Better save validation

core/src/mindustry/io/SaveFileReader.java

@@ -2,6 +2,7 @@ package mindustry.io;
 
 import arc.struct.*;
 import arc.struct.ObjectMap.*;
+import arc.util.*;
 import arc.util.io.*;
 import mindustry.world.*;
 
@@ -60,9 +61,11 @@ public abstract class SaveFileReader{
     protected final DataOutputStream dataBytesSmall = new DataOutputStream(byteOutputSmall);
 
     protected int lastRegionLength;
+    protected @Nullable CounterInputStream currCounter;
 
     protected void region(String name, DataInput stream, CounterInputStream counter, IORunner<DataInput> cons) throws IOException{
         counter.resetCount();
+        this.currCounter = counter;
         int length;
         try{
             length = readChunk(stream, cons);
@@ -70,8 +73,8 @@ public abstract class SaveFileReader{
             throw new IOException("Error reading region \"" + name + "\".", e);
         }
 
-        if(length != counter.count() - 4){
-            throw new IOException("Error reading region \"" + name + "\": read length mismatch. Expected: " + length + "; Actual: " + (counter.count() - 4));
+        if(length != counter.count - 4){
+            throw new IOException("Error reading region \"" + name + "\": read length mismatch. Expected: " + length + "; Actual: " + (counter.count - 4));
         }
     }
 
@@ -114,8 +117,11 @@ public abstract class SaveFileReader{
     /** Reads a chunk of some length. Use the runner for reading to catch more descriptive errors. */
     public int readChunk(DataInput input, boolean isShort, IORunner<DataInput> runner) throws IOException{
         int length = isShort ? input.readUnsignedShort() : input.readInt();
+        int pos = currCounter.count;
         lastRegionLength = length;
         runner.accept(input);
+
+        if(pos + length != currCounter.count) throw new IOException("Read length mismatch. Expected: " + length + ", Actual: " + (currCounter.count - pos));
         return length;
     }