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serialbit

Snippet info

Language

Lua

Visibility

public

Author

scandaloussolution

Created

2024-11-02T11:24:27.249592Z

Updated

2024-11-07T17:38:37.823249Z

	local BuffDatatypes = (function()
	--[[
	Converts datatypes to buffers.
--]]
		-- imports
		local Converter = (function()
			-- imports
			local helpers = (function()
				local helpers = {}

				function helpers.buffer_concat(buff1: buffer, buff2: buffer): buffer
					local buff1_size = buffer.len(buff1)
					local new_buff = buffer.create(buff1_size + buffer.len(buff2))
					buffer.copy(new_buff, 0, buff1)
					buffer.copy(new_buff, buff1_size, buff2)

					return new_buff
				end

				function helpers.buffer_sizeinc(buff: buffer, increment: number): buffer
					local new_buff = buffer.create(buffer.len(buff) + increment)
					buffer.copy(new_buff, 0, buff)

					return new_buff
				end

				function helpers.buffer_resize(buff: buffer, size: number): buffer
					local buff_len = buffer.len(buff)
					if not (buff_len > size) then
						return error(`buffer size smaller than given size ({size})`, 2)
					end

					local new_buff = buffer.create(size)
					buffer.copy(new_buff, 0, buff)

					return new_buff
				end

				return helpers
			end)()

			-- variables
			local number_idx_types = {
				[0] = "u8",
				"u16",
				"u32",
				"i8",
				"i16",
				"i32",
				"f32",
				"f64"
			}
			local number_types_size = {
				["u8"] = 1,
				["i8"] = 1,
				["u16"] = 2,
				["i16"] = 2,
				["u32"] = 4,
				["i32"] = 4,
				["f32"] = 4,
				["f64"] = 8
			}
			local face_bits = {
				["Top"] = 		0b000001,
				["Bottom"] = 	0b000010,
				["Left"] = 		0b000100,
				["Right"] = 	0b001000,
				["Back"] = 		0b010000,
				["Front"] = 	0b100000
			}
			local face_normals = {
				[0] = Enum.NormalId.Top,
				Enum.NormalId.Bottom,
				Enum.NormalId.Left,
				Enum.NormalId.Right,
				Enum.NormalId.Back,
				Enum.NormalId.Front,
			}

			-- functions

			-- TODO: make use of float64 on floats when the decimal is not accurate in float32
			local function get_number_type(value: number): (number, number) -- type, size
				if value % 1 ~= 0 then -- if number is float
					if (value >= -131072 and value <= 131072) then -- float32 (3 decimal places accurate probably)
						return 6, 4
					end
				else -- if number is integer
					if (value < 0) then -- if number is negative
						if (value >= -128) then -- int8
							return 3, 1
						elseif (value >= -32768) then -- int16
							return 4, 2
						elseif (value >= -2147483648) then -- int32
							return 5, 4
						end
					end

					-- if number is positive
					if (value <= 255) then -- uint8
						return 0, 1
					elseif (value <= 65535) then -- uint16
						return 1, 2
					elseif (value <= 4294967295) then -- uint32
						return 2, 4
					end
				end
				return 7, 8 -- float64
			end

			-- serializers
			local _serializers = {}
--[[
Template:
_serializers["datatype"] = function(value: datatype, buff_obj: buffer?, offset: number?): buffer
	local offset: number = offset or 0
	local buff_obj: buffer = buff_obj or buffer.create()

	return buff_obj
end
--]]

			_serializers["nil"] = function(value: nil, buff_obj: buffer?): nil
				return nil
			end
			_serializers["boolean"] = function(value: boolean, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(1) -- uint8

				buffer.writeu8(buff_obj, offset, (if value then 1 else 0))
				return buff_obj
			end
			_serializers["number"] = function(value: number, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local number_type_idx, number_size = get_number_type(value)
				local number_type = number_idx_types[number_type_idx]
				local buff_obj: buffer = buff_obj or buffer.create(1 + number_size) -- uint8 + sizeof number

				buffer.writeu8(buff_obj, offset, number_type_idx)
				buffer[`write{number_type}`](buff_obj, offset + 1, value)
				return buff_obj
			end
			_serializers["string"] = function(value: string, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local string_lenght = #value
				local buff_obj: buffer = buff_obj or buffer.create(2 + string_lenght) -- uint16 + string lenght

				buffer.writeu16(buff_obj, offset, string_lenght)
				buffer.writestring(buff_obj, offset + 2, value)
				return buff_obj
			end
			_serializers["Vector2"] = function(value: Vector2, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(8) -- 2 float32

				buffer.writef32(buff_obj, offset, value.X)
				buffer.writef32(buff_obj, offset + 4, value.Y)
				return buff_obj
			end
			_serializers["Vector3"] = function(value: Vector3, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(12) -- 3 float32

				buffer.writef32(buff_obj, offset, value.X)
				buffer.writef32(buff_obj, offset + 4, value.Y)
				buffer.writef32(buff_obj, offset + 8, value.Z)
				return buff_obj
			end
			_serializers["Vector2int16"] = function(value: Vector2int16, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(4) -- 2 int16

				buffer.writei16(buff_obj, offset, value.X)
				buffer.writei16(buff_obj, offset + 2, value.Y)
				return buff_obj
			end
			_serializers["Vector3int16"] = function(value: Vector3int16, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(6) -- 3 int16

				buffer.writei16(buff_obj, offset, value.X)
				buffer.writei16(buff_obj, offset + 2, value.Y)
				buffer.writei16(buff_obj, offset + 4, value.Z)
				return buff_obj
			end
			_serializers["CFrame"] = function(value: CFrame, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(24) -- 6 float32 (2 Vector3)
				local idx = 0

				_serializers["Vector3"](value.Position, buff_obj, offset)
				_serializers["Vector3"](Vector3.new(value:ToOrientation()), buff_obj, offset + 12)
				return buff_obj
			end
			_serializers["EnumItem"] = function(value: EnumItem, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local enum_parent_name = tostring(value.EnumType)
				local buff_obj: buffer = buff_obj or buffer.create(4 + (2 + #enum_parent_name)) -- uint32 + sizeof string

				buffer.writeu32(buff_obj, offset, value.Value)
				_serializers["string"](enum_parent_name, buff_obj, offset + 4)
				return buff_obj
			end
			_serializers["Color3"] = function(value: Color3, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(3) -- 3 uint8
				-- makes sure we get integers instead of floats :D
				local color_hex = value:ToHex()
				local color_R = tonumber(string.sub(color_hex, 1, 2), 16)
				local color_G = tonumber(string.sub(color_hex, 3, 4), 16)
				local color_B = tonumber(string.sub(color_hex, 5, 6), 16)

				buffer.writeu8(buff_obj, offset, color_R)
				buffer.writeu8(buff_obj, offset + 1, color_G)
				buffer.writeu8(buff_obj, offset + 2, color_B)
				return buff_obj
			end
			_serializers["ColorSequenceKeypoint"] = function(value: ColorSequenceKeypoint, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(4 + 3) -- float32 + 3 uint8

				buffer.writef32(buff_obj, offset, value.Time)
				_serializers["Color3"](value.Value, buff_obj, offset + 4)
				return buff_obj
			end
			_serializers["ColorSequence"] = function(value: ColorSequence, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local seq_size = #value.Keypoints
				local buff_obj: buffer = buff_obj or buffer.create(2 + (7 * seq_size)) -- uint16 + ((float32 + 3 uint8) * seq_size)
				local index = 0

				buffer.writeu16(buff_obj, offset, seq_size)
				for _, keypoint in value.Keypoints do
					local current_pos = (2 +(7 * index)) + offset

					_serializers["ColorSequenceKeypoint"](keypoint, buff_obj, current_pos)
					index += 1
				end
				return buff_obj
			end
			_serializers["NumberSequenceKeypoint"] = function(value: NumberSequenceKeypoint, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(12) -- 3 float32

				buffer.writef32(buff_obj, offset, value.Value)
				buffer.writef32(buff_obj, offset + 4, value.Time)
				buffer.writef32(buff_obj, offset + 8, value.Envelope)
				return buff_obj
			end
			_serializers["NumberSequence"] = function(value: NumberSequence, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local seq_size = #value.Keypoints
				local buff_obj: buffer = buff_obj or buffer.create(2 + (12 * seq_size)) -- uint16 + (3 float32 * seq_size)
				local index = 0

				buffer.writeu16(buff_obj, offset, seq_size)
				for _, keypoint in value.Keypoints do
					local current_pos = (2 + (12 * index)) + offset

					_serializers["NumberSequenceKeypoint"](keypoint, buff_obj, current_pos)
					index += 1
				end
				return buff_obj
			end
			_serializers["Rect"] = function(value: Rect, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(16) -- 4 float32

				_serializers["Vector2"](value.Min, buff_obj, offset)
				_serializers["Vector2"](value.Max, buff_obj, offset + 8)
				return buff_obj
			end
			_serializers["Ray"] = function(value: Ray, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(24) -- 6 float32

				_serializers["Vector3"](value.Origin, buff_obj, offset)
				_serializers["Vector3"](value.Direction, buff_obj, offset + 12)
				return buff_obj
			end
			_serializers["PhysicalProperties"] = function(value: PhysicalProperties, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(20) -- 5 float32

				buffer.writef32(buff_obj, offset, value.Density)
				buffer.writef32(buff_obj, offset + 4, value.Friction)
				buffer.writef32(buff_obj, offset + 8, value.Elasticity)
				buffer.writef32(buff_obj, offset + 12, value.FrictionWeight)
				buffer.writef32(buff_obj, offset + 16, value.ElasticityWeight)
				return buff_obj
			end
			_serializers["NumberRange"] = function(value: NumberRange, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(8) -- 2 float32

				buffer.writef32(buff_obj, offset, value.Min)
				buffer.writef32(buff_obj, offset + 4, value.Max)
				return buff_obj
			end
			_serializers["UDim"] = function(value: UDim, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(8) -- 2 float32

				buffer.writef32(buff_obj, offset, value.Scale)
				buffer.writef32(buff_obj, offset + 4, value.Offset)
				return buff_obj
			end
			_serializers["UDim2"] = function(value: UDim2, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(16) -- 4 float32

				_serializers["UDim"](value.X, buff_obj, offset)
				_serializers["UDim"](value.Y, buff_obj, offset + 8)
				return buff_obj
			end
			_serializers["BrickColor"] = function(value: BrickColor, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(2) -- uint16

				buffer.writeu16(buff_obj, offset, value.Number)
				return buff_obj
			end
			_serializers["Faces"] = function(value: Faces, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local buff_obj: buffer = buff_obj or buffer.create(1) -- uint8
				local bit_result = 0

				bit_result += bit32.band((if value.Top then 1 else 0), face_bits.Top)
				bit_result += bit32.band(bit32.lshift((if value.Bottom then 1 else 0), 1), face_bits.Bottom)
				bit_result += bit32.band(bit32.lshift((if value.Left then 1 else 0), 2), face_bits.Left)
				bit_result += bit32.band(bit32.lshift((if value.Right then 1 else 0), 3), face_bits.Right)
				bit_result += bit32.band(bit32.lshift((if value.Back then 1 else 0), 4), face_bits.Back)
				bit_result += bit32.band(bit32.lshift((if value.Front then 1 else 0), 5), face_bits.Front)

				buffer.writeu8(buff_obj, offset, bit_result)
				return buff_obj
			end
			_serializers["Font"] = function(value: Font, buff_obj: buffer?, offset: number?): buffer
				local offset: number = offset or 0
				local string_size = (2 + #value.Family) -- uint16 + string lenght
				local buff_obj: buffer = buff_obj or buffer.create(string_size + 2 + 1) -- string_size + uint16 + uint8

				buffer.writeu16(buff_obj, offset, value.Weight.Value)
				buffer.writeu8(buff_obj, offset + 2, value.Style.Value)
				_serializers["string"](value.Family, buff_obj, offset + 3)
				return buff_obj
			end

			-- deserializers
			local _deserializers = {}
--[[
Template:
_deserializers["datatype"] = function(buff_obj: buffer, offset: number?): datatype
	local offset: number = offset or 0
	
	return 
end
--]]

			_deserializers["nil"] = function(buff_obj: buffer, offset: number?): nil
				return nil
			end
			_deserializers["boolean"] = function(buff_obj: buffer, offset: number?): boolean
				local offset: number = offset or 0

				return buffer.readu8(buff_obj, offset) == 1
			end
			_deserializers["number"] = function(buff_obj: buffer, offset: number?): number
				local offset: number = offset or 0
				local number_type_idx = buffer.readu8(buff_obj, offset)
				local number_type = number_idx_types[number_type_idx]

				return buffer[`read{number_type}`](buff_obj, offset + 1)
			end
			_deserializers["string"] = function(buff_obj: buffer, offset: number?): string
				local offset: number = offset or 0
				local string_lenght = buffer.readu16(buff_obj, offset)

				return buffer.readstring(buff_obj, offset + 2, string_lenght)
			end
			_deserializers["Vector2"] = function(buff_obj: buffer, offset: number?): Vector2
				local offset: number = offset or 0

				return Vector2.new(
					buffer.readf32(buff_obj, offset),
					buffer.readf32(buff_obj, offset + 4)
				)
			end
			_deserializers["Vector3"] = function(buff_obj: buffer, offset: number?): Vector3
				local offset: number = offset or 0

				return Vector3.new(
					buffer.readf32(buff_obj, offset),
					buffer.readf32(buff_obj, offset + 4),
					buffer.readf32(buff_obj, offset + 8)
				)
			end
			_deserializers["Vector2int16"] = function(buff_obj: buffer, offset: number?): Vector2int16
				local offset: number = offset or 0

				return Vector2int16.new(
					buffer.readi16(buff_obj, offset),
					buffer.readi16(buff_obj, offset + 2)
				)
			end
			_deserializers["Vector3int16"] = function(buff_obj: buffer, offset: number?): Vector3int16
				local offset: number = offset or 0

				return Vector3int16.new(
					buffer.readi16(buff_obj, offset),
					buffer.readi16(buff_obj, offset + 2),
					buffer.readi16(buff_obj, offset + 4)
				)
			end
			_deserializers["CFrame"] = function(buff_obj: buffer, offset: number?): CFrame
				local offset: number = offset or 0
				local position = _deserializers["Vector3"](buff_obj, offset)
				local orientation = _deserializers["Vector3"](buff_obj, offset + 12)
				local orientation_cframe = CFrame.fromOrientation(orientation.X, orientation.Y, orientation.Z)

				return (CFrame.identity + position) * orientation_cframe
			end
			_deserializers["EnumItem"] = function(buff_obj: buffer, offset: number?): EnumItem
				local offset: number = offset or 0
				local enum_value = buffer.readu32(buff_obj, offset)
				local enum_parent_name = _deserializers["string"](buff_obj, offset + 4)

				for _, enum_item in Enum[enum_parent_name]:GetEnumItems() do
					if enum_item.Value ~= enum_value then continue end
					return enum_item
				end
				return warn(`Cannot find EnumItem '{enum_value}' of 'Enum.{enum_parent_name}'`):: never
			end
			_deserializers["Color3"] = function(buff_obj: buffer, offset: number?): Color3
				local offset: number = offset or 0

				return Color3.fromRGB(
					buffer.readu8(buff_obj, offset),
					buffer.readu8(buff_obj, offset + 1),
					buffer.readu8(buff_obj, offset + 2)
				)
			end
			_deserializers["ColorSequenceKeypoint"] = function(buff_obj: buffer, offset: number?): ColorSequenceKeypoint
				local offset: number = offset or 0

				return ColorSequenceKeypoint.new(
					buffer.readf32(buff_obj, offset),
					_deserializers["Color3"](buff_obj, offset + 4)
				)
			end
			_deserializers["ColorSequence"] = function(buff_obj: buffer, offset: number?): ColorSequence
				local offset: number = offset or 0
				local raw_sequence = {}
				local seq_size = buffer.readu16(buff_obj, offset)

				for index = 0, (seq_size - 1) do
					local current_pos = (2 + (7 * index)) + offset

					table.insert(raw_sequence, _deserializers["ColorSequenceKeypoint"](buff_obj, current_pos))
				end
				return ColorSequence.new(raw_sequence)
			end
			_deserializers["NumberSequenceKeypoint"] = function(buff_obj: buffer, offset: number?): NumberSequenceKeypoint
				local offset: number = offset or 0

				return NumberSequenceKeypoint.new(
					buffer.readf32(buff_obj, offset),
					buffer.readf32(buff_obj, offset + 4),
					buffer.readf32(buff_obj, offset + 8)
				)
			end
			_deserializers["NumberSequence"] = function(buff_obj: buffer, offset: number?): NumberSequence
				local offset: number = offset or 0
				local raw_sequence = {}
				local seq_size = buffer.readu16(buff_obj, offset)

				for index = 0, (seq_size - 1) do
					local current_pos = (2 + (12 * index)) + offset

					table.insert(raw_sequence, _deserializers["NumberSequenceKeypoint"](buff_obj, current_pos))
				end
				table.sort(raw_sequence, function(a, b)
					return a.Time < b.Time
				end)
				return NumberSequence.new(raw_sequence)
			end
			_deserializers["Rect"] = function(buff_obj: buffer, offset: number?): Rect
				local offset: number = offset or 0

				return Rect.new(
					_deserializers["Vector2"](buff_obj, offset),
					_deserializers["Vector2"](buff_obj, offset + 8)
				)
			end
			_deserializers["Ray"] = function(buff_obj: buffer, offset: number?): Ray
				local offset: number = offset or 0

				return Ray.new(
					_deserializers["Vector3"](buff_obj, offset),
					_deserializers["Vector3"](buff_obj, offset + 12)
				)
			end
			_deserializers["PhysicalProperties"] = function(buff_obj: buffer, offset: number?): PhysicalProperties
				local offset: number = offset or 0

				return PhysicalProperties.new(
					buffer.readf32(buff_obj, offset),
					buffer.readf32(buff_obj, offset + 4),
					buffer.readf32(buff_obj, offset + 8),
					buffer.readf32(buff_obj, offset + 12),
					buffer.readf32(buff_obj, offset + 16)
				)
			end
			_deserializers["NumberRange"] = function(buff_obj: buffer, offset: number?): NumberRange
				local offset: number = offset or 0

				return NumberRange.new(
					buffer.readf32(buff_obj, offset),
					buffer.readf32(buff_obj, offset + 4)
				)
			end
			_deserializers["UDim"] = function(buff_obj: buffer, offset: number?): UDim
				local offset: number = offset or 0

				return UDim.new(
					buffer.readf32(buff_obj, offset),
					buffer.readf32(buff_obj, offset + 4)
				)
			end
			_deserializers["UDim2"] = function(buff_obj: buffer, offset: number?): UDim2
				local offset: number = offset or 0

				return UDim2.new(
					_deserializers["UDim"](buff_obj, offset),
					_deserializers["UDim"](buff_obj, offset + 8)
				)
			end
			_deserializers["BrickColor"] = function(buff_obj: buffer, offset: number?): BrickColor
				local offset: number = offset or 0

				return BrickColor.new(buffer.readu16(buff_obj, offset))
			end
			_deserializers["Faces"] = function(buff_obj: buffer, offset: number?): Faces
				local offset: number = offset or 0
				local face_bits = buffer.readu8(buff_obj, offset)
				local raw_faces = {}

				for index, face in face_normals do
					if bit32.extract(face_bits, index, 1) == 0 then continue end
					table.insert(raw_faces, face)
				end
				return Faces.new(unpack(raw_faces))
			end
			_deserializers["Font"] = function(buff_obj: buffer, offset: number?): Font
				local offset: number = offset or 0
				local weight_value = buffer.readu16(buff_obj, offset)
				local style_value = buffer.readu8(buff_obj, offset + 2)
				local weight_enum, style_enum

				-- hardcoded :(
				for _, enum_item in Enum.FontWeight:GetEnumItems() do
					if enum_item.Value ~= weight_value then continue end
					weight_enum = enum_item
					break
				end

