swfutils/src/main/java/flash/swf/ActionDecoder.java - royale-compiler - Git at Google

 /*
  *
  *  Licensed to the Apache Software Foundation (ASF) under one or more
  *  contributor license agreements.  See the NOTICE file distributed with
  *  this work for additional information regarding copyright ownership.
  *  The ASF licenses this file to You under the Apache License, Version 2.0
  *  (the "License"); you may not use this file except in compliance with
  *  the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  *  Unless required by applicable law or agreed to in writing, software
  *  distributed under the License is distributed on an "AS IS" BASIS,
  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  *
  */

 package flash.swf;

 import flash.swf.actions.Branch;
 import flash.swf.actions.ConstantPool;
 import flash.swf.actions.DefineFunction;
 import flash.swf.actions.GetURL;
 import flash.swf.actions.GetURL2;
 import flash.swf.actions.GotoFrame;
 import flash.swf.actions.GotoFrame2;
 import flash.swf.actions.GotoLabel;
 import flash.swf.actions.Push;
 import flash.swf.actions.SetTarget;
 import flash.swf.actions.StoreRegister;
 import flash.swf.actions.StrictMode;
 import flash.swf.actions.Try;
 import flash.swf.actions.Unknown;
 import flash.swf.actions.WaitForFrame;
 import flash.swf.actions.With;
 import flash.swf.debug.DebugTable;
 import flash.swf.debug.LineRecord;
 import flash.swf.debug.RegisterRecord;
 import flash.swf.types.ActionList;
 import flash.swf.types.ClipActionRecord;
 import flash.swf.types.ClipActions;

 import java.io.IOException;
 import java.util.ArrayList;

 /**
  * AS2 decoder.
  */
 public class ActionDecoder
         implements ActionConstants
 {
     private SwfDecoder reader;
     private DebugTable debug;
     private boolean keepOffsets;
     private int actionCount;

     public ActionDecoder(SwfDecoder reader)
     {
         this(reader, null);
     }

     public ActionDecoder(SwfDecoder reader, DebugTable debug)
     {
         this.reader = reader;
         this.debug = debug;
     }

     public void setKeepOffsets(boolean b)
     {
         keepOffsets = b;
     }

 	/**
      * consume actions until length bytes are used up.
      * @param length
      * @throws IOException
      */
     public ActionList decode(int length) throws IOException { return decode(length, true); }

 	/**
      * consume actions until length bytes are used up
      * @param length
 	 * @param throwExceptions - if false exceptions will NOT be thrown. This is
 	 * used for decoding a series of opcodes which may not be complete on their own.
      * @throws IOException
      */
     public ActionList decode(int length, boolean throwExceptions) throws IOException
     {
         int startOffset = reader.getOffset();
 		int end = startOffset+length;
         boolean ending = false;

         ActionFactory factory = new ActionFactory(length, startOffset, actionCount);
 		try
 		{
 			for (int offset = startOffset; offset < end; offset = reader.getOffset())
 			{
 				int opcode = reader.readUI8();

 				if (opcode > 0)
 				{
 					if (ending)
 						throw new SwfFormatException("unexpected bytes after sactionEnd: " + opcode);
                     factory.setActionOffset(actionCount, offset);
 					decodeAction(opcode, offset, factory);
                     actionCount++;
 				}
 				else if (opcode == 0)
 				{
 					ending = true;
 				}
 				else
 				{
 					break;
 				}
 			}
             // keep track of the end too
             factory.setActionOffset(actionCount, reader.getOffset());
 		}
 		catch(ArrayIndexOutOfBoundsException aio)
 		{
 			if (throwExceptions)
 				throw aio;
 		}
 		catch(SwfFormatException swf)
 		{
 			if (throwExceptions)
 				throw swf;
 		}

         return factory.createActionList(keepOffsets);
     }

     public ClipActions decodeClipActions(int length) throws IOException
     {
         ClipActions a = new ClipActions();
         reader.readUI16(); // must be 0
         a.allEventFlags = decodeClipEventFlags(reader);

         ArrayList<ClipActionRecord> list = new ArrayList<ClipActionRecord>();

