Add asm client version reader

src/main/java/net/runelite/deob/clientver/ClientVersion.java

@@ -0,0 +1,44 @@
+package net.runelite.deob.clientver;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Enumeration;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import org.objectweb.asm.ClassReader;
+
+public class ClientVersion
+{
+	private File jar;
+
+	public ClientVersion(File jar)
+	{
+		this.jar = jar;
+	}
+
+	public int getVersion() throws IOException
+	{
+		try (JarFile jar = new JarFile(this.jar))
+		{
+			for (Enumeration<JarEntry> it = jar.entries(); it.hasMoreElements();)
+			{
+				JarEntry entry = it.nextElement();
+
+				if (!entry.getName().equals("client.class"))
+					continue;
+
+				InputStream in = jar.getInputStream(entry);
+
+				ClassReader reader = new ClassReader(in);
+				VersionClassVisitor v = new VersionClassVisitor();
+				reader.accept(v, 0);
+				return v.getVersion();
+				//entries.put(entry.getName(), entry);
+			}
+		}
+
+		return -1;
+	}
+}

src/main/java/net/runelite/deob/clientver/VersionClassVisitor.java

@@ -0,0 +1,33 @@
+package net.runelite.deob.clientver;
+
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+
+public class VersionClassVisitor extends ClassVisitor
+{
+	private VersionMethodVisitor vmv = new VersionMethodVisitor();
+
+	public VersionClassVisitor()
+	{
+		super(Opcodes.ASM5);
+	}
+
+	@Override
+	public MethodVisitor visitMethod(int access,
+		String name,
+		String desc,
+		String signature,
+		String[] exceptions)
+	{
+		if (!name.equals("init"))
+			return null;
+
+		return vmv;
+	}
+
+	public int getVersion()
+	{
+		return vmv.getVersion();
+	}
+}

src/main/java/net/runelite/deob/clientver/VersionMethodVisitor.java

@@ -0,0 +1,36 @@
+package net.runelite.deob.clientver;
+
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+
+public class VersionMethodVisitor extends MethodVisitor
+{
+	private int state = 0;
+	private int version = -1;
+
+	VersionMethodVisitor()
+	{
+		super(Opcodes.ASM5);
+	}
+
+	@Override
+	public void visitIntInsn(int opcode, int operand)
+	{
+		if (state == 2)
+		{
+			version = operand;
+			++state;
+		}
+
+		if (operand == 765 || operand == 503)
+		{
+			++state;
+			return;
+		}
+	}
+
+	public int getVersion()
+	{
+		return version;
+	}
+}

src/test/java/net/runelite/deob/clientver/ClientVersionTest.java

@@ -0,0 +1,18 @@
+package net.runelite.deob.clientver;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URISyntaxException;
+import org.junit.Test;
+
+public class ClientVersionTest
+{
+	@Test
+	public void test() throws IOException, URISyntaxException
+	{
+		File f = new File(ClientVersionTest.class.getResource("/gamepack_v21.jar").toURI());
+		ClientVersion ver = new ClientVersion(f);
+		System.out.println(ver.getVersion());
+	}
+
+}