				-- I could just do some simple comparison but I don't wanna deal with changes so this is done instead
				for _, enum_item in Enum.FontStyle:GetEnumItems() do
					if enum_item.Value ~= style_value then continue end
					style_enum = enum_item
					break
				end

				return Font.new(
					_deserializers["string"](buff_obj, offset + 3),
					weight_enum,
					style_enum
				)
			end

			return {serializers = _serializers, deserializers = _deserializers}
		end)()
		local Serializers = Converter.serializers
		local Deserializers = Converter.deserializers
		local TypeEnums = (function()
			local data_types = {
				["nil"] = 0,
				["boolean"] = 1,
				["number"] = 2,
				["string"] = 3,
				["Vector2"] = 4,
				["Vector3"] = 5,
				["Vector2int16"] = 6,
				["Vector3int16"] = 7,
				["CFrame"] = 8,
				["EnumItem"] = 9,
				["Color3"] = 10,
				["ColorSequenceKeypoint"] = 11,
				["ColorSequence"] = 12,
				["NumberSequenceKeypoint"] = 13,
				["NumberSequence"] = 14,
				["Rect"] = 15,
				["Ray"] = 16,
				["PhysicalProperties"] = 17,
				["NumberRange"] = 18,
				["UDim"] = 19,
				["UDim2"] = 20,
				["BrickColor"] = 21,
				["Faces"] = 22,
				["Font"] = 23
			}

			-- main
			local module = {}

			function module.toTypeValue(typeName: string): number?
				return data_types[typeName]
			end

			function module.toTypeName(index: number): string?
				for typeName, typeIdx in data_types do
					if typeIdx ~= index then continue end
					return typeName
				end
				return nil
			end

			return module
		end)()

		-- main
		local module = {
			types = TypeEnums
		}

		function module.serialize(value: any): buffer?
			local converter = Serializers[typeof(value)]
			if not converter then return end

			return converter(value)
		end

		function module.deserialize(datatype: number | string, value: buffer): any
			datatype = (if typeof(datatype) == "number" then TypeEnums.toTypeName(datatype) else datatype):: string
			local converter = Deserializers[datatype]
			if not converter then return end

			return converter(value)
		end

		return module
	end)()
	local Dump = (function()
		--dunno why i coded this with a different coding style from SerialBit

		local HttpService = game:GetService("HttpService")

		local URL = "https://raw.githubusercontent.com/CloneTrooper1019/Roblox-Client-Tracker/roblox/API-Dump.json"

		local EdgeCases = (function()
			--If x property exists but other properties also exist, we ignore that property.
			return {
				["Position"] = {
					"CFrame"
				},
				["Orientation"] = {
					"CFrame"
				},
				["Color"] = {
					"Color3"
				},
				["BackgroundColor"] = {
					"BackgroundColor3"
				},
				["TextColor"] = {
					"TextColor3",
				},
				["WorldCFrame"] = {
					"CFrame",
				},
				["WorldAxis"] = {
					"Orientation",
				},
				["WorldSecondaryAxis"] = {
					"Orientation",
				},
				["Axis"] = {
					"Orientation",
				},
				["SecondaryAxis"] = {
					"Orientation",
				},
			}
		end)()

		-- Based from "ApiDump" module from Reclass.

		local Dump = {}
		Dump.fetchCache = nil
		Dump.ignoredTags = {
			ReadOnly = true,
			Hidden = true,
			Deprecated = true,
		}
		Dump.fromClassCache = {}
		Dump.subclassesFromCache = {}
		Dump.membersFromCache = {}
		Dump.propertiesFromCache = {}
		Dump.instanceCache = {}

		function Dump:fetch(reload)
			if not reload then
				if self.fetchCache then
					return self.fetchCache
				end
			end
			local Success, Return = pcall(function()
				return HttpService:JSONDecode(HttpService:GetAsync(URL))
			end)
			if not Success then
				warn(Return)
				return
			end
			self.fetchCache = Return

			table.clear(self.fromClassCache)
			table.clear(self.subclassesFromCache)
			table.clear(self.membersFromCache)
			table.clear(self.propertiesFromCache)
			table.clear(self.instanceCache)

			return Return
		end


		--Dump:fromClass(classname : string)
		--Returns raw info of class.

		function Dump:fromClass(classname)
			local cache = self.fromClassCache[classname]
			if cache then return cache end

			local fetch = self:fetch()

			for _, object in fetch.Classes do
				if object.Name == classname then
					self.fromClassCache[classname] = object
					return object
				end
			end
		end

		--Dump:subclassesFromClass(classname : string)
		--Returns list subclasses from a class.

		function Dump:subclassesFromClass(classname)
			local cache = self.subclassesFromCache[classname]
			if cache then return cache end

			local fetch = self:fetch()

			local subclasses = {}
			for _, object in fetch.Classes do
				if object.Superclass == classname then
					table.insert(subclasses, object)
				end
			end

			self.subclassesFromCache[classname] = subclasses

			return subclasses
		end

		--Dump:membersFromClass(classname : string)
		--Returns class members.

		function Dump:membersFromClass(classname)
			local cache = self.membersFromCache[classname]
			if cache then return cache end

			local entries, properties = {}, {}

			local object = self:fromClass(classname)
			while object and object.Superclass ~= "<<<ROOT>>>" do
				table.insert(entries, 1, object)
				object = self:fromClass(object.Superclass)
			end
			table.insert(entries, 1, object)
			if not object then error(`{classname} doesn't exist`, 2) end

			for i = 1, #entries do
				local members = entries[i].Members
				for i = 1, #members do
					table.insert(properties, members[i])
				end
			end

			self.membersFromCache[classname] = properties
			return properties
		end

		--Dump:propertiesFromClass(classname : string)
		--Returns list of names of properties from a class, may not be accurate. See :propertiesFromInstance for accurate results.

		function Dump:propertiesFromClass(classname)
			local cache = self.propertiesFromCache[classname]
			if cache then return cache end
			local members = self:membersFromClass(classname)
			local properties = {}
			local inst

			for i = 1, #members do
				local member = members[i]
				if member.MemberType ~= "Property" then
					continue
				end

				local valid = true
				if member.Tags then
					local tags = member.Tags
					for i = 1, #tags do
						if self.ignoredTags[tags[i]] then
							valid = false
							break
						end
					end
				end

				if valid then
					table.insert(properties, member.Name)
				end
			end

			return properties
		end

		--Dump:propertiesFromInstance(object : Instance)
		--Returns list of names of changed properties, returns empty if it's default

		function Dump:propertiesFromInstance(object, check)
			local classname = object.ClassName
			local properties = self:propertiesFromClass(classname)
			local validProperties = {}
			local inst = object

			if not check and not self.instanceCache[classname] then
				local Success, Response = pcall(function()
					return Instance.new(classname)
				end)
				if Success then
					self.instanceCache[classname] = Response
				end
			end
			inst = check or self.instanceCache[classname]

			for i = 1, #properties do
				local name = properties[i]

				local Edge = EdgeCases[name]
				if Edge then
					local Count = 0
					for i = 1, #Edge do
						if table.find(properties, Edge[i]) then
							Count += 1
						end
					end

					if Count == #Edge then 
						--print(`Ignored seting property '{name}' because it was superseded by: {table.concat(Edge, ",")}`)
						continue 
					end
				end

				local valid, isSame = pcall(function()
					return inst[name] == object[name] 
				end)

				if (not valid) or isSame then
					continue
				end

				table.insert(validProperties, name)
			end

			return validProperties, properties
		end

		return Dump
	end)()
	local Base91 = (function()
		local MAKE_JSON_SAFE = true -- If this is true, " will be replaced by ' in the encoding

		local CHAR_SET = [[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,./:;<=>?@[]^_`{|}~"]]

		local encode_CharSet = {}
		local decode_CharSet = {}
		for i = 1, 91 do
			encode_CharSet[i-1] = string.sub(CHAR_SET, i, i)
			decode_CharSet[string.sub(CHAR_SET, i, i)] = i-1
		end

		if MAKE_JSON_SAFE then
			encode_CharSet[90] = "'"
			decode_CharSet['"'] = nil
			decode_CharSet["'"] = 90
		end

		local function encodeBase91(input)
			local output = {}
			local c = 1

			local counter = 0
			local numBits = 0

			for i = 1, #input do
				counter = bit32.bor(counter, bit32.lshift(string.byte(input, i), numBits))
				numBits = numBits+8
				if numBits > 13 then
					local entry = bit32.band(counter, 8191) -- 2^13-1 = 8191
					if entry > 88 then -- Voodoo magic (https://www.reddit.com/r/learnprogramming/comments/8sbb3v/understanding_base91_encoding/e0y85ot/)
						counter = bit32.rshift(counter, 13)
						numBits = numBits-13
					else
						entry = bit32.band(counter, 16383) -- 2^14-1 = 16383
						counter = bit32.rshift(counter, 14)
						numBits = numBits-14
					end
					output[c] = encode_CharSet[entry%91]..encode_CharSet[math.floor(entry/91)]
					c = c+1
				end
			end

			if numBits > 0 then
				output[c] = encode_CharSet[counter%91]
				if numBits > 7 or counter > 90 then
					output[c+1] = encode_CharSet[math.floor(counter/91)]
				end
			end

			return table.concat(output)
		end

		local function decodeBase91(input)
			local output = {}
			local c = 1

			local counter = 0
			local numBits = 0
			local entry = -1

			for i = 1, #input do
				if decode_CharSet[string.sub(input, i, i)] then
					if entry == -1 then
						entry = decode_CharSet[string.sub(input, i, i)]
					else
						entry = entry+decode_CharSet[string.sub(input, i, i)]*91
						counter = bit32.bor(counter, bit32.lshift(entry, numBits))
						if bit32.band(entry, 8191) > 88 then
							numBits = numBits+13
						else
							numBits = numBits+14
						end

						while numBits > 7 do
							output[c] = string.char(counter%256)
							c = c+1
							counter = bit32.rshift(counter, 8)
							numBits = numBits-8
						end
						entry = -1
					end
				end
			end

			if entry ~= -1 then
				output[c] = string.char(bit32.bor(counter, bit32.lshift(entry, numBits))%256)
			end

			return table.concat(output)
		end

		if MAKE_JSON_SAFE then
			encode_CharSet[90] = '"'
			decode_CharSet["'"] = nil
			decode_CharSet['"'] = 90
		end

		return {
			encode = encodeBase91,
			decode = decodeBase91,
		}
	end)()
	local LibDeflate = (function()
	--[[
	-------------------------------
	---       INFORMATION       ---
	-------------------------------
	
	Written by Haoqian He
	Edited/Forked by Scarious
	
	This is the forked version of the LibDeflate library by Haoqian He intended for luau. Credit for the original source code and such
	goes to their respective creators (basic credits can be viewed under CREDITS, and more expansive credits/licensing info can be viewed
	under LICENSING AND COPYRIGHT.
	
	Original documentation can be viewed here: https://safeteewow.github.io/LibDeflate/source/LibDeflate.lua.html
	
	You can access the LibDeflate library (and most LibDeflate methods seen in the original documentation) by using Compression.Library
	
	
	-------------------------------
	---      DOCUMENTATION      ---
	-------------------------------
	
	Compression Methods:
	
	Compression.Deflate.Compress(data, configs?)
	Compression.Zlib.Compress(data, configs?)
	
	
	Decompression Methods:
	
	Compression.Deflate.Decompress(compressedData)
	Compression.Zlib.Decompress(compressedData)
	
	
	USAGE:
	
		configs table:
	
		{
			level = 0; -- integer 0 -> 9 where 0 is no compression and 9 is most compression
			strategy = "" -- "huffman_only", "fixed", "dynamic"
		}
		
		note :: the higher the level, the slower the compression will be
			 :: configs table is optional, if not supplied (aka nil) default level+strategy will be used
			 
		
		methods:
		
		Method: Compression.Deflate.Compress(data, configs?):
	
			Description: Compresses a string using the raw deflate format
			
			Input:
				- String: data = The data to be compressed
				- table?: configs = The configuration table to control the compression
				
			Output:
				- String: compressedData = The compressed data
				- int: paddedBits = The number of bits padded at the end of the output


		Method: Compression.Deflate.Decompress(compressedData):
	
			Description: Decompresses a raw deflate compressed data.
			
			Input:
				- String: compressedData = The data to be decompressed
				
			Output:
				- String: data = The decompressed data



		Method: Compression.Zlib.Compress(data, configs?):
	
			Description: Compresses a string using the zlib format
			
			Input:
				- String: data = The data to be compressed
				- table?: configs = The configuration table to control the compression
				
			Output:
				- String: compressedData = The compressed data
				- int: paddedBits = The number of bits padded at the end of the output
		
		
		Method: Compression.Deflate.Decompress(compressedData):
	
			Description: Decompresses a zlib compressed data.
			
			Input:
				- String: compressedData = The data to be decompressed
				
			Output:
				- String: data = The decompressed data
		
		
	-------------------------------
	---         CREDITS         ---
	-------------------------------
	
	- LibDeflate Library: Haoqian He
	- zlib: Jean-loup Gailly and Mark Adler
	- puff: Mark Adler
	- LibCompress: jjsheets and Galmok (WoW)
	- 6bit encoding/decoding: WeakAuras2 (WoW)
	

	-------------------------------
	--- LICENSING AND COPYRIGHT ---
	-------------------------------

	LibDeflate 1.0.2-release <br>
	Pure Lua compressor and decompressor with high compression ratio using
	DEFLATE/zlib format.
	@file LibDeflate.lua
	@author Haoqian He (Github: SafeteeWoW; World of Warcraft: Safetyy-Illidan(US))
	@copyright LibDeflate <2018-2020> Haoqian He
	@license zlib License
	This library is implemented according to the following specifications.
	Report a bug if LibDeflate is not fully compliant with those specs.
	Both compressors and decompressors have been implemented in the library.
	1. RFC1950: DEFLATE Compressed Data Format Specification version 1.3
	https://tools.ietf.org/html/rfc1951
	2. RFC1951: ZLIB Compressed Data Format Specification version 3.3
	https://tools.ietf.org/html/rfc1950


	zlib License
	(C) 2018-2020 Haoqian He
	This software is provided 'as-is', without any express or implied
	warranty.  In no event will the authors be held liable for any damages
	arising from the use of this software.
	Permission is granted to anyone to use this software for any purpose,
	including commercial applications, and to alter it and redistribute it
	freely, subject to the following restrictions:
	1. The origin of this software must not be misrepresented; you must not
	   claim that you wrote the original software. If you use this software
	   in a product, an acknowledgment in the product documentation would be
	   appreciated but is not required.
	2. Altered source versions must be plainly marked as such, and must not be
	   misrepresented as being the original software.
	3. This notice may not be removed or altered from any source distribution.
	License History:
		1. GNU General Public License Version 3 in v1.0.0 and earlier versions.
		2. GNU Lesser General Public License Version 3 in v1.0.1
		3. the zlib License since v1.0.2
		
	Credits and Disclaimer:
	This library rewrites the code from the algorithm
	and the ideas of the following projects,
	and uses their code to help to test the correctness of this library,
	but their code is not included directly in the library itself.
	Their original licenses shall be comply when used:
		1. zlib, by Jean-loup Gailly (compression) and Mark Adler (decompression).
			http://www.zlib.net/
			Licensed under zlib License. http://www.zlib.net/zlib_license.html
			For the compression algorithm.
		2. puff, by Mark Adler. https://github.com/madler/zlib/tree/master/contrib/puff
			Licensed under zlib License. http://www.zlib.net/zlib_license.html
			For the decompression algorithm.
		3. LibCompress, by jjsheets and Galmok of European Stormrage (Horde)
			https://www.wowace.com/projects/libcompress
			Licensed under GPLv2.
			https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
			For the code to create customized codec.
		4. WeakAuras2,
			https://github.com/WeakAuras/WeakAuras2
			Licensed under GPLv2.
			For the 6bit encoding and decoding.
]]

		local Compression = {}
		local LibDeflate = {}

		Compression.Deflate = {}
		Compression.Zlib = {}
		Compression.Library = LibDeflate

--[[
	Method: Compression.Deflate.Compress
	
	Description: Compresses a string using the raw deflate format
	
	Input:
		- String: data = The data to be compressed
		- table?: configs = The configuration table to control the compression
		
	Output:
		- String: compressedData = The compressed data
		- int: paddedBits = The number of bits padded at the end of the output
		
	For more information see:
		- LibDeflate:CompressDeflate
		- compression_configs
]]

		function Compression.Deflate.Compress(data, configs)
			return LibDeflate:CompressDeflate(data, configs)
		end


--[[
	Method: Compression.Deflate.Decompress
	
	Description: Decompresses a raw deflate compressed data.
	
	Input:
		- String: compressedData = The data to be decompressed
		
	Output:
		- String: data = The decompressed data
		
	For more information see:
		- LibDeflate:DecompressDeflate
		- compression_configs
]]

		function Compression.Deflate.Decompress(compressedData)
			return LibDeflate:DecompressDeflate(compressedData)
		end



--[[
	Method: Compression.Zlib.Compress
	
	Description: Compresses a string using the zlib format
	
	Input:
		- String: data = The data to be compressed
		- table?: configs = The configuration table to control the compression
		
	Output:
		- String: compressedData = The compressed data
		- int: paddedBits = The number of bits padded at the end of the output
		
	For more information see:
		- LibDeflate:CompressZlib
		- compression_configs
]]

		function Compression.Zlib.Compress(data, configs)
			return LibDeflate:CompressZlib(data, configs)
		end


--[[
	Method: Compression.Deflate.Decompress
	
	Description: Decompresses a zlib compressed data.
	
	Input:
		- String: compressedData = The data to be decompressed
		
	Output:
		- String: data = The decompressed data
		
	For more information see:
		- LibDeflate:DecompressZlib
		- compression_configs
]]

		function Compression.Zlib.Decompress(compressedData)
			return LibDeflate:DecompressZlib(compressedData)
		end





--[[

	LIBDEFLATE LIBRARY:

]]


		do
			-- Semantic version. all lowercase.
			-- Suffix can be alpha1, alpha2, beta1, beta2, rc1, rc2, etc.
			-- NOTE: Two version numbers needs to modify.
			-- 1. On the top of LibDeflate.lua
			-- 2. _VERSION
			-- 3. _MINOR

			-- version to store the official version of LibDeflate
			local _VERSION = "1.0.2-release"

			-- When MAJOR is changed, I should name it as LibDeflate2
			local _MAJOR = "LibDeflate"

			-- Update this whenever a new version, for LibStub version registration.
			-- 0 : v0.x
			-- 1 : v1.0.0
			-- 2 : v1.0.1
			-- 3 : v1.0.2
			local _MINOR = 3

			local _COPYRIGHT =
				"LibDeflate ".._VERSION
				.." Copyright (C) 2018-2020 Haoqian He."
				.." Licensed under the zlib License"

			-- Register in the World of Warcraft library "LibStub" if detected.
			LibDeflate = {}

			LibDeflate._VERSION = _VERSION
			LibDeflate._MAJOR = _MAJOR
			LibDeflate._MINOR = _MINOR
			LibDeflate._COPYRIGHT = _COPYRIGHT
		end

		-- localize Lua api for faster access.
		local assert = assert
		local error = error
		local pairs = pairs
		local string_byte = string.byte
		local string_char = string.char
		local string_find = string.find
		local string_gsub = string.gsub
		local string_sub = string.sub
		local table_concat = table.concat
		local table_sort = table.sort
		local tostring = tostring
		local type = type

		-- Converts i to 2^i, (0<=i<=32)
		-- This is used to implement bit left shift and bit right shift.
		-- "x >> y" in C:   "(x-x%_pow2[y])/_pow2[y]" in Lua
		-- "x << y" in C:   "x*_pow2[y]" in Lua
		local _pow2 = {}

		-- Converts any byte to a character, (0<=byte<=255)
		local _byte_to_char = {}

		-- _reverseBitsTbl[len][val] stores the bit reverse of
		-- the number with bit length "len" and value "val"
		-- For example, decimal number 6 with bits length 5 is binary 00110
		-- It's reverse is binary 01100,
		-- which is decimal 12 and 12 == _reverseBitsTbl[5][6]
		-- 1<=len<=9, 0<=val<=2^len-1
		-- The reason for 1<=len<=9 is that the max of min bitlen of huffman code
		-- of a huffman alphabet is 9?
		local _reverse_bits_tbl = {}

		-- Convert a LZ77 length (3<=len<=258) to
		-- a deflate literal/LZ77_length code (257<=code<=285)
		local _length_to_deflate_code = {}

		-- convert a LZ77 length (3<=len<=258) to
		-- a deflate literal/LZ77_length code extra bits.
		local _length_to_deflate_extra_bits = {}

		-- Convert a LZ77 length (3<=len<=258) to
		-- a deflate literal/LZ77_length code extra bit length.
		local _length_to_deflate_extra_bitlen = {}

		-- Convert a small LZ77 distance (1<=dist<=256) to a deflate code.
		local _dist256_to_deflate_code = {}

		-- Convert a small LZ77 distance (1<=dist<=256) to
		-- a deflate distance code extra bits.
		local _dist256_to_deflate_extra_bits = {}

		-- Convert a small LZ77 distance (1<=dist<=256) to
		-- a deflate distance code extra bit length.
		local _dist256_to_deflate_extra_bitlen = {}

		-- Convert a literal/LZ77_length deflate code to LZ77 base length
		-- The key of the table is (code - 256), 257<=code<=285
		local _literal_deflate_code_to_base_len = {
			3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
			35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258,
		}

		-- Convert a literal/LZ77_length deflate code to base LZ77 length extra bits
		-- The key of the table is (code - 256), 257<=code<=285
		local _literal_deflate_code_to_extra_bitlen = {
			0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
			3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0,
		}

		-- Convert a distance deflate code to base LZ77 distance. (0<=code<=29)
		local _dist_deflate_code_to_base_dist = {
			[0] = 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
			257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
			8193, 12289, 16385, 24577,
		}

		-- Convert a distance deflate code to LZ77 bits length. (0<=code<=29)
		local _dist_deflate_code_to_extra_bitlen = {
			[0] = 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
			7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13,
		}

		-- The code order of the first huffman header in the dynamic deflate block.
		-- See the page 12 of RFC1951
		local _rle_codes_huffman_bitlen_order = {16, 17, 18,
			0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15,
		}

		-- The following tables are used by fixed deflate block.
		-- The value of these tables are assigned at the bottom of the source.

