/* ConstantRuntimeEnvironment Copyright (C) 1999 Jochen Hoenicke.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 */

package jode.obfuscator;
import jode.jvm.Interpreter;
import jode.jvm.SimpleRuntimeEnvironment;
import jode.jvm.InterpreterException;
import jode.bytecode.Reference;
import jode.bytecode.BytecodeInfo;
import jode.bytecode.TypeSignature;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;

///#def COLLECTIONS java.util
import java.util.Set;
import java.util.HashSet;
///#enddef

public class ConstantRuntimeEnvironment extends SimpleRuntimeEnvironment {

    /**
     * The references that may be used in constant methods.
     */
    static Set whiteList = new HashSet();

    static void addWhite(Reference ref) {
	whiteList.add(ref);
    }

    public static boolean isWhite(Reference ref) {
	return whiteList.contains(ref);
    }

    public static boolean isWhite(String retTypeSig) {
	return retTypeSig.length() == 1 // primitive type
	    || whiteList.contains(retTypeSig);
    }

    static {
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "toCharArray", "()[C"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "<init>", 
		  "(Ljava/lang/String;)V"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "<init>", "()V"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(Ljava/lang/String;)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(C)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(B)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(S)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(Z)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(F)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(I)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(J)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "append", 
		  "(D)Ljava/lang/StringBuffer;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/StringBuffer;", "toString", 
		  "()Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "<init>", "()V"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "<init>", "([C)V"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "<init>", "([CII)V"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "<init>", 
		  "(Ljava/lang/String;)V"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "<init>", 
		  "(Ljava/lang/StringBuffer;)V"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "length", "()I"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "replace", 
		  "(CC)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(Z)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(B)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(S)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(C)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(D)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(F)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(I)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(J)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "valueOf", 
		  "(Ljava/lang/Object;)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "substring", 
		  "(I)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/String;", "substring", 
		  "(II)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava.lang/reflect/Modifier;", "toString", 
		  "(I)Ljava/lang/String;"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "abs", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "abs", "(F)F"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "abs", "(I)I"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "abs", "(J)J"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "acos", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "asin", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "atan", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "atan2", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "ceil", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "cos", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "exp", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "floor", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "IEEEremainder", "(DD)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "log", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "max", "(DD)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "max", "(FF)F"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "max", "(II)I"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "max", "(JJ)J"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "min", "(DD)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "min", "(FF)F"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "min", "(II)I"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "min", "(JJ)J"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "pow", "(DD)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "rint", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "round", "(D)J"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "round", "(F)I"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "sin", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "sqrt", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "tan", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "toDegrees", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "toRadians", "(D)D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "E", "D"));
	addWhite(Reference.getReference
		 ("Ljava/lang/Math;", "PI", "D"));

	whiteList.add("Ljava/lang/String;");
//  	whiteList.add("Ljava/lang/Class;");
//  	whiteList.add("Ljava/lang/reflect/Method;");
//  	whiteList.add("Ljava/lang/reflect/Field;");
    }

    private Interpreter interpreter;
    
    public ConstantRuntimeEnvironment() {
	interpreter = new Interpreter(this);
    }

    public static Object getDefaultValue(String typeSig) {
	switch(typeSig.charAt(0)) {
	case 'Z':
	case 'B':
	case 'S':
	case 'C':
	case 'I':
	    return new Integer(0);
	case 'J':
	    return new Long(0L);
	case 'D':
	    return new Double(0.0);
	case 'F':
	    return new Float(0.0F);
	default:
	    return null;
	}
    }

    public Object getField(Reference ref, Object obj)
	throws InterpreterException {
	if (isWhite(ref))
	    return super.getField(ref, obj);
	FieldIdentifier fi
	    = (FieldIdentifier) Main.getClassBundle().getIdentifier(ref);
	if (fi != null && !fi.isNotConstant()) {
	    Object result = fi.getConstant();
	    if (result == null)
		result = getDefaultValue(ref.getType());
	    return result;
	}
	throw new InterpreterException("Field " + ref + " not constant");
    }

    public void putField(Reference ref, Object obj, Object value)
	throws InterpreterException {
	throw new InterpreterException("Modifying Field " + ref + ".");
    }
    
    public Object invokeConstructor(Reference ref, Object[] params)
	throws InterpreterException, InvocationTargetException {
	if (isWhite(ref))
	    return super.invokeConstructor(ref, params);
	throw new InterpreterException("Creating new Object " + ref + ".");
    }
    
    public Object invokeMethod(Reference ref, boolean isVirtual, 
			       Object cls, Object[] params) 
	throws InterpreterException, InvocationTargetException {
	if (isWhite(ref))
	    return super.invokeMethod(ref, isVirtual, cls, params);
	MethodIdentifier mi
	    = (MethodIdentifier) Main.getClassBundle().getIdentifier(ref);
	if (mi != null) {
	    BytecodeInfo code = mi.info.getBytecode();
	    if (code != null)
		return interpreter.interpretMethod(code, cls, params);
	}
	throw new InterpreterException("Invoking library method " + ref + ".");
    }
    
    public boolean instanceOf(Object obj, String className)
	throws InterpreterException {
	Class clazz;
	try {
	    clazz = Class.forName(className);
	} catch (ClassNotFoundException ex) {
	    throw new InterpreterException
		("Class "+ex.getMessage()+" not found");
	}
	return obj != null && clazz.isInstance(obj);
    }

    public Object newArray(String type, int[] dimensions)
	throws InterpreterException, NegativeArraySizeException {
	if (type.length() == dimensions.length + 1) {
	    Class clazz;
	    try {
		clazz = TypeSignature
		    .getClass(type.substring(dimensions.length));
	    } catch (ClassNotFoundException ex) {
		throw new InterpreterException
		    ("Class "+ex.getMessage()+" not found");
	    }
	    return Array.newInstance(clazz, dimensions);
	}
	throw new InterpreterException("Creating object array.");
    }
}