simple RLE implementation

RLE.cs

using System;
using System.Collections.Generic;

public static class RLE
{
	public const byte ESCAPE = 92; // '\'
	public const byte MAX_DUPLICATE_COUNT = byte.MaxValue;
	
	public static byte[] Compress(byte[] input)
	{
		if (input != null)
		{
			m_innerBuffer.Clear();
			
			var inputIndex = 0;
			while (inputIndex < input.Length)
			{
				if (input[inputIndex] == ESCAPE)
				{
					// special handle escape
					m_innerBuffer.Add(ESCAPE);
					m_innerBuffer.Add(ESCAPE);
					++inputIndex;
				}
				else
				{
					// try find duplicate
					int duplicateCount = 0;
					
					for (int i = inputIndex + 1; i < input.Length; ++i)
					{
						if (input[i] == input[inputIndex])
						{
							++duplicateCount;
							// check max duplicate count
							if (duplicateCount == MAX_DUPLICATE_COUNT)
							{
								break;
							}
						}
						else
						{
							break;
						}
					}
					
					// do not compress less then 3 duplicate since meta data will take 3 byte
					if (duplicateCount > 2)
					{
						m_innerBuffer.Add(ESCAPE);
						// NOTE we should make value before count, since count could be 'ESCAPE'
						m_innerBuffer.Add(input[inputIndex]);
						// NOTE we do -3 offset for extend range mapping
						m_innerBuffer.Add((byte)(duplicateCount - 3));
						inputIndex += duplicateCount + 1;
					}
					else
					{
						m_innerBuffer.Add(input[inputIndex]);
						++inputIndex;
					}
				}
			}
			
			return m_innerBuffer.ToArray();
		}
		
		return null;
	}
	
	public static byte[] Decompress(byte[] input)
	{
		if (input != null)
		{
			m_innerBuffer.Clear();
			
			var inputIndex = 0;
			while (inputIndex < input.Length)
			{
				if (input[inputIndex] == ESCAPE)
				{
					if (inputIndex + 1 >= input.Length)
					{
						throw new Exception("[RLE]Unexpected Escape(0xFF) detected ...");
					}
					else
					{
						if (input[inputIndex + 1] == ESCAPE)
						{
							m_innerBuffer.Add(ESCAPE);
							inputIndex += 2;
						}
						else
						{
							if (inputIndex + 2 >= input.Length)
							{
								throw new Exception("[RLE]Error compress data format ...");
							}
							else
							{
								var value = input[inputIndex + 1];
								// NOTE we do +3 offset since we compress do -3 offset
								var duplicateCount = input[inputIndex + 2] + 3;
								for (int i = 0; i <= duplicateCount; ++i)
								{
									m_innerBuffer.Add(value);
								}
								inputIndex += 3;
							}
						}
					}
				}
				else
				{
					m_innerBuffer.Add(input[inputIndex]);
					++inputIndex;
				}
			}
			
			return m_innerBuffer.ToArray();
		}
		
		return null;
	}
	
	static List<byte> m_innerBuffer = new List<byte>(1024);
}