/// <summary>
/// Generates an assembly code that will decode an integer with a set of InstructionInfo.
/// </summary>
/// <param name="instructionInfoList"></param>
/// <param name="generateCallDelegate"></param>
/// <param name="level"></param>
public static AstNodeStm GenerateSwitchCode(IEnumerable <InstructionInfo> instructionInfoList,
Func <InstructionInfo, AstNodeStm> generateCallDelegate, int level = 0)
{
//var ILGenerator = SafeILGenerator._UnsafeGetILGenerator();
var instructionInfos = instructionInfoList as InstructionInfo[] ?? instructionInfoList.ToArray();
var commonMask =
instructionInfos.Aggregate(0xFFFFFFFF, (Base, instructionInfo) => Base & instructionInfo.Mask);
var maskGroups = instructionInfos.GroupBy(instructionInfo => instructionInfo.Value & commonMask);
#if false
int ShiftOffset = 0;
var CommonMaskShifted = CommonMask >> ShiftOffset;
uint MinValue = 0;
#else
var shiftOffset = BitUtils.GetFirstBit1(commonMask);
var commonMaskShifted = commonMask >> shiftOffset;
var enumerable = maskGroups as IGrouping <uint, InstructionInfo>[] ?? maskGroups.ToArray();
var minValue = enumerable
.Select(maskGroup => (maskGroup.First().Value >> shiftOffset) & commonMaskShifted).Min();
#endif
//var MaskGroupsCount = MaskGroups.Count();
//Console.WriteLine("[" + Level + "]{0:X}", CommonMask);
//var MaskedLocal = SafeILGenerator.DeclareLocal<int>();
return(Ast.Statements(
Ast.Switch(
Ast.Binary(
Ast.Binary(Ast.Binary(Ast.Argument <uint>(0), ">>", shiftOffset), "&", commonMaskShifted),
"-", minValue),
Ast.Default(generateCallDelegate(null)),
enumerable.Select(maskGroup =>
Ast.Case(
((maskGroup.First().Value >> shiftOffset) & commonMaskShifted) - minValue,
(maskGroup.Count() > 1)
? GenerateSwitchCode(maskGroup, generateCallDelegate, level + 1)
: generateCallDelegate(maskGroup.First())
)
).ToArray()
),
Ast.Throw(Ast.New <Exception>("Unexpected reach!"))
));
}