		-- The huffman code of the literal/LZ77_length deflate codes,
		-- in fixed deflate block.
		local _fix_block_literal_huffman_code

		-- Convert huffman code of the literal/LZ77_length to deflate codes,
		-- in fixed deflate block.
		local _fix_block_literal_huffman_to_deflate_code

		-- The bit length of the huffman code of literal/LZ77_length deflate codes,
		-- in fixed deflate block.
		local _fix_block_literal_huffman_bitlen

		-- The count of each bit length of the literal/LZ77_length deflate codes,
		-- in fixed deflate block.
		local _fix_block_literal_huffman_bitlen_count

		-- The huffman code of the distance deflate codes,
		-- in fixed deflate block.
		local _fix_block_dist_huffman_code

		-- Convert huffman code of the distance to deflate codes,
		-- in fixed deflate block.
		local _fix_block_dist_huffman_to_deflate_code

		-- The bit length of the huffman code of the distance deflate codes,
		-- in fixed deflate block.
		local _fix_block_dist_huffman_bitlen

		-- The count of each bit length of the huffman code of
		-- the distance deflate codes,
		-- in fixed deflate block.
		local _fix_block_dist_huffman_bitlen_count

		for i = 0, 255 do
			_byte_to_char[i] = string_char(i)
		end

		do
			local pow = 1
			for i = 0, 32 do
				_pow2[i] = pow
				pow = pow * 2
			end
		end

		for i = 1, 9 do
			_reverse_bits_tbl[i] = {}
			for j=0, _pow2[i+1]-1 do
				local reverse = 0
				local value = j
				for _ = 1, i do
					-- The following line is equivalent to "res | (code %2)" in C.
					reverse = reverse - reverse%2
						+ (((reverse%2==1) or (value % 2) == 1) and 1 or 0)
					value = (value-value%2)/2
					reverse = reverse * 2
				end
				_reverse_bits_tbl[i][j] = (reverse-reverse%2)/2
			end
		end

		-- The source code is written according to the pattern in the numbers
		-- in RFC1951 Page10.
		do
			local a = 18
			local b = 16
			local c = 265
			local bitlen = 1
			for len = 3, 258 do
				if len <= 10 then
					_length_to_deflate_code[len] = len + 254
					_length_to_deflate_extra_bitlen[len] = 0
				elseif len == 258 then
					_length_to_deflate_code[len] = 285
					_length_to_deflate_extra_bitlen[len] = 0
				else
					if len > a then
						a = a + b
						b = b * 2
						c = c + 4
						bitlen = bitlen + 1
					end
					local t = len-a-1+b/2
					_length_to_deflate_code[len] = (t-(t%(b/8)))/(b/8) + c
					_length_to_deflate_extra_bitlen[len] = bitlen
					_length_to_deflate_extra_bits[len] = t % (b/8)
				end
			end
		end

		-- The source code is written according to the pattern in the numbers
		-- in RFC1951 Page11.
		do
			_dist256_to_deflate_code[1] = 0
			_dist256_to_deflate_code[2] = 1
			_dist256_to_deflate_extra_bitlen[1] = 0
			_dist256_to_deflate_extra_bitlen[2] = 0

			local a = 3
			local b = 4
			local code = 2
			local bitlen = 0
			for dist = 3, 256 do
				if dist > b then
					a = a * 2
					b = b * 2
					code = code + 2
					bitlen = bitlen + 1
				end
				_dist256_to_deflate_code[dist] = (dist <= a) and code or (code+1)
				_dist256_to_deflate_extra_bitlen[dist] = (bitlen < 0) and 0 or bitlen
				if b >= 8 then
					_dist256_to_deflate_extra_bits[dist] = (dist-b/2-1) % (b/4)
				end
			end
		end

		--- Calculate the Adler-32 checksum of the string. <br>
		-- See RFC1950 Page 9 https://tools.ietf.org/html/rfc1950 for the
		-- definition of Adler-32 checksum.
		-- @param str [string] the input string to calcuate its Adler-32 checksum.
		-- @return [integer] The Adler-32 checksum, which is greater or equal to 0,
		-- and less than 2^32 (4294967296).
		function LibDeflate:Adler32(str)
			-- This function is loop unrolled by better performance.
			--
			-- Here is the minimum code:
			--
			-- local a = 1
			-- local b = 0
			-- for i=1, #str do
			-- 		local s = string.byte(str, i, i)
			-- 		a = (a+s)%65521
			-- 		b = (b+a)%65521
			-- 		end
			-- return b*65536+a
			if type(str) ~= "string" then
				error(("Usage: LibDeflate:Adler32(str):"
					.." 'str' - string expected got '%s'."):format(type(str)), 2)
			end
			local strlen = #str

			local i = 1
			local a = 1
			local b = 0
			while i <= strlen - 15 do
				local x1, x2, x3, x4, x5, x6, x7, x8,
				x9, x10, x11, x12, x13, x14, x15, x16 = string_byte(str, i, i+15)
				b = (b+16*a+16*x1+15*x2+14*x3+13*x4+12*x5+11*x6+10*x7+9*x8+8*x9
					+7*x10+6*x11+5*x12+4*x13+3*x14+2*x15+x16)%65521
				a = (a+x1+x2+x3+x4+x5+x6+x7+x8+x9+x10+x11+x12+x13+x14+x15+x16)%65521
				i =  i + 16
			end
			while (i <= strlen) do
				local x = string_byte(str, i, i)
				a = (a + x) % 65521
				b = (b + a) % 65521
				i = i + 1
			end
			return (b*65536+a) % 4294967296
		end

		-- Compare adler32 checksum.
		-- adler32 should be compared with a mod to avoid sign problem
		-- 4072834167 (unsigned) is the same adler32 as -222133129
		local function IsEqualAdler32(actual, expected)
			return (actual % 4294967296) == (expected % 4294967296)
		end

		--- Create a preset dictionary.
		--
		-- This function is not fast, and the memory consumption of the produced
		-- dictionary is about 50 times of the input string. Therefore, it is suggestted
		-- to run this function only once in your program.
		--
		-- It is very important to know that if you do use a preset dictionary,
		-- compressors and decompressors MUST USE THE SAME dictionary. That is,
		-- dictionary must be created using the same string. If you update your program
		-- with a new dictionary, people with the old version won't be able to transmit
		-- data with people with the new version. Therefore, changing the dictionary
		-- must be very careful.
		--
		-- The parameters "strlen" and "adler32" add a layer of verification to ensure
		-- the parameter "str" is not modified unintentionally during the program
		-- development.
		--
		-- @usage local dict_str = "1234567890"
		--
		-- -- print(dict_str:len(), LibDeflate:Adler32(dict_str))
		-- -- Hardcode the print result below to verify it to avoid acciently
		-- -- modification of 'str' during the program development.
		-- -- string length: 10, Adler-32: 187433486,
		-- -- Don't calculate string length and its Adler-32 at run-time.
		--
		-- local dict = LibDeflate:CreateDictionary(dict_str, 10, 187433486)
		--
		-- @param str [string] The string used as the preset dictionary. <br>
		-- You should put stuffs that frequently appears in the dictionary
		-- string and preferablely put more frequently appeared stuffs toward the end
		-- of the string. <br>
		-- Empty string and string longer than 32768 bytes are not allowed.
		-- @param strlen [integer] The length of 'str'. Please pass in this parameter
		-- as a hardcoded constant, in order to verify the content of 'str'. The value
		-- of this parameter should be known before your program runs.
		-- @param adler32 [integer] The Adler-32 checksum of 'str'. Please pass in this
		-- parameter as a hardcoded constant, in order to verify the content of 'str'.
		-- The value of this parameter should be known before your program runs.
		-- @return  [table] The dictionary used for preset dictionary compression and
		-- decompression.
		-- @raise error if 'strlen' does not match the length of 'str',
		-- or if 'adler32' does not match the Adler-32 checksum of 'str'.
		function LibDeflate:CreateDictionary(str, strlen, adler32)
			if type(str) ~= "string" then
				error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
					.." 'str' - string expected got '%s'."):format(type(str)), 2)
			end
			if type(strlen) ~= "number" then
				error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
					.." 'strlen' - number expected got '%s'."):format(
						type(strlen)), 2)
			end
			if type(adler32) ~= "number" then
				error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
					.." 'adler32' - number expected got '%s'."):format(
						type(adler32)), 2)
			end
			if strlen ~= #str then
				error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
					.." 'strlen' does not match the actual length of 'str'."
					.." 'strlen': %u, '#str': %u ."
					.." Please check if 'str' is modified unintentionally.")
					:format(strlen, #str))
			end
			if strlen == 0 then
				error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
					.." 'str' - Empty string is not allowed."), 2)
			end
			if strlen > 32768 then
				error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
					.." 'str' - string longer than 32768 bytes is not allowed."
					.." Got %d bytes."):format(strlen), 2)
			end
			local actual_adler32 = self:Adler32(str)
			if not IsEqualAdler32(adler32, actual_adler32) then
				error(("Usage: LibDeflate:CreateDictionary(str, strlen, adler32):"
					.." 'adler32' does not match the actual adler32 of 'str'."
					.." 'adler32': %u, 'Adler32(str)': %u ."
					.." Please check if 'str' is modified unintentionally.")
					:format(adler32, actual_adler32))
			end

			local dictionary = {}
			dictionary.adler32 = adler32
			dictionary.hash_tables = {}
			dictionary.string_table = {}
			dictionary.strlen = strlen
			local string_table = dictionary.string_table
			local hash_tables = dictionary.hash_tables
			string_table[1] = string_byte(str, 1, 1)
			string_table[2] = string_byte(str, 2, 2)
			if strlen >= 3 then
				local i = 1
				local hash = string_table[1]*256+string_table[2]
				while i <= strlen - 2 - 3 do
					local x1, x2, x3, x4 = string_byte(str, i+2, i+5)
					string_table[i+2] = x1
					string_table[i+3] = x2
					string_table[i+4] = x3
					string_table[i+5] = x4
					hash = (hash*256+x1)%16777216
					local t = hash_tables[hash]
					if not t then t = {}; hash_tables[hash] = t end
					t[#t+1] = i-strlen
					i = i + 1
					hash = (hash*256+x2)%16777216
					t = hash_tables[hash]
					if not t then t = {}; hash_tables[hash] = t end
					t[#t+1] = i-strlen
					i = i + 1
					hash = (hash*256+x3)%16777216
					t = hash_tables[hash]
					if not t then t = {}; hash_tables[hash] = t end
					t[#t+1] = i-strlen
					i = i + 1
					hash = (hash*256+x4)%16777216
					t = hash_tables[hash]
					if not t then t = {}; hash_tables[hash] = t end
					t[#t+1] = i-strlen
					i = i + 1
				end
				while i <= strlen - 2 do
					local x = string_byte(str, i+2)
					string_table[i+2] = x
					hash = (hash*256+x)%16777216
					local t = hash_tables[hash]
					if not t then t = {}; hash_tables[hash] = t end
					t[#t+1] = i-strlen
					i = i + 1
				end
			end
			return dictionary
		end

		-- Check if the dictionary is valid.
		-- @param dictionary The preset dictionary for compression and decompression.
		-- @return true if valid, false if not valid.
		-- @return if not valid, the error message.
		local function IsValidDictionary(dictionary)
			if type(dictionary) ~= "table" then
				return false, ("'dictionary' - table expected got '%s'.")
					:format(type(dictionary))
			end
			if type(dictionary.adler32) ~= "number"
				or type(dictionary.string_table) ~= "table"
				or type(dictionary.strlen) ~= "number"
				or dictionary.strlen <= 0
				or dictionary.strlen > 32768
				or dictionary.strlen ~= #dictionary.string_table
				or type(dictionary.hash_tables) ~= "table"
			then
				return false, ("'dictionary' - corrupted dictionary.")
					:format(type(dictionary))
			end
			return true, ""
		end

--[[
	key of the configuration table is the compression level,
	and its value stores the compression setting.
	These numbers come from zlib source code.
	Higher compression level usually means better compression.
	(Because LibDeflate uses a simplified version of zlib algorithm,
	there is no guarantee that higher compression level does not create
	bigger file than lower level, but I can say it's 99% likely)
	Be careful with the high compression level. This is a pure lua
	implementation compressor/decompressor, which is significant slower than
	a C/C++ equivalant compressor/decompressor. Very high compression level
	costs significant more CPU time, and usually compression size won't be
	significant smaller when you increase compression level by 1, when the
	level is already very high. Benchmark yourself if you can afford it.
	See also https://github.com/madler/zlib/blob/master/doc/algorithm.txt,
	https://github.com/madler/zlib/blob/master/deflate.c for more information.
	The meaning of each field:
	@field 1 use_lazy_evaluation:
		true/false. Whether the program uses lazy evaluation.
		See what is "lazy evaluation" in the link above.
		lazy_evaluation improves ratio, but relatively slow.
	@field 2 good_prev_length:
		Only effective if lazy is set, Only use 1/4 of max_chain,
		if prev length of lazy match is above this.
	@field 3 max_insert_length/max_lazy_match:
		If not using lazy evaluation,
		insert new strings in the hash table only if the match length is not
		greater than this length.
		If using lazy evaluation, only continue lazy evaluation,
		if previous match length is strictly smaller than this value.
	@field 4 nice_length:
		Number. Don't continue to go down the hash chain,
		if match length is above this.
	@field 5 max_chain:
		Number. The maximum number of hash chains we look.
--]]
		local _compression_level_configs = {
			[0] = {false, nil, 0, 0, 0}, -- level 0, no compression
			[1] = {false, nil, 4, 8, 4}, -- level 1, similar to zlib level 1
			[2] = {false, nil, 5, 18, 8}, -- level 2, similar to zlib level 2
			[3] = {false, nil, 6, 32, 32},	-- level 3, similar to zlib level 3
			[4] = {true, 4,	4, 16, 16},	-- level 4, similar to zlib level 4
			[5] = {true, 8,	16,	32,	32}, -- level 5, similar to zlib level 5
			[6] = {true, 8,	16,	128, 128}, -- level 6, similar to zlib level 6
			[7] = {true, 8,	32,	128, 256}, -- (SLOW) level 7, similar to zlib level 7
			[8] = {true, 32, 128, 258, 1024} , --(SLOW) level 8,similar to zlib level 8
			[9] = {true, 32, 258, 258, 4096},
			-- (VERY SLOW) level 9, similar to zlib level 9
		}

		-- Check if the compression/decompression arguments is valid
		-- @param str The input string.
		-- @param check_dictionary if true, check if dictionary is valid.
		-- @param dictionary The preset dictionary for compression and decompression.
		-- @param check_configs if true, check if config is valid.
		-- @param configs The compression configuration table
		-- @return true if valid, false if not valid.
		-- @return if not valid, the error message.
		local function IsValidArguments(str,
			check_dictionary, dictionary,
			check_configs, configs)

			if type(str) ~= "string" then
				return false,
				("'str' - string expected got '%s'."):format(type(str))
			end
			if check_dictionary then
				local dict_valid, dict_err = IsValidDictionary(dictionary)
				if not dict_valid then
					return false, dict_err
				end
			end
			if check_configs then
				local type_configs = type(configs)
				if type_configs ~= "nil" and type_configs ~= "table" then
					return false,
					("'configs' - nil or table expected got '%s'.")
						:format(type(configs))
				end
				if type_configs == "table" then
					for k, v in pairs(configs) do
						if k ~= "level" and k ~= "strategy" then
							return false,
							("'configs' - unsupported table key in the configs: '%s'.")
								:format(k)
						elseif k == "level" and not _compression_level_configs[v] then
							return false,
							("'configs' - unsupported 'level': %s."):format(tostring(v))
						elseif k == "strategy" and v ~= "fixed" and v ~= "huffman_only"
							and v ~= "dynamic" then
							-- random_block_type is for testing purpose
							return false, ("'configs' - unsupported 'strategy': '%s'.")
								:format(tostring(v))
						end
					end
				end
			end
			return true, ""
		end



--[[ --------------------------------------------------------------------------
	Compress code
--]] --------------------------------------------------------------------------

		-- partial flush to save memory
		local _FLUSH_MODE_MEMORY_CLEANUP = 0
		-- full flush with partial bytes
		local _FLUSH_MODE_OUTPUT = 1
		-- write bytes to get to byte boundary
		local _FLUSH_MODE_BYTE_BOUNDARY = 2
		-- no flush, just get num of bits written so far
		local _FLUSH_MODE_NO_FLUSH = 3

--[[
	Create an empty writer to easily write stuffs as the unit of bits.
	Return values:
	1. WriteBits(code, bitlen):
	2. WriteString(str):
	3. Flush(mode):
--]]

		local step = 0

		local function CreateWriter()
			local buffer_size = 0
			local cache = 0
			local cache_bitlen = 0
			local total_bitlen = 0
			local buffer = {}
			-- When buffer is big enough, flush into result_buffer to save memory.
			local result_buffer = {}

			-- Write bits with value "value" and bit length of "bitlen" into writer.
			-- @param value: The value being written
			-- @param bitlen: The bit length of "value"
			-- @return nil
			local function WriteBits(value, bitlen)
				step += 1
				cache = cache + value * _pow2[cache_bitlen]
				cache_bitlen = cache_bitlen + bitlen
				total_bitlen = total_bitlen + bitlen

				if step % 800 == 0 then
					task.wait()
				end
				-- Only bulk to buffer every 4 bytes. This is quicker.
				if cache_bitlen >= 32 then
					buffer_size = buffer_size + 1
					buffer[buffer_size] =
						_byte_to_char[cache % 256]
						.._byte_to_char[((cache-cache%256)/256 % 256)]
						.._byte_to_char[((cache-cache%65536)/65536 % 256)]
						.._byte_to_char[((cache-cache%16777216)/16777216 % 256)]
					local rshift_mask = _pow2[32 - cache_bitlen + bitlen]
					cache = (value - value%rshift_mask)/rshift_mask
					cache_bitlen = cache_bitlen - 32
				end
			end

			-- Write the entire string into the writer.
			-- @param str The string being written
			-- @return nil
			local function WriteString(str)
				for _ = 1, cache_bitlen, 8 do
					buffer_size = buffer_size + 1
					buffer[buffer_size] = string_char(cache % 256)
					cache = (cache-cache%256)/256
				end
				cache_bitlen = 0
				buffer_size = buffer_size + 1
				buffer[buffer_size] = str
				total_bitlen = total_bitlen + #str*8
			end

