implements Map<String, TagValue>, Serializable {
+    private final LinkedHashMap<String, TagValue> map;
+
+    public CompoundTag() {
+        this.map = new LinkedHashMap<>();
+    }
+
+    public CompoundTag(String key, TagValue value) {
+        this.map = new LinkedHashMap<>();
+        this.map.put(key, value);
+    }
+
+    public CompoundTag(Map<String, TagValue> map) {
+        this.map = new LinkedHashMap<>(map);
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.COMPOUND;
+    }
+
+    public CompoundTag append(String key, TagValue value) {
+        this.map.put(key, value);
+        return this;
+    }
+
+    // Map methods
+
+    @Override
+    public int size() {
+        return map.size();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return map.isEmpty();
+    }
+
+    @Override
+    public boolean containsKey(Object key) {
+        return map.containsKey(key);
+    }
+
+    @Override
+    public boolean containsValue(Object value) {
+        return map.containsValue(value);
+    }
+
+    @Override
+    public TagValue get(Object key) {
+        return map.get(key);
+    }
+
+    @Override
+    public TagValue put(String key, TagValue value) {
+        return map.put(key, value);
+    }
+
+    @Override
+    public TagValue remove(Object value) {
+        return map.remove(value);
+    }
+
+    @Override
+    public void putAll(Map<? extends String, ? extends TagValue> map) {
+        this.map.putAll(map);
+    }
+
+    @Override
+    public void clear() {
+        map.clear();
+    }
+
+    @Override
+    public Set<String> keySet() {
+        return map.keySet();
+    }
+
+    @Override
+    public Collection<TagValue> values() {
+        return map.values();
+    }
+
+    @Override
+    public Set<Entry<String, TagValue>> entrySet() {
+        return map.entrySet();
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        CompoundTag that = (CompoundTag) o;
+        return map.equals(that.map);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(map);
+    }
+
+    @Override
+    public String toString() {
+        return "CompoundTag{"
+                + map
+                + '}';
+    }
+}

src/main/java/mc/nbt/DoubleTag.java

@@ -0,0 +1,40 @@
+package mc.nbt;
+
+import java.util.Objects;
+
+public class DoubleTag extends TagValue {
+    private final double value;
+
+    public DoubleTag(double value) {
+        this.value = value;
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.DOUBLE;
+    }
+
+    public double getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        DoubleTag doubleTag = (DoubleTag) o;
+        return Double.compare(doubleTag.getValue(), getValue()) == 0;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "DoubleTag{" +
+                "value=" + value +
+                '}';
+    }
+}

src/main/java/mc/nbt/EndTag.java

@@ -0,0 +1,27 @@
+package mc.nbt;
+
+public class EndTag extends TagValue {
+    private static final EndTag INSTANCE = new EndTag();
+
+    private EndTag() {
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.END;
+    }
+
+    @Override
+    public String getName() {
+        return null;
+    }
+
+    @Override
+    public void setName(String name) {
+        throw new UnsupportedOperationException();
+    }
+
+    public static EndTag getInstance() {
+        return INSTANCE;
+    }
+}

src/main/java/mc/nbt/FloatTag.java

@@ -0,0 +1,40 @@
+package mc.nbt;
+
+import java.util.Objects;
+
+public class FloatTag extends TagValue {
+    private final float value;
+
+    public FloatTag(float value) {
+        this.value = value;
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.FLOAT;
+    }
+
+    public float getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        FloatTag floatTag = (FloatTag) o;
+        return Float.compare(floatTag.getValue(), getValue()) == 0;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "FloatTag{" +
+                "value=" + value +
+                '}';
+    }
+}

