Add simple tool for quickly loading all classes to merge

src/dev/w1zzrd/asm/Injector.java

@@ -0,0 +1,39 @@
+package dev.w1zzrd.asm;
+
+import jdk.internal.org.objectweb.asm.tree.ClassNode;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.Enumeration;
+import java.util.Objects;
+
+public class Injector {
+    public static void injectAll(ClassLoader loader, Merger merger) throws IOException {
+        Enumeration<URL> resources = loader.getResources("");
+        while (resources.hasMoreElements())
+            injectDirectory(new File(resources.nextElement().getPath()), merger);
+    }
+
+    private static void injectDirectory(File file, Merger merger) throws IOException {
+        if (file.isDirectory())
+            for (File child : Objects.requireNonNull(file.listFiles()))
+                injectDirectory(child, merger);
+        else injectFile(file, merger);
+    }
+
+    private static void injectFile(File file, Merger merger) throws IOException {
+        URL url = null;
+        try {
+            url = file.toURI().toURL();
+        } catch (MalformedURLException e) {
+            e.printStackTrace();
+        }
+        ClassNode cNode;
+
+        assert url != null;
+        if(url.getPath().endsWith(".class") && merger.shouldInject(cNode = Merger.getClassNode(url)))
+            merger.inject(cNode);
+    }
+}