			-- Flush current stuffs in the writer and return it.
			-- This operation will free most of the memory.
			-- @param mode See the descrtion of the constant and the source code.
			-- @return The total number of bits stored in the writer right now.
			-- for byte boundary mode, it includes the padding bits.
			-- for output mode, it does not include padding bits.
			-- @return Return the outputs if mode is output.
			local function FlushWriter(mode)
				if mode == _FLUSH_MODE_NO_FLUSH then
					return total_bitlen
				end

				if mode == _FLUSH_MODE_OUTPUT
					or mode == _FLUSH_MODE_BYTE_BOUNDARY then
					-- Full flush, also output cache.
					-- Need to pad some bits if cache_bitlen is not multiple of 8.
					local padding_bitlen = (8 - cache_bitlen % 8) % 8

					if cache_bitlen > 0 then
						-- padding with all 1 bits, mainly because "\000" is not
						-- good to be tranmitted. I do this so "\000" is a little bit
						-- less frequent.
						cache = cache - _pow2[cache_bitlen]
							+ _pow2[cache_bitlen+padding_bitlen]
						for _ = 1, cache_bitlen, 8 do
							buffer_size = buffer_size + 1
							buffer[buffer_size] = _byte_to_char[cache % 256]
							cache = (cache-cache%256)/256
						end

						cache = 0
						cache_bitlen = 0
					end
					if mode == _FLUSH_MODE_BYTE_BOUNDARY then
						total_bitlen = total_bitlen + padding_bitlen
						return total_bitlen
					end
				end

				local flushed = table_concat(buffer)
				buffer = {}
				buffer_size = 0
				result_buffer[#result_buffer+1] = flushed

				if mode == _FLUSH_MODE_MEMORY_CLEANUP then
					return total_bitlen
				else
					return total_bitlen, table_concat(result_buffer)
				end
			end

			return WriteBits, WriteString, FlushWriter
		end

		-- Push an element into a max heap
		-- @param heap A max heap whose max element is at index 1.
		-- @param e The element to be pushed. Assume element "e" is a table
		--  and comparison is done via its first entry e[1]
		-- @param heap_size current number of elements in the heap.
		--  NOTE: There may be some garbage stored in
		--  heap[heap_size+1], heap[heap_size+2], etc..
		-- @return nil
		local function MinHeapPush(heap, e, heap_size)
			heap_size = heap_size + 1
			heap[heap_size] = e
			local value = e[1]
			local pos = heap_size
			local parent_pos = (pos-pos%2)/2

			while (parent_pos >= 1 and heap[parent_pos][1] > value) do
				local t = heap[parent_pos]
				heap[parent_pos] = e
				heap[pos] = t
				pos = parent_pos
				parent_pos = (parent_pos-parent_pos%2)/2
			end
		end

		-- Pop an element from a max heap
		-- @param heap A max heap whose max element is at index 1.
		-- @param heap_size current number of elements in the heap.
		-- @return the poped element
		-- Note: This function does not change table size of "heap" to save CPU time.
		local function MinHeapPop(heap, heap_size)
			local top = heap[1]
			local e = heap[heap_size]
			local value = e[1]
			heap[1] = e
			heap[heap_size] = top
			heap_size = heap_size - 1

			local pos = 1
			local left_child_pos = pos * 2
			local right_child_pos = left_child_pos + 1

			while (left_child_pos <= heap_size) do
				local left_child = heap[left_child_pos]
				if (right_child_pos <= heap_size
					and heap[right_child_pos][1] < left_child[1]) then
					local right_child = heap[right_child_pos]
					if right_child[1] < value then
						heap[right_child_pos] = e
						heap[pos] = right_child
						pos = right_child_pos
						left_child_pos = pos * 2
						right_child_pos = left_child_pos + 1
					else
						break
					end
				else
					if left_child[1] < value then
						heap[left_child_pos] = e
						heap[pos] = left_child
						pos = left_child_pos
						left_child_pos = pos * 2
						right_child_pos = left_child_pos + 1
					else
						break
					end
				end
			end

			return top
		end

		-- Deflate defines a special huffman tree, which is unique once the bit length
		-- of huffman code of all symbols are known.
		-- @param bitlen_count Number of symbols with a specific bitlen
		-- @param symbol_bitlen The bit length of a symbol
		-- @param max_symbol The max symbol among all symbols,
		--		which is (number of symbols - 1)
		-- @param max_bitlen The max huffman bit length among all symbols.
		-- @return The huffman code of all symbols.
		local function GetHuffmanCodeFromBitlen(bitlen_counts, symbol_bitlens
			, max_symbol, max_bitlen)
			local huffman_code = 0
			local next_codes = {}
			local symbol_huffman_codes = {}
			for bitlen = 1, max_bitlen do
				huffman_code = (huffman_code+(bitlen_counts[bitlen-1] or 0))*2
				next_codes[bitlen] = huffman_code
			end
			for symbol = 0, max_symbol do
				local bitlen = symbol_bitlens[symbol]
				if bitlen then
					huffman_code = next_codes[bitlen]
					next_codes[bitlen] = huffman_code + 1

					-- Reverse the bits of huffman code,
					-- because most signifant bits of huffman code
					-- is stored first into the compressed data.
					-- @see RFC1951 Page5 Section 3.1.1
					if bitlen <= 9 then -- Have cached reverse for small bitlen.
						symbol_huffman_codes[symbol] =
							_reverse_bits_tbl[bitlen][huffman_code]
					else
						local reverse = 0
						for _ = 1, bitlen do
							reverse = reverse - reverse%2
								+ (((reverse%2==1)
									or (huffman_code % 2) == 1) and 1 or 0)
							huffman_code = (huffman_code-huffman_code%2)/2
							reverse = reverse*2
						end
						symbol_huffman_codes[symbol] = (reverse-reverse%2)/2
					end
				end
			end
			return symbol_huffman_codes
		end

		-- A helper function to sort heap elements
		-- a[1], b[1] is the huffman frequency
		-- a[2], b[2] is the symbol value.
		local function SortByFirstThenSecond(a, b)
			return a[1] < b[1] or
				(a[1] == b[1] and a[2] < b[2])
		end

		-- Calculate the huffman bit length and huffman code.
		-- @param symbol_count: A table whose table key is the symbol, and table value
		--		is the symbol frenquency (nil means 0 frequency).
		-- @param max_bitlen: See description of return value.
		-- @param max_symbol: The maximum symbol
		-- @return a table whose key is the symbol, and the value is the huffman bit
		--		bit length. We guarantee that all bit length <= max_bitlen.
		--		For 0<=symbol<=max_symbol, table value could be nil if the frequency
		--		of the symbol is 0 or nil.
		-- @return a table whose key is the symbol, and the value is the huffman code.
		-- @return a number indicating the maximum symbol whose bitlen is not 0.
		local function GetHuffmanBitlenAndCode(symbol_counts, max_bitlen, max_symbol)
			local heap_size
			local max_non_zero_bitlen_symbol = -1
			local leafs = {}
			local heap = {}
			local symbol_bitlens = {}
			local symbol_codes = {}
			local bitlen_counts = {}

	--[[
		tree[1]: weight, temporarily used as parent and bitLengths
		tree[2]: symbol
		tree[3]: left child
		tree[4]: right child
	--]]
			local number_unique_symbols = 0
			for symbol, count in pairs(symbol_counts) do
				number_unique_symbols = number_unique_symbols + 1
				leafs[number_unique_symbols] = {count, symbol}
			end

			if (number_unique_symbols == 0) then
				-- no code.
				return {}, {}, -1
			elseif (number_unique_symbols == 1) then
				-- Only one code. In this case, its huffman code
				-- needs to be assigned as 0, and bit length is 1.
				-- This is the only case that the return result
				-- represents an imcomplete huffman tree.
				local symbol = leafs[1][2]
				symbol_bitlens[symbol] = 1
				symbol_codes[symbol] = 0
				return symbol_bitlens, symbol_codes, symbol
			else
				table_sort(leafs, SortByFirstThenSecond)
				heap_size = number_unique_symbols
				for i = 1, heap_size do
					heap[i] = leafs[i]
				end

				while (heap_size > 1) do
					-- Note: pop does not change table size of heap
					local leftChild = MinHeapPop(heap, heap_size)
					heap_size = heap_size - 1
					local rightChild = MinHeapPop(heap, heap_size)
					heap_size = heap_size - 1
					local newNode =
						{leftChild[1]+rightChild[1], -1, leftChild, rightChild}
					MinHeapPush(heap, newNode, heap_size)
					heap_size = heap_size + 1
				end

				-- Number of leafs whose bit length is greater than max_len.
				local number_bitlen_overflow = 0

				-- Calculate bit length of all nodes
				local fifo = {heap[1], 0, 0, 0} -- preallocate some spaces.
				local fifo_size = 1
				local index = 1
				heap[1][1] = 0
				while (index <= fifo_size) do -- Breath first search
					local e = fifo[index]
					local bitlen = e[1]
					local symbol = e[2]
					local left_child = e[3]
					local right_child = e[4]
					if left_child then
						fifo_size = fifo_size + 1
						fifo[fifo_size] = left_child
						left_child[1] = bitlen + 1
					end
					if right_child then
						fifo_size = fifo_size + 1
						fifo[fifo_size] = right_child
						right_child[1] = bitlen + 1
					end
					index = index + 1

					if (bitlen > max_bitlen) then
						number_bitlen_overflow = number_bitlen_overflow + 1
						bitlen = max_bitlen
					end
					if symbol >= 0 then
						symbol_bitlens[symbol] = bitlen
						max_non_zero_bitlen_symbol =
							(symbol > max_non_zero_bitlen_symbol)
							and symbol or max_non_zero_bitlen_symbol
						bitlen_counts[bitlen] = (bitlen_counts[bitlen] or 0) + 1
					end
				end

				-- Resolve bit length overflow
				-- @see ZLib/trees.c:gen_bitlen(s, desc), for reference
				if (number_bitlen_overflow > 0) then
					repeat
						local bitlen = max_bitlen - 1
						while ((bitlen_counts[bitlen] or 0) == 0) do
							bitlen = bitlen - 1
						end
						-- move one leaf down the tree
						bitlen_counts[bitlen] = bitlen_counts[bitlen] - 1
						-- move one overflow item as its brother
						bitlen_counts[bitlen+1] = (bitlen_counts[bitlen+1] or 0) + 2
						bitlen_counts[max_bitlen] = bitlen_counts[max_bitlen] - 1
						number_bitlen_overflow = number_bitlen_overflow - 2
					until (number_bitlen_overflow <= 0)

					index = 1
					for bitlen = max_bitlen, 1, -1 do
						local n = bitlen_counts[bitlen] or 0
						while (n > 0) do
							local symbol = leafs[index][2]
							symbol_bitlens[symbol] = bitlen
							n = n - 1
							index = index + 1
						end
					end
				end

				symbol_codes = GetHuffmanCodeFromBitlen(bitlen_counts, symbol_bitlens,
					max_symbol, max_bitlen)
				return symbol_bitlens, symbol_codes, max_non_zero_bitlen_symbol
			end
		end

		-- Calculate the first huffman header in the dynamic huffman block
		-- @see RFC1951 Page 12
		-- @param lcode_bitlen: The huffman bit length of literal/LZ77_length.
		-- @param max_non_zero_bitlen_lcode: The maximum literal/LZ77_length symbol
		--		whose huffman bit length is not zero.
		-- @param dcode_bitlen: The huffman bit length of LZ77 distance.
		-- @param max_non_zero_bitlen_dcode: The maximum LZ77 distance symbol
		--		whose huffman bit length is not zero.
		-- @return The run length encoded codes.
		-- @return The extra bits. One entry for each rle code that needs extra bits.
		--		(code == 16 or 17 or 18).
		-- @return The count of appearance of each rle codes.
		local function RunLengthEncodeHuffmanBitlen(
			lcode_bitlens,
			max_non_zero_bitlen_lcode,
			dcode_bitlens,
			max_non_zero_bitlen_dcode)
			local rle_code_tblsize = 0
			local rle_codes = {}
			local rle_code_counts = {}
			local rle_extra_bits_tblsize = 0
			local rle_extra_bits = {}
			local prev = nil
			local count = 0

			-- If there is no distance code, assume one distance code of bit length 0.
			-- RFC1951: One distance code of zero bits means that
			-- there are no distance codes used at all (the data is all literals).
			max_non_zero_bitlen_dcode = (max_non_zero_bitlen_dcode < 0)
				and 0 or max_non_zero_bitlen_dcode
			local max_code = max_non_zero_bitlen_lcode+max_non_zero_bitlen_dcode+1

			for code = 0, max_code+1 do
				local len = (code <= max_non_zero_bitlen_lcode)
					and (lcode_bitlens[code] or 0)
					or ((code <= max_code)
						and (dcode_bitlens[code-max_non_zero_bitlen_lcode-1] or 0) or nil)
				if len == prev then
					count = count + 1
					if len ~= 0 and count == 6 then
						rle_code_tblsize = rle_code_tblsize + 1
						rle_codes[rle_code_tblsize] = 16
						rle_extra_bits_tblsize = rle_extra_bits_tblsize + 1
						rle_extra_bits[rle_extra_bits_tblsize] = 3
						rle_code_counts[16] = (rle_code_counts[16] or 0) + 1
						count = 0
					elseif len == 0 and count == 138 then
						rle_code_tblsize = rle_code_tblsize + 1
						rle_codes[rle_code_tblsize] = 18
						rle_extra_bits_tblsize = rle_extra_bits_tblsize + 1
						rle_extra_bits[rle_extra_bits_tblsize] = 127
						rle_code_counts[18] = (rle_code_counts[18] or 0) + 1
						count = 0
					end
				else
					if count == 1 then
						rle_code_tblsize = rle_code_tblsize + 1
						rle_codes[rle_code_tblsize] = prev
						rle_code_counts[prev] = (rle_code_counts[prev] or 0) + 1
					elseif count == 2 then
						rle_code_tblsize = rle_code_tblsize + 1
						rle_codes[rle_code_tblsize] = prev
						rle_code_tblsize = rle_code_tblsize + 1
						rle_codes[rle_code_tblsize] = prev
						rle_code_counts[prev] = (rle_code_counts[prev] or 0) + 2
					elseif count >= 3 then
						rle_code_tblsize = rle_code_tblsize + 1
						local rleCode = (prev ~= 0) and 16 or (count <= 10 and 17 or 18)
						rle_codes[rle_code_tblsize] = rleCode
						rle_code_counts[rleCode] = (rle_code_counts[rleCode] or 0) + 1
						rle_extra_bits_tblsize = rle_extra_bits_tblsize + 1
						rle_extra_bits[rle_extra_bits_tblsize] =
							(count <= 10) and (count - 3) or (count - 11)
					end

					prev = len
					if len and len ~= 0 then
						rle_code_tblsize = rle_code_tblsize + 1
						rle_codes[rle_code_tblsize] = len
						rle_code_counts[len] = (rle_code_counts[len] or 0) + 1
						count = 0
					else
						count = 1
					end
				end
			end

			return rle_codes, rle_extra_bits, rle_code_counts
		end

		-- Load the string into a table, in order to speed up LZ77.
		-- Loop unrolled 16 times to speed this function up.
		-- @param str The string to be loaded.
		-- @param t The load destination
		-- @param start str[index] will be the first character to be loaded.
		-- @param end str[index] will be the last character to be loaded
		-- @param offset str[index] will be loaded into t[index-offset]
		-- @return t
		local function LoadStringToTable(str, t, start, stop, offset)
			local i = start - offset
			while i <= stop - 15 - offset do
				t[i], t[i+1], t[i+2], t[i+3], t[i+4], t[i+5], t[i+6], t[i+7], t[i+8],
				t[i+9], t[i+10], t[i+11], t[i+12], t[i+13], t[i+14], t[i+15] =
					string_byte(str, i + offset, i + 15 + offset)
				i = i + 16
			end
			while (i <= stop - offset) do
				t[i] = string_byte(str, i + offset, i + offset)
				i = i + 1
			end
			return t
		end

		-- Do LZ77 process. This function uses the majority of the CPU time.
		-- @see zlib/deflate.c:deflate_fast(), zlib/deflate.c:deflate_slow()
		-- @see https://github.com/madler/zlib/blob/master/doc/algorithm.txt
		-- This function uses the algorithms used above. You should read the
		-- algorithm.txt above to understand what is the hash function and the
		-- lazy evaluation.
		--
		-- The special optimization used here is hash functions used here.
		-- The hash function is just the multiplication of the three consective
		-- characters. So if the hash matches, it guarantees 3 characters are matched.
		-- This optimization can be implemented because Lua table is a hash table.
		--
		-- @param level integer that describes compression level.
		-- @param string_table table that stores the value of string to be compressed.
		--			The index of this table starts from 1.
		--			The caller needs to make sure all values needed by this function
		--			are loaded.
		--			Assume "str" is the origin input string into the compressor
		--			str[block_start]..str[block_end+3] needs to be loaded into
		--			string_table[block_start-offset]..string_table[block_end-offset]
		--			If dictionary is presented, the last 258 bytes of the dictionary
		--			needs to be loaded into sing_table[-257..0]
		--			(See more in the description of offset.)
		-- @param hash_tables. The table key is the hash value (0<=hash<=16777216=256^3)
		--			The table value is an array0 that stores the indexes of the
		--			input data string to be compressed, such that
		--			hash == str[index]*str[index+1]*str[index+2]
		--			Indexes are ordered in this array.
		-- @param block_start The indexes of the input data string to be compressed.
		--				that starts the LZ77 block.
		-- @param block_end The indexes of the input data string to be compressed.
		--				that stores the LZ77 block.
		-- @param offset str[index] is stored in string_table[index-offset],
		--			This offset is mainly an optimization to limit the index
		--			of string_table, so lua can access this table quicker.
		-- @param dictionary See LibDeflate:CreateDictionary
		-- @return literal/LZ77_length deflate codes.
		-- @return the extra bits of literal/LZ77_length deflate codes.
		-- @return the count of each literal/LZ77 deflate code.
		-- @return LZ77 distance deflate codes.
		-- @return the extra bits of LZ77 distance deflate codes.
		-- @return the count of each LZ77 distance deflate code.
		local function GetBlockLZ77Result(level, string_table, hash_tables, block_start,
			block_end, offset, dictionary)
			local config = _compression_level_configs[level]
			local config_use_lazy
			, config_good_prev_length
			, config_max_lazy_match
			, config_nice_length
			, config_max_hash_chain =
				config[1], config[2], config[3], config[4], config[5]

			local config_max_insert_length = (not config_use_lazy)
				and config_max_lazy_match or 2147483646
			local config_good_hash_chain =
				(config_max_hash_chain-config_max_hash_chain%4/4)

			local hash

			local dict_hash_tables
			local dict_string_table
			local dict_string_len = 0

			if dictionary then
				dict_hash_tables = dictionary.hash_tables
				dict_string_table = dictionary.string_table
				dict_string_len = dictionary.strlen
				assert(block_start == 1)
				if block_end >= block_start and dict_string_len >= 2 then
					hash = dict_string_table[dict_string_len-1]*65536
						+ dict_string_table[dict_string_len]*256 + string_table[1]
					local t = hash_tables[hash]
					if not t then t = {}; hash_tables[hash] = t end
					t[#t+1] = -1
				end
				if block_end >= block_start+1 and dict_string_len >= 1 then
					hash = dict_string_table[dict_string_len]*65536
						+ string_table[1]*256 + string_table[2]
					local t = hash_tables[hash]
					if not t then t = {}; hash_tables[hash] = t end
					t[#t+1] = 0
				end
			end

			local dict_string_len_plus3 = dict_string_len + 3

			hash = (string_table[block_start-offset] or 0)*256
				+ (string_table[block_start+1-offset] or 0)

			local lcodes = {}
			local lcode_tblsize = 0
			local lcodes_counts = {}
			local dcodes = {}
			local dcodes_tblsize = 0
			local dcodes_counts = {}

			local lextra_bits = {}
			local lextra_bits_tblsize = 0
			local dextra_bits = {}
			local dextra_bits_tblsize = 0

			local match_available = false
			local prev_len
			local prev_dist
			local cur_len = 0
			local cur_dist = 0

			local index = block_start
			local index_end = block_end + (config_use_lazy and 1 or 0)