         ClipActionRecord record = decodeClipActionRecord();
         while (record != null)
         {
             list.add(record);
             record = decodeClipActionRecord();
         }

         a.clipActionRecords = list;

         return a;
     }

     private ClipActionRecord decodeClipActionRecord() throws IOException
     {
         int flags = decodeClipEventFlags(reader);
         if (flags != 0)
         {
             ClipActionRecord c = new ClipActionRecord();

             c.eventFlags = flags;

             // this tells us how big the action block is
             int size = (int)reader.readUI32();

             if ((flags & ClipActionRecord.keyPress) != 0)
             {
                 size--;
                 c.keyCode = reader.readUI8();
             }

             c.actionList = decode(size);

             return c;
         }
         else
         {
             return null;
         }
     }

     private int decodeClipEventFlags(SwfDecoder r) throws IOException
     {
         int flags;
         if (r.swfVersion >= 6)
             flags = (int)r.readUI32();
         else
             flags = r.readUI16();
         return flags;
     }

     private void decodeAction(int opcode, int offset, ActionFactory factory) throws IOException
     {
         LineRecord line = debug != null ? debug.getLine(offset) : null;
 		if (line != null)
 		{
             factory.setLine(offset, line);
 		}

  		// interleave register records in the action list
 		RegisterRecord record = (debug != null) ? debug.getRegisters(offset) : null;
 		if (record != null)
 		{
  			factory.setRegister(offset, record);
  		}

         Action a;
         if (opcode < 0x80)
         {
 			a = ActionFactory.createAction(opcode);
             factory.setAction(offset, a);
 			return;
         }

         int len = reader.readUI16();
         int pos = offset+3;

         switch (opcode)
         {
         case sactionDefineFunction:
             a = decodeDefineFunction(pos, len);
             factory.setAction(offset, a);
 			return;

         case sactionDefineFunction2:
             a = decodeDefineFunction2(pos, len);
             factory.setAction(offset, a);
 			return;

         case sactionWith:
             a = decodeWith(factory);
 			break;

 		case sactionTry:
 			a = decodeTry(factory);
 			break;

 		case sactionPush:
 			Push p = decodePush(offset, pos+len, factory);
 			checkConsumed(pos, len, p);
 			return;

         case sactionStrictMode:
             a = decodeStrictMode();
             break;

         case sactionCall:
             // this actions opcode has the high bit set, but there is no length.  considered a permanent bug.
             a = ActionFactory.createCall();
             break;

         case sactionGotoFrame:
             a = decodeGotoFrame();
             break;

         case sactionGetURL:
             a = decodeGetURL();
             break;

         case sactionStoreRegister:
             a = decodeStoreRegister();
             break;

         case sactionConstantPool:
             a = decodeConstantPool();
             break;

         case sactionWaitForFrame:
             a = decodeWaitForFrame(opcode, factory);
             break;

         case sactionSetTarget:
             a = decodeSetTarget();
             break;

         case sactionGotoLabel:
             a = decodeGotoLabel();
             break;

         case sactionWaitForFrame2:
             a = decodeWaitForFrame(opcode, factory);
             break;

         case sactionGetURL2:
             a = decodeGetURL2();
             break;

         case sactionJump:
         case sactionIf:
             a = decodeBranch(opcode, factory);
             break;

         case sactionGotoFrame2:
             a = decodeGotoFrame2();
             break;

         default:
             a = decodeUnknown(opcode, len);
             break;
         }
         checkConsumed(pos, len, a);
         factory.setAction(offset, a);
 	}

     private Try decodeTry(ActionFactory factory) throws IOException
     {
         Try a = new Try();

         a.flags = reader.readUI8();
         int trySize = reader.readUI16();
         int catchSize = reader.readUI16();
         int finallySize = reader.readUI16();

 		if (a.hasRegister())
 			a.catchReg = reader.readUI8();
 		else
 	       	a.catchName = reader.readString();

 		// we have now consumed the try action.  what follows is label mgmt

         int tryEnd = reader.getOffset() + trySize;
 		a.endTry = factory.getLabel(tryEnd);

