feat: compression, file utility functions and iterable ListTag

Author: BitBuf

build.gradle

@@ -4,7 +4,7 @@ plugins {
 }
 
 group "dev.dewy"
-version "1.0.0"
+version "1.0.1"
 
 task sourcesJar(type: Jar, dependsOn: classes) {
     classifier = "sources"

src/main/java/dev/dewy/nbt/tags/CompoundTag.java

@@ -2,14 +2,15 @@
 
 import dev.dewy.nbt.Tag;
 import dev.dewy.nbt.TagType;
+import dev.dewy.nbt.utils.CompressionType;
 import dev.dewy.nbt.utils.Pair;
 import dev.dewy.nbt.utils.ReadFunction;
 
-import java.io.DataInput;
-import java.io.DataOutput;
-import java.io.IOException;
+import java.io.*;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.zip.GZIPInputStream;
+import java.util.zip.GZIPOutputStream;
 
 /**
  * Implementation of the compound tag. A map in its raw form.
@@ -114,6 +115,24 @@ public void writeRoot(DataOutput output, String rootName) throws IOException {
         write(output);
     }
 
+    /**
+     * Write the compound tag to a {@link File} with a name of its own, using a given compression scheme.
+     *
+     * @param rootName The root compound's name.
+     * @param file The file to be written to.
+     * @param compression The compression to be applied.
+     * @throws IOException If any IO error occurs.
+     */
+    public void writeRootToFile(String rootName, File file, CompressionType compression) throws IOException {
+        DataOutputStream out = compression == CompressionType.GZIP
+                ? new DataOutputStream(new GZIPOutputStream(new BufferedOutputStream(new FileOutputStream(file))))
+                : new DataOutputStream(new BufferedOutputStream(new FileOutputStream(file)));
+
+        writeRoot(out, rootName);
+
+        out.close();
+    }
+
     @Override
     public ReadFunction<DataInput, CompoundTag> getReader() {
         return read;
@@ -260,4 +279,35 @@ public static Pair<String, CompoundTag> readNamedRoot(DataInput input) throws IO
 
         return new Pair<>(input.readUTF(), read.read(input));
     }
+
+    /**
+     * Reads a root compound (full NBT structure) from a {@link File} with a given kind of compression.
+     *
+     * @param file The file to read from.
+     * @param compression The compression of the file.
+     * @throws IOException if any kind of IO error occurs.
+     * @return The root compound read from the file.
+     */
+    public static CompoundTag readRootFromFile(File file, CompressionType compression) throws IOException {
+        return readNamedRootFromFile(file, compression).getRight();
+    }
+
+    /**
+     * Reads a root compound (full NBT structure) from a {@link File} with a given kind of compression, with its name attached.
+     *
+     * @param file The file to read from.
+     * @param compression The compression of the file.
+     * @throws IOException if any kind of IO error occurs.
+     * @return A {@link Pair} with the name of the root tag on the left and the root tag object on the right.
+     */
+    public static Pair<String, CompoundTag> readNamedRootFromFile(File file, CompressionType compression) throws IOException {
+        DataInputStream in = compression == CompressionType.GZIP
+                ? new DataInputStream(new GZIPInputStream(new BufferedInputStream(new FileInputStream(file))))
+                : new DataInputStream(new BufferedInputStream(new FileInputStream(file)));
+
+        Pair<String, CompoundTag> result = readNamedRoot(in);
+
+        in.close();
+        return result;
+    }
 }

src/main/java/dev/dewy/nbt/tags/ListTag.java

@@ -8,14 +8,17 @@
 import java.io.DataOutput;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
+import java.util.Spliterator;
+import java.util.function.Consumer;
 
 /**
  * Implementation of the list tag.
  *
  * @author dewy
  */
-public class ListTag<T extends Tag> implements Tag {
+public class ListTag<T extends Tag> implements Tag, Iterable<T> {
     private List<T> value;
 
     /**
@@ -199,6 +202,20 @@ public int indexOf(T tag) {
         return this.value.indexOf(tag);
     }
 
+    @Override
+    public Iterator<T> iterator() {
+        return this.value.iterator();
+    }
+
+    @Override
+    public void forEach(Consumer<? super T> action) {
+        this.value.forEach(action);
+    }
+
+    @Override
+    public Spliterator<T> spliterator() {
+        return this.value.spliterator();
+    }
 
     @Override
     public boolean equals(Object o) {

src/main/java/dev/dewy/nbt/utils/CompressionType.java

@@ -0,0 +1,18 @@
+package dev.dewy.nbt.utils;
+
+/**
+ * Defines the types of compression to be used for NBT data.
+ *
+ * @author dewy
+ */
+public enum CompressionType {
+    /**
+     * No compression.
+     */
+    NONE,
+
+    /**
+     * GZIP compression (adaptive Lempel-Ziv coding, deflate mode).
+     */
+    GZIP
+}

src/test/java/dev/dewy/nbt/test/NBTTest.java

@@ -5,7 +5,7 @@
 import dev.dewy.nbt.tags.StringTag;
 import dev.dewy.nbt.tags.array.ByteArrayTag;
 import dev.dewy.nbt.tags.number.ShortTag;
-import dev.dewy.nbt.utils.Pair;
+import dev.dewy.nbt.utils.CompressionType;
 
 import java.io.*;
 import java.util.Arrays;
@@ -40,37 +40,36 @@ private static void write() {
 
         // Writing root compound to sample.nbt
 
-        try (DataOutputStream out = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("sample.nbt")))) {
-            root.writeRoot(out, "sample");
+        try {
+            root.writeRootToFile("sample", new File("sample.nbt"), CompressionType.GZIP);
         } catch (IOException e) {
             e.printStackTrace();
         }
     }
 
     private static void read() {
-        try (DataInputStream in = new DataInputStream(new BufferedInputStream(new FileInputStream("sample.nbt")))) {
-            // Reading the root tag from sample.nbt
+        CompoundTag root;
 
-            CompoundTag root = CompoundTag.readRoot(in);
-
-            // Decompiling root tag contents.
+        try {
+            root = CompoundTag.readRootFromFile(new File("sample.nbt"), CompressionType.GZIP);
+        } catch (IOException e) {
+            e.printStackTrace();
+            return;
+        }
 
-            ShortTag number = (ShortTag) root.get("number");
-            ByteArrayTag array = (ByteArrayTag) root.get("array");
-            StringTag string = (StringTag) root.get("string");
-            ListTag<StringTag> cheeses = (ListTag<StringTag>) root.get("cheeses");
+        ShortTag number = (ShortTag) root.get("number");
+        ByteArrayTag array = (ByteArrayTag) root.get("array");
+        StringTag string = (StringTag) root.get("string");
+        ListTag<StringTag> cheeses = (ListTag<StringTag>) root.get("cheeses");
 
-            // Printing them out.
+        // Printing them out.
 
-            System.out.println(number.getValue());
-            System.out.println(Arrays.toString(array.getValue()));
-            System.out.println(string.getValue());
+        System.out.println(number.getValue());
+        System.out.println(Arrays.toString(array.getValue()));
+        System.out.println(string.getValue());
 
-            for (StringTag s : cheeses.getValue()) {
-                System.out.println(s.getValue());
-            }
-        } catch (IOException e) {
-            e.printStackTrace();
+        for (StringTag s : cheeses) {
+            System.out.println(s.getValue());
         }
     }
 }