			-- the zlib source code writes separate code for lazy evaluation and
			-- not lazy evaluation, which is easier to understand.
			-- I put them together, so it is a bit harder to understand.
			-- because I think this is easier for me to maintain it.
			while (index <= index_end) do
				local string_table_index = index - offset
				local offset_minus_three = offset - 3
				prev_len = cur_len
				prev_dist = cur_dist
				cur_len = 0

				hash = (hash*256+(string_table[string_table_index+2] or 0))%16777216

				local chain_index
				local cur_chain
				local hash_chain = hash_tables[hash]
				local chain_old_size
				if not hash_chain then
					chain_old_size = 0
					hash_chain = {}
					hash_tables[hash] = hash_chain
					if dict_hash_tables then
						cur_chain = dict_hash_tables[hash]
						chain_index = cur_chain and #cur_chain or 0
					else
						chain_index = 0
					end
				else
					chain_old_size = #hash_chain
					cur_chain = hash_chain
					chain_index = chain_old_size
				end

				if index <= block_end then
					hash_chain[chain_old_size+1] = index
				end

				if (chain_index > 0 and index + 2 <= block_end
					and (not config_use_lazy or prev_len < config_max_lazy_match)) then

					local depth =
						(config_use_lazy and prev_len >= config_good_prev_length)
						and config_good_hash_chain or config_max_hash_chain

					local max_len_minus_one = block_end - index
					max_len_minus_one = (max_len_minus_one >= 257) and 257 or max_len_minus_one
					max_len_minus_one = max_len_minus_one + string_table_index
					local string_table_index_plus_three = string_table_index + 3

					while chain_index >= 1 and depth > 0 do
						local prev = cur_chain[chain_index]

						if index - prev > 32768 then
							break
						end
						if prev < index then
							local sj = string_table_index_plus_three

							if prev >= -257 then
								local pj = prev - offset_minus_three
								while (sj <= max_len_minus_one
									and string_table[pj]
									== string_table[sj]) do
									sj = sj + 1
									pj = pj + 1
								end
							else
								local pj = dict_string_len_plus3 + prev
								while (sj <= max_len_minus_one
									and dict_string_table[pj]
									== string_table[sj]) do
									sj = sj + 1
									pj = pj + 1
								end
							end
							local j = sj - string_table_index
							if j > cur_len then
								cur_len = j
								cur_dist = index - prev
							end
							if cur_len >= config_nice_length then
								break
							end
						end

						chain_index = chain_index - 1
						depth = depth - 1
						if chain_index == 0 and prev > 0 and dict_hash_tables then
							cur_chain = dict_hash_tables[hash]
							chain_index = cur_chain and #cur_chain or 0
						end
					end
				end

				if not config_use_lazy then
					prev_len, prev_dist = cur_len, cur_dist
				end
				if ((not config_use_lazy or match_available)
					and (prev_len > 3 or (prev_len == 3 and prev_dist < 4096))
					and cur_len <= prev_len )then
					local code = _length_to_deflate_code[prev_len]
					local length_extra_bits_bitlen =
						_length_to_deflate_extra_bitlen[prev_len]
					local dist_code, dist_extra_bits_bitlen, dist_extra_bits
					if prev_dist <= 256 then -- have cached code for small distance.
						dist_code = _dist256_to_deflate_code[prev_dist]
						dist_extra_bits = _dist256_to_deflate_extra_bits[prev_dist]
						dist_extra_bits_bitlen =
							_dist256_to_deflate_extra_bitlen[prev_dist]
					else
						dist_code = 16
						dist_extra_bits_bitlen = 7
						local a = 384
						local b = 512

						while true do
							if prev_dist <= a then
								dist_extra_bits = (prev_dist-(b/2)-1) % (b/4)
								break
							elseif prev_dist <= b then
								dist_extra_bits = (prev_dist-(b/2)-1) % (b/4)
								dist_code = dist_code + 1
								break
							else
								dist_code = dist_code + 2
								dist_extra_bits_bitlen = dist_extra_bits_bitlen + 1
								a = a*2
								b = b*2
							end
						end
					end
					lcode_tblsize = lcode_tblsize + 1
					lcodes[lcode_tblsize] = code
					lcodes_counts[code] = (lcodes_counts[code] or 0) + 1

					dcodes_tblsize = dcodes_tblsize + 1
					dcodes[dcodes_tblsize] = dist_code
					dcodes_counts[dist_code] = (dcodes_counts[dist_code] or 0) + 1

					if length_extra_bits_bitlen > 0 then
						local lenExtraBits = _length_to_deflate_extra_bits[prev_len]
						lextra_bits_tblsize = lextra_bits_tblsize + 1
						lextra_bits[lextra_bits_tblsize] = lenExtraBits
					end
					if dist_extra_bits_bitlen > 0 then
						dextra_bits_tblsize = dextra_bits_tblsize + 1
						dextra_bits[dextra_bits_tblsize] = dist_extra_bits
					end

					for i=index+1, index+prev_len-(config_use_lazy and 2 or 1) do
						hash = (hash*256+(string_table[i-offset+2] or 0))%16777216
						if prev_len <= config_max_insert_length then
							hash_chain = hash_tables[hash]
							if not hash_chain then
								hash_chain = {}
								hash_tables[hash] = hash_chain
							end
							hash_chain[#hash_chain+1] = i
						end
					end
					index = index + prev_len - (config_use_lazy and 1 or 0)
					match_available = false
				elseif (not config_use_lazy) or match_available then
					local code = string_table[config_use_lazy
						and (string_table_index-1) or string_table_index]
					lcode_tblsize = lcode_tblsize + 1
					lcodes[lcode_tblsize] = code
					lcodes_counts[code] = (lcodes_counts[code] or 0) + 1
					index = index + 1
				else
					match_available = true
					index = index + 1
				end
			end

			-- Write "end of block" symbol
			lcode_tblsize = lcode_tblsize + 1
			lcodes[lcode_tblsize] = 256
			lcodes_counts[256] = (lcodes_counts[256] or 0) + 1

			return lcodes, lextra_bits, lcodes_counts, dcodes, dextra_bits
			, dcodes_counts
		end

		-- Get the header data of dynamic block.
		-- @param lcodes_count The count of each literal/LZ77_length codes.
		-- @param dcodes_count The count of each Lz77 distance codes.
		-- @return a lots of stuffs.
		-- @see RFC1951 Page 12
		local function GetBlockDynamicHuffmanHeader(lcodes_counts, dcodes_counts)
			local lcodes_huffman_bitlens, lcodes_huffman_codes
			, max_non_zero_bitlen_lcode =
				GetHuffmanBitlenAndCode(lcodes_counts, 15, 285)
			local dcodes_huffman_bitlens, dcodes_huffman_codes
			, max_non_zero_bitlen_dcode =
				GetHuffmanBitlenAndCode(dcodes_counts, 15, 29)

			local rle_deflate_codes, rle_extra_bits, rle_codes_counts =
				RunLengthEncodeHuffmanBitlen(lcodes_huffman_bitlens
					,max_non_zero_bitlen_lcode, dcodes_huffman_bitlens
					, max_non_zero_bitlen_dcode)

			local rle_codes_huffman_bitlens, rle_codes_huffman_codes =
				GetHuffmanBitlenAndCode(rle_codes_counts, 7, 18)

			local HCLEN = 0
			for i = 1, 19 do
				local symbol = _rle_codes_huffman_bitlen_order[i]
				local length = rle_codes_huffman_bitlens[symbol] or 0
				if length ~= 0 then
					HCLEN = i
				end
			end

			HCLEN = HCLEN - 4
			local HLIT = max_non_zero_bitlen_lcode + 1 - 257
			local HDIST = max_non_zero_bitlen_dcode + 1 - 1
			if HDIST < 0 then HDIST = 0 end

			return HLIT, HDIST, HCLEN, rle_codes_huffman_bitlens
			, rle_codes_huffman_codes, rle_deflate_codes, rle_extra_bits
			, lcodes_huffman_bitlens, lcodes_huffman_codes
			, dcodes_huffman_bitlens, dcodes_huffman_codes
		end

		-- Get the size of dynamic block without writing any bits into the writer.
		-- @param ... Read the source code of GetBlockDynamicHuffmanHeader()
		-- @return the bit length of the dynamic block
		local function GetDynamicHuffmanBlockSize(lcodes, dcodes, HCLEN
			, rle_codes_huffman_bitlens, rle_deflate_codes
			, lcodes_huffman_bitlens, dcodes_huffman_bitlens)

			local block_bitlen = 17 -- 1+2+5+5+4
			block_bitlen = block_bitlen + (HCLEN+4)*3

			for i = 1, #rle_deflate_codes do
				local code = rle_deflate_codes[i]
				block_bitlen = block_bitlen + rle_codes_huffman_bitlens[code]
				if code >= 16 then
					block_bitlen = block_bitlen +
						((code == 16) and 2 or (code == 17 and 3 or 7))
				end
			end

			local length_code_count = 0
			for i = 1, #lcodes do
				local code = lcodes[i]
				local huffman_bitlen = lcodes_huffman_bitlens[code]
				block_bitlen = block_bitlen + huffman_bitlen
				if code > 256 then -- Length code
					length_code_count = length_code_count + 1
					if code > 264 and code < 285 then -- Length code with extra bits
						local extra_bits_bitlen =
							_literal_deflate_code_to_extra_bitlen[code-256]
						block_bitlen = block_bitlen + extra_bits_bitlen
					end
					local dist_code = dcodes[length_code_count]
					local dist_huffman_bitlen = dcodes_huffman_bitlens[dist_code]
					block_bitlen = block_bitlen + dist_huffman_bitlen

					if dist_code > 3 then -- dist code with extra bits
						local dist_extra_bits_bitlen = (dist_code-dist_code%2)/2 - 1
						block_bitlen = block_bitlen + dist_extra_bits_bitlen
					end
				end
			end
			return block_bitlen
		end

		-- Write dynamic block.
		-- @param ... Read the source code of GetBlockDynamicHuffmanHeader()
		local function CompressDynamicHuffmanBlock(WriteBits, is_last_block
			, lcodes, lextra_bits, dcodes, dextra_bits, HLIT, HDIST, HCLEN
			, rle_codes_huffman_bitlens, rle_codes_huffman_codes
			, rle_deflate_codes, rle_extra_bits
			, lcodes_huffman_bitlens, lcodes_huffman_codes
			, dcodes_huffman_bitlens, dcodes_huffman_codes)

			WriteBits(is_last_block and 1 or 0, 1) -- Last block identifier
			WriteBits(2, 2) -- Dynamic Huffman block identifier

			WriteBits(HLIT, 5)
			WriteBits(HDIST, 5)
			WriteBits(HCLEN, 4)

			for i = 1, HCLEN+4 do
				local symbol = _rle_codes_huffman_bitlen_order[i]
				local length = rle_codes_huffman_bitlens[symbol] or 0
				WriteBits(length, 3)
			end

			local rleExtraBitsIndex = 1
			for i=1, #rle_deflate_codes do
				local code = rle_deflate_codes[i]
				WriteBits(rle_codes_huffman_codes[code]
					, rle_codes_huffman_bitlens[code])
				if code >= 16 then
					local extraBits = rle_extra_bits[rleExtraBitsIndex]
					WriteBits(extraBits, (code == 16) and 2 or (code == 17 and 3 or 7))
					rleExtraBitsIndex = rleExtraBitsIndex + 1
				end
			end

			local length_code_count = 0
			local length_code_with_extra_count = 0
			local dist_code_with_extra_count = 0

			for i=1, #lcodes do
				local deflate_codee = lcodes[i]
				local huffman_code = lcodes_huffman_codes[deflate_codee]
				local huffman_bitlen = lcodes_huffman_bitlens[deflate_codee]
				WriteBits(huffman_code, huffman_bitlen)
				if deflate_codee > 256 then -- Length code
					length_code_count = length_code_count + 1
					if deflate_codee > 264 and deflate_codee < 285 then
						-- Length code with extra bits
						length_code_with_extra_count = length_code_with_extra_count + 1
						local extra_bits = lextra_bits[length_code_with_extra_count]
						local extra_bits_bitlen =
							_literal_deflate_code_to_extra_bitlen[deflate_codee-256]
						WriteBits(extra_bits, extra_bits_bitlen)
					end
					-- Write distance code
					local dist_deflate_code = dcodes[length_code_count]
					local dist_huffman_code = dcodes_huffman_codes[dist_deflate_code]
					local dist_huffman_bitlen =
						dcodes_huffman_bitlens[dist_deflate_code]
					WriteBits(dist_huffman_code, dist_huffman_bitlen)

					if dist_deflate_code > 3 then -- dist code with extra bits
						dist_code_with_extra_count = dist_code_with_extra_count + 1
						local dist_extra_bits = dextra_bits[dist_code_with_extra_count]
						local dist_extra_bits_bitlen =
							(dist_deflate_code-dist_deflate_code%2)/2 - 1
						WriteBits(dist_extra_bits, dist_extra_bits_bitlen)
					end
				end
			end
		end

		-- Get the size of fixed block without writing any bits into the writer.
		-- @param lcodes literal/LZ77_length deflate codes
		-- @param decodes LZ77 distance deflate codes
		-- @return the bit length of the fixed block
		local function GetFixedHuffmanBlockSize(lcodes, dcodes)
			local block_bitlen = 3
			local length_code_count = 0
			for i=1, #lcodes do
				local code = lcodes[i]
				local huffman_bitlen = _fix_block_literal_huffman_bitlen[code]
				block_bitlen = block_bitlen + huffman_bitlen
				if code > 256 then -- Length code
					length_code_count = length_code_count + 1
					if code > 264 and code < 285 then -- Length code with extra bits
						local extra_bits_bitlen =
							_literal_deflate_code_to_extra_bitlen[code-256]
						block_bitlen = block_bitlen + extra_bits_bitlen
					end
					local dist_code = dcodes[length_code_count]
					block_bitlen = block_bitlen + 5

					if dist_code > 3 then -- dist code with extra bits
						local dist_extra_bits_bitlen =
							(dist_code-dist_code%2)/2 - 1
						block_bitlen = block_bitlen + dist_extra_bits_bitlen
					end
				end
			end
			return block_bitlen
		end

		-- Write fixed block.
		-- @param lcodes literal/LZ77_length deflate codes
		-- @param decodes LZ77 distance deflate codes
		local function CompressFixedHuffmanBlock(WriteBits, is_last_block,
			lcodes, lextra_bits, dcodes, dextra_bits)
			WriteBits(is_last_block and 1 or 0, 1) -- Last block identifier
			WriteBits(1, 2) -- Fixed Huffman block identifier
			local length_code_count = 0
			local length_code_with_extra_count = 0
			local dist_code_with_extra_count = 0
			for i=1, #lcodes do
				local deflate_code = lcodes[i]
				local huffman_code = _fix_block_literal_huffman_code[deflate_code]
				local huffman_bitlen = _fix_block_literal_huffman_bitlen[deflate_code]
				WriteBits(huffman_code, huffman_bitlen)
				if deflate_code > 256 then -- Length code
					length_code_count = length_code_count + 1
					if deflate_code > 264 and deflate_code < 285 then
						-- Length code with extra bits
						length_code_with_extra_count = length_code_with_extra_count + 1
						local extra_bits = lextra_bits[length_code_with_extra_count]
						local extra_bits_bitlen =
							_literal_deflate_code_to_extra_bitlen[deflate_code-256]
						WriteBits(extra_bits, extra_bits_bitlen)
					end
					-- Write distance code
					local dist_code = dcodes[length_code_count]
					local dist_huffman_code = _fix_block_dist_huffman_code[dist_code]
					WriteBits(dist_huffman_code, 5)

					if dist_code > 3 then -- dist code with extra bits
						dist_code_with_extra_count = dist_code_with_extra_count + 1
						local dist_extra_bits = dextra_bits[dist_code_with_extra_count]
						local dist_extra_bits_bitlen = (dist_code-dist_code%2)/2 - 1
						WriteBits(dist_extra_bits, dist_extra_bits_bitlen)
					end
				end
			end
		end

		-- Get the size of store block without writing any bits into the writer.
		-- @param block_start The start index of the origin input string
		-- @param block_end The end index of the origin input string
		-- @param Total bit lens had been written into the compressed result before,
		-- because store block needs to shift to byte boundary.
		-- @return the bit length of the fixed block
		local function GetStoreBlockSize(block_start, block_end, total_bitlen)
			assert(block_end-block_start+1 <= 65535)
			local block_bitlen = 3
			total_bitlen = total_bitlen + 3
			local padding_bitlen = (8-total_bitlen%8)%8
			block_bitlen = block_bitlen + padding_bitlen
			block_bitlen = block_bitlen + 32
			block_bitlen = block_bitlen + (block_end - block_start + 1) * 8
			return block_bitlen
		end

		-- Write the store block.
		-- @param ... lots of stuffs
		-- @return nil
		local function CompressStoreBlock(WriteBits, WriteString, is_last_block, str
			, block_start, block_end, total_bitlen)
			assert(block_end-block_start+1 <= 65535)
			WriteBits(is_last_block and 1 or 0, 1) -- Last block identifer.
			WriteBits(0, 2) -- Store block identifier.
			total_bitlen = total_bitlen + 3
			local padding_bitlen = (8-total_bitlen%8)%8
			if padding_bitlen > 0 then
				WriteBits(_pow2[padding_bitlen]-1, padding_bitlen)
			end
			local size = block_end - block_start + 1
			WriteBits(size, 16)

			-- Write size's one's complement
			local comp = (255 - size % 256) + (255 - (size-size%256)/256)*256
			WriteBits(comp, 16)

			WriteString(str:sub(block_start, block_end))
		end

		-- Do the deflate
		-- Currently using a simple way to determine the block size
		-- (This is why the compression ratio is little bit worse than zlib when
		-- the input size is very large
		-- The first block is 64KB, the following block is 32KB.
		-- After each block, there is a memory cleanup operation.
		-- This is not a fast operation, but it is needed to save memory usage, so
		-- the memory usage does not grow unboundly. If the data size is less than
		-- 64KB, then memory cleanup won't happen.
		-- This function determines whether to use store/fixed/dynamic blocks by
		-- calculating the block size of each block type and chooses the smallest one.
		local function Deflate(configs, WriteBits, WriteString, FlushWriter, str
			, dictionary)
			local string_table = {}
			local hash_tables = {}
			local is_last_block = nil
			local block_start
			local block_end
			local bitlen_written
			local total_bitlen = FlushWriter(_FLUSH_MODE_NO_FLUSH)
			local strlen = #str
			local offset

			local level
			local strategy
			if configs then
				if configs.level then
					level = configs.level
				end
				if configs.strategy then
					strategy = configs.strategy
				end
			end

			if not level then
				if strlen < 2048 then
					level = 7
				elseif strlen > 65536 then
					level = 3
				else
					level = 5
				end
			end

			while not is_last_block do
				if not block_start then
					block_start = 1
					block_end = 64*1024 - 1
					offset = 0
				else
					block_start = block_end + 1
					block_end = block_end + 32*1024
					offset = block_start - 32*1024 - 1
				end

				if block_end >= strlen then
					block_end = strlen
					is_last_block = true
				else
					is_last_block = false
				end

				local lcodes, lextra_bits, lcodes_counts, dcodes, dextra_bits
				, dcodes_counts

				local HLIT, HDIST, HCLEN, rle_codes_huffman_bitlens
				, rle_codes_huffman_codes, rle_deflate_codes
				, rle_extra_bits, lcodes_huffman_bitlens, lcodes_huffman_codes
				, dcodes_huffman_bitlens, dcodes_huffman_codes

				local dynamic_block_bitlen
				local fixed_block_bitlen
				local store_block_bitlen

				if level ~= 0 then

					-- GetBlockLZ77 needs block_start to block_end+3 to be loaded.
					LoadStringToTable(str, string_table, block_start, block_end + 3
						, offset)
					if block_start == 1 and dictionary then
						local dict_string_table = dictionary.string_table
						local dict_strlen = dictionary.strlen
						for i=0, (-dict_strlen+1)<-257
							and -257 or (-dict_strlen+1), -1 do
							string_table[i] = dict_string_table[dict_strlen+i]
						end
					end

					if strategy == "huffman_only" then
						lcodes = {}
						LoadStringToTable(str, lcodes, block_start, block_end
							, block_start-1)
						lextra_bits = {}
						lcodes_counts = {}
						lcodes[block_end - block_start+2] = 256 -- end of block
						for i=1, block_end - block_start+2 do
							local code = lcodes[i]
							lcodes_counts[code] = (lcodes_counts[code] or 0) + 1
						end
						dcodes = {}
						dextra_bits = {}
						dcodes_counts = {}
					else
						lcodes, lextra_bits, lcodes_counts, dcodes, dextra_bits
						, dcodes_counts = GetBlockLZ77Result(level, string_table
							, hash_tables, block_start, block_end, offset, dictionary
						)
					end