src/main/java/mc/nbt/IntegerArrayTag.java

@@ -0,0 +1,41 @@
+package mc.nbt;
+
+import java.util.Arrays;
+import java.util.Objects;
+
+public class IntegerArrayTag extends TagValue {
+    private final int[] value;
+
+    public IntegerArrayTag(int[] value) {
+        this.value = Objects.requireNonNull(value);
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.INTEGER_ARRAY;
+    }
+
+    public int[] getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        IntegerArrayTag that = (IntegerArrayTag) o;
+        return Arrays.equals(getValue(), that.getValue());
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "IntegerArrayTag{" +
+                "value.length=" + value.length +
+                '}';
+    }
+}

src/main/java/mc/nbt/IntegerTag.java

@@ -0,0 +1,40 @@
+package mc.nbt;
+
+import java.util.Objects;
+
+public class IntegerTag extends TagValue {
+    private final int value;
+
+    public IntegerTag(int value) {
+        this.value = value;
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.INTEGER;
+    }
+
+    public int getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        IntegerTag that = (IntegerTag) o;
+        return getValue() == that.getValue();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "IntegerTag{" +
+                "value=" + value +
+                '}';
+    }
+}

src/main/java/mc/nbt/ListTag.java

@@ -0,0 +1,173 @@
+package mc.nbt;
+
+import java.util.*;
+
+public class ListTag extends TagValue implements List<TagValue> {
+
+    private final TagType listType;
+    private final List<TagValue> list;
+
+    public ListTag(TagType listType, int initialCapacity) {
+        this.listType = Objects.requireNonNull(listType);
+        this.list = new ArrayList<>(initialCapacity);
+    }
+
+    public ListTag(TagType listType) {
+        this.listType = Objects.requireNonNull(listType);
+        this.list = new ArrayList<>();
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.LIST;
+    }
+
+    public TagType getListType() {
+        return listType;
+    }
+
+    public ListTag append(TagValue tag) {
+        list.add(tag);
+        return this;
+    }
+
+    // List methods
+
+    @Override
+    public int size() {
+        return list.size();
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return list.isEmpty();
+    }
+
+    @Override
+    public boolean contains(Object o) {
+        return list.contains(o);
+    }
+
+    @Override
+    public Iterator<TagValue> iterator() {
+        return list.iterator();
+    }
+
+    @Override
+    public Object[] toArray() {
+        return list.toArray();
+    }
+
+    @SuppressWarnings("SuspiciousToArrayCall")
+    @Override
+    public <A> A[] toArray(A[] array) {
+        return list.toArray(array);
+    }
+
+    @Override
+    public boolean add(TagValue tag) {
+        return list.add(tag);
+    }
+
+    @Override
+    public boolean remove(Object o) {
+        return list.remove(o);
+    }
+
+    @SuppressWarnings("SlowListContainsAll")
+    @Override
+    public boolean containsAll(Collection<?> collection) {
+        return list.containsAll(collection);
+    }
+
+    @Override
+    public boolean addAll(Collection<? extends TagValue> collection) {
+        return list.addAll(collection);
+    }
+
+    @Override
+    public boolean addAll(int index, Collection<? extends TagValue> collection) {
+        return list.addAll(index, collection);
+    }
+
+    @Override
+    public boolean removeAll(Collection<?> collection) {
+        return list.removeAll(collection);
+    }
+
+    @Override
+    public boolean retainAll(Collection<?> collection) {
+        return list.retainAll(collection);
+    }
+
+    @Override
+    public void clear() {
+        list.clear();
+    }
+
+    @Override
+    public TagValue get(int index) {
+        return list.get(index);
+    }
+
+    @Override
+    public TagValue set(int index, TagValue element) {
+        return list.set(index, element);
+    }
+
+    @Override
+    public void add(int index, TagValue element) {
+        list.add(index, element);
+    }
+
+    @Override
+    public TagValue remove(int index) {
+        return list.remove(index);
+    }
+
+    @Override
+    public int indexOf(Object o) {
+        return list.indexOf(o);
+    }
+
+    @Override
+    public int lastIndexOf(Object o) {
+        return list.lastIndexOf(o);
+    }
+
+    @Override
+    public ListIterator<TagValue> listIterator() {
+        return list.listIterator();
+    }
+
+    @Override
+    public ListIterator<TagValue> listIterator(int index) {
+        return list.listIterator(index);
+    }
+
+    @Override
+    public List<TagValue> subList(int fromIndex, int toIndex) {
+        return list.subList(fromIndex, toIndex);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ListTag listTag = (ListTag) o;
+        return list.equals(listTag.list) && getListType() == listTag.getListType();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(list, getListType());
+    }
+
+    @Override
+    public String toString() {
+        return "ListTag{" +
+                "listType=" + listType +
+                ", list=" + list +
+                '}';
+    }
+}

