BizHawk/BizHawk.Emulation/Util.cs

using System;
using System.Diagnostics;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Text;

namespace BizHawk
{
    public struct Tuple<T1,T2> : IEquatable<Tuple<T1, T2>>
    {
        private readonly T1 first;
        private readonly T2 second;
        public T1 First { get { return first; } }
        public T2 Second { get { return second; } }

        public Tuple(T1 o1, T2 o2)
        {
            first = o1;
            second = o2;
        }

        public bool Equals(Tuple<T1, T2> other)
        {
            return first.Equals(other.first) &&
            second.Equals(other.second);
        }

        public override bool Equals(object obj)
        {
            if (obj is Tuple<T1, T2>)
                    return this.Equals((Tuple<T1, T2>)obj);
            else
                    return false;
        }

        public override int GetHashCode()
        {
            return first.GetHashCode() ^ second.GetHashCode();
        }
    }

    public static class Extensions
    {
        public static bool IsBinary(this string str)
        {
            for (int i = 0; i < str.Length; i++)
            {
                char c = str[i];
                if (c == '0' || c == '1')
                    continue;
                return false;
            }
            return true;
        }

        public static bool In(this string str, params string[] options)
        {
            foreach (string opt in options)
            {
                if (opt.Equals(str, StringComparison.CurrentCultureIgnoreCase)) return true;
            }
            return false;
        }

        public static bool In(this string str, IEnumerable<string> options)
        {
            foreach (string opt in options)
            {
                if (opt.Equals(str,StringComparison.CurrentCultureIgnoreCase)) return true;
            }
            return false;
        }

        public static bool In<T>(this string str, IEnumerable<T> options, Func<T, string, bool> eval)
        {
            foreach (T opt in options)
            {
                if (eval(opt, str) == true)
                    return true;
            }
            return false;
        }

        public static bool NotIn(this string str, params string[] options)
        {
            foreach (string opt in options)
            {
                if (opt.ToLower() == str.ToLower()) return false;
            }
            return true;
        }

        public static bool NotIn(this string str, IEnumerable<string> options)
        {
            foreach (string opt in options)
            {
                if (opt.ToLower() == str.ToLower()) return false;
            }
            return true;
        }
        
        public static bool In(this int i, params int[] options)
        {
            foreach (int j in options)
            {
                if (i == j) return true;
            }
            return false;
        }

        public static bool In(this int i, IEnumerable<int> options)
        {
            foreach (int j in options)
            {
                if (i == j) return true;
            }
            return false;
        }

        public static bool ContainsStartsWith(this IEnumerable<string> options, string str)
        {
            foreach (string opt in options)
            {
                if (opt.StartsWith(str)) return true;
            }
            return false;
        }

        public static string GetOptionValue(this IEnumerable<string> options, string str)
        {
            try
            {
                foreach (string opt in options)
                {
                    if (opt.StartsWith(str))
                    {
                        return opt.Split('=')[1];
                    }
                }
            }
            catch (Exception) { }
            return null;
        }

        public static bool IsValidRomExtentsion(this string str, params string[] romExtensions)
        {
            string strUpper = str.ToUpper();
            foreach (string ext in romExtensions)
            {
                if (strUpper.EndsWith(ext.ToUpper())) return true;
            }
            return false;
        }

        public static string ToCommaSeparated(this List<string> list)
        {
            var sb = new StringBuilder();
            for (int i = 0; i < list.Count; i++)
            {
                if (i > 0) sb.Append(",");
                sb.Append(list[i]);
            }
            return sb.ToString();
        }

        public static void SaveAsHex(this byte[] buffer, TextWriter writer)
        {
            for (int i=0; i<buffer.Length; i++)
            {
                writer.Write("{0:X2}", buffer[i]);
            }
            writer.WriteLine();
        }

        public static void SaveAsHex(this byte[] buffer, TextWriter writer, int length)
        {
            for (int i = 0; i < length; i++)
            {
                writer.Write("{0:X2}", buffer[i]);
            }
            writer.WriteLine();
        }

