Compare.java

package unluac.test;

import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;

import unluac.parse.BHeader;
import unluac.parse.LFunction;
import unluac.parse.LLocal;
import unluac.parse.LObject;

public class Compare {

  /**
   * Determines if two files of lua bytecode are the same
   * (except possibly for line numbers).
   */
  public static boolean bytecode_equal(String file1, String file2) {
    LFunction main1 = file_to_function(file1);
    LFunction main2 = file_to_function(file2);
    return function_equal(main1, main2);
  }

  public static boolean function_equal(LFunction f1, LFunction f2) {
    if(f1.maximumStackSize != f2.maximumStackSize) {
      return false;
    }
    if(f1.numParams != f2.numParams) {
      return false;
    }
    if(f1.numUpvalues != f2.numUpvalues) {
      return false;
    }
    if(f1.vararg != f2.vararg) {
      return false;
    }
    if(f1.code.length != f2.code.length) {
      return false;
    }
    for(int i = 0; i < f1.code.length; i++) {
      if(f1.code[i] != f2.code[i]) {
        return false;
      }
    }
    if(f1.constants.length != f2.constants.length) {
      return false;
    }
    for(int i = 0; i < f1.constants.length; i++) {
      if(!object_equal(f1.constants[i], f2.constants[i])) {
        return false;
      }
    }
    if(f1.locals.length != f2.locals.length) {
      return false;
    }
    for(int i = 0; i < f1.locals.length; i++) {
      if(!local_equal(f1.locals[i], f2.locals[i])) {
        return false;
      }
    }
    if(f1.upvalues.length != f2.upvalues.length) {
      return false;
    }
    for(int i = 0; i < f1.upvalues.length; i++) {
      if(!f1.upvalues[i].equals(f2.upvalues[i])) {
        return false;
      }
    }
    if(f1.functions.length != f2.functions.length) {
      return false;
    }
    for(int i = 0; i < f1.functions.length; i++) {
      if(!function_equal(f1.functions[i], f2.functions[i])) {
        return false;
      }
    }
    return true;
  }
  
  public static boolean object_equal(LObject o1, LObject o2) {
    return o1.equals(o2);
  }
  
  public static boolean local_equal(LLocal l1, LLocal l2) {
    if(l1.start != l2.start) {
      return false;
    }
    if(l1.end != l2.end) {
      return false;
    }
    if(!l1.name.equals(l2.name)) {
      return false;
    }
    return true;
  }
  
  public static LFunction file_to_function(String filename) {
    try {
      RandomAccessFile file = new RandomAccessFile(filename, "r");
      ByteBuffer buffer = ByteBuffer.allocate((int) file.length());
      buffer.order(ByteOrder.LITTLE_ENDIAN);
      int len = (int) file.length();
      FileChannel in = file.getChannel();
      while(len > 0) len -= in.read(buffer);
      buffer.rewind();
      BHeader header = new BHeader(buffer);
      return header.function.parse(buffer, header);
    } catch(IOException e) {
      return null;
    }
  }
  
}