					HLIT, HDIST, HCLEN, rle_codes_huffman_bitlens
					, rle_codes_huffman_codes, rle_deflate_codes
					, rle_extra_bits, lcodes_huffman_bitlens, lcodes_huffman_codes
					, dcodes_huffman_bitlens, dcodes_huffman_codes =
						GetBlockDynamicHuffmanHeader(lcodes_counts, dcodes_counts)
					dynamic_block_bitlen = GetDynamicHuffmanBlockSize(
						lcodes, dcodes, HCLEN, rle_codes_huffman_bitlens
						, rle_deflate_codes, lcodes_huffman_bitlens
						, dcodes_huffman_bitlens)
					fixed_block_bitlen = GetFixedHuffmanBlockSize(lcodes, dcodes)
				end

				store_block_bitlen = GetStoreBlockSize(block_start, block_end
					, total_bitlen)

				local min_bitlen = store_block_bitlen
				min_bitlen = (fixed_block_bitlen and fixed_block_bitlen < min_bitlen)
					and fixed_block_bitlen or min_bitlen
				min_bitlen = (dynamic_block_bitlen
					and dynamic_block_bitlen < min_bitlen)
					and dynamic_block_bitlen or min_bitlen

				if level == 0 or (strategy ~= "fixed" and strategy ~= "dynamic" and
					store_block_bitlen == min_bitlen) then
					CompressStoreBlock(WriteBits, WriteString, is_last_block
						, str, block_start, block_end, total_bitlen)
					total_bitlen = total_bitlen + store_block_bitlen
				elseif strategy ~= "dynamic" and (
					strategy == "fixed" or fixed_block_bitlen == min_bitlen) then
					CompressFixedHuffmanBlock(WriteBits, is_last_block,
						lcodes, lextra_bits, dcodes, dextra_bits)
					total_bitlen = total_bitlen + fixed_block_bitlen
				elseif strategy == "dynamic" or dynamic_block_bitlen == min_bitlen then
					CompressDynamicHuffmanBlock(WriteBits, is_last_block, lcodes
						, lextra_bits, dcodes, dextra_bits, HLIT, HDIST, HCLEN
						, rle_codes_huffman_bitlens, rle_codes_huffman_codes
						, rle_deflate_codes, rle_extra_bits
						, lcodes_huffman_bitlens, lcodes_huffman_codes
						, dcodes_huffman_bitlens, dcodes_huffman_codes)
					total_bitlen = total_bitlen + dynamic_block_bitlen
				end

				if is_last_block then
					bitlen_written = FlushWriter(_FLUSH_MODE_NO_FLUSH)
				else
					bitlen_written = FlushWriter(_FLUSH_MODE_MEMORY_CLEANUP)
				end

				assert(bitlen_written == total_bitlen)

				-- Memory clean up, so memory consumption does not always grow linearly
				-- , even if input string is > 64K.
				-- Not a very efficient operation, but this operation won't happen
				-- when the input data size is less than 64K.
				if not is_last_block then
					local j
					if dictionary and block_start == 1 then
						j = 0
						while (string_table[j]) do
							string_table[j] = nil
							j = j - 1
						end
					end
					dictionary = nil
					j = 1
					for i = block_end-32767, block_end do
						string_table[j] = string_table[i-offset]
						j = j + 1
					end

					for k, t in pairs(hash_tables) do
						local tSize = #t
						if tSize > 0 and block_end+1 - t[1] > 32768 then
							if tSize == 1 then
								hash_tables[k] = nil
							else
								local new = {}
								local newSize = 0
								for i = 2, tSize do
									j = t[i]
									if block_end+1 - j <= 32768 then
										newSize = newSize + 1
										new[newSize] = j
									end
								end
								hash_tables[k] = new
							end
						end
					end
				end
			end
		end

		--- The description to compression configuration table. <br>
		-- Any field can be nil to use its default. <br>
		-- Table with keys other than those below is an invalid table.
		-- @class table
		-- @name compression_configs
		-- @field level The compression level ranged from 0 to 9. 0 is no compression.
		-- 9 is the slowest but best compression. Use nil for default level.
		-- @field strategy The compression strategy. "fixed" to only use fixed deflate
		-- compression block. "dynamic" to only use dynamic block. "huffman_only" to
		-- do no LZ77 compression. Only do huffman compression.


		-- @see LibDeflate:CompressDeflate(str, configs)
		-- @see LibDeflate:CompressDeflateWithDict(str, dictionary, configs)
		local function CompressDeflateInternal(str, dictionary, configs)
			local WriteBits, WriteString, FlushWriter = CreateWriter()
			Deflate(configs, WriteBits, WriteString, FlushWriter, str, dictionary)
			local total_bitlen, result = FlushWriter(_FLUSH_MODE_OUTPUT)
			local padding_bitlen = (8-total_bitlen%8)%8
			return result, padding_bitlen
		end

		-- @see LibDeflate:CompressZlib
		-- @see LibDeflate:CompressZlibWithDict
		local function CompressZlibInternal(str, dictionary, configs)
			local WriteBits, WriteString, FlushWriter = CreateWriter()

			local CM = 8 -- Compression method
			local CINFO = 7 --Window Size = 32K
			local CMF = CINFO*16+CM
			WriteBits(CMF, 8)

			local FDIST = dictionary and 1 or 0
			local FLEVEL = 2 -- Default compression
			local FLG = FLEVEL*64+FDIST*32
			local FCHECK = (31-(CMF*256+FLG)%31)
			-- The FCHECK value must be such that CMF and FLG,
			-- when viewed as a 16-bit unsigned integer stored
			-- in MSB order (CMF*256 + FLG), is a multiple of 31.
			FLG = FLG + FCHECK
			WriteBits(FLG, 8)

			if FDIST == 1 then
				local adler32 = dictionary.adler32
				local byte0 = adler32 % 256
				adler32 = (adler32 - byte0) / 256
				local byte1 = adler32 % 256
				adler32 = (adler32 - byte1) / 256
				local byte2 = adler32 % 256
				adler32 = (adler32 - byte2) / 256
				local byte3 = adler32 % 256
				WriteBits(byte3, 8)
				WriteBits(byte2, 8)
				WriteBits(byte1, 8)
				WriteBits(byte0, 8)
			end

			Deflate(configs, WriteBits, WriteString, FlushWriter, str, dictionary)
			FlushWriter(_FLUSH_MODE_BYTE_BOUNDARY)

			local adler32 = LibDeflate:Adler32(str)

			-- Most significant byte first
			local byte3 = adler32%256
			adler32 = (adler32 - byte3) / 256
			local byte2 = adler32%256
			adler32 = (adler32 - byte2) / 256
			local byte1 = adler32%256
			adler32 = (adler32 - byte1) / 256
			local byte0 = adler32%256

			WriteBits(byte0, 8)
			WriteBits(byte1, 8)
			WriteBits(byte2, 8)
			WriteBits(byte3, 8)
			local total_bitlen, result = FlushWriter(_FLUSH_MODE_OUTPUT)
			local padding_bitlen = (8-total_bitlen%8)%8
			return result, padding_bitlen
		end

		--- Compress using the raw deflate format.
		-- @param str [string] The data to be compressed.
		-- @param configs [table/nil] The configuration table to control the compression
		-- . If nil, use the default configuration.
		-- @return [string] The compressed data.
		-- @return [integer] The number of bits padded at the end of output.
		-- 0 <= bits < 8  <br>
		-- This means the most significant "bits" of the last byte of the returned
		-- compressed data are padding bits and they don't affect decompression.
		-- You don't need to use this value unless you want to do some postprocessing
		-- to the compressed data.
		-- @see compression_configs
		-- @see LibDeflate:DecompressDeflate
		function LibDeflate:CompressDeflate(str, configs)
			local arg_valid, arg_err = IsValidArguments(str, false, nil, true, configs)
			if not arg_valid then
				error(("Usage: LibDeflate:CompressDeflate(str, configs): "
					..arg_err), 2)
			end
			return CompressDeflateInternal(str, nil, configs)
		end

		--- Compress using the raw deflate format with a preset dictionary.
		-- @param str [string] The data to be compressed.
		-- @param dictionary [table] The preset dictionary produced by
		-- LibDeflate:CreateDictionary
		-- @param configs [table/nil] The configuration table to control the compression
		-- . If nil, use the default configuration.
		-- @return [string] The compressed data.
		-- @return [integer] The number of bits padded at the end of output.
		-- 0 <= bits < 8  <br>
		-- This means the most significant "bits" of the last byte of the returned
		-- compressed data are padding bits and they don't affect decompression.
		-- You don't need to use this value unless you want to do some postprocessing
		-- to the compressed data.
		-- @see compression_configs
		-- @see LibDeflate:CreateDictionary
		-- @see LibDeflate:DecompressDeflateWithDict
		function LibDeflate:CompressDeflateWithDict(str, dictionary, configs)
			local arg_valid, arg_err = IsValidArguments(str, true, dictionary
				, true, configs)
			if not arg_valid then
				error(("Usage: LibDeflate:CompressDeflateWithDict"
					.."(str, dictionary, configs): "
					..arg_err), 2)
			end
			return CompressDeflateInternal(str, dictionary, configs)
		end

		--- Compress using the zlib format.
		-- @param str [string] the data to be compressed.
		-- @param configs [table/nil] The configuration table to control the compression
		-- . If nil, use the default configuration.
		-- @return [string] The compressed data.
		-- @return [integer] The number of bits padded at the end of output.
		-- Should always be 0.
		-- Zlib formatted compressed data never has padding bits at the end.
		-- @see compression_configs
		-- @see LibDeflate:DecompressZlib
		function LibDeflate:CompressZlib(str, configs)
			local arg_valid, arg_err = IsValidArguments(str, false, nil, true, configs)
			if not arg_valid then
				error(("Usage: LibDeflate:CompressZlib(str, configs): "
					..arg_err), 2)
			end
			return CompressZlibInternal(str, nil, configs)
		end

		--- Compress using the zlib format with a preset dictionary.
		-- @param str [string] the data to be compressed.
		-- @param dictionary [table] A preset dictionary produced
		-- by LibDeflate:CreateDictionary()
		-- @param configs [table/nil] The configuration table to control the compression
		-- . If nil, use the default configuration.
		-- @return [string] The compressed data.
		-- @return [integer] The number of bits padded at the end of output.
		-- Should always be 0.
		-- Zlib formatted compressed data never has padding bits at the end.
		-- @see compression_configs
		-- @see LibDeflate:CreateDictionary
		-- @see LibDeflate:DecompressZlibWithDict
		function LibDeflate:CompressZlibWithDict(str, dictionary, configs)
			local arg_valid, arg_err = IsValidArguments(str, true, dictionary
				, true, configs)
			if not arg_valid then
				error(("Usage: LibDeflate:CompressZlibWithDict"
					.."(str, dictionary, configs): "
					..arg_err), 2)
			end
			return CompressZlibInternal(str, dictionary, configs)
		end

--[[ --------------------------------------------------------------------------
	Decompress code
--]] --------------------------------------------------------------------------

--[[
	Create a reader to easily reader stuffs as the unit of bits.
	Return values:
	1. ReadBits(bitlen)
	2. ReadBytes(bytelen, buffer, buffer_size)
	3. Decode(huffman_bitlen_count, huffman_symbol, min_bitlen)
	4. ReaderBitlenLeft()
	5. SkipToByteBoundary()
--]]
		local function CreateReader(input_string)
			local input = input_string
			local input_strlen = #input_string
			local input_next_byte_pos = 1
			local cache_bitlen = 0
			local cache = 0

			-- Read some bits.
			-- To improve speed, this function does not
			-- check if the input has been exhausted.
			-- Use ReaderBitlenLeft() < 0 to check it.
			-- @param bitlen the number of bits to read
			-- @return the data is read.
			local function ReadBits(bitlen)
				local rshift_mask = _pow2[bitlen]
				local code
				if bitlen <= cache_bitlen then
					code = cache % rshift_mask
					cache = (cache - code) / rshift_mask
					cache_bitlen = cache_bitlen - bitlen
				else -- Whether input has been exhausted is not checked.
					local lshift_mask = _pow2[cache_bitlen]
					local byte1, byte2, byte3, byte4 = string_byte(input
						, input_next_byte_pos, input_next_byte_pos+3)
					-- This requires lua number to be at least double ()
					cache = cache + ((byte1 or 0)+(byte2 or 0)*256
						+ (byte3 or 0)*65536+(byte4 or 0)*16777216)*lshift_mask
					input_next_byte_pos = input_next_byte_pos + 4
					cache_bitlen = cache_bitlen + 32 - bitlen
					code = cache % rshift_mask
					cache = (cache - code) / rshift_mask
				end
				return code
			end

			-- Read some bytes from the reader.
			-- Assume reader is on the byte boundary.
			-- @param bytelen The number of bytes to be read.
			-- @param buffer The byte read will be stored into this buffer.
			-- @param buffer_size The buffer will be modified starting from
			--	buffer[buffer_size+1], ending at buffer[buffer_size+bytelen-1]
			-- @return the new buffer_size
			local function ReadBytes(bytelen, buffer, buffer_size)
				assert(cache_bitlen % 8 == 0)

				local byte_from_cache = (cache_bitlen/8 < bytelen)
					and (cache_bitlen/8) or bytelen
				for _=1, byte_from_cache do
					local byte = cache % 256
					buffer_size = buffer_size + 1
					buffer[buffer_size] = string_char(byte)
					cache = (cache - byte) / 256
				end
				cache_bitlen = cache_bitlen - byte_from_cache*8
				bytelen = bytelen - byte_from_cache
				if (input_strlen - input_next_byte_pos - bytelen + 1) * 8
					+ cache_bitlen < 0 then
					return -1 -- out of input
				end
				for i=input_next_byte_pos, input_next_byte_pos+bytelen-1 do
					buffer_size = buffer_size + 1
					buffer[buffer_size] = string_sub(input, i, i)
				end

				input_next_byte_pos = input_next_byte_pos + bytelen
				return buffer_size
			end

			-- Decode huffman code
			-- To improve speed, this function does not check
			-- if the input has been exhausted.
			-- Use ReaderBitlenLeft() < 0 to check it.
			-- Credits for Mark Adler. This code is from puff:Decode()
			-- @see puff:Decode(...)
			-- @param huffman_bitlen_count
			-- @param huffman_symbol
			-- @param min_bitlen The minimum huffman bit length of all symbols
			-- @return The decoded deflate code.
			--	Negative value is returned if decoding fails.
			local function Decode(huffman_bitlen_counts, huffman_symbols, min_bitlen)
				local code = 0
				local first = 0
				local index = 0
				local count
				if min_bitlen > 0 then
					if cache_bitlen < 15 and input then
						local lshift_mask = _pow2[cache_bitlen]
						local byte1, byte2, byte3, byte4 =
							string_byte(input, input_next_byte_pos
								, input_next_byte_pos+3)
						-- This requires lua number to be at least double ()
						cache = cache + ((byte1 or 0)+(byte2 or 0)*256
							+(byte3 or 0)*65536+(byte4 or 0)*16777216)*lshift_mask
						input_next_byte_pos = input_next_byte_pos + 4
						cache_bitlen = cache_bitlen + 32
					end

					local rshift_mask = _pow2[min_bitlen]
					cache_bitlen = cache_bitlen - min_bitlen
					code = cache % rshift_mask
					cache = (cache - code) / rshift_mask
					-- Reverse the bits
					code = _reverse_bits_tbl[min_bitlen][code]

					count = huffman_bitlen_counts[min_bitlen]
					if code < count then
						return huffman_symbols[code]
					end
					index = count
					first = count * 2
					code = code * 2
				end

				for bitlen = min_bitlen+1, 15 do
					local bit
					bit = cache % 2
					cache = (cache - bit) / 2
					cache_bitlen = cache_bitlen - 1

					code = (bit==1) and (code + 1 - code % 2) or code
					count = huffman_bitlen_counts[bitlen] or 0
					local diff = code - first
					if diff < count then
						return huffman_symbols[index + diff]
					end
					index = index + count
					first = first + count
					first = first * 2
					code = code * 2
				end
				-- invalid literal/length or distance code
				-- in fixed or dynamic block (run out of code)
				return -10
			end

			local function ReaderBitlenLeft()
				return (input_strlen - input_next_byte_pos + 1) * 8 + cache_bitlen
			end

			local function SkipToByteBoundary()
				local skipped_bitlen = cache_bitlen%8
				local rshift_mask = _pow2[skipped_bitlen]
				cache_bitlen = cache_bitlen - skipped_bitlen
				cache = (cache - cache % rshift_mask) / rshift_mask
			end

			return ReadBits, ReadBytes, Decode, ReaderBitlenLeft, SkipToByteBoundary
		end

		-- Create a deflate state, so I can pass in less arguments to functions.
		-- @param str the whole string to be decompressed.
		-- @param dictionary The preset dictionary. nil if not provided.
		--		This dictionary should be produced by LibDeflate:CreateDictionary(str)
		-- @return The decomrpess state.
		local function CreateDecompressState(str, dictionary)
			local ReadBits, ReadBytes, Decode, ReaderBitlenLeft
			, SkipToByteBoundary = CreateReader(str)
			local state =
				{
					ReadBits = ReadBits,
					ReadBytes = ReadBytes,
					Decode = Decode,
					ReaderBitlenLeft = ReaderBitlenLeft,
					SkipToByteBoundary = SkipToByteBoundary,
					buffer_size = 0,
					buffer = {},
					result_buffer = {},
					dictionary = dictionary,
				}
			return state
		end

		-- Get the stuffs needed to decode huffman codes
		-- @see puff.c:construct(...)
		-- @param huffman_bitlen The huffman bit length of the huffman codes.
		-- @param max_symbol The maximum symbol
		-- @param max_bitlen The min huffman bit length of all codes
		-- @return zero or positive for success, negative for failure.
		-- @return The count of each huffman bit length.
		-- @return A table to convert huffman codes to deflate codes.
		-- @return The minimum huffman bit length.
		local function GetHuffmanForDecode(huffman_bitlens, max_symbol, max_bitlen)
			local huffman_bitlen_counts = {}
			local min_bitlen = max_bitlen
			for symbol = 0, max_symbol do
				local bitlen = huffman_bitlens[symbol] or 0
				min_bitlen = (bitlen > 0 and bitlen < min_bitlen)
					and bitlen or min_bitlen
				huffman_bitlen_counts[bitlen] = (huffman_bitlen_counts[bitlen] or 0)+1
			end

			if huffman_bitlen_counts[0] == max_symbol+1 then -- No Codes
				return 0, huffman_bitlen_counts, {}, 0 -- Complete, but decode will fail
			end

			local left = 1
			for len = 1, max_bitlen do
				left = left * 2
				left = left - (huffman_bitlen_counts[len] or 0)
				if left < 0 then
					return left -- Over-subscribed, return negative
				end
			end

			-- Generate offsets info symbol table for each length for sorting
			local offsets = {}
			offsets[1] = 0
			for len = 1, max_bitlen-1 do
				offsets[len + 1] = offsets[len] + (huffman_bitlen_counts[len] or 0)
			end

			local huffman_symbols = {}
			for symbol = 0, max_symbol do
				local bitlen = huffman_bitlens[symbol] or 0
				if bitlen ~= 0 then
					local offset = offsets[bitlen]
					huffman_symbols[offset] = symbol
					offsets[bitlen] = offsets[bitlen] + 1
				end
			end

			-- Return zero for complete set, positive for incomplete set.
			return left, huffman_bitlen_counts, huffman_symbols, min_bitlen
		end