        public static void SaveAsHex(this short[] buffer, TextWriter writer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                writer.Write("{0:X4}", buffer[i]);
            }
            writer.WriteLine();
        }

        public static void SaveAsHex(this ushort[] buffer, TextWriter writer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                writer.Write("{0:X4}", buffer[i]);
            }
            writer.WriteLine();
        }

		public static void SaveAsHex(this int[] buffer, TextWriter writer)
		{
			for (int i = 0; i < buffer.Length; i++)
			{
				writer.Write("{0:X8}", buffer[i]);
			}
			writer.WriteLine();
		}

		public static void SaveAsHex(this uint[] buffer, TextWriter writer)
		{
			for (int i = 0; i < buffer.Length; i++)
			{
				writer.Write("{0:X8}", buffer[i]);
			}
			writer.WriteLine();
		}

		public static void Write(this BinaryWriter bw, int[] buffer)
		{
			for (int i = 0; i < buffer.Length; i++)
				bw.Write(buffer[i]);
		}

		public static void Write(this BinaryWriter bw, uint[] buffer)
		{
			for (int i = 0; i < buffer.Length; i++)
				bw.Write(buffer[i]);
		}

		public static void Write(this BinaryWriter bw, short[] buffer)
		{
			for (int i = 0; i < buffer.Length; i++)
				bw.Write(buffer[i]);
		}

		public static void Write(this BinaryWriter bw, ushort[] buffer)
		{
			for (int i = 0; i < buffer.Length; i++)
				bw.Write(buffer[i]);
		}

		public static int[] ReadInts(this BinaryReader br, int num)
		{
			int[] ret = new int[num];
			for (int i = 0; i < num; i++)
				ret[i] = br.ReadInt32();
			return ret;
		}

		public static short[] ReadShorts(this BinaryReader br, int num)
		{
			short[] ret = new short[num];
			for (int i = 0; i < num; i++)
				ret[i] = br.ReadInt16();
			return ret;
		}


        public static void ReadFromHex(this byte[] buffer, string hex)
        {
            if (hex.Length % 2 != 0)
                throw new Exception("Hex value string does not appear to be properly formatted.");
            for (int i=0; i<buffer.Length && i*2<hex.Length; i++)
            {
                string bytehex = "" + hex[i*2] + hex[i*2 + 1];
                buffer[i] = byte.Parse(bytehex, NumberStyles.HexNumber);
            }
        }

        public static void ReadFromHex(this short[] buffer, string hex)
        {
            if (hex.Length % 4 != 0)
                throw new Exception("Hex value string does not appear to be properly formatted.");
            for (int i = 0; i < buffer.Length && i * 4 < hex.Length; i++)
            {
                string shorthex = "" + hex[i * 4] + hex[(i * 4) + 1] + hex[(i * 4) + 2] + hex[(i * 4) + 3];
                buffer[i] = short.Parse(shorthex, NumberStyles.HexNumber);
            }
        }

        public static void ReadFromHex(this ushort[] buffer, string hex)
        {
            if (hex.Length % 4 != 0)
                throw new Exception("Hex value string does not appear to be properly formatted.");
            for (int i = 0; i < buffer.Length && i * 4 < hex.Length; i++)
            {
                string ushorthex = "" + hex[i*4] + hex[(i*4)+1] + hex[(i*4)+2] + hex[(i*4)+3];
                buffer[i] = ushort.Parse(ushorthex, NumberStyles.HexNumber);
            }
        }

		public static void ReadFromHex(this int[] buffer, BinaryWriter bw)
		{
			for (int i = 0; i < buffer.Length; i++)
				bw.Write(buffer[i]);
		}

		public static void SaveAsHex(this uint[] buffer, BinaryWriter bw)
		{
			for (int i = 0; i < buffer.Length; i++)
				bw.Write(buffer[i]);
		}

