require 'mscorlib'
require 'System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

module Zlib
	
	MAX_WBITS = 15
	Z_DEFLATED = 8 

class GZipFile
	
	def close
	end

end

class GZipReader < GZipFile
	
	def initialize io
		@io = io
		ms = System::IO::MemoryStream.new
		
		@io.read.each_byte {|b|  ms.WriteByte b}
		
		ms.Position = 0
		@gzipstream = System::IO::Compression::GZipStream.new ms, System::IO::Compression::CompressionMode.Decompress
	end
	
	def read
		byte = 0
		sb = System::Text::StringBuilder.new
		while true
			byte = @gzipstream.ReadByte
		break if byte == -1
			sb.Append System::Convert.ToChar byte
		end 
	
	sb.ToString
	
	end
	
	def close
		@io.close
	end
end

class ZStream
	
	def finish
	end

end


class Inflate < ZStream

	def initialize window_bits=MAX_WBITS
		@w_bits = window_bits	
		if @w_bits < 0 then 
			@rawdeflate = true
			@w_bits *= -1 
		end	
	end
	
	def inflate zstring
		byte_array = []
		zstring.each_byte {|b| byte_array << b}	
	
		
		
		unless @rawdeflate then
		byte_array.reverse!
		compression_method_and_flags = byte_array.pop
		
		flags = byte_array.pop
		

		#CMF and FLG, when viewed as a 16-bit unsigned integer stored inMSB order (CMF*256 + FLG), is a multiple of 31
		if ((compression_method_and_flags << 0x08) + flags) % 31 != 0 then raise Zlib::DataError.new("incorrect header check") end
		
		compression_method = compression_method_and_flags & 0x0F 
		#CM = 8 denotes the “deflate” compression method with a window size up to 32K.
		if compression_method != Zlib::Z_DEFLATED then raise Zlib::DataError.new("unknown compression method") end
		compression_info = compression_method_and_flags >> 0x04 
		#For CM = 8, CINFO is the base-2 logarithm of the LZ77 window size,minus eight (CINFO=7 indicates a 32K window size)
		if (compression_info + 8) > @w_bits then raise Zlib::DataError.new("invalid window size") end
		
		preset_dictionary_flag = (flags & 0x20) >> 0x05
		compression_level = (flags & 0xC0) >> 0x06
		byte_array.reverse!
		end
		ms = System::IO::MemoryStream.new
		
		byte_array.each{|b|  ms.WriteByte b}
		
		ms.Position = 0
		
		deflatestream = System::IO::Compression::DeflateStream.new ms, System::IO::Compression::CompressionMode.Decompress

		byte = 0
		sb = System::Text::StringBuilder.new
		while true
			byte = deflatestream.ReadByte
		break if byte == -1
			sb.Append System::Convert.ToChar byte
		end 
	
		sb.ToString
		
	end
	
	def finish
		
	end

end


class Error < Exception
end

class NeedDict < Error
end

class DataError < Error
end

end