         // place the catchLabel to mark the end point of the catch handler
 		if (a.hasCatch())
             a.endCatch = factory.getLabel(tryEnd + catchSize);

         // place the finallyLabel to mark the end point of the finally handler
 		if (a.hasFinally())
             a.endFinally = factory.getLabel(tryEnd + finallySize + (a.hasCatch() ? catchSize : 0));

         return a;
     }

     private GotoFrame2 decodeGotoFrame2() throws IOException
     {
         GotoFrame2 a = new GotoFrame2();
         a.playFlag = reader.readUI8();
         return a;
     }

     private Branch decodeBranch(int code, ActionFactory factory) throws IOException
     {
         Branch a = new Branch(code);
         int offset = reader.readSI16();
         int target = offset + reader.getOffset();
         a.target = factory.getLabel(target);
         return a;
     }

     private WaitForFrame decodeWaitForFrame(int opcode, ActionFactory factory) throws IOException
     {
         WaitForFrame a = new WaitForFrame(opcode);
         if (opcode == sactionWaitForFrame)
             a.frame = reader.readUI16();
         int skipCount = reader.readUI8();
         int skipTarget = actionCount+1 + skipCount;
         factory.addSkipEntry(a, skipTarget);
         return a;
     }

 	private GetURL2 decodeGetURL2() throws IOException
     {
         GetURL2 a = new GetURL2();
         a.method = reader.readUI8();
         return a;
     }

     private GotoLabel decodeGotoLabel() throws IOException
     {
         GotoLabel a = new GotoLabel();
         a.label = reader.readString();
         return a;
     }

     private SetTarget decodeSetTarget() throws IOException
     {
         SetTarget a = new SetTarget();
         a.targetName = reader.readString();
         return a;
     }

     private ConstantPool decodeConstantPool() throws IOException
     {
         ConstantPool cpool = new ConstantPool();
         int count = reader.readUI16();
         cpool.pool = new String[count];
         for (int i = 0; i < count; i++)
         {
             cpool.pool[i] = reader.readString();
         }
         return cpool;
     }

     private StoreRegister decodeStoreRegister() throws IOException
     {
         int register = reader.readUI8();
 		return ActionFactory.createStoreRegister(register);
     }

     private GetURL decodeGetURL() throws IOException
     {
         GetURL a = new GetURL();
         a.url = reader.readString();
         a.target = reader.readString();
         return a;
     }

     private GotoFrame decodeGotoFrame() throws IOException
     {
         GotoFrame a = new GotoFrame();
         a.frame = reader.readUI16();
         return a;
     }

     private Unknown decodeUnknown(int opcode, int length) throws IOException
     {
         Unknown a = new Unknown(opcode);
         a.data = new byte[length];
         reader.readFully(a.data);
         return a;
     }

     private StrictMode decodeStrictMode() throws IOException
     {
         boolean mode = reader.readUI8() != 0;
         return ActionFactory.createStrictMode(mode);
     }

     private Push decodePush(int offset, int end, ActionFactory factory) throws IOException
     {
         Push p;
         do
         {
             int pushType = reader.readUI8();
             switch (pushType)
             {
             case Push.kPushStringType: // string
                 p = ActionFactory.createPush(reader.readString());
                 break;
             case Push.kPushFloatType: // float
                 float fvalue = Float.intBitsToFloat((int) reader.readUI32());
                 p = ActionFactory.createPush(fvalue); // value
                 break;
             case Push.kPushNullType: // null
                 p = ActionFactory.createPushNull();
                 break;
             case Push.kPushUndefinedType: // undefined
                 p = ActionFactory.createPushUndefined();
                 break;
             case Push.kPushRegisterType: // register
                 p = ActionFactory.createPushRegister(reader.readUI8());
                 break;
             case Push.kPushBooleanType: // boolean
                 p = ActionFactory.createPush(reader.readUI8() != 0);
                 break;
             case Push.kPushDoubleType: // double
 				// read two 32 bit little-endian values in big-endian order.  weird.
                 long hx = reader.readUI32();
                 long lx = reader.readUI32();
                 p = ActionFactory.createPush(Double.longBitsToDouble((hx << 32) | (lx & 0xFFFFFFFFL)));
                 break;
             case Push.kPushIntegerType: // integer
                 p = ActionFactory.createPush((int)reader.readUI32());
                 break;
             case Push.kPushConstant8Type: // 8-bit cpool reference
                 p = ActionFactory.createPushCpool(reader.readUI8());
                 break;
             case Push.kPushConstant16Type: // 16-bit cpool reference
                 p = ActionFactory.createPushCpool(reader.readUI16());
                 break;
             default:
                 throw new SwfFormatException("Unknown push data type "+pushType);
             }
 			factory.setAction(offset, p);
             offset = reader.getOffset();
         }
         while (offset < end);
         return p;
     }