		//these don't work??? they dont get chosen by compiler
		public static void WriteBit(this BinaryWriter bw, Bit bit) { bw.Write((bool)bit); }
		public static Bit ReadBit(this BinaryReader br) { return br.ReadBoolean(); }
    }

    public static class Colors
    {
        public static int ARGB(byte red, byte green, byte blue)
        {
            return (int) ((uint)((red << 0x10) | (green << 8) | blue | (0xFF << 0x18)));
        }

        public static int ARGB(byte red, byte green, byte blue, byte alpha)
        {
            return (int) ((uint)((red << 0x10) | (green << 8) | blue | (alpha << 0x18)));
        }

        public static int Luminosity(byte lum)
        {
            return (int)((uint)((lum << 0x10) | (lum << 8) | lum | (0xFF << 0x18)));
        }
    }



	//I think this is a little faster with uint than with byte
	public struct Bit
	{
		Bit(uint val) { this.val = val; }
		uint val;
		public static implicit operator Bit(int rhs) { Debug.Assert((rhs & ~1) == 0); return new Bit((uint)(rhs)); }
		public static implicit operator Bit(uint rhs) { Debug.Assert((rhs & ~1) == 0); return new Bit((uint)(rhs)); }
		public static implicit operator Bit(byte rhs) { Debug.Assert((rhs & ~1) == 0); return new Bit((uint)(rhs)); }
		public static implicit operator Bit(bool rhs) { return new Bit(rhs ? (byte)1 : (byte)0); }
		public static implicit operator long(Bit rhs) { return (long)rhs.val; }
		public static implicit operator int(Bit rhs) { return (int)rhs.val; }
		public static implicit operator uint(Bit rhs) { return (uint)rhs.val; }
		public static implicit operator byte(Bit rhs) { return (byte)rhs.val; }
		public static implicit operator bool(Bit rhs) { return rhs.val != 0; }
		public override string ToString()
		{
			return val.ToString();
		}
		public static bool operator ==(Bit lhs, Bit rhs) { return lhs.val == rhs.val; }
		public static bool operator !=(Bit lhs, Bit rhs) { return lhs.val != rhs.val; }
		public override int GetHashCode() { return val.GetHashCode(); }
		public override bool Equals(object obj) { return this == (Bit)obj; } //this is probably wrong
	}



    public static class Util
    {
		public static bool IsPowerOfTwo(int x)
		{
			if (x == 0) return true;
			if (x == 1) return true;
			return (x & (x - 1)) == 0;
		}

        public static int SaveRamBytesUsed(byte[] SaveRAM)
        {
            for (int j = SaveRAM.Length - 1; j >= 0; j--)
                if (SaveRAM[j] != 0)
                    return j + 1;
            return 0;
        }

		/// <summary>
		/// conerts bytes to an uppercase string of hex numbers in upper case without any spacing or anything
		/// //could be extension method
		/// </summary>
		public static string BytesToHexString(byte[] bytes)
		{
			StringBuilder sb = new StringBuilder();
			foreach (byte b in bytes)
				sb.AppendFormat("{0:X2}", b);
			return sb.ToString();
		}

		//could be extension method
		public static byte[] HexStringToBytes(string str)
		{
			MemoryStream ms = new MemoryStream();
			if (str.Length % 2 != 0) throw new ArgumentException();
			int len = str.Length/2;
			for (int i = 0; i < len; i++)
			{
				int d = 0;
				for (int j = 0; j < 2; j++)
				{
					char c = char.ToLower(str[i * 2 + j]);
					if (c >= '0' && c <= '9')
						d += (c - '0');
					else if (c >= 'a' && c <= 'f')
						d += (c - 'a') + 10;
					else throw new ArgumentException();
					if (j == 0) d <<= 4;
				}
				ms.WriteByte((byte)d);
			}
			return ms.ToArray();
		}