src/main/java/mc/nbt/LongArrayTag.java

@@ -0,0 +1,41 @@
+package mc.nbt;
+
+import java.util.Arrays;
+import java.util.Objects;
+
+public class LongArrayTag extends TagValue {
+    private final long[] value;
+
+    public LongArrayTag(long[] value) {
+        this.value = Objects.requireNonNull(value);
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.LONG_ARRAY;
+    }
+
+    public long[] getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        LongArrayTag that = (LongArrayTag) o;
+        return Arrays.equals(getValue(), that.getValue());
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "LongArrayTag{" +
+                "value.length=" + value.length +
+                '}';
+    }
+}

src/main/java/mc/nbt/LongTag.java

@@ -0,0 +1,40 @@
+package mc.nbt;
+
+import java.util.Objects;
+
+public class LongTag extends TagValue {
+    private final long value;
+
+    public LongTag(long value) {
+        this.value = value;
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.LONG;
+    }
+
+    public long getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        LongTag longTag = (LongTag) o;
+        return getValue() == longTag.getValue();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "LongTag{" +
+                "value=" + value +
+                '}';
+    }
+}

src/main/java/mc/nbt/ShortTag.java

@@ -0,0 +1,40 @@
+package mc.nbt;
+
+import java.util.Objects;
+
+public class ShortTag extends TagValue {
+    private final short value;
+
+    public ShortTag(short value) {
+        this.value = value;
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.SHORT;
+    }
+
+    public short getValue() {
+        return value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        ShortTag shortTag = (ShortTag) o;
+        return getValue() == shortTag.getValue();
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "ShortTag{" +
+                "value=" + value +
+                '}';
+    }
+}

src/main/java/mc/nbt/StringTag.java

@@ -0,0 +1,41 @@
+package mc.nbt;
+
+import java.util.Objects;
+
+public class StringTag extends TagValue {
+
+    private final String value;
+
+    public StringTag(String value) {
+        this.value = Objects.requireNonNull(value);
+    }
+
+    @Override
+    public TagType getType() {
+        return TagType.STRING;
+    }
+
+    public String getValue() {
+        return this.value;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        StringTag stringTag = (StringTag) o;
+        return getValue().equals(stringTag.getValue());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(getValue());
+    }
+
+    @Override
+    public String toString() {
+        return "StringTag{" +
+                "value='" + value + '\'' +
+                '}';
+    }
+}

src/main/java/mc/nbt/TagType.java

@@ -0,0 +1,40 @@
+package mc.nbt;
+
+public enum TagType {
+    BYTE(1),
+    SHORT(2),
+    INTEGER(3),
+    LONG(4),
+    FLOAT(5),
+    DOUBLE(6),
+
+    BYTE_ARRAY(7),
+    INTEGER_ARRAY(11),
+    LONG_ARRAY(12),
+
+    STRING(8),
+    LIST(9),
+    COMPOUND(10),
+
+    END(0);
+
+    private final int id;
+
+    TagType(int id) {
+        this.id = id;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public static TagType valueOfId(int id) {
+        for (TagType type : TagType.values()) {
+            if (type.id == id) {
+                return type;
+            }
+        }
+
+        throw new RuntimeException("Unknown tag id: " + id); //TODO семантический exception
+    }
+}

