avoid stream to array copying

src/org/jetbrains/java/decompiler/struct/attr/StructGenericSignatureAttribute.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2017 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
 package org.jetbrains.java.decompiler.struct.attr;
 
 import org.jetbrains.java.decompiler.struct.consts.ConstantPool;
+import org.jetbrains.java.decompiler.util.DataInputFullStream;
 
 import java.io.IOException;
 
@@ -24,8 +25,8 @@ public class StructGenericSignatureAttribute extends StructGeneralAttribute {
   private String signature;
 
   @Override
-  public void initContent(ConstantPool pool) throws IOException {
-    int index = stream().readUnsignedShort();
+  public void initContent(DataInputFullStream data, ConstantPool pool) throws IOException {
+    int index = data.readUnsignedShort();
     signature = pool.getPrimitiveConstant(index).getString();
   }