     private DefineFunction decodeDefineFunction(int pos, int len) throws IOException
     {
         DefineFunction a = new DefineFunction(ActionConstants.sactionDefineFunction);
         a.name = reader.readString();
         int number = reader.readUI16();
         a.params = new String[number];

         for (int i = 0; i < number; i++)
         {
             a.params[i] = reader.readString();
         }

         a.codeSize = reader.readUI16();

         checkConsumed(pos, len, a);

         a.actionList = decode(a.codeSize);

         return a;
     }

     private DefineFunction decodeDefineFunction2(int pos, int len) throws IOException
     {
         DefineFunction a = new DefineFunction(ActionConstants.sactionDefineFunction2);
         a.name = reader.readString();
         int number = reader.readUI16();
         a.params = new String[number];
         a.paramReg = new int[number];

         a.regCount = reader.readUI8();
         a.flags = reader.readUI16();

         for (int i = 0; i < number; i++)
         {
             a.paramReg[i] = reader.readUI8();
             a.params[i] = reader.readString();
         }

         a.codeSize = reader.readUI16();

         checkConsumed(pos, len, a);

         a.actionList = decode(a.codeSize);

         return a;
     }

     private void checkConsumed(int pos, int len, Action a) throws IOException
     {
         int consumed = reader.getOffset() - pos;
         if (consumed != len)
         {
             throw new SwfFormatException(a.getClass().getName() + ": " + consumed + " was read. " + len + " was required.");
         }
     }

     private With decodeWith(ActionFactory factory) throws IOException
     {
         With a = new With();
         int size = reader.readUI16();
 		int target = size + reader.getOffset();
         a.endWith = factory.getLabel(target);
         return a;
     }
 }
	/*
	*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*
	*/

	package flash.swf;

	import flash.swf.actions.Branch;
	import flash.swf.actions.ConstantPool;
	import flash.swf.actions.DefineFunction;
	import flash.swf.actions.GetURL;
	import flash.swf.actions.GetURL2;
	import flash.swf.actions.GotoFrame;
	import flash.swf.actions.GotoFrame2;
	import flash.swf.actions.GotoLabel;
	import flash.swf.actions.Push;
	import flash.swf.actions.SetTarget;
	import flash.swf.actions.StoreRegister;
	import flash.swf.actions.StrictMode;
	import flash.swf.actions.Try;
	import flash.swf.actions.Unknown;
	import flash.swf.actions.WaitForFrame;
	import flash.swf.actions.With;
	import flash.swf.debug.DebugTable;
	import flash.swf.debug.LineRecord;
	import flash.swf.debug.RegisterRecord;
	import flash.swf.types.ActionList;
	import flash.swf.types.ClipActionRecord;
	import flash.swf.types.ClipActions;

	import java.io.IOException;
	import java.util.ArrayList;

	/**
	* AS2 decoder.
	*/
	public class ActionDecoder
	implements ActionConstants
	{
	private SwfDecoder reader;
	private DebugTable debug;
	private boolean keepOffsets;
	private int actionCount;

	public ActionDecoder(SwfDecoder reader)
	{
	this(reader, null);
	}

	public ActionDecoder(SwfDecoder reader, DebugTable debug)
	{
	this.reader = reader;
	this.debug = debug;
	}

	public void setKeepOffsets(boolean b)
	{
	keepOffsets = b;
	}

	/**
	* consume actions until length bytes are used up.
	* @param length
	* @throws IOException
	*/
	public ActionList decode(int length) throws IOException { return decode(length, true); }