src/main/java/mc/nbt/TagValue.java

@@ -0,0 +1,135 @@
+package mc.nbt;
+
+public abstract class TagValue {
+    protected String name;
+
+    TagValue() {
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public abstract TagType getType();
+
+    public ByteTag asByte() {
+        throwIfInvalidType(TagType.BYTE);
+        return (ByteTag) this;
+    }
+
+    public ByteArrayTag asByteArray() {
+        throwIfInvalidType(TagType.BYTE_ARRAY);
+        return (ByteArrayTag) this;
+    }
+
+    public ShortTag asShort() {
+        throwIfInvalidType(TagType.SHORT);
+        return (ShortTag) this;
+    }
+
+    public IntegerTag asInteger() {
+        throwIfInvalidType(TagType.INTEGER);
+        return (IntegerTag) this;
+    }
+
+    public IntegerArrayTag asIntegerArray() {
+        throwIfInvalidType(TagType.INTEGER_ARRAY);
+        return (IntegerArrayTag) this;
+    }
+
+    public LongTag asLong() {
+        throwIfInvalidType(TagType.LONG);
+        return (LongTag) this;
+    }
+
+    public LongArrayTag asLongArray() {
+        throwIfInvalidType(TagType.LONG_ARRAY);
+        return (LongArrayTag) this;
+    }
+
+    public FloatTag asFloat() {
+        throwIfInvalidType(TagType.FLOAT);
+        return (FloatTag) this;
+    }
+
+    public DoubleTag asDouble() {
+        throwIfInvalidType(TagType.DOUBLE);
+        return (DoubleTag) this;
+    }
+
+    public StringTag asString() {
+        throwIfInvalidType(TagType.STRING);
+        return (StringTag) this;
+    }
+
+    public ListTag asList() {
+        throwIfInvalidType(TagType.LIST);
+        return (ListTag) this;
+    }
+
+    public CompoundTag asCompound() {
+        throwIfInvalidType(TagType.COMPOUND);
+        return (CompoundTag) this;
+    }
+
+    public boolean isByte() {
+        return getType() == TagType.BYTE;
+    }
+
+    public boolean isByteArray() {
+        return getType() == TagType.BYTE_ARRAY;
+    }
+
+    public boolean isShort() {
+        return getType() == TagType.SHORT;
+    }
+
+    public boolean isInteger() {
+        return getType() == TagType.INTEGER;
+    }
+
+    public boolean isIntegerArray() {
+        return getType() == TagType.INTEGER_ARRAY;
+    }
+
+    public boolean isLong() {
+        return getType() == TagType.LONG;
+    }
+
+    public boolean isLongArray() {
+        return getType() == TagType.LONG_ARRAY;
+    }
+
+    public boolean isFloat() {
+        return getType() == TagType.FLOAT;
+    }
+
+    public boolean isDouble() {
+        return getType() == TagType.DOUBLE;
+    }
+
+    public boolean isString() {
+        return getType() == TagType.STRING;
+    }
+
+    public boolean isCompound() {
+        return getType() == TagType.COMPOUND;
+    }
+
+    public boolean isEnd() {
+        return getType() == TagType.END;
+    }
+
+    private void throwIfInvalidType(TagType expectedType) {
+        if (getType() != expectedType) {
+            //TODO семантический exception
+            throw new RuntimeException(
+                    "Value expected to be type %s is of unexpected type %s"
+                            .formatted(expectedType, getType()));
+        }
+    }
+}

src/main/java/mc/nbt/codec/ByteArrayTagCodec.java

@@ -0,0 +1,26 @@
+package mc.nbt.codec;
+
+import mc.nbt.ByteArrayTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class ByteArrayTagCodec implements Codec<ByteArrayTag> {
+
+    @Override
+    public void encode(ByteArrayTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeInt(tag.getValue().length);
+        outputStream.write(tag.getValue());
+    }
+
+    @SuppressWarnings("ResultOfMethodCallIgnored")
+    @Override
+    public ByteArrayTag decode(NbtInputStream inputStream) throws IOException {
+        int len = inputStream.readInt();
+        byte[] bytes = new byte[len];
+        inputStream.read(bytes);
+
+        return new ByteArrayTag(bytes);
+    }
+}