		-- Decode a fixed or dynamic huffman blocks, excluding last block identifier
		-- and block type identifer.
		-- @see puff.c:codes()
		-- @param state decompression state that will be modified by this function.
		--	@see CreateDecompressState
		-- @param ... Read the source code
		-- @return 0 on success, other value on failure.
		local function DecodeUntilEndOfBlock(state, lcodes_huffman_bitlens
			, lcodes_huffman_symbols, lcodes_huffman_min_bitlen
			, dcodes_huffman_bitlens, dcodes_huffman_symbols
			, dcodes_huffman_min_bitlen)
			local buffer, buffer_size, ReadBits, Decode, ReaderBitlenLeft
			, result_buffer =
				state.buffer, state.buffer_size, state.ReadBits, state.Decode
			, state.ReaderBitlenLeft, state.result_buffer
			local dictionary = state.dictionary
			local dict_string_table
			local dict_strlen

			local buffer_end = 1
			if dictionary and not buffer[0] then
				-- If there is a dictionary, copy the last 258 bytes into
				-- the string_table to make the copy in the main loop quicker.
				-- This is done only once per decompression.
				dict_string_table = dictionary.string_table
				dict_strlen = dictionary.strlen
				buffer_end = -dict_strlen + 1
				for i=0, (-dict_strlen+1)<-257 and -257 or (-dict_strlen+1), -1 do
					buffer[i] = _byte_to_char[dict_string_table[dict_strlen+i]]
				end
			end

			repeat
				local symbol = Decode(lcodes_huffman_bitlens
					, lcodes_huffman_symbols, lcodes_huffman_min_bitlen)
				if symbol < 0 or symbol > 285 then
					-- invalid literal/length or distance code in fixed or dynamic block
					return -10
				elseif symbol < 256 then -- Literal
					buffer_size = buffer_size + 1
					buffer[buffer_size] = _byte_to_char[symbol]
				elseif symbol > 256 then -- Length code
					symbol = symbol - 256
					local bitlen = _literal_deflate_code_to_base_len[symbol]
					bitlen = (symbol >= 8)
						and (bitlen
							+ ReadBits(_literal_deflate_code_to_extra_bitlen[symbol]))
						or bitlen
					symbol = Decode(dcodes_huffman_bitlens, dcodes_huffman_symbols
						, dcodes_huffman_min_bitlen)
					if symbol < 0 or symbol > 29 then
						-- invalid literal/length or distance code in fixed or dynamic block
						return -10
					end
					local dist = _dist_deflate_code_to_base_dist[symbol]
					dist = (dist > 4) and (dist
						+ ReadBits(_dist_deflate_code_to_extra_bitlen[symbol])) or dist

					local char_buffer_index = buffer_size-dist+1
					if char_buffer_index < buffer_end then
						-- distance is too far back in fixed or dynamic block
						return -11
					end
					if char_buffer_index >= -257 then
						for _=1, bitlen do
							buffer_size = buffer_size + 1
							buffer[buffer_size] = buffer[char_buffer_index]
							char_buffer_index = char_buffer_index + 1
						end
					else
						char_buffer_index = dict_strlen + char_buffer_index
						for _=1, bitlen do
							buffer_size = buffer_size + 1
							buffer[buffer_size] =
								_byte_to_char[dict_string_table[char_buffer_index]]
							char_buffer_index = char_buffer_index + 1
						end
					end
				end

				if ReaderBitlenLeft() < 0 then
					return 2 -- available inflate data did not terminate
				end

				if buffer_size >= 65536 then
					result_buffer[#result_buffer+1] =
						table_concat(buffer, "", 1, 32768)
					for i=32769, buffer_size do
						buffer[i-32768] = buffer[i]
					end
					buffer_size = buffer_size - 32768
					buffer[buffer_size+1] = nil
					-- NOTE: buffer[32769..end] and buffer[-257..0] are not cleared.
					-- This is why "buffer_size" variable is needed.
				end
			until symbol == 256

			state.buffer_size = buffer_size

			return 0
		end

		-- Decompress a store block
		-- @param state decompression state that will be modified by this function.
		-- @return 0 if succeeds, other value if fails.
		local function DecompressStoreBlock(state)
			local buffer, buffer_size, ReadBits, ReadBytes, ReaderBitlenLeft
			, SkipToByteBoundary, result_buffer =
				state.buffer, state.buffer_size, state.ReadBits, state.ReadBytes
			, state.ReaderBitlenLeft, state.SkipToByteBoundary, state.result_buffer

			SkipToByteBoundary()
			local bytelen = ReadBits(16)
			if ReaderBitlenLeft() < 0 then
				return 2 -- available inflate data did not terminate
			end
			local bytelenComp = ReadBits(16)
			if ReaderBitlenLeft() < 0 then
				return 2 -- available inflate data did not terminate
			end

			if bytelen % 256 + bytelenComp % 256 ~= 255 then
				return -2 -- Not one's complement
			end
			if (bytelen-bytelen % 256)/256
				+ (bytelenComp-bytelenComp % 256)/256 ~= 255 then
				return -2 -- Not one's complement
			end

			-- Note that ReadBytes will skip to the next byte boundary first.
			buffer_size = ReadBytes(bytelen, buffer, buffer_size)
			if buffer_size < 0 then
				return 2 -- available inflate data did not terminate
			end

			-- memory clean up when there are enough bytes in the buffer.
			if buffer_size >= 65536 then
				result_buffer[#result_buffer+1] = table_concat(buffer, "", 1, 32768)
				for i=32769, buffer_size do
					buffer[i-32768] = buffer[i]
				end
				buffer_size = buffer_size - 32768
				buffer[buffer_size+1] = nil
			end
			state.buffer_size = buffer_size
			return 0
		end

		-- Decompress a fixed block
		-- @param state decompression state that will be modified by this function.
		-- @return 0 if succeeds other value if fails.
		local function DecompressFixBlock(state)
			return DecodeUntilEndOfBlock(state
				, _fix_block_literal_huffman_bitlen_count
				, _fix_block_literal_huffman_to_deflate_code, 7
				, _fix_block_dist_huffman_bitlen_count
				, _fix_block_dist_huffman_to_deflate_code, 5)
		end

		-- Decompress a dynamic block
		-- @param state decompression state that will be modified by this function.
		-- @return 0 if success, other value if fails.
		local function DecompressDynamicBlock(state)
			local ReadBits, Decode = state.ReadBits, state.Decode
			local nlen = ReadBits(5) + 257
			local ndist = ReadBits(5) + 1
			local ncode = ReadBits(4) + 4
			if nlen > 286 or ndist > 30 then
				-- dynamic block code description: too many length or distance codes
				return -3
			end

			local rle_codes_huffman_bitlens = {}

			for i = 1, ncode do
				rle_codes_huffman_bitlens[_rle_codes_huffman_bitlen_order[i]] =
					ReadBits(3)
			end

			local rle_codes_err, rle_codes_huffman_bitlen_counts,
			rle_codes_huffman_symbols, rle_codes_huffman_min_bitlen =
				GetHuffmanForDecode(rle_codes_huffman_bitlens, 18, 7)
			if rle_codes_err ~= 0 then -- Require complete code set here
				-- dynamic block code description: code lengths codes incomplete
				return -4
			end

			local lcodes_huffman_bitlens = {}
			local dcodes_huffman_bitlens = {}
			-- Read length/literal and distance code length tables
			local index = 0
			while index < nlen + ndist do
				local symbol -- Decoded value
				local bitlen -- Last length to repeat

				symbol = Decode(rle_codes_huffman_bitlen_counts
					, rle_codes_huffman_symbols, rle_codes_huffman_min_bitlen)

				if symbol < 0 then
					return symbol -- Invalid symbol
				elseif symbol < 16 then
					if index < nlen then
						lcodes_huffman_bitlens[index] = symbol
					else
						dcodes_huffman_bitlens[index-nlen] = symbol
					end
					index = index + 1
				else
					bitlen = 0
					if symbol == 16 then
						if index == 0 then
							-- dynamic block code description: repeat lengths
							-- with no first length
							return -5
						end
						if index-1 < nlen then
							bitlen = lcodes_huffman_bitlens[index-1]
						else
							bitlen = dcodes_huffman_bitlens[index-nlen-1]
						end
						symbol = 3 + ReadBits(2)
					elseif symbol == 17 then -- Repeat zero 3..10 times
						symbol = 3 + ReadBits(3)
					else -- == 18, repeat zero 11.138 times
						symbol = 11 + ReadBits(7)
					end
					if index + symbol > nlen + ndist then
						-- dynamic block code description:
						-- repeat more than specified lengths
						return -6
					end
					while symbol > 0 do -- Repeat last or zero symbol times
						symbol = symbol - 1
						if index < nlen then
							lcodes_huffman_bitlens[index] = bitlen
						else
							dcodes_huffman_bitlens[index-nlen] = bitlen
						end
						index = index + 1
					end
				end
			end

			if (lcodes_huffman_bitlens[256] or 0) == 0 then
				-- dynamic block code description: missing end-of-block code
				return -9
			end

			local lcodes_err, lcodes_huffman_bitlen_counts
			, lcodes_huffman_symbols, lcodes_huffman_min_bitlen =
				GetHuffmanForDecode(lcodes_huffman_bitlens, nlen-1, 15)
			--dynamic block code description: invalid literal/length code lengths,
			-- Incomplete code ok only for single length 1 code
			if (lcodes_err ~=0 and (lcodes_err < 0
				or nlen ~= (lcodes_huffman_bitlen_counts[0] or 0)
				+(lcodes_huffman_bitlen_counts[1] or 0))) then
				return -7
			end

			local dcodes_err, dcodes_huffman_bitlen_counts
			, dcodes_huffman_symbols, dcodes_huffman_min_bitlen =
				GetHuffmanForDecode(dcodes_huffman_bitlens, ndist-1, 15)
			-- dynamic block code description: invalid distance code lengths,
			-- Incomplete code ok only for single length 1 code
			if (dcodes_err ~=0 and (dcodes_err < 0
				or ndist ~= (dcodes_huffman_bitlen_counts[0] or 0)
				+ (dcodes_huffman_bitlen_counts[1] or 0))) then
				return -8
			end

			-- Build buffman table for literal/length codes
			return DecodeUntilEndOfBlock(state, lcodes_huffman_bitlen_counts
				, lcodes_huffman_symbols, lcodes_huffman_min_bitlen
				, dcodes_huffman_bitlen_counts, dcodes_huffman_symbols
				, dcodes_huffman_min_bitlen)
		end

		-- Decompress a deflate stream
		-- @param state: a decompression state
		-- @return the decompressed string if succeeds. nil if fails.
		local function Inflate(state)
			local ReadBits = state.ReadBits

			local is_last_block
			while not is_last_block do
				is_last_block = (ReadBits(1) == 1)
				local block_type = ReadBits(2)
				local status
				if block_type == 0 then
					status = DecompressStoreBlock(state)
				elseif block_type == 1 then
					status = DecompressFixBlock(state)
				elseif block_type == 2 then
					status = DecompressDynamicBlock(state)
				else
					return nil, -1 -- invalid block type (type == 3)
				end
				if status ~= 0 then
					return nil, status
				end
			end

			state.result_buffer[#state.result_buffer+1] =
				table_concat(state.buffer, "", 1, state.buffer_size)
			local result = table_concat(state.result_buffer)
			return result
		end

		-- @see LibDeflate:DecompressDeflate(str)
		-- @see LibDeflate:DecompressDeflateWithDict(str, dictionary)
		local function DecompressDeflateInternal(str, dictionary)
			local state = CreateDecompressState(str, dictionary)
			local result, status = Inflate(state)
			if not result then
				return nil, status
			end

			local bitlen_left = state.ReaderBitlenLeft()
			local bytelen_left = (bitlen_left - bitlen_left % 8) / 8
			return result, bytelen_left
		end

		-- @see LibDeflate:DecompressZlib(str)
		-- @see LibDeflate:DecompressZlibWithDict(str)
		local function DecompressZlibInternal(str, dictionary)
			local state = CreateDecompressState(str, dictionary)
			local ReadBits = state.ReadBits

			local CMF = ReadBits(8)
			if state.ReaderBitlenLeft() < 0 then
				return nil, 2 -- available inflate data did not terminate
			end
			local CM = CMF % 16
			local CINFO = (CMF - CM) / 16
			if CM ~= 8 then
				return nil, -12 -- invalid compression method
			end
			if CINFO > 7 then
				return nil, -13 -- invalid window size
			end

			local FLG = ReadBits(8)
			if state.ReaderBitlenLeft() < 0 then
				return nil, 2 -- available inflate data did not terminate
			end
			if (CMF*256+FLG)%31 ~= 0 then
				return nil, -14 -- invalid header checksum
			end

			local FDIST = ((FLG-FLG%32)/32 % 2)
			local FLEVEL = ((FLG-FLG%64)/64 % 4) -- luacheck: ignore FLEVEL

			if FDIST == 1 then
				if not dictionary then
					return nil, -16 -- need dictonary, but dictionary is not provided.
				end
				local byte3 = ReadBits(8)
				local byte2 = ReadBits(8)
				local byte1 = ReadBits(8)
				local byte0 = ReadBits(8)
				local actual_adler32 = byte3*16777216+byte2*65536+byte1*256+byte0
				if state.ReaderBitlenLeft() < 0 then
					return nil, 2 -- available inflate data did not terminate
				end
				if not IsEqualAdler32(actual_adler32, dictionary.adler32) then
					return nil, -17 -- dictionary adler32 does not match
				end
			end
			local result, status = Inflate(state)
			if not result then
				return nil, status
			end
			state.SkipToByteBoundary()

			local adler_byte0 = ReadBits(8)
			local adler_byte1 = ReadBits(8)
			local adler_byte2 = ReadBits(8)
			local adler_byte3 = ReadBits(8)
			if state.ReaderBitlenLeft() < 0 then
				return nil, 2 -- available inflate data did not terminate
			end

			local adler32_expected = adler_byte0*16777216
				+ adler_byte1*65536 + adler_byte2*256 + adler_byte3
			local adler32_actual = LibDeflate:Adler32(result)
			if not IsEqualAdler32(adler32_expected, adler32_actual) then
				return nil, -15 -- Adler32 checksum does not match
			end

			local bitlen_left = state.ReaderBitlenLeft()
			local bytelen_left = (bitlen_left - bitlen_left % 8) / 8
			return result, bytelen_left
		end

		--- Decompress a raw deflate compressed data.
		-- @param str [string] The data to be decompressed.
		-- @return [string/nil] If the decompression succeeds, return the decompressed
		-- data. If the decompression fails, return nil. You should check if this return
		-- value is non-nil to know if the decompression succeeds.
		-- @return [integer] If the decompression succeeds, return the number of
		-- unprocessed bytes in the input compressed data. This return value is a
		-- positive integer if the input data is a valid compressed data appended by an
		-- arbitary non-empty string. This return value is 0 if the input data does not
		-- contain any extra bytes.<br>
		-- If the decompression fails (The first return value of this function is nil),
		-- this return value is undefined.
		-- @see LibDeflate:CompressDeflate
		function LibDeflate:DecompressDeflate(str)
			local arg_valid, arg_err = IsValidArguments(str)
			if not arg_valid then
				error(("Usage: LibDeflate:DecompressDeflate(str): "
					..arg_err), 2)
			end
			return DecompressDeflateInternal(str)
		end

		--- Decompress a raw deflate compressed data with a preset dictionary.
		-- @param str [string] The data to be decompressed.
		-- @param dictionary [table] The preset dictionary used by
		-- LibDeflate:CompressDeflateWithDict when the compressed data is produced.
		-- Decompression and compression must use the same dictionary.
		-- Otherwise wrong decompressed data could be produced without generating any
		-- error.
		-- @return [string/nil] If the decompression succeeds, return the decompressed
		-- data. If the decompression fails, return nil. You should check if this return
		-- value is non-nil to know if the decompression succeeds.
		-- @return [integer] If the decompression succeeds, return the number of
		-- unprocessed bytes in the input compressed data. This return value is a
		-- positive integer if the input data is a valid compressed data appended by an
		-- arbitary non-empty string. This return value is 0 if the input data does not
		-- contain any extra bytes.<br>
		-- If the decompression fails (The first return value of this function is nil),
		-- this return value is undefined.
		-- @see LibDeflate:CompressDeflateWithDict
		function LibDeflate:DecompressDeflateWithDict(str, dictionary)
			local arg_valid, arg_err = IsValidArguments(str, true, dictionary)
			if not arg_valid then
				error(("Usage: LibDeflate:DecompressDeflateWithDict(str, dictionary): "
					..arg_err), 2)
			end
			return DecompressDeflateInternal(str, dictionary)
		end

		--- Decompress a zlib compressed data.
		-- @param str [string] The data to be decompressed
		-- @return [string/nil] If the decompression succeeds, return the decompressed
		-- data. If the decompression fails, return nil. You should check if this return
		-- value is non-nil to know if the decompression succeeds.
		-- @return [integer] If the decompression succeeds, return the number of
		-- unprocessed bytes in the input compressed data. This return value is a
		-- positive integer if the input data is a valid compressed data appended by an
		-- arbitary non-empty string. This return value is 0 if the input data does not
		-- contain any extra bytes.<br>
		-- If the decompression fails (The first return value of this function is nil),
		-- this return value is undefined.
		-- @see LibDeflate:CompressZlib
		function LibDeflate:DecompressZlib(str)
			local arg_valid, arg_err = IsValidArguments(str)
			if not arg_valid then
				error(("Usage: LibDeflate:DecompressZlib(str): "
					..arg_err), 2)
			end
			return DecompressZlibInternal(str)
		end

		--- Decompress a zlib compressed data with a preset dictionary.
		-- @param str [string] The data to be decompressed
		-- @param dictionary [table] The preset dictionary used by
		-- LibDeflate:CompressDeflateWithDict when the compressed data is produced.
		-- Decompression and compression must use the same dictionary.
		-- Otherwise wrong decompressed data could be produced without generating any
		-- error.
		-- @return [string/nil] If the decompression succeeds, return the decompressed
		-- data. If the decompression fails, return nil. You should check if this return
		-- value is non-nil to know if the decompression succeeds.
		-- @return [integer] If the decompression succeeds, return the number of
		-- unprocessed bytes in the input compressed data. This return value is a
		-- positive integer if the input data is a valid compressed data appended by an
		-- arbitary non-empty string. This return value is 0 if the input data does not
		-- contain any extra bytes.<br>
		-- If the decompression fails (The first return value of this function is nil),
		-- this return value is undefined.
		-- @see LibDeflate:CompressZlibWithDict
		function LibDeflate:DecompressZlibWithDict(str, dictionary)
			local arg_valid, arg_err = IsValidArguments(str, true, dictionary)
			if not arg_valid then
				error(("Usage: LibDeflate:DecompressZlibWithDict(str, dictionary): "
					..arg_err), 2)
			end
			return DecompressZlibInternal(str, dictionary)
		end

		-- Calculate the huffman code of fixed block
		do
			_fix_block_literal_huffman_bitlen = {}
			for sym=0, 143 do
				_fix_block_literal_huffman_bitlen[sym] = 8
			end
			for sym=144, 255 do
				_fix_block_literal_huffman_bitlen[sym] = 9
			end
			for sym=256, 279 do
				_fix_block_literal_huffman_bitlen[sym] = 7
			end
			for sym=280, 287 do
				_fix_block_literal_huffman_bitlen[sym] = 8
			end

			_fix_block_dist_huffman_bitlen = {}
			for dist=0, 31 do
				_fix_block_dist_huffman_bitlen[dist] = 5
			end
			local status
			status, _fix_block_literal_huffman_bitlen_count
			, _fix_block_literal_huffman_to_deflate_code =
				GetHuffmanForDecode(_fix_block_literal_huffman_bitlen, 287, 9)
			assert(status == 0)
			status, _fix_block_dist_huffman_bitlen_count,
			_fix_block_dist_huffman_to_deflate_code =
				GetHuffmanForDecode(_fix_block_dist_huffman_bitlen, 31, 5)
			assert(status == 0)

			_fix_block_literal_huffman_code =
				GetHuffmanCodeFromBitlen(_fix_block_literal_huffman_bitlen_count
					, _fix_block_literal_huffman_bitlen, 287, 9)
			_fix_block_dist_huffman_code =
				GetHuffmanCodeFromBitlen(_fix_block_dist_huffman_bitlen_count
					, _fix_block_dist_huffman_bitlen, 31, 5)
		end

		-- Prefix encoding algorithm
		-- Credits to LibCompress.
		-- The code has been rewritten by the author of LibDeflate.
		------------------------------------------------------------------------------

		-- to be able to match any requested byte value, the search
		-- string must be preprocessed characters to escape with %:
		-- ( ) . % + - * ? [ ] ^ $
		-- "illegal" byte values:
		-- 0 is replaces %z
		local _gsub_escape_table = {
			["\000"] = "%z", ["("] = "%(", [")"] = "%)", ["."] = "%.",
			["%"] = "%%", ["+"] = "%+", ["-"] = "%-", ["*"] = "%*",
			["?"] = "%?", ["["] = "%[", ["]"] = "%]", ["^"] = "%^",
			["$"] = "%$",
		}

		local function escape_for_gsub(str)
			return str:gsub("([%z%(%)%.%%%+%-%*%?%[%]%^%$])", _gsub_escape_table)
		end