		//could be extension method
		public static void WriteByteBuffer(BinaryWriter bw, byte[] data)
		{
			if (data == null) bw.Write(0);
			else
			{
				bw.Write(data.Length);
				bw.Write(data);
			}
		}

		public static short[] ByteBufferToShortBuffer(byte[] buf)
		{
			int num = buf.Length/2;
			short[] ret = new short[num];
			for (int i = 0; i < num; i++)
			{
				ret[i] =(short)(buf[i * 2] | (buf[i * 2 + 1] << 8));
			}
			return ret;
		}

		public static byte[] ShortBufferToByteBuffer(short[] buf)
		{
			int num = buf.Length;
			byte[] ret = new byte[num * 2];
			for (int i = 0; i < num; i++)
			{
				ret[i * 2 + 0] = (byte)(buf[i] & 0xFF);
				ret[i * 2 + 1] = (byte)((buf[i]>>8) & 0xFF);
			}
			return ret;
		}

		public static byte[] ReadByteBuffer(BinaryReader br, bool return_null)
		{
			int len = br.ReadInt32();
			if (len == 0 && return_null) return null;
			byte[] ret = new byte[len];
			int ofs = 0;
			while (len > 0)
			{
				int done = br.Read(ret, ofs, len);
				ofs += done;
				len -= done;
			}
			return ret;
		}

		public static unsafe int memcmp(void* a, string b, int len)
		{
			fixed (byte* bp = System.Text.Encoding.ASCII.GetBytes(b))
				return memcmp(a, bp, len);
		}

		public static unsafe int memcmp(void* a, void* b, int len)
		{
			byte* ba = (byte*)a;
			byte* bb = (byte*)b;
			for (int i = 0; i < len; i++)
			{
				byte _a = ba[i];
				byte _b = bb[i];
				int c = _a - _b;
				if (c != 0) return c;
			}
			return 0;
		}

		public static unsafe void memset(void* ptr, int val, int len)
		{
			byte* bptr = (byte*)ptr;
			for (int i = 0; i < len; i++)
				bptr[i] = (byte)val;
		}

		public static byte[] ReadAllBytes(Stream stream)
		{
			const int BUFF_SIZE = 4096;
			byte[] buffer = new byte[BUFF_SIZE];

			int bytesRead = 0;
			var inStream = new BufferedStream(stream);
			var outStream = new MemoryStream();

			while ((bytesRead = inStream.Read(buffer, 0, BUFF_SIZE)) > 0)
			{
				outStream.Write(buffer, 0, bytesRead);
			}

			return outStream.ToArray();
		}

		public static string FormatFileSize(long filesize)
		{
			Decimal size = (Decimal)filesize;

			Decimal OneKiloByte = 1024M;
			Decimal OneMegaByte = OneKiloByte * 1024M;
			Decimal OneGigaByte = OneMegaByte * 1024M;

			string suffix;
			if (size > 1024*1024*1024)
			{
				size /= 1024*1024*1024;
				suffix = "GB";
			}
			else if (size > 1024*1024)
			{
				size /= 1024*1024;
				suffix = "MB";
			}
			else if (size > 1024)
			{
				size /= 1024;
				suffix = "KB";
			}
			else
			{
				suffix = " B";
			}

			string precision = "2";
			return String.Format("{0:N" + precision + "}{1}", size, suffix);
		}

	}

	public class Serializer
	{
		BinaryReader br;
		BinaryWriter bw;
		TextReader tr;
		TextWriter tw;
		public BinaryReader BinaryReader { get { return br; } }
		public BinaryWriter BinaryWriter { get { return bw; } }
		public TextReader TextReader { get { return tr; } }
		public TextWriter TextWriter { get { return tw; } }
		public Serializer() { }
		public Serializer(BinaryWriter _bw) { StartWrite(_bw); }
		public Serializer(BinaryReader _br) { StartRead(_br); }
		public Serializer(TextWriter _tw) { StartWrite(_tw); }
		public Serializer(TextReader _tr) { StartRead(_tr); }
		public void StartWrite(BinaryWriter _bw) { this.bw = _bw; isReader = false; }
		public void StartRead(BinaryReader _br) { this.br = _br; isReader = true; }
		public void StartWrite(TextWriter _tw) { this.tw = _tw; isReader = false; isText = true; }
		public void StartRead(TextReader _tr) { this.tr = _tr; isReader = true; isText = true; }
		public static Serializer CreateBinaryWriter(BinaryWriter _bw) { return new Serializer(_bw); }
		public static Serializer CreateBinaryReader(BinaryReader _br) { return new Serializer(_br); }
		public static Serializer CreateTextWriter(TextWriter _tw) { return new Serializer(_tw); }
		public static Serializer CreateTextReader(TextReader _tr) { return new Serializer(_tr); }

		public bool IsReader { get { return isReader; } }
		public bool IsWriter { get { return !IsReader; } }
		public bool IsText { get { return isText; } }
		bool isText;
		bool isReader;