src/main/java/mc/nbt/codec/ByteTagCodec.java

@@ -0,0 +1,20 @@
+package mc.nbt.codec;
+
+import mc.nbt.ByteTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class ByteTagCodec implements Codec<ByteTag> {
+
+    @Override
+    public void encode(ByteTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeByte(tag.getValue());
+    }
+
+    @Override
+    public ByteTag decode(NbtInputStream inputStream) throws IOException {
+        return new ByteTag(inputStream.readByte());
+    }
+}

src/main/java/mc/nbt/codec/Codec.java

@@ -0,0 +1,14 @@
+package mc.nbt.codec;
+
+import mc.nbt.TagValue;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public interface Codec<T extends TagValue> {
+
+    void encode(T tag, NbtOutputStream outputStream) throws IOException;
+
+    T decode(NbtInputStream inputStream) throws IOException;
+}

src/main/java/mc/nbt/codec/CodecRegistry.java

@@ -0,0 +1,39 @@
+package mc.nbt.codec;
+
+import mc.nbt.TagType;
+import mc.nbt.TagValue;
+
+import java.util.Map;
+import java.util.Objects;
+
+public class CodecRegistry {
+    private static final CodecRegistry INSTANCE = new CodecRegistry();
+
+    private final Map<TagType, Codec<? extends TagValue>> codecs;
+
+    private CodecRegistry() {
+        codecs = Map.ofEntries(
+                Map.entry(TagType.BYTE, new ByteTagCodec()),
+                Map.entry(TagType.SHORT, new ShortTagCodec()),
+                Map.entry(TagType.INTEGER, new IntegerTagCodec()),
+                Map.entry(TagType.LONG, new LongTagCodec()),
+                Map.entry(TagType.FLOAT, new FloatTagCodec()),
+                Map.entry(TagType.DOUBLE, new DoubleTagCodec()),
+                Map.entry(TagType.BYTE_ARRAY, new ByteArrayTagCodec()),
+                Map.entry(TagType.INTEGER_ARRAY, new IntegerArrayTagCodec()),
+                Map.entry(TagType.LONG_ARRAY, new LongArrayTagCodec()),
+                Map.entry(TagType.STRING, new StringTagCodec()),
+                Map.entry(TagType.LIST, new ListTagCodec()),
+                Map.entry(TagType.COMPOUND, new CompoundTagCodec()),
+                Map.entry(TagType.END, new EndTagCodec())
+        );
+    }
+
+    public Codec<? extends TagValue> get(TagType tagType) {
+        return codecs.get(Objects.requireNonNull(tagType));
+    }
+
+    public static CodecRegistry getInstance() {
+        return INSTANCE;
+    }
+}

src/main/java/mc/nbt/codec/CompoundTagCodec.java

@@ -0,0 +1,40 @@
+package mc.nbt.codec;
+
+import mc.nbt.CompoundTag;
+import mc.nbt.EndTag;
+import mc.nbt.TagValue;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+import java.util.Map;
+
+public class CompoundTagCodec implements Codec<CompoundTag> {
+
+    @Override
+    public void encode(CompoundTag tag, NbtOutputStream outputStream) throws IOException {
+        for (Map.Entry<String, TagValue> entry : tag.entrySet()) {
+            if (entry.getValue() == null) //TODO по-хорошему, пользователю нужно запретить вставлять null-теги
+                continue;
+
+            outputStream.writeTag(entry.getKey(), entry.getValue());
+        }
+
+        outputStream.writeTag(EndTag.getInstance());
+    }
+
+    @Override
+    public CompoundTag decode(NbtInputStream inputStream) throws IOException {
+        var compoundTag = new CompoundTag();
+
+        do {
+            var tagValue = inputStream.readTag();
+            if (tagValue.isEnd())
+                break;
+
+            compoundTag.append(tagValue.getName(), tagValue);
+        } while (true);
+
+        return compoundTag;
+    }
+}

