RedPowerFix.java

import mcpc.patchengine.api.IPatch;
import mcpc.patchengine.asm.util.ClassUtil;
import mcpc.patchengine.asm.util.MethodUtil;
import mcpc.patchengine.asm.util.NavigationUtil;
import mcpc.patchengine.common.Configuration;
import mcpc.patchengine.common.Constants;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.tree.*;

/**
 * Created by thomas on 8/7/2014.
 */
public class RedPowerFix implements IPatch {

    private String classname = "com.eloraam.redpower.core.CoreLib";

    @Override
    public String[] getClassNames() {
        return new String[]{classname};
    }

    @Override
    public void loadConfigurations(Configuration configuration) {

    }

    @Override
    public void transform(String s, ClassNode classNode) {
        if (s.equalsIgnoreCase(classname)) {

            MethodNode method = ClassUtil.getMethod(classNode, "compareItemStack", String.format("(Lur;Lur;)I", new Object[] { Constants.ItemStackClass, Constants.ItemStackClass }));

            if (method == null) {
                System.out.println("[PatchEngine - Redpower2] A LibCore class Without this methode has no reason of exist. Crash Bitch!! ");
                return;
            }

            LabelNode label = NavigationUtil.getPreviousLabel(method.instructions, method.instructions.size() - 1);
            InsnList instructions = new InsnList();

            //ASM code (- is to remove and + is to add code
            /*  - iconst_0
                - ireturn
                + aload_0
                + invokevirtual ur.o() //Something like this
                + ifeq 63
                + iconst_m1
                + ireturn
                + iconst_0
                + ireturn
             */
             
             //psudo code (Compiled with normal minecraf (paramUr1 is a itemstack)
             /*
                if (paramUr1.o()) {
                    return -1;
                }
             */
             
             //psudo code (workspace)
             /*
                if (paramUr1.hasTagCompound()) {
                    return -1;
                }
             */
             
             //redpower2 code (original)
             /*
                public static int compareItemStack(ur paramUr1, ur paramUr2)
                {
                    if (paramUr1.c != paramUr2.c) {
                      return paramUr1.c - paramUr2.c;
                    }
                    if (paramUr1.j() == paramUr2.j()) {
                      return 0;
                    }
                    if (paramUr1.b().l()) {
                      return paramUr1.j() - paramUr2.j();
                    }
                    return 0;
                }
             */
             
             //redpower2 code (How i want it)
             /*
                public static int compareItemStack(ur paramUr1, ur paramUr2)
                {
                    if (paramUr1.c != paramUr2.c) {
                      return paramUr1.c - paramUr2.c;
                    }
                    if (paramUr1.j() == paramUr2.j()) {
                      return 0;
                    }
                    if (paramUr1.b().l()) {
                      return paramUr1.j() - paramUr2.j();
                    }
                    if (paramUr1.o()) {
                        return -1;
                    }
                    return 0;
                }
             */
            
            instructions.add( new VarInsnNode(Opcodes.ALOAD, 0));
            instructions.add( new MethodInsnNode(Opcodes.INVOKEVIRTUAL, "ur", "o", "()Z") );
            LabelNode l3 = new LabelNode();
            instructions.add( new JumpInsnNode(Opcodes.IFEQ, l3) );
            instructions.add( new InsnNode(Opcodes.ICONST_M1) );
            instructions.add( new InsnNode(Opcodes.IRETURN));
            instructions.add( l3 );

            method.instructions.insert(MethodUtil.getLastLabel(method), instructions);


            System.out.println("[PatchEngine - Redpower2] Fixed ItemStack Compare methode");
        }
    }
}