		Stack<string> sections = new Stack<string>();
		public void BeginSection(string name)
		{
			sections.Push(name);
			if (IsText)
				if (IsWriter) { tw.WriteLine("[{0}]", name);}
				else { tr.ReadLine(); }
		}

		public void EndSection()
		{
			string name = sections.Pop();
			if (IsText)
				if (IsWriter) tw.WriteLine("[/{0}]", name);
				else tr.ReadLine();
		}

		public unsafe void SyncEnum<T>(string name, ref T val) where T : struct
		{
			if (typeof(T).BaseType != typeof(System.Enum))
				throw new InvalidOperationException();
			if(isText) SyncEnumText<T>(name, ref val);
			else if (IsReader) val = (T)Enum.ToObject(typeof(T), br.ReadInt32());
			else bw.Write(Convert.ToInt32(val));
		}

		public unsafe void SyncEnumText<T>(string name, ref T val) where T : struct
		{
			if (IsReader) val = (T)Enum.Parse(typeof(T), tr.ReadLine().Split(' ')[1]);
			else tw.WriteLine("{0} {1}", name, val.ToString());
		}

		public void Sync(string name, ref byte[] val, bool use_null)
		{
			if (IsText) SyncText(name, ref val, use_null);
			else if (IsReader) val = Util.ReadByteBuffer(br, use_null);
			else Util.WriteByteBuffer(bw, val);
		}
		public void SyncText(string name, ref byte[] val, bool use_null)
		{
			if (IsReader)
			{
				string[] parts = tr.ReadLine().Split(' ');
				val = Util.HexStringToBytes(parts[1]);
				if (val.Length == 0 && use_null) val = null;
			}
			else
			{
				byte[] temp = val;
				if (temp == null) temp = new byte[0];
				tw.WriteLine("{0} {1}", name, Util.BytesToHexString(temp));
			}
		}

		public void Sync(string name, ref short[] val, bool use_null)
		{
			if (IsText) SyncText(name, ref val, use_null);
			else if (IsReader)
			{
				val = Util.ByteBufferToShortBuffer(Util.ReadByteBuffer(br, false));
				if (val == null && !use_null) val = new short[0];
			}
			else Util.WriteByteBuffer(bw, Util.ShortBufferToByteBuffer(val));
		}
		public void SyncText(string name, ref short[] val, bool use_null)
		{
			if (IsReader)
			{
				string[] parts = tr.ReadLine().Split(' ');
				byte[] bytes = Util.HexStringToBytes(parts[1]);
				val = Util.ByteBufferToShortBuffer(bytes);
				if (val.Length == 0 && use_null) val = null;
			}
			else
			{
				short[] temp = val;
				if (temp == null) temp = new short[0];
				tw.WriteLine("{0} {1}", name, Util.BytesToHexString(Util.ShortBufferToByteBuffer(temp)));
			}
		}

