пробуем читать региональные файлы (r.X.Z.mca)

anvil-loader/build.gradle

@@ -4,6 +4,10 @@ version '1.0-SNAPSHOT'
 dependencies {
     /* Core */
     compile_excludeCopy project(':core')
+
+    /* Simple log */
+    compile_excludeCopy (group: 'org.slf4j', name: 'slf4j-simple', version: slf4j_version)
+
     /* Named Binary Tags */
     compile (group: 'com.flowpowered', name: 'flow-nbt', version: '1.0.0')
 }

anvil-loader/src/main/java/mc/world/anvil/Main.java

@@ -1,9 +1,5 @@
 package mc.world.anvil;
 
-import com.flowpowered.nbt.Tag;
-import com.flowpowered.nbt.stream.NBTInputStream;
-
-import java.io.FileInputStream;
 import java.io.IOException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -12,13 +8,7 @@ public class Main {
     public static void main(String[] args) throws IOException {
         final Path levelDatPath = Paths.get(args[0]);
 
-        FileInputStream fis = new FileInputStream(levelDatPath.toFile());
-        NBTInputStream nbtInputStream = new NBTInputStream(fis);
-
-        Tag rootTag = nbtInputStream.readTag();
-        System.out.println(rootTag.toString());
-
-        nbtInputStream.close();
-        fis.close();
+        RegionFile regionFile = new RegionFile(levelDatPath.toFile());
+        regionFile.getChunk(0,0);
     }
 }

anvil-loader/src/main/java/mc/world/anvil/RegionFile.java

@@ -0,0 +1,95 @@
+package mc.world.anvil;
+
+import com.flowpowered.nbt.Tag;
+import com.flowpowered.nbt.stream.NBTInputStream;
+import lombok.extern.slf4j.Slf4j;
+import mc.core.world.chunk.Chunk;
+
+import javax.annotation.Nullable;
+import java.io.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.zip.InflaterInputStream;
+
+@Slf4j
+public class RegionFile implements Closeable {
+    private RandomAccessFile file;
+    private List<Boolean> sectorFree; //TODO заменить на Trove TByteList
+    private final int[] offsets = new int[1024];
+
+    public RegionFile(File file) throws IOException {
+        this.file = new RandomAccessFile(file, "rw");
+
+        int sizeOfSectorFree = (int)this.file.length() / 4096;
+        sectorFree = new ArrayList<>(sizeOfSectorFree);
+        sectorFree.add(false);
+        sectorFree.add(false);
+        for (int i = 0; i < sizeOfSectorFree-2; i++) {
+            sectorFree.add(true);
+        }
+
+        for (int i = 0; i < offsets.length; ++i) {
+            int read = this.file.readInt();
+            offsets[i] = read;
+
+            if (read != 0 && (read >> 8) + (read & 255) <= this.sectorFree.size()) {
+                for (int j = 0; j < (read & 255); ++j) {
+                    this.sectorFree.set((read >> 8) + j, false);
+                }
+            }
+        }
+
+        this.file.skipBytes(1024);
+    }
+
+    @Nullable
+    public Chunk getChunk(int x, int z) {
+        int offset = getOffset(x, z);
+
+        if (offset == 0) return null;
+
+        int v1 = offset >> 8;  // j
+        int v2 = offset & 255; // k
+
+        if (v1 + v2 > sectorFree.size()) return null;
+
+        try {
+            file.seek((long) (v1 * 4096));
+            int read = file.readInt();
+            if (read <= 0 || read > 4096 * v2) return null;
+
+            boolean gzippedData = (file.readByte() == 0x01);
+
+            if (gzippedData) {
+                log.info("GZipped");
+            } else {
+                log.info("Inflaten");
+
+                byte[] buffer = new byte[read - 1];
+                file.read(buffer);
+                InflaterInputStream inputStream = new InflaterInputStream(new ByteArrayInputStream(buffer));
+
+                NBTInputStream nbtInputStream = new NBTInputStream(inputStream, false);
+
+                Tag rootTag = nbtInputStream.readTag();
+                log.info(rootTag.toString());
+
+                nbtInputStream.close();
+            }
+        } catch (IOException e) {
+            log.error("Get chunk", e);
+            return null;
+        }
+
+        return null;
+    }
+
+    private int getOffset(int x, int z) {
+        return offsets[x + z * 32];
+    }
+
+    @Override
+    public void close() throws IOException {
+        if (file != null) file.close();
+    }
+}