	/**
	* consume actions until length bytes are used up
	* @param length
	* @param throwExceptions - if false exceptions will NOT be thrown. This is
	* used for decoding a series of opcodes which may not be complete on their own.
	* @throws IOException
	*/
	public ActionList decode(int length, boolean throwExceptions) throws IOException
	{
	int startOffset = reader.getOffset();
	int end = startOffset+length;
	boolean ending = false;

	ActionFactory factory = new ActionFactory(length, startOffset, actionCount);
	try
	{
	for (int offset = startOffset; offset < end; offset = reader.getOffset())
	{
	int opcode = reader.readUI8();

	if (opcode > 0)
	{
	if (ending)
	throw new SwfFormatException("unexpected bytes after sactionEnd: " + opcode);
	factory.setActionOffset(actionCount, offset);
	decodeAction(opcode, offset, factory);
	actionCount++;
	}
	else if (opcode == 0)
	{
	ending = true;
	}
	else
	{
	break;
	}
	}
	// keep track of the end too
	factory.setActionOffset(actionCount, reader.getOffset());
	}
	catch(ArrayIndexOutOfBoundsException aio)
	{
	if (throwExceptions)
	throw aio;
	}
	catch(SwfFormatException swf)
	{
	if (throwExceptions)
	throw swf;
	}

	return factory.createActionList(keepOffsets);
	}

	public ClipActions decodeClipActions(int length) throws IOException
	{
	ClipActions a = new ClipActions();
	reader.readUI16(); // must be 0
	a.allEventFlags = decodeClipEventFlags(reader);

	ArrayList<ClipActionRecord> list = new ArrayList<ClipActionRecord>();

	ClipActionRecord record = decodeClipActionRecord();
	while (record != null)
	{
	list.add(record);
	record = decodeClipActionRecord();
	}

	a.clipActionRecords = list;

	return a;
	}

	private ClipActionRecord decodeClipActionRecord() throws IOException
	{
	int flags = decodeClipEventFlags(reader);
	if (flags != 0)
	{
	ClipActionRecord c = new ClipActionRecord();

	c.eventFlags = flags;

	// this tells us how big the action block is
	int size = (int)reader.readUI32();

	if ((flags & ClipActionRecord.keyPress) != 0)
	{
	size--;
	c.keyCode = reader.readUI8();
	}

	c.actionList = decode(size);

	return c;
	}
	else
	{
	return null;
	}
	}

	private int decodeClipEventFlags(SwfDecoder r) throws IOException
	{
	int flags;
	if (r.swfVersion >= 6)
	flags = (int)r.readUI32();
	else
	flags = r.readUI16();
	return flags;
	}

	private void decodeAction(int opcode, int offset, ActionFactory factory) throws IOException
	{
	LineRecord line = debug != null ? debug.getLine(offset) : null;
	if (line != null)
	{
	factory.setLine(offset, line);
	}

	// interleave register records in the action list
	RegisterRecord record = (debug != null) ? debug.getRegisters(offset) : null;
	if (record != null)
	{
	factory.setRegister(offset, record);
	}

	Action a;
	if (opcode < 0x80)
	{
	a = ActionFactory.createAction(opcode);
	factory.setAction(offset, a);
	return;
	}

	int len = reader.readUI16();
	int pos = offset+3;

	switch (opcode)
	{
	case sactionDefineFunction:
	a = decodeDefineFunction(pos, len);
	factory.setAction(offset, a);
	return;

	case sactionDefineFunction2:
	a = decodeDefineFunction2(pos, len);
	factory.setAction(offset, a);
	return;

	case sactionWith:
	a = decodeWith(factory);
	break;

	case sactionTry:
	a = decodeTry(factory);
	break;

	case sactionPush:
	Push p = decodePush(offset, pos+len, factory);
	checkConsumed(pos, len, p);
	return;

	case sactionStrictMode:
	a = decodeStrictMode();
	break;

