MSIL Scanner

Dissassembler.Scanner.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.Reflection.Emit;
using System.IO;

namespace Oosaki.Msil
{
    public partial class Dissassembler
    {
        public static Dictionary<short, OpCode> OpeCodes;

        static Dissassembler()
        {
            OpeCodes = typeof(OpCodes).GetFields(BindingFlags.Public | BindingFlags.Static)
                .Where(field => field.FieldType == typeof(OpCode))
                .Select(field => (OpCode)field.GetValue(null))
                .ToDictionary(op => op.Value, op => op);
        }

        public IEnumerable<int> Scan(byte[] ilbytes)
        {
            ByteArrayStream stream = new ByteArrayStream(ilbytes);
            return Scan( new BinaryReader(stream),ilbytes.Length );
        }

        /// <summary>
        /// Scan IL from BinaryReader
        /// </summary>
        /// <param name="binaryReader"></param>
        /// <param name="length"></param>
        /// <returns>IL opecode offsets</returns>
        public IEnumerable<int> Scan(BinaryReader binaryReader,int length)
        {
            int offset = 0;
            Dictionary< OperandType, Action> operandTaker = new Dictionary<OperandType,Action>() {
                {OperandType.InlineBrTarget, ()=> { binaryReader.ReadInt32(); offset+=4; } },
                {OperandType.InlineField, ()=> { binaryReader.ReadInt32(); offset+=4; } },
                {OperandType.InlineI, ()=> { binaryReader.ReadInt32(); offset+=4; } },
                {OperandType.InlineI8, () => { binaryReader.ReadInt64(); offset+=8; } },
                {OperandType.InlineMethod, () => {binaryReader.ReadInt32(); offset+=4; } },
                {OperandType.InlineNone, () => {} },
                {OperandType.InlinePhi, ()=> { throw new BadImageFormatException( "InlinePhi operand not supported" ); } },
                {OperandType.InlineR, ()=> {binaryReader.ReadDouble(); offset+=8; } },
                {OperandType.InlineSig, () => {binaryReader.ReadInt32(); offset+=4; } },
                {OperandType.InlineString, () => {binaryReader.ReadInt32(); offset+=4; } },
                {OperandType.InlineSwitch, () => { int cnt=binaryReader.ReadInt32(); offset+=4; 
                    binaryReader.ReadBytes( cnt*4 ); offset+=cnt*4; } },
                {OperandType.InlineTok, ()=> { binaryReader.ReadInt32(); offset+=4; } },
                {OperandType.InlineType, ()=> {binaryReader.ReadInt32(); offset+=4; } },
                {OperandType.InlineVar, ()=> {binaryReader.ReadInt16(); offset+=2; } },
                {OperandType.ShortInlineBrTarget, ()=> {binaryReader.ReadByte(); offset++; } },
                {OperandType.ShortInlineI, ()=>{binaryReader.ReadByte(); offset++; } },
                {OperandType.ShortInlineR, ()=>{binaryReader.ReadSingle(); offset++; } },
                {OperandType.ShortInlineVar, ()=>{binaryReader.ReadByte(); offset++; } }
            };

            while (offset < length)
            {
                yield return offset;
                byte op1 = binaryReader.ReadByte();
                offset++;
                OpCode opCode;
                if (!OpeCodes.TryGetValue((short)op1, out opCode))
                {
                    byte op2 = binaryReader.ReadByte();
                    offset++;
                    short op = (short)((((short)op1) << 8) | op2);
                    if (!OpeCodes.TryGetValue(op, out opCode))
                    {
                        throw new BadImageFormatException(string.Format("{0:x4} is invalid il opecode", op));
                    }
                }
                operandTaker[opCode.OperandType]();
            }
        }
    }
}