public CodeBody Decompile()
{
// Skip native funcs
var Func = DataContainer as ME3Function;
if (Func != null && Func.FunctionFlags.HasFlag(FunctionFlags.Native))
{
var comment = new ExpressionOnlyStatement(null, null, new SymbolReference(null, null, null, "// Native function"));
return new CodeBody(new List<Statement>() { comment }, null, null);
}
Position = 0;
_totalPadding = 0;
CurrentScope = new Stack<int>();
var statements = new List<Statement>();
StatementLocations = new Dictionary<UInt16, Statement>();
StartPositions = new Stack<UInt16>();
Scopes = new List<List<Statement>>();
LabelTable = new List<LabelTableEntry>();
ForEachScopes = new Stack<UInt16>();
DecompileDefaultParameterValues(statements);
Scopes.Add(statements);
CurrentScope.Push(Scopes.Count - 1);
while (Position < Size && !CurrentIs(StandardByteCodes.EndOfScript))
{
var current = DecompileStatement();
if (current == null && CurrentByte == (byte)StandardByteCodes.EndOfScript)
break; // Natural end after label table, no error
if (current == null)
break; // TODO: ERROR!
statements.Add(current);
}
CurrentScope.Pop(); ;
AddStateLabels();
return new CodeBody(statements, null, null);
}
public bool VisitNode(ExpressionOnlyStatement node)
{
throw new NotImplementedException();
}
public bool VisitNode(ExpressionOnlyStatement node)
{
// expression;
Write("");
node.Value.AcceptVisitor(this);
return true;
}
public Statement DecompileStatement()
{
StartPositions.Push((UInt16)Position);
var token = CurrentByte;
switch (token)
{
// return [expression];
case (byte)StandardByteCodes.Return:
return DecompileReturn();
// switch (expression)
case (byte)StandardByteCodes.Switch:
return DecompileSwitch();
// case expression :
case (byte)StandardByteCodes.Case:
return DecompileCase();
// if (expression) // while / for / do until
case (byte)StandardByteCodes.JumpIfNot:
return DecompileConditionalJump();
// continue
case (byte)StandardByteCodes.Jump: // TODO: UDK seems to compile this from break when inside ForEach, handle?
return DecompileJump();
// continue (iterator)
case (byte)StandardByteCodes.IteratorNext:
PopByte(); // pop iteratornext token
return DecompileJump();
// break;
case (byte)StandardByteCodes.IteratorPop:
return DecompileIteratorPop();
// stop;
case (byte)StandardByteCodes.Stop:
PopByte();
var stopStatement = new StopStatement(null, null);
StatementLocations.Add(StartPositions.Pop(), stopStatement);
return stopStatement;
// Goto label
case (byte)StandardByteCodes.GotoLabel:
PopByte();
var labelExpr = DecompileExpression();
var func = new SymbolReference(null, null, null, "goto");
var call = new FunctionCall(func, new List<Expression>() { labelExpr }, null, null);
var gotoLabel = new ExpressionOnlyStatement(null, null, call);
StatementLocations.Add(StartPositions.Pop(), gotoLabel);
return gotoLabel;
// assignable expression = expression;
case (byte)StandardByteCodes.Let:
case (byte)StandardByteCodes.LetBool:
case (byte)StandardByteCodes.LetDelegate:
return DecompileAssign();
// [skip x bytes]
case (byte)StandardByteCodes.Skip: // TODO: this should never occur as statement, possibly remove?
PopByte();
ReadUInt16();
StartPositions.Pop();
return DecompileStatement();
case (byte)StandardByteCodes.Nothing:
PopByte();
StartPositions.Pop();
return DecompileStatement(); // TODO, should probably have a nothing expression or statement, this is ugly
// foreach IteratorFunction(...)
case (byte)StandardByteCodes.Iterator:
return DecompileForEach();
// foreach arrayName(valuevariable[, indexvariable])
case (byte)StandardByteCodes.DynArrayIterator:
return DecompileForEach(isDynArray: true);
case (byte)StandardByteCodes.LabelTable:
DecompileLabelTable();
StartPositions.Pop();
return DecompileStatement();
#region unsupported
case (byte)StandardByteCodes.OptIfLocal: // TODO: verify, handle syntax
return DecompileConditionalJump(isOpt: true);
case (byte)StandardByteCodes.OptIfInstance: // TODO: verify, handle syntax
return DecompileConditionalJump(isOpt: true);
#endregion
default:
var expr = DecompileExpression();
if (expr != null)
{
var statement = new ExpressionOnlyStatement(null, null, expr);
StatementLocations.Add(StartPositions.Pop(), statement);
return statement;
}
// ERROR!
break;
}
return null;
}
private void DecompileDefaultParameterValues(List<Statement> statements)
{
OptionalParams = new Stack<FunctionParameter>();
var func = DataContainer as ME3Function;
if (func != null) // Gets all optional params for default value parsing
{
for (int n = 0; n < Parameters.Count; n++)
{
if (func.Parameters[n].PropertyFlags.HasFlag(PropertyFlags.OptionalParm))
OptionalParams.Push(Parameters[n]);
}
}
while (CurrentByte == (byte)StandardByteCodes.DefaultParmValue
|| CurrentByte == (byte)StandardByteCodes.Nothing)
{
StartPositions.Push((UInt16)Position);
var token = PopByte();
if (token == (byte)StandardByteCodes.DefaultParmValue) // default value assigned
{
ReadInt16(); //MemSize of value
var value = DecompileExpression();
PopByte(); // end of value
var builder = new CodeBuilderVisitor(); // what a wonderful hack, TODO.
value.AcceptVisitor(builder);
if (OptionalParams.Count != 0)
{
var parm = OptionalParams.Pop();
parm.Variables.First().Name += " = " + builder.GetCodeString();
StartPositions.Pop();
}
else
{ // TODO: weird, research how to deal with this
var comment = new SymbolReference(null, null, null, "// Orphaned Default Parm: " + builder.GetCodeString());
var statement = new ExpressionOnlyStatement(null, null, comment);
StatementLocations.Add(StartPositions.Pop(), statement);
statements.Add(statement);
}
}
}
}