src/main/java/mc/nbt/codec/DoubleTagCodec.java

@@ -0,0 +1,20 @@
+package mc.nbt.codec;
+
+import mc.nbt.DoubleTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class DoubleTagCodec implements Codec<DoubleTag> {
+
+    @Override
+    public void encode(DoubleTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeDouble(tag.getValue());
+    }
+
+    @Override
+    public DoubleTag decode(NbtInputStream inputStream) throws IOException {
+        return new DoubleTag(inputStream.readDouble());
+    }
+}

src/main/java/mc/nbt/codec/EndTagCodec.java

@@ -0,0 +1,20 @@
+package mc.nbt.codec;
+
+import mc.nbt.EndTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class EndTagCodec implements Codec<EndTag> {
+
+    @Override
+    public void encode(EndTag tag, NbtOutputStream outputStream) throws IOException {
+        // nothing
+    }
+
+    @Override
+    public EndTag decode(NbtInputStream inputStream) throws IOException {
+        return EndTag.getInstance();
+    }
+}

src/main/java/mc/nbt/codec/FloatTagCodec.java

@@ -0,0 +1,20 @@
+package mc.nbt.codec;
+
+import mc.nbt.FloatTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class FloatTagCodec implements Codec<FloatTag> {
+
+    @Override
+    public void encode(FloatTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeFloat(tag.getValue());
+    }
+
+    @Override
+    public FloatTag decode(NbtInputStream inputStream) throws IOException {
+        return new FloatTag(inputStream.readFloat());
+    }
+}

src/main/java/mc/nbt/codec/IntegerArrayTagCodec.java

@@ -0,0 +1,30 @@
+package mc.nbt.codec;
+
+import mc.nbt.IntegerArrayTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class IntegerArrayTagCodec implements Codec<IntegerArrayTag> {
+
+    @Override
+    public void encode(IntegerArrayTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeInt(tag.getValue().length);
+        for (int item : tag.getValue()) {
+            outputStream.writeInt(item);
+        }
+    }
+
+    @Override
+    public IntegerArrayTag decode(NbtInputStream inputStream) throws IOException {
+        int len = inputStream.readInt();
+        int[] ints = new int[len];
+
+        for (int i = 0; i < len; i++) {
+            ints[i] = inputStream.readInt();
+        }
+
+        return new IntegerArrayTag(ints);
+    }
+}

src/main/java/mc/nbt/codec/IntegerTagCodec.java

@@ -0,0 +1,20 @@
+package mc.nbt.codec;
+
+import mc.nbt.IntegerTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class IntegerTagCodec implements Codec<IntegerTag> {
+
+    @Override
+    public void encode(IntegerTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeInt(tag.getValue());
+    }
+
+    @Override
+    public IntegerTag decode(NbtInputStream inputStream) throws IOException {
+        return new IntegerTag(inputStream.readInt());
+    }
+}

src/main/java/mc/nbt/codec/ListTagCodec.java

@@ -0,0 +1,45 @@
+package mc.nbt.codec;
+
+import mc.nbt.ListTag;
+import mc.nbt.TagType;
+import mc.nbt.TagValue;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class ListTagCodec implements Codec<ListTag> {
+
+    @SuppressWarnings({"rawtypes", "unchecked"})
+    @Override
+    public void encode(ListTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeByte(tag.getListType().getId());
+        outputStream.writeInt(tag.size());
+
+        Codec codec = CodecRegistry.getInstance().get(tag.getListType());
+        for (TagValue tagValue : tag) {
+            codec.encode(tagValue, outputStream);
+        }
+    }
+
+    @SuppressWarnings("rawtypes")
+    @Override
+    public ListTag decode(NbtInputStream inputStream) throws IOException {
+        int listTypeId = inputStream.readByte();
+        TagType listType = TagType.valueOfId(listTypeId);
+
+        int size = inputStream.readInt();
+        ListTag list = new ListTag(listType, size);
+
+        Codec codec = CodecRegistry.getInstance().get(listType);
+
+        if (size > 0) {
+            for (int i = 0; i < size; i++) {
+                var tagValue = codec.decode(inputStream);
+                list.add(tagValue);
+            }
+        }
+
+        return list;
+    }
+}

