public static InstructionCollection Disassemble(byte[] codes)
{
BinaryReader rdr = new BinaryReader(new MemoryStream(codes));
InstructionCollection ret = new InstructionCollection();
Dictionary <uint, List <Instruction> > dicBrTarget = new Dictionary <uint, List <Instruction> >();
Dictionary <Instruction, uint[]> switches = new Dictionary <Instruction, uint[]>();
Dictionary <uint, Instruction> dicOffsets = new Dictionary <uint, Instruction>();
var startOffset = rdr.BaseStream.Position;
while (rdr.BaseStream.Position < codes.Length)
{
var currOffset = (uint)(rdr.BaseStream.Position - startOffset);
ushort c = rdr.ReadByte();
if (c == 0xfe)
{
c = (ushort)((c << 8) + rdr.ReadByte());
}
OpCode code;
if (!OpCodes.Opcodes.TryGetValue(c, out code))
{
throw new InvalidOperationException(string.Format("Invalid opcode {0:x2} at offset {1}", c, currOffset));
}
Instruction inst = new Instruction(ret, code);
uint targetInst;
switch (code.OperandType)
{
case OperandType.InlineBrTarget:
targetInst = (uint)(rdr.BaseStream.Position + 4 + rdr.ReadUInt32());
if (!dicBrTarget.ContainsKey(targetInst))
{
dicBrTarget.Add(targetInst, new List <Instruction>()
{
inst
});
}
else
{
dicBrTarget[targetInst].Add(inst);
}
break;
case OperandType.InlineField:
case OperandType.InlineMethod:
case OperandType.InlineTok:
case OperandType.InlineType:
case OperandType.InlineSig:
case OperandType.InlineString:
inst.Operand = new Operand(new MetadataToken(rdr.ReadUInt32()));
break;
case OperandType.InlineI:
inst.Operand = new Operand(rdr.ReadUInt32());
break;
case OperandType.InlineI8:
inst.Operand = new Operand(rdr.ReadUInt64());
break;
case OperandType.InlineR:
inst.Operand = new Operand(rdr.ReadDouble());
break;
case OperandType.InlineSwitch:
uint count = rdr.ReadUInt32();
uint[] insts = new uint[count];
uint bas = (uint)rdr.BaseStream.Position + count * 4;
for (int i = 0; i < count; i++)
{
insts[i] = bas + rdr.ReadUInt32();
}
switches[inst] = insts;
break;
case OperandType.InlineVar:
inst.Operand = new Operand(rdr.ReadUInt16());
break;
case OperandType.InlineParam:
inst.Operand = new Operand(rdr.ReadUInt16());
break;
case OperandType.ShortInlineBrTarget:
{
targetInst = (uint)(rdr.BaseStream.Position + 1 + rdr.ReadSByte());
if (!dicBrTarget.ContainsKey(targetInst))
{
dicBrTarget.Add(targetInst, new List <Instruction>()
{
inst
});
}
else
{
dicBrTarget[targetInst].Add(inst);
}
break;
}
case OperandType.ShortInlineI:
inst.Operand = new Operand(rdr.ReadByte());
break;
case OperandType.ShortInlineR:
inst.Operand = new Operand(rdr.ReadSingle());
break;
case OperandType.ShortInlineVar:
inst.Operand = new Operand(rdr.ReadByte());
break;
case OperandType.ShortInlineParam:
inst.Operand = new Operand(rdr.ReadByte());
break;
}
ret.Add(inst);
dicOffsets[currOffset] = inst;
}
// Resolve branches
foreach (var kvp in dicBrTarget)
{
Instruction targetIns;
if (!dicOffsets.TryGetValue(kvp.Key, out targetIns))
{
// Invalid offset
targetIns = null;
}
foreach (var ii in kvp.Value)
{
ii.Operand = new Operand(targetIns);
}
}
foreach (var kvp in switches)
{
var i = kvp.Key;
var instsO = kvp.Value;
var insts = new Instruction[instsO.Length];
for (int idx = 0; idx < insts.Length; idx++)
{
Instruction targetIns;
if (!dicOffsets.TryGetValue(instsO[idx], out targetIns))
{
// Invalid offset
targetIns = null;
}
insts[idx] = targetIns;
}
i.Operand = new Operand(insts);
}
/*
* foreach (Instruction i in ret)
* {
* uint os = ret.ComputeOffset(i);
* if (dicBrTarget.ContainsKey(os))
* {
* foreach (Instruction ii in dicBrTarget[os])
* {
* ii.Operand = new Operand(i);
* }
* }
* }
*
* foreach (Instruction i in switches.Keys)
* {
* uint[] instsO = switches[i];
* Instruction[] insts = new Instruction[instsO.Length];
* foreach (Instruction ii in ret)
* {
* int idx = Array.IndexOf(instsO, ret.ComputeOffset(ii));
* if (idx != -1)
* {
* insts[idx] = ii;
* }
* }
* i.Operand = new Operand(insts);
* }
*/
return(ret);
}
public void Emit(OpCode op, byte num)
{
coll.Add(new Instruction(coll, op, new Operand(num)));
}