		public void Sync(string name, ref Bit val)
		{
			if (IsText) SyncText(name, ref val);
			else if (IsReader) Read(ref val);
			else Write(ref val);
		}
		public void SyncText(string name, ref Bit val)
		{
			if (IsReader) ReadText(name, ref val);
			else WriteText(name, ref val);
		}
		public void Sync(string name, ref byte val)
		{
			if (IsText) SyncText(name, ref val);
			else if (IsReader) Read(ref val);
			else Write(ref val);
		}
		void SyncText(string name, ref byte val)
		{
			if (IsReader) ReadText(name, ref val);
			else WriteText(name, ref val);
		}
		public void Sync(string name, ref ushort val)
		{
			if (IsText) SyncText(name, ref val);
			else if (IsReader) Read(ref val);
			else Write(ref val);
		}
		void SyncText(string name, ref ushort val)
		{
			if (IsReader) ReadText(name, ref val);
			else WriteText(name, ref val);
		}
		public void Sync(string name, ref uint val)
		{
			if (IsText) SyncText(name, ref val);
			else if (IsReader) Read(ref val);
			else Write(ref val);
		}
		void SyncText(string name, ref uint val)
		{
			if (IsReader) ReadText(name, ref val);
			else WriteText(name, ref val);
		}
		public void Sync(string name, ref sbyte val)
		{
			if (IsText) SyncText(name, ref val);
			else if (IsReader) Read(ref val);
			else Write(ref val);
		}
		void SyncText(string name, ref sbyte val)
		{
			if (IsReader) ReadText(name, ref val);
			else WriteText(name, ref val);
		}
		public void Sync(string name, ref short val)
		{
			if (IsText) SyncText(name, ref val);
			else if (IsReader) Read(ref val);
			else Write(ref val);
		}
		void SyncText(string name, ref short val)
		{
			if (IsReader) ReadText(name, ref val);
			else WriteText(name, ref val);
		}
		public void Sync(string name, ref int val)
		{
			if (IsText) SyncText(name, ref val);
			else if (IsReader) Read(ref val);
			else Write(ref val);
		}
		void SyncText(string name, ref int val)
		{
			if (IsReader) ReadText(name, ref val);
			else WriteText(name, ref val);
		}
		public void Sync(string name, ref bool val)
		{
			if (IsText) SyncText(name, ref val);
			else if (IsReader) Read(ref val);
			else Write(ref val);
		}
		void SyncText(string name, ref bool val)
		{
			if (IsReader) ReadText(name, ref val);
			else WriteText(name, ref val);
		}

		void Read(ref Bit val) { val = br.ReadBit(); }
		void Write(ref Bit val) { bw.WriteBit(val); }
		void ReadText(string name, ref Bit val) { val = (Bit)int.Parse(tr.ReadLine().Split(' ')[1]); }
		void WriteText(string name, ref Bit val) { tw.WriteLine("{0} {1}", name, (int)val); }

		void Read(ref byte val) { val = br.ReadByte(); }
		void Write(ref byte val) { bw.Write(val); }
		void ReadText(string name, ref byte val) { val = byte.Parse(tr.ReadLine().Split(' ')[1].Replace("0x", ""), NumberStyles.HexNumber); }
		void WriteText(string name, ref byte val) { tw.WriteLine("{0} 0x{1:X2}", name, val); }

		void Read(ref ushort val) { val = br.ReadUInt16(); }
		void Write(ref ushort val) { bw.Write(val); }
		void ReadText(string name, ref ushort val) { val = ushort.Parse(tr.ReadLine().Split(' ')[1].Replace("0x", ""), NumberStyles.HexNumber); }
		void WriteText(string name, ref ushort val) { tw.WriteLine("{0} 0x{1:X4}", name, val); }

		void Read(ref uint val) { val = br.ReadUInt32(); }
		void Write(ref uint val) { bw.Write(val); }
		void ReadText(string name, ref uint val) { val = uint.Parse(tr.ReadLine().Split(' ')[1].Replace("0x", ""), NumberStyles.HexNumber); }
		void WriteText(string name, ref uint val) { tw.WriteLine("{0} 0x{1:X8}", name, val); }

		void Read(ref sbyte val) { val = br.ReadSByte(); }
		void Write(ref sbyte val) { bw.Write(val); }
		void ReadText(string name, ref sbyte val) { val = sbyte.Parse(tr.ReadLine().Split(' ')[1].Replace("0x", ""), NumberStyles.HexNumber); }
		void WriteText(string name, ref sbyte val) { tw.WriteLine("{0} 0x{1:X2}", name, val); }