src/main/java/mc/nbt/codec/LongArrayTagCodec.java

@@ -0,0 +1,30 @@
+package mc.nbt.codec;
+
+import mc.nbt.LongArrayTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class LongArrayTagCodec implements Codec<LongArrayTag> {
+
+    @Override
+    public void encode(LongArrayTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeInt(tag.getValue().length);
+        for (long value : tag.getValue()) {
+            outputStream.writeLong(value);
+        }
+    }
+
+    @Override
+    public LongArrayTag decode(NbtInputStream inputStream) throws IOException {
+        int len = inputStream.readInt();
+        long[] longs = new long[len];
+
+        for (int i = 0; i < len; i++) {
+            longs[i] = inputStream.readLong();
+        }
+
+        return new LongArrayTag(longs);
+    }
+}

src/main/java/mc/nbt/codec/LongTagCodec.java

@@ -0,0 +1,20 @@
+package mc.nbt.codec;
+
+import mc.nbt.LongTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class LongTagCodec implements Codec<LongTag> {
+
+    @Override
+    public void encode(LongTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeLong(tag.getValue());
+    }
+
+    @Override
+    public LongTag decode(NbtInputStream inputStream) throws IOException {
+        return new LongTag(inputStream.readLong());
+    }
+}

src/main/java/mc/nbt/codec/ShortTagCodec.java

@@ -0,0 +1,20 @@
+package mc.nbt.codec;
+
+import mc.nbt.ShortTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class ShortTagCodec implements Codec<ShortTag> {
+
+    @Override
+    public void encode(ShortTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeShort(tag.getValue());
+    }
+
+    @Override
+    public ShortTag decode(NbtInputStream inputStream) throws IOException {
+        return new ShortTag(inputStream.readShort());
+    }
+}

src/main/java/mc/nbt/codec/StringTagCodec.java

@@ -0,0 +1,19 @@
+package mc.nbt.codec;
+
+import mc.nbt.StringTag;
+import mc.nbt.io.NbtInputStream;
+import mc.nbt.io.NbtOutputStream;
+
+import java.io.IOException;
+
+public class StringTagCodec implements Codec<StringTag> {
+    @Override
+    public void encode(StringTag tag, NbtOutputStream outputStream) throws IOException {
+        outputStream.writeString(tag.getValue());
+    }
+
+    @Override
+    public StringTag decode(NbtInputStream inputStream) throws IOException {
+        return new StringTag(inputStream.readString());
+    }
+}