	case sactionCall:
	// this actions opcode has the high bit set, but there is no length. considered a permanent bug.
	a = ActionFactory.createCall();
	break;

	case sactionGotoFrame:
	a = decodeGotoFrame();
	break;

	case sactionGetURL:
	a = decodeGetURL();
	break;

	case sactionStoreRegister:
	a = decodeStoreRegister();
	break;

	case sactionConstantPool:
	a = decodeConstantPool();
	break;

	case sactionWaitForFrame:
	a = decodeWaitForFrame(opcode, factory);
	break;

	case sactionSetTarget:
	a = decodeSetTarget();
	break;

	case sactionGotoLabel:
	a = decodeGotoLabel();
	break;

	case sactionWaitForFrame2:
	a = decodeWaitForFrame(opcode, factory);
	break;

	case sactionGetURL2:
	a = decodeGetURL2();
	break;

	case sactionJump:
	case sactionIf:
	a = decodeBranch(opcode, factory);
	break;

	case sactionGotoFrame2:
	a = decodeGotoFrame2();
	break;

	default:
	a = decodeUnknown(opcode, len);
	break;
	}
	checkConsumed(pos, len, a);
	factory.setAction(offset, a);
	}

	private Try decodeTry(ActionFactory factory) throws IOException
	{
	Try a = new Try();

	a.flags = reader.readUI8();
	int trySize = reader.readUI16();
	int catchSize = reader.readUI16();
	int finallySize = reader.readUI16();

	if (a.hasRegister())
	a.catchReg = reader.readUI8();
	else
	a.catchName = reader.readString();

	// we have now consumed the try action. what follows is label mgmt

	int tryEnd = reader.getOffset() + trySize;
	a.endTry = factory.getLabel(tryEnd);

	// place the catchLabel to mark the end point of the catch handler
	if (a.hasCatch())
	a.endCatch = factory.getLabel(tryEnd + catchSize);

	// place the finallyLabel to mark the end point of the finally handler
	if (a.hasFinally())
	a.endFinally = factory.getLabel(tryEnd + finallySize + (a.hasCatch() ? catchSize : 0));

	return a;
	}

	private GotoFrame2 decodeGotoFrame2() throws IOException
	{
	GotoFrame2 a = new GotoFrame2();
	a.playFlag = reader.readUI8();
	return a;
	}

	private Branch decodeBranch(int code, ActionFactory factory) throws IOException
	{
	Branch a = new Branch(code);
	int offset = reader.readSI16();
	int target = offset + reader.getOffset();
	a.target = factory.getLabel(target);
	return a;
	}

	private WaitForFrame decodeWaitForFrame(int opcode, ActionFactory factory) throws IOException
	{
	WaitForFrame a = new WaitForFrame(opcode);
	if (opcode == sactionWaitForFrame)
	a.frame = reader.readUI16();
	int skipCount = reader.readUI8();
	int skipTarget = actionCount+1 + skipCount;
	factory.addSkipEntry(a, skipTarget);
	return a;
	}

	private GetURL2 decodeGetURL2() throws IOException
	{
	GetURL2 a = new GetURL2();
	a.method = reader.readUI8();
	return a;
	}

	private GotoLabel decodeGotoLabel() throws IOException
	{
	GotoLabel a = new GotoLabel();
	a.label = reader.readString();
	return a;
	}

	private SetTarget decodeSetTarget() throws IOException
	{
	SetTarget a = new SetTarget();
	a.targetName = reader.readString();
	return a;
	}

	private ConstantPool decodeConstantPool() throws IOException
	{
	ConstantPool cpool = new ConstantPool();
	int count = reader.readUI16();
	cpool.pool = new String[count];
	for (int i = 0; i < count; i++)
	{
	cpool.pool[i] = reader.readString();
	}
	return cpool;
	}

	private StoreRegister decodeStoreRegister() throws IOException
	{
	int register = reader.readUI8();
	return ActionFactory.createStoreRegister(register);
	}

	private GetURL decodeGetURL() throws IOException
	{
	GetURL a = new GetURL();
	a.url = reader.readString();
	a.target = reader.readString();
	return a;
	}