		void Read(ref short val) { val = br.ReadInt16(); }
		void Write(ref short val) { bw.Write(val); }
		void ReadText(string name, ref short val) { val = short.Parse(tr.ReadLine().Split(' ')[1].Replace("0x", ""), NumberStyles.HexNumber); }
		void WriteText(string name, ref short val) { tw.WriteLine("{0} 0x{1:X4}", name, val); }

		void Read(ref int val) { val = br.ReadInt32(); }
		void Write(ref int val) { bw.Write(val); }
		void ReadText(string name, ref int val) { val = int.Parse(tr.ReadLine().Split(' ')[1].Replace("0x",""), NumberStyles.HexNumber); }
		void WriteText(string name, ref int val) { tw.WriteLine("{0} 0x{1:X8}", name, val); }

		void Read(ref bool val) { val = br.ReadBoolean(); }
		void Write(ref bool val) { bw.Write(val); }
		void ReadText(string name, ref bool val) { val = bool.Parse(tr.ReadLine().Split(' ')[1]); }
		void WriteText(string name, ref bool val) { tw.WriteLine("{0} {1}", name, val); }


	}


	public static class BITREV
	{
		public static byte[] byte_8;
		static BITREV()
		{
			make_byte_8();
		}
		static void make_byte_8()
		{
			int bits = 8;
			int n = 1 << 8;
			byte_8 = new byte[n];

			int m = 1;
			int a = n >> 1;
			int j = 2;

			byte_8[0] = 0;
			byte_8[1] = (byte)a;

			while ((--bits) != 0)
			{
				m <<= 1;
				a >>= 1;
				for (int i = 0; i < m; i++)
					byte_8[j++] = (byte)(byte_8[i] + a);
			}
		}
	}

	/// <summary>
	/// a Dictionary-of-lists with key K and values List&lt;V&gt;
	/// </summary>
	[Serializable]
	public class Bag<K, V> : BagBase<K, V, Dictionary<K, List<V>>, List<V>> { }

	/// <summary>
	/// a Dictionary-of-lists with key K and values List&lt;V&gt;
	/// </summary>
	[Serializable]
	public class SortedBag<K, V> : BagBase<K, V, SortedDictionary<K, List<V>>, List<V>> { }

	/// <summary>
	/// A dictionary that creates new values on the fly as necessary so that any key you need will be defined. 
	/// </summary>
	/// <typeparam name="K">dictionary keys</typeparam>
	/// <typeparam name="V">dictionary values</typeparam>
	public class WorkingDictionary<K, V> : Dictionary<K, V> where V : new()
	{
		public new V this[K key]
		{
			get
			{
				V temp;
				if (!TryGetValue(key, out temp))
					temp = this[key] = new V();
				return temp;
			}
			set { base[key] = value; }
		}
	}

	/// <summary>
	/// base class for Bag and SortedBag
	/// </summary>
	/// <typeparam name="K">dictionary keys</typeparam>
	/// <typeparam name="V">list values</typeparam>
	/// <typeparam name="D">dictionary type</typeparam>
	/// <typeparam name="L">list type</typeparam>
	[Serializable]
	public class BagBase<K, V, D, L> : IEnumerable<V>
		where D : IDictionary<K, L>, new()
		where L : IList<V>, IEnumerable<V>, new()
	{
		D dictionary = new D();
		public void Add(K key, V val)
		{
			this[key].Add(val);
		}

		public bool ContainsKey(K key) { return dictionary.ContainsKey(key); }

		IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); }
		public IEnumerator<V> GetEnumerator()
		{
			foreach (L lv in dictionary.Values)
				foreach (V v in lv)
					yield return v;
		}

		public IEnumerable KeyValuePairEnumerator { get { return dictionary; } }

		/// <summary>
		/// the list of keys contained herein
		/// </summary>
		public IList<K> Keys { get { return new List<K>(dictionary.Keys); } }



		public L this[K key]
		{
			get
			{
				L slot;
				if (!dictionary.TryGetValue(key, out slot))
					dictionary[key] = slot = new L();
				return slot;
			}
			set
			{
				dictionary[key] = value;
			}
		}
	}


}