public Statement DecompileStatement(ushort?startPosition = null)
{
StartPositions.Push(startPosition ?? (ushort)Position);
var token = PeekByte;
switch (token)
{
// return [expression];
case (byte)OpCodes.Return:
return(DecompileReturn());
// switch (expression)
case (byte)OpCodes.Switch:
return(DecompileSwitch());
// case expression :
case (byte)OpCodes.Case:
return(DecompileCase());
// if (expression) // while / for / do until
case (byte)OpCodes.JumpIfNot:
{
PopByte();
var jump = new IfNotJump(ReadUInt16(), DecompileExpression(), Position - StartPositions.Peek());
StatementLocations.Add(StartPositions.Pop(), jump);
return(jump);
}
case (byte)OpCodes.Jump:
{
PopByte();
ushort jumpLoc = ReadUInt16();
if (ForEachScopes.Count > 0 && jumpLoc == ForEachScopes.Peek())
{
var brk = new BreakStatement();
StatementLocations.Add(StartPositions.Pop(), brk);
return(brk);
}
var jump = new UnconditionalJump(jumpLoc);
StatementLocations.Add(StartPositions.Pop(), jump);
return(jump);
}
// continue (iterator)
case (byte)OpCodes.IteratorNext:
{
PopByte();
var itNext = new ContinueStatement();
StatementLocations.Add(StartPositions.Pop(), itNext);
if (PopByte() != (byte)OpCodes.Jump)
{
return(null); //there should always be a jump after an iteratornext that's not at the end of the loop
}
//skip the jump address
PopByte();
PopByte();
return(itNext);
}
// break;
case (byte)OpCodes.IteratorPop:
{
PopByte();
return(DecompileStatement(StartPositions.Pop()));
}
// stop;
case (byte)OpCodes.Stop:
PopByte();
var stopStatement = new StopStatement(null, null);
StatementLocations.Add(StartPositions.Pop(), stopStatement);
return(stopStatement);
// Goto label
case (byte)OpCodes.GotoLabel:
PopByte();
var gotoLabel = new StateGoto(DecompileExpression());
StatementLocations.Add(StartPositions.Pop(), gotoLabel);
return(gotoLabel);
// assignable expression = expression;
case (byte)OpCodes.Let:
case (byte)OpCodes.LetBool:
case (byte)OpCodes.LetDelegate:
return(DecompileAssign());
// [skip x bytes]
case (byte)OpCodes.Skip: // TODO: this should never occur as statement, possibly remove?
PopByte();
ReadUInt16();
StartPositions.Pop();
return(DecompileStatement());
case (byte)OpCodes.Nothing:
PopByte();
StartPositions.Pop();
return(DecompileStatement()); // TODO, should probably have a nothing expression or statement, this is ugly
// foreach IteratorFunction(...)
case (byte)OpCodes.Iterator:
return(DecompileForEach());
// foreach arrayName(valuevariable[, indexvariable])
case (byte)OpCodes.DynArrayIterator:
return(DecompileForEach(true));
case (byte)OpCodes.LabelTable:
DecompileLabelTable();
StartPositions.Pop();
return(DecompileStatement());
case (byte)OpCodes.OptIfLocal:
case (byte)OpCodes.OptIfInstance:
{
PopByte();
IEntry obj = ReadObject();
var condition = new SymbolReference(null, obj.ObjectName.Instanced);
bool not = Convert.ToBoolean(ReadByte());
if (obj.ClassName == "BoolProperty")
{
var ifJump = new IfNotJump(
ReadUInt16(), not ? (Expression)condition : new PreOpReference(new PreOpDeclaration("!", SymbolTable.BoolType, 0, null), condition),
Position - StartPositions.Peek());
StatementLocations.Add(StartPositions.Pop(), ifJump);
return(ifJump);
}
var nullJump = new NullJump(ReadUInt16(), condition, not)
{
SizeOfExpression = Position - StartPositions.Peek()
};
StatementLocations.Add(StartPositions.Pop(), nullJump);
return(nullJump);
}
case (byte)OpCodes.FilterEditorOnly:
{
PopByte();
var edFilter = new InEditorJump(ReadUInt16());
StatementLocations.Add(StartPositions.Pop(), edFilter);
return(edFilter);
}
case (byte)OpCodes.EatReturnValue:
PopByte();
ReadObject();
return(DecompileStatement(StartPositions.Pop()));
case (byte)OpCodes.Assert:
return(DecompileAssert());
default:
var expr = DecompileExpression();
if (expr != null)
{
var statement = new ExpressionOnlyStatement(expr, null, null);
StatementLocations.Add(StartPositions.Pop(), statement);
return(statement);
}
// ERROR!
return(null);
}
}