		--- Create a custom codec with encoder and decoder. <br>
		-- This codec is used to convert an input string to make it not contain
		-- some specific bytes.
		-- This created codec and the parameters of this function do NOT take
		-- localization into account. One byte (0-255) in the string is exactly one
		-- character (0-255).
		-- Credits to LibCompress.
		-- The code has been rewritten by the author of LibDeflate. <br>
		-- @param reserved_chars [string] The created encoder will ensure encoded
		-- data does not contain any single character in reserved_chars. This parameter
		-- should be non-empty.
		-- @param escape_chars [string] The escape character(s) used in the created
		-- codec. The codec converts any character included in reserved\_chars /
		-- escape\_chars / map\_chars to (one escape char + one character not in
		-- reserved\_chars / escape\_chars / map\_chars).
		-- You usually only need to provide a length-1 string for this parameter.
		-- Length-2 string is only needed when
		-- reserved\_chars + escape\_chars + map\_chars is longer than 127.
		-- This parameter should be non-empty.
		-- @param map_chars [string] The created encoder will map every
		-- reserved\_chars:sub(i, i) (1 <= i <= #map\_chars) to map\_chars:sub(i, i).
		-- This parameter CAN be empty string.
		-- @return [table/nil] If the codec cannot be created, return nil.<br>
		-- If the codec can be created according to the given
		-- parameters, return the codec, which is a encode/decode table.
		-- The table contains two functions: <br>
		-- t:Encode(str) returns the encoded string. <br>
		-- t:Decode(str) returns the decoded string if succeeds. nil if fails.
		-- @return [nil/string] If the codec is successfully created, return nil.
		-- If not, return a string that describes the reason why the codec cannot be
		-- created.
		-- @usage
		-- -- Create an encoder/decoder that maps all "\000" to "\003",
		-- -- and escape "\001" (and "\002" and "\003") properly
		-- local codec = LibDeflate:CreateCodec("\000\001", "\002", "\003")
		--
		-- local encoded = codec:Encode(SOME_STRING)
		-- -- "encoded" does not contain "\000" or "\001"
		-- local decoded = codec:Decode(encoded)
		-- -- assert(decoded == SOME_STRING)
		function LibDeflate:CreateCodec(reserved_chars, escape_chars
			, map_chars)
			if type(reserved_chars) ~= "string"
				or type(escape_chars) ~= "string"
				or type(map_chars) ~= "string" then
				error(
					"Usage: LibDeflate:CreateCodec(reserved_chars,"
						.." escape_chars, map_chars):"
						.." All arguments must be string.", 2)
			end

			if escape_chars == "" then
				return nil, "No escape characters supplied."
			end
			if #reserved_chars < #map_chars then
				return nil, "The number of reserved characters must be"
					.." at least as many as the number of mapped chars."
			end
			if reserved_chars == "" then
				return nil, "No characters to encode."
			end

			local encode_bytes = reserved_chars..escape_chars..map_chars
			-- build list of bytes not available as a suffix to a prefix byte
			local taken = {}
			for i = 1, #encode_bytes do
				local byte = string_byte(encode_bytes, i, i)
				if taken[byte] then
					return nil, "There must be no duplicate characters in the"
						.." concatenation of reserved_chars, escape_chars and"
						.." map_chars."
				end
				taken[byte] = true
			end

			local decode_patterns = {}
			local decode_repls = {}

			-- the encoding can be a single gsub
			-- , but the decoding can require multiple gsubs
			local encode_search = {}
			local encode_translate = {}

			-- map single byte to single byte
			if #map_chars > 0 then
				local decode_search = {}
				local decode_translate = {}
				for i = 1, #map_chars do
					local from = string_sub(reserved_chars, i, i)
					local to = string_sub(map_chars, i, i)
					encode_translate[from] = to
					encode_search[#encode_search+1] = from
					decode_translate[to] = from
					decode_search[#decode_search+1] = to
				end
				decode_patterns[#decode_patterns+1] =
					"([".. escape_for_gsub(table_concat(decode_search)).."])"
				decode_repls[#decode_repls+1] = decode_translate
			end

			local escape_char_index = 1
			local escape_char = string_sub(escape_chars
				, escape_char_index, escape_char_index)
			-- map single byte to double-byte
			local r = 0 -- suffix char value to the escapeChar

			local decode_search = {}
			local decode_translate = {}
			for i = 1, #encode_bytes do
				local c = string_sub(encode_bytes, i, i)
				if not encode_translate[c] then
					while r >= 256 or taken[r] do
						r = r + 1
						if r > 255 then -- switch to next escapeChar
							decode_patterns[#decode_patterns+1] =
								escape_for_gsub(escape_char)
								.."(["
								.. escape_for_gsub(table_concat(decode_search)).."])"
							decode_repls[#decode_repls+1] = decode_translate

							escape_char_index = escape_char_index + 1
							escape_char = string_sub(escape_chars, escape_char_index
								, escape_char_index)
							r = 0
							decode_search = {}
							decode_translate = {}

							if not escape_char or escape_char == "" then
								-- actually I don't need to check
								-- "not ecape_char", but what if Lua changes
								-- the behavior of string.sub() in the future?
								-- we are out of escape chars and we need more!
								return nil, "Out of escape characters."
							end
						end
					end

					local char_r = _byte_to_char[r]
					encode_translate[c] = escape_char..char_r
					encode_search[#encode_search+1] = c
					decode_translate[char_r] = c
					decode_search[#decode_search+1] = char_r
					r = r + 1
				end
				if i == #encode_bytes then
					decode_patterns[#decode_patterns+1] =
						escape_for_gsub(escape_char).."(["
						.. escape_for_gsub(table_concat(decode_search)).."])"
					decode_repls[#decode_repls+1] = decode_translate
				end
			end

			local codec = {}

			local encode_pattern = "(["
				.. escape_for_gsub(table_concat(encode_search)).."])"
			local encode_repl = encode_translate

			function codec:Encode(str)
				if type(str) ~= "string" then
					error(("Usage: codec:Encode(str):"
						.." 'str' - string expected got '%s'."):format(type(str)), 2)
				end
				return string_gsub(str, encode_pattern, encode_repl)
			end

			local decode_tblsize = #decode_patterns
			local decode_fail_pattern = "(["
				.. escape_for_gsub(reserved_chars).."])"

			function codec:Decode(str)
				if type(str) ~= "string" then
					error(("Usage: codec:Decode(str):"
						.." 'str' - string expected got '%s'."):format(type(str)), 2)
				end
				if string_find(str, decode_fail_pattern) then
					return nil
				end
				for i = 1, decode_tblsize do
					str = string_gsub(str, decode_patterns[i], decode_repls[i])
				end
				return str
			end

			return codec
		end

		local _addon_channel_codec


		-- Credits to WeakAuras2 and Galmok for the 6 bit encoding algorithm.
		-- The code has been rewritten by the author of LibDeflate.
		-- The result of encoding will be 25% larger than the
		-- origin string, but every single byte of the encoding result will be
		-- printable characters as the following.
		local _byte_to_6bit_char = {
			[0]="a", "b", "c", "d", "e", "f", "g", "h",
			"i", "j", "k", "l", "m", "n", "o", "p",
			"q", "r", "s", "t", "u", "v", "w", "x",
			"y", "z", "A", "B", "C", "D", "E", "F",
			"G", "H", "I", "J", "K", "L", "M", "N",
			"O", "P", "Q", "R", "S", "T", "U", "V",
			"W", "X", "Y", "Z", "0", "1", "2", "3",
			"4", "5", "6", "7", "8", "9", "(", ")",
		}

		local _6bit_to_byte = {
			[97]=0,[98]=1,[99]=2,[100]=3,[101]=4,[102]=5,[103]=6,[104]=7,
			[105]=8,[106]=9,[107]=10,[108]=11,[109]=12,[110]=13,[111]=14,[112]=15,
			[113]=16,[114]=17,[115]=18,[116]=19,[117]=20,[118]=21,[119]=22,[120]=23,
			[121]=24,[122]=25,[65]=26,[66]=27,[67]=28,[68]=29,[69]=30,[70]=31,
			[71]=32,[72]=33,[73]=34,[74]=35,[75]=36,[76]=37,[77]=38,[78]=39,
			[79]=40,[80]=41,[81]=42,[82]=43,[83]=44,[84]=45,[85]=46,[86]=47,
			[87]=48,[88]=49,[89]=50,[90]=51,[48]=52,[49]=53,[50]=54,[51]=55,
			[52]=56,[53]=57,[54]=58,[55]=59,[56]=60,[57]=61,[40]=62,[41]=63,
		}

		--- Encode the string to make it printable. <br>
		--
		-- Credit to WeakAuras2, this function is equivalant to the implementation
		-- it is using right now. <br>
		-- The code has been rewritten by the author of LibDeflate. <br>
		-- The encoded string will be 25% larger than the origin string. However, every
		-- single byte of the encoded string will be one of 64 printable ASCII
		-- characters, which are can be easier copied, pasted and displayed.
		-- (26 lowercase letters, 26 uppercase letters, 10 numbers digits,
		-- left parenthese, or right parenthese)
		-- @param str [string] The string to be encoded.
		-- @return [string] The encoded string.
		function LibDeflate:EncodeForPrint(str)
			if type(str) ~= "string" then
				error(("Usage: LibDeflate:EncodeForPrint(str):"
					.." 'str' - string expected got '%s'."):format(type(str)), 2)
			end
			local strlen = #str
			local strlenMinus2 = strlen - 2
			local i = 1
			local buffer = {}
			local buffer_size = 0
			while i <= strlenMinus2 do
				local x1, x2, x3 = string_byte(str, i, i+2)
				i = i + 3
				local cache = x1+x2*256+x3*65536
				local b1 = cache % 64
				cache = (cache - b1) / 64
				local b2 = cache % 64
				cache = (cache - b2) / 64
				local b3 = cache % 64
				local b4 = (cache - b3) / 64
				buffer_size = buffer_size + 1
				buffer[buffer_size] =
					_byte_to_6bit_char[b1].._byte_to_6bit_char[b2]
					.._byte_to_6bit_char[b3].._byte_to_6bit_char[b4]
			end

			local cache = 0
			local cache_bitlen = 0
			while i <= strlen do
				local x = string_byte(str, i, i)
				cache = cache + x * _pow2[cache_bitlen]
				cache_bitlen = cache_bitlen + 8
				i = i + 1
			end
			while cache_bitlen > 0 do
				local bit6 = cache % 64
				buffer_size = buffer_size + 1
				buffer[buffer_size] = _byte_to_6bit_char[bit6]
				cache = (cache - bit6) / 64
				cache_bitlen = cache_bitlen - 6
			end

			return table_concat(buffer)
		end

		--- Decode the printable string produced by LibDeflate:EncodeForPrint.
		-- "str" will have its prefixed and trailing control characters or space
		-- removed before it is decoded, so it is easier to use if "str" comes form
		-- user copy and paste with some prefixed or trailing spaces.
		-- Then decode fails if the string contains any characters cant be produced by
		-- LibDeflate:EncodeForPrint. That means, decode fails if the string contains a
		-- characters NOT one of 26 lowercase letters, 26 uppercase letters,
		-- 10 numbers digits, left parenthese, or right parenthese.
		-- @param str [string] The string to be decoded
		-- @return [string/nil] The decoded string if succeeds. nil if fails.
		function LibDeflate:DecodeForPrint(str)
			if type(str) ~= "string" then
				error(("Usage: LibDeflate:DecodeForPrint(str):"
					.." 'str' - string expected got '%s'."):format(type(str)), 2)
			end
			str = str:gsub("^[%c ]+", "")
			str = str:gsub("[%c ]+$", "")

			local strlen = #str
			if strlen == 1 then
				return nil
			end
			local strlenMinus3 = strlen - 3
			local i = 1
			local buffer = {}
			local buffer_size = 0
			while i <= strlenMinus3 do
				local x1, x2, x3, x4 = string_byte(str, i, i+3)
				x1 = _6bit_to_byte[x1]
				x2 = _6bit_to_byte[x2]
				x3 = _6bit_to_byte[x3]
				x4 = _6bit_to_byte[x4]
				if not (x1 and x2 and x3 and x4) then
					return nil
				end
				i = i + 4
				local cache = x1+x2*64+x3*4096+x4*262144
				local b1 = cache % 256
				cache = (cache - b1) / 256
				local b2 = cache % 256
				local b3 = (cache - b2) / 256
				buffer_size = buffer_size + 1
				buffer[buffer_size] =
					_byte_to_char[b1].._byte_to_char[b2].._byte_to_char[b3]
			end

			local cache  = 0
			local cache_bitlen = 0
			while i <= strlen do
				local x = string_byte(str, i, i)
				x =  _6bit_to_byte[x]
				if not x then
					return nil
				end
				cache = cache + x * _pow2[cache_bitlen]
				cache_bitlen = cache_bitlen + 6
				i = i + 1
			end

			while cache_bitlen >= 8 do
				local byte = cache % 256
				buffer_size = buffer_size + 1
				buffer[buffer_size] = _byte_to_char[byte]
				cache = (cache - byte) / 256
				cache_bitlen = cache_bitlen - 8
			end

			return table_concat(buffer)
		end

		local function InternalClearCache()
			_addon_channel_codec = nil
		end

		-- For test. Don't use the functions in this table for real application.
		-- Stuffs in this table is subject to change.
		LibDeflate.internals = {
			LoadStringToTable = LoadStringToTable,
			IsValidDictionary = IsValidDictionary,
			IsEqualAdler32 = IsEqualAdler32,
			_byte_to_6bit_char = _byte_to_6bit_char,
			_6bit_to_byte = _6bit_to_byte,
			InternalClearCache = InternalClearCache,
		}

		return Compression
	end)()

	local SerialBit = {}

	local DefaultOptions = {
		CompressionLevel = 9,

		Encode = true,
	}

	function SerialBit.serialize(Inst, Options)
		Options = Options or DefaultOptions

		for Name, Value in DefaultOptions do
			if Options[Name] == nil then
				Options[Name] = Value
			end
		end

		local Objects = Inst:GetDescendants()
		table.insert(Objects, Inst)

		local UniqueIds = {}
		for Index, Object in ipairs(Objects) do
			UniqueIds[Object] = Index
		end

		local SerializedString = ""
		local PropertiesIndexArray = {}

		local ObjectCount = 0
		for Index, Object in ipairs(Objects) do
			local ClassNameSize = #Object.ClassName
			local Chunk, ChunkSize = {}, ClassNameSize + 2

			local PropertyNames = Dump:propertiesFromInstance(Object)
			for _, Name in PropertyNames do
				local Success, Response = pcall(function()
					return Object[Name]
				end)
				if Success then
					local Type = BuffDatatypes.types.toTypeValue(typeof(Response))
					if typeof(Response) == "Instance" then
						if not UniqueIds[Response] then continue end
						Response = UniqueIds[Response]
						Type = 255
					end
					if not Type then continue end
					local PropertyIndex = table.find(PropertiesIndexArray, Name)
					if not PropertyIndex then
						table.insert(PropertiesIndexArray, Name)
						PropertyIndex = #PropertiesIndexArray
					end
					local ValueBuffer = BuffDatatypes.serialize(Response)
					Chunk[PropertyIndex] = {ValueBuffer, Type}
					ChunkSize += buffer.len(ValueBuffer) + 10
				end
			end
			local ChunkBuffer = buffer.create(ChunkSize)
			local Offset = 1
			buffer.writeu8(ChunkBuffer, Offset, ClassNameSize)
			buffer.writestring(ChunkBuffer, Offset + 1, Object.ClassName)
			Offset += ClassNameSize + 1
			local Count = 0
			for Property, Value in Chunk do
				Count += 1
				local Size = buffer.len(Value[1])
				buffer.writeu32(ChunkBuffer, Offset, Size) -- ValueSize, the size of the value defined below
				buffer.writeu16(ChunkBuffer, Offset + 4, Property) -- PropertyIndex, the number index of the property
				buffer.writeu8(ChunkBuffer, Offset + 6, Value[2])
				buffer.copy(ChunkBuffer, Offset + 7, Value[1]) -- Value, the value of this property
				Offset += Size + 10
			end
			buffer.writeu8(ChunkBuffer, 0, Count)
			local Serialized = buffer.tostring(ChunkBuffer)
			SerializedString ..= Serialized
			ObjectCount += 1
			if Index % 300 == 0 then
				task.wait()
			end
		end

		local SerializedPropertiesIndex
		do
			local BufferSize = 2
			for Index, Name in PropertiesIndexArray do
				BufferSize += #Name + 1
			end
			SerializedPropertiesIndex = buffer.create(BufferSize)
			local Offset = 2
			for Index, Name in ipairs(PropertiesIndexArray) do
				buffer.writeu8(SerializedPropertiesIndex, Offset, #Name)
				buffer.writestring(SerializedPropertiesIndex, Offset + 1, Name)
				Offset += #Name + 1
			end
			buffer.writeu16(SerializedPropertiesIndex, 0, #PropertiesIndexArray)
		end

		SerializedString = buffer.tostring(SerializedPropertiesIndex) .. string.pack("I4", ObjectCount) .. SerializedString

		if Options.CompressionLevel > 0 then
			SerializedString = LibDeflate.Zlib.Compress(SerializedString, { level = Options.CompressionLevel })
		end

		if Options.Encode then
			SerializedString = Base91.encode(SerializedString)
		end

		return SerializedString
	end

	function SerialBit.reconstruct(SerializedString)
		local Base91Charset = [[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,./:;<=>?@[]^_`{|}~"]]
		local ValidBase91 = true
		for Index = 1, #SerializedString do
			if not Base91Charset:find(SerializedString:sub(Index, Index), 1, true) then
				ValidBase91 = false
			end
		end
		if ValidBase91 then
			pcall(function() -- Attempt to decode
				SerializedString = Base91.decode(SerializedString)
			end)
		end
		if #SerializedString > 1 and SerializedString:byte(1) == 0x78 and SerializedString:byte(2) == 0x9C then
			pcall(function() -- Attempt to decompress
				SerializedString = LibDeflate.Zlib.Decompress(SerializedString)
			end)
		end
		local SerializedBuffer = buffer.fromstring(SerializedString)

		local PropertyIndexArray = {}
		local Offset = 2
		for Index = 1, buffer.readu16(SerializedBuffer, 0) do
			local NameSize = buffer.readu8(SerializedBuffer, Offset)
			local Name = buffer.readstring(SerializedBuffer, Offset + 1, NameSize)
			PropertyIndexArray[Index] = Name
			Offset += NameSize + 1
		end
		
		local Instances = buffer.readu32(SerializedBuffer, Offset)
		Offset += 4

		local Objects = {}
		local InstancePrefix = "INST_"

		local RootObjects = {}

		for Index = 1, Instances do
			local Properties = buffer.readu8(SerializedBuffer, Offset)
			local ClassNameSize = buffer.readu8(SerializedBuffer, Offset + 1)
			local ClassNameString = buffer.readstring(SerializedBuffer, Offset + 2, ClassNameSize)
			Offset += ClassNameSize + 2

			local Values = {}

			for Index = 1, Properties do
				local ValueSize = buffer.readu32(SerializedBuffer, Offset)
				local PropertyIndex = buffer.readu16(SerializedBuffer, Offset + 4)
				local PropertyType = buffer.readu8(SerializedBuffer, Offset + 6)
				
				local ValueBuffer = buffer.create(ValueSize)
				buffer.copy(ValueBuffer, 0, SerializedBuffer, Offset + 7, ValueSize)

				Offset += ValueSize + 10

				local Value
				pcall(function()
					if PropertyType == 255 then -- 255 is reserved for instances
						Value = InstancePrefix..BuffDatatypes.deserialize("number", ValueBuffer)
					else
						Value = BuffDatatypes.deserialize(PropertyType, ValueBuffer)
					end
					Values[PropertyIndexArray[PropertyIndex]] = Value
				end)
			end
			
			if ClassNameString == "MeshPart" then
				local NewValues = table.clone(Values)
				NewValues.MeshId = nil
				NewValues.CollisionFidelity = nil
				NewValues.RenderFidelity = nil
				table.insert(Objects, {game:GetService("InsertService"):CreateMeshPartAsync(Values.MeshId, Values.CollisionFidelity or Enum.CollisionFidelity.Default, Values.RenderFidelity or Enum.RenderFidelity.Automatic), NewValues})
			elseif ClassNameString == "SurfaceAppearance" then
				table.insert(Objects, {nil, Values, ClassNameString})
			else
				table.insert(Objects, {Instance.new(ClassNameString), Values})
			end

			if Index % 450 == 0 then
				task.wait()
			end
		end
		
		for Index, Object in Objects do
			if Object[3] == "SurfaceAppearance" then
				local ParentValue = Object[2].Parent
				if ParentValue and Object[2].ColorMap then
					local Number = ParentValue:sub(#InstancePrefix + 1)
					Number = tonumber(Number)
					local Parent = Objects[Number]
					if Parent then
						Objects[Number][2].TextureID = Object[2].ColorMap
					end
				end
			end
		end

		for Index, Object in Objects do
			local Inst = Object[1]
			if not Inst then continue end
			
			local Properties = Object[2]

			for Name, Value in Properties do
				if typeof(Value) == "string" and Value:sub(1, #InstancePrefix) == InstancePrefix then
					local Number = Value:sub(#InstancePrefix + 1)
					Number = tonumber(Number)
					Value = Objects[Number][1]
				end
				local _, Err = pcall(function()
					Inst[Name] = Value
				end)
				if Err then
					warn(Err)
				end
			end

			if not Inst.Parent then
				table.insert(RootObjects, Inst)
			end

			if Index % 450 == 0 then
				task.wait()
			end
		end

		return RootObjects
	end

	return SerialBit
INFO