/*
*
* 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.Push;
import flash.swf.actions.StoreRegister;
import flash.swf.actions.StrictMode;
import flash.swf.actions.Label;
import flash.swf.actions.WaitForFrame;
import flash.swf.types.ActionList;
import flash.swf.debug.LineRecord;
import flash.swf.debug.RegisterRecord;
import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;
/**
* This is a factory for decoding ActionScript bytecode. It keeps
* track of temporary information we need while decoding but can
* discard once we are done.
* @author Edwin Smith
*/
final public class ActionFactory
{
public static final Object UNDEFINED = new Object()
{
public String toString()
{
return "undefined";
}
};
public static final Object STACKTOP = new Object()
{
public String toString()
{
return "stack";
}
};
/** flyweight action objects for 1-byte opcodes 0..7F */
private static final Action[] actionFlyweights = new Action[0x80];
private static final Push[] pushCpoolFlyweights = new Push[256];
private static final Push[] pushRegisterFlyweights = new Push[256];
private static final StoreRegister[] storeRegisterFlyweights = new StoreRegister[256];
private static final Push pushTrueFlyweight = new Push(Boolean.TRUE);
private static final Push pushFalseFlyweight = new Push(Boolean.FALSE);
private static final Push pushUndefinedFlyweight = new Push(UNDEFINED);
private static final Push pushNullFlyweight = new Push(null);
private static final Push pushFloat0Flyweight = new Push(new Float(0));
private static final Push pushInteger0Flyweight = new Push(new Integer(0));
private static final Push pushDouble0Flyweight = new Push(new Double(0));
private static final Action callFlyweight = new Action(ActionConstants.sactionCall);
private static final StrictMode strictTrueFlyweight = new StrictMode(true);
private static final StrictMode strictFalseFlyweight = new StrictMode(false);
static
{
for (int i=0; i < 0x80; i++)
{
ActionFactory.actionFlyweights[i] = new Action(i);
}
for (int i=0; i < 256; i++)
{
ActionFactory.pushRegisterFlyweights[i] = new Push(new Byte((byte)i));
ActionFactory.pushCpoolFlyweights[i] = new Push(new Short((short)i));
ActionFactory.storeRegisterFlyweights[i] = new StoreRegister(i);
}
}
public static Action createAction(int code)
{
return actionFlyweights[code];
}
public static Push createPushCpool(int index)
{
return (index < pushCpoolFlyweights.length)
? pushCpoolFlyweights[index]
: new Push(new Short((short)index));
}
public static Push createPush(String s)
{
return new Push(s);
}
public static Push createPush(float fvalue)
{
return fvalue == 0
? pushFloat0Flyweight
: new Push(new Float(fvalue));
}
public static Push createPushNull()
{
return pushNullFlyweight;
}
public static Push createPushUndefined()
{
return pushUndefinedFlyweight;
}
public static Push createPushRegister(int regno)
{
return pushRegisterFlyweights[regno];
}
public static Push createPush(boolean b)
{
return (b ? pushTrueFlyweight : pushFalseFlyweight);
}
public static Push createPush(double dvalue)
{
return dvalue == 0
? pushDouble0Flyweight
: new Push(new Double(dvalue));
}
public static Push createPush(int ivalue)
{
return ivalue == 0
? pushInteger0Flyweight
: new Push(new Integer(ivalue));
}
public static StoreRegister createStoreRegister(int register)
{
return storeRegisterFlyweights[register];
}
public static Action createCall()
{
return callFlyweight;
}
public static StrictMode createStrictMode(boolean mode)
{
return mode ? strictTrueFlyweight : strictFalseFlyweight;
}
private final int startOffset;
private final int startCount;
private final Action[] actions;
private final Label[] labels;
private final LineRecord[] lines;
private final RegisterRecord[] registers;
private final int[] actionOffsets;
private int count;
private List<SkipEntry> skipRecords;
public ActionFactory(int length, int startOffset, int startCount)
{
this.startOffset = startOffset;
this.startCount = startCount;
labels = new Label[length+1]; // length+1 to handle labels after last action
lines = new LineRecord[length];
registers = new RegisterRecord[length];
actions = new Action[length];
actionOffsets = new int[length+1];
skipRecords = new ArrayList<SkipEntry>();
}
public void setLine(int offset, LineRecord line)
{
int i = offset-startOffset;
if (lines[i] == null)
count++;
lines[i] = line;
}
public void setRegister(int offset, RegisterRecord record)
{
int i = offset-startOffset;
if (registers[i] == null)
count++;
registers[i] = record;
}
public void setAction(int offset, Action a)
{
int i = offset-startOffset;
if (actions[i] == null)
count++;
actions[i] = a;
}
public Label getLabel(int target)
{
int i = target-startOffset;
Label label = null;
// See http://bugs.adobe.com/jira/browse/SDK-23169, for a SWF
// where i is negative. This seems like a broken SWF, because
// a branch is trying to jump before the start of the
// DoInitAction. To avoid a ArrayIndexOutOfBoundsException,
// do a range check.
if ((i >= 0) && (i < labels.length))
{
label = labels[i];
if (label == null)
{
labels[i] = label = new Label();
count++;
}
}
return label;
}
public void setActionOffset(int actionCount, int offset)
{
actionOffsets[actionCount-startCount] = offset;
}
/**
* now that everything has been decoded, build a single actionlist
* with the labels and jump targets merged in.
* @param keepOffsets
* @return
*/
public ActionList createActionList(boolean keepOffsets)
{
processSkipEntries();
ActionList list = new ActionList(keepOffsets);
list.grow(count);
Action a;
int length = actions.length;
if (keepOffsets)
{
for (int i=0; i < length; i++)
{
int offset = startOffset+i;
if ((a=actions[i]) != null)
list.insert(offset, a);
if ((a=lines[i]) != null)
list.insert(offset, a);
if ((a=registers[i]) != null)
list.insert(offset, a);
if ((a=labels[i]) != null)
list.insert(offset, a);
}
if ((a=labels[length]) != null)
list.insert(startOffset+length, a);
}
else
{
for (int i=0; i < length; i++)
{
if ((a=labels[i]) != null)
list.append(a);
if ((a=lines[i]) != null)
list.append(a);
if ((a=registers[i]) != null)
list.append(a);
if ((a=actions[i]) != null)
list.append(a);
}
if ((a=labels[length]) != null)
list.append(a);
}
return list;
}
private static class SkipEntry
{
WaitForFrame action;
int skipTarget;
public SkipEntry(WaitForFrame action, int skipTarget)
{
this.action = action;
this.skipTarget = skipTarget;
}
}
/**
* postprocess skip records now that we now the offset of each encoded action
*/
private void processSkipEntries()
{
for (Iterator<SkipEntry> i = skipRecords.iterator(); i.hasNext();)
{
SkipEntry skipRecord = i.next();
int labelOffset = actionOffsets[skipRecord.skipTarget-startCount];
skipRecord.action.skipTarget = getLabel(labelOffset);
}
}
public void addSkipEntry(WaitForFrame a, int skipTarget)
{
skipRecords.add(new SkipEntry(a, skipTarget));
}
}