	private GotoFrame decodeGotoFrame() throws IOException
	{
	GotoFrame a = new GotoFrame();
	a.frame = reader.readUI16();
	return a;
	}

	private Unknown decodeUnknown(int opcode, int length) throws IOException
	{
	Unknown a = new Unknown(opcode);
	a.data = new byte[length];
	reader.readFully(a.data);
	return a;
	}

	private StrictMode decodeStrictMode() throws IOException
	{
	boolean mode = reader.readUI8() != 0;
	return ActionFactory.createStrictMode(mode);
	}

	private Push decodePush(int offset, int end, ActionFactory factory) throws IOException
	{
	Push p;
	do
	{
	int pushType = reader.readUI8();
	switch (pushType)
	{
	case Push.kPushStringType: // string
	p = ActionFactory.createPush(reader.readString());
	break;
	case Push.kPushFloatType: // float
	float fvalue = Float.intBitsToFloat((int) reader.readUI32());
	p = ActionFactory.createPush(fvalue); // value
	break;
	case Push.kPushNullType: // null
	p = ActionFactory.createPushNull();
	break;
	case Push.kPushUndefinedType: // undefined
	p = ActionFactory.createPushUndefined();
	break;
	case Push.kPushRegisterType: // register
	p = ActionFactory.createPushRegister(reader.readUI8());
	break;
	case Push.kPushBooleanType: // boolean
	p = ActionFactory.createPush(reader.readUI8() != 0);
	break;
	case Push.kPushDoubleType: // double
	// read two 32 bit little-endian values in big-endian order. weird.
	long hx = reader.readUI32();
	long lx = reader.readUI32();
	p = ActionFactory.createPush(Double.longBitsToDouble((hx << 32) \| (lx & 0xFFFFFFFFL)));
	break;
	case Push.kPushIntegerType: // integer
	p = ActionFactory.createPush((int)reader.readUI32());
	break;
	case Push.kPushConstant8Type: // 8-bit cpool reference
	p = ActionFactory.createPushCpool(reader.readUI8());
	break;
	case Push.kPushConstant16Type: // 16-bit cpool reference
	p = ActionFactory.createPushCpool(reader.readUI16());
	break;
	default:
	throw new SwfFormatException("Unknown push data type "+pushType);
	}
	factory.setAction(offset, p);
	offset = reader.getOffset();
	}
	while (offset < end);
	return p;
	}

	private DefineFunction decodeDefineFunction(int pos, int len) throws IOException
	{
	DefineFunction a = new DefineFunction(ActionConstants.sactionDefineFunction);
	a.name = reader.readString();
	int number = reader.readUI16();
	a.params = new String[number];

	for (int i = 0; i < number; i++)
	{
	a.params[i] = reader.readString();
	}

	a.codeSize = reader.readUI16();

	checkConsumed(pos, len, a);

	a.actionList = decode(a.codeSize);

	return a;
	}

	private DefineFunction decodeDefineFunction2(int pos, int len) throws IOException
	{
	DefineFunction a = new DefineFunction(ActionConstants.sactionDefineFunction2);
	a.name = reader.readString();
	int number = reader.readUI16();
	a.params = new String[number];
	a.paramReg = new int[number];

	a.regCount = reader.readUI8();
	a.flags = reader.readUI16();

	for (int i = 0; i < number; i++)
	{
	a.paramReg[i] = reader.readUI8();
	a.params[i] = reader.readString();
	}

	a.codeSize = reader.readUI16();

	checkConsumed(pos, len, a);

	a.actionList = decode(a.codeSize);

	return a;
	}

	private void checkConsumed(int pos, int len, Action a) throws IOException
	{
	int consumed = reader.getOffset() - pos;
	if (consumed != len)
	{
	throw new SwfFormatException(a.getClass().getName() + ": " + consumed + " was read. " + len + " was required.");
	}
	}

	private With decodeWith(ActionFactory factory) throws IOException
	{
	With a = new With();
	int size = reader.readUI16();
	int target = size + reader.getOffset();
	a.endWith = factory.getLabel(target);
	return a;
	}
	}