src/main/java/mc/nbt/io/NbtInputStream.java

@@ -0,0 +1,91 @@
+package mc.nbt.io;
+
+import mc.nbt.EndTag;
+import mc.nbt.TagType;
+import mc.nbt.TagValue;
+import mc.nbt.codec.Codec;
+import mc.nbt.codec.CodecRegistry;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.zip.GZIPInputStream;
+
+public class NbtInputStream extends InputStream {
+
+    private final DataInputStream dataInputStream;
+
+    public NbtInputStream(InputStream inputStream, boolean compressed) throws IOException {
+        this.dataInputStream = new DataInputStream(compressed
+                ? new GZIPInputStream(inputStream)
+                : inputStream);
+    }
+
+    public NbtInputStream(InputStream inputStream) throws IOException {
+        this(inputStream, false);
+    }
+
+    @SuppressWarnings("rawtypes")
+    public TagValue readTag() throws IOException {
+        var tagType = TagType.valueOfId(read());
+        if (tagType == TagType.END) {
+            return EndTag.getInstance();
+        }
+
+        Codec codec = CodecRegistry.getInstance().get(tagType);
+        String name = readString();
+        var tagValue = codec.decode(this);
+
+        tagValue.setName(name);
+        return tagValue;
+    }
+
+    public byte readByte() throws IOException {
+        return dataInputStream.readByte();
+    }
+
+    public short readShort() throws IOException {
+        return dataInputStream.readShort();
+    }
+
+    public int readInt() throws IOException {
+        return dataInputStream.readInt();
+    }
+
+    public long readLong() throws IOException {
+        return dataInputStream.readLong();
+    }
+
+    public float readFloat() throws IOException {
+        return dataInputStream.readFloat();
+    }
+
+    public double readDouble() throws IOException {
+        return dataInputStream.readDouble();
+    }
+
+    public String readString() throws IOException {
+        int length = readShort();
+        if (length <= 0) {
+            return "";
+        }
+
+        byte[] buff = new byte[length];
+        if (read(buff, 0, length) < length) {
+            throw new IOException("Unexpected end of stream");
+        }
+
+        return new String(buff, StandardCharsets.UTF_8);
+    }
+
+    @Override
+    public int read() throws IOException {
+        return dataInputStream.read();
+    }
+
+    @Override
+    public void close() throws IOException {
+        dataInputStream.close();
+    }
+}

src/main/java/mc/nbt/io/NbtOutputStream.java

@@ -0,0 +1,84 @@
+package mc.nbt.io;
+
+import mc.nbt.TagValue;
+import mc.nbt.codec.Codec;
+import mc.nbt.codec.CodecRegistry;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.zip.GZIPOutputStream;
+
+public class NbtOutputStream extends OutputStream {
+
+    private final DataOutputStream dataOutputStream;
+
+    public NbtOutputStream(OutputStream outputStream, boolean compressed) throws IOException {
+        this.dataOutputStream = new DataOutputStream(compressed
+                ? new GZIPOutputStream(outputStream)
+                : outputStream);
+    }
+
+    public NbtOutputStream(OutputStream outputStream) throws IOException {
+        this(outputStream, false);
+    }
+
+
+    @SuppressWarnings({"unchecked", "rawtypes"})
+    public void writeTag(String name, TagValue tagValue) throws IOException {
+        Codec codec = CodecRegistry.getInstance().get(tagValue.getType());
+
+        writeByte(tagValue.getType().getId());
+        writeString(name);
+
+        codec.encode(tagValue, this);
+    }
+
+    public void writeTag(TagValue tagValue) throws IOException {
+        writeTag(tagValue.getName(), tagValue);
+    }
+
+    public void writeByte(int value) throws IOException {
+        dataOutputStream.writeByte(value);
+    }
+
+    public void writeShort(int value) throws IOException {
+        dataOutputStream.writeShort(value);
+    }
+
+    public void writeInt(int value) throws IOException {
+        dataOutputStream.writeInt(value);
+    }
+
+    public void writeLong(long value) throws IOException {
+        dataOutputStream.writeLong(value);
+    }
+
+    public void writeFloat(float value) throws IOException {
+        dataOutputStream.writeFloat(value);
+    }
+
+    public void writeDouble(double value) throws IOException {
+        dataOutputStream.writeDouble(value);
+    }
+
+    public void writeString(String value) throws IOException {
+        if (value == null || value.isEmpty()) {
+            writeShort(0);
+        } else {
+            writeShort(value.length());
+            write(value.getBytes(StandardCharsets.UTF_8));
+        }
+    }
+
+    @Override
+    public void write(int b) throws IOException {
+        dataOutputStream.write(b);
+    }
+
+    @Override
+    public void close() throws IOException {
+        this.dataOutputStream.close();
+    }
+}