wnsrc/lua/niknaks/modules/sh_bitbuffer.lua

--[[
| This file was obtained through the combined efforts
| of Madbluntz & Plymouth Antiquarian Society.
|
| Credits: lifestorm, Gregory Wayne Rossel JR.,
| 	Maloy, DrPepper10 @ RIP, Atle!
|
| Visit for more: https://plymouth.thetwilightzone.ru/
--]]

-- Copyright © 2022-2072, Nak, https://steamcommunity.com/id/Nak2/
-- All Rights Reserved. Not allowed to be reuploaded.
-- License: https://github.com/Nak2/NikNaks/blob/main/LICENSE

local NikNaks = NikNaks
local s_char, s_byte, tostring = string.char, string.byte, tostring
local band, brshift, blshift, bor, bswap = bit.band, bit.rshift, bit.lshift, bit.bor, bit.bswap
local log, ldexp, frexp, floor, ceil, max, setmetatable, source = math.log, math.ldexp, math.frexp, math.floor, math.ceil, math.max, setmetatable, jit.util.funcinfo( NikNaks.AutoInclude )["source"]

--- @class BitBufferModule
--- @operator call(string|table): BitBuffer
NikNaks.BitBuffer = {}

--- @class BitBuffer
--- @field _data table
--- @field _tell number
--- @field _len number
--- @field _little_endian boolean
local meta = {}
meta.__index = meta
function meta:__tostring()
	return "BitBuffer [" .. self:Size() .. "]"
end

--- Fixes bit-shift errors
--- @param int number
--- @param shift number
--- @return number
local function rshift( int, shift )
	if shift > 31 then return 0x0 end
	return brshift( int, shift )
end

--- @param int number
--- @param shift number
--- @return number
local function lshift( int, shift )
	if shift > 31 then return 0x0 end
	return blshift( int, shift )
end

-- "Crams" the data into the bitbuffer. Ignoring offsets
local function unsaferawdata( self, str )
	if #str <= 0 then return end

	local len = #str
	local p = #self._data
	local whole = lshift(rshift(len - 4,2), 2) -- Bytes

	for i = 1, whole, 4 do
		local a, b, c, d = s_byte( str, i, i + 3)
		p = p + 1
		self._data[ p ] = bor( lshift( a, 24 ), lshift( b, 16 ), lshift( c, 8 ), d )
	end

	self._tell = lshift( p, 5 )
	for i = whole + 1, len do
		meta.WriteByte( self, s_byte( str, i ) )
	end

	self._len = max( self._len, lshift(len, 3) )
end

--- @param little_endian? boolean
--- @return BitBuffer
local function create( data, little_endian )
	--- @type BitBuffer
	local t = {}
	t._data = {}
	t._tell = 0
	t._len = 0
	t._little_endian = false
	setmetatable( t, meta )

	if not data then return t end
	local mt = getmetatable( data )

	if type(data) == "string" then
		unsaferawdata( t, data )
		t._tell = 0 -- Reset tell
	elseif not mt then
		local q = #data
		for i = 1, q do
			t._data[i] = data[i]
		end
		t._len = q * 32
	end

	if little_endian == nil then
		t._little_endian = true
	else
		t._little_endian = little_endian
	end

	return t
end

NikNaks.BitBuffer.Create = create
setmetatable( NikNaks.BitBuffer, {
	--- Creates a new BitBuffer
	--- @param data string|table
	--- @param little_endian boolean?
	--- @return BitBuffer
	__call = function( _, data, little_endian ) return create( data, little_endian ) end
} )

-- Simple int->string and reverse. ( Little-Endian )
do
	--- Takes a string of 1-4 charectors and converts it into a Little-Endian int
	--- @param str string
	--- @return number
	function NikNaks.BitBuffer.StringToInt( str )
		local a, b, c, d = s_byte( str, 1, 4 )
		if d then
			return bor( blshift( d, 24 ), blshift( c, 16 ), blshift( b, 8 ), a )
		elseif c then
			return bor( blshift( c, 16 ), blshift( b, 8 ), a )
		elseif b then
			return bor( blshift( b, 8 ), a )
		else
			return a
		end
	end

	local q = 0xFF
	--- Takes an Little-Endian number and converts it into a 4 char-string
	--- @param int number
	--- @return string
	function NikNaks.BitBuffer.IntToString( int )
		local a, b, c, d = brshift( int, 24 ), band( brshift(int, 16), q ), band( brshift(int, 8), q ), band( int, q )
		return s_char(d,c,b,a)
	end
end

-- To signed and unsigned
local to_signed
do
	local maxint = {}
	for i = 1, 32 do
		local n = i
		maxint[i] = math.pow( 2, n - 1 )
	end

	function to_signed( int, bits )
		if int < 0 then return int end -- Already signed
		local maximum = maxint[bits]
		return int - band( int, maximum ) * 2
	end
end

-- Access
do
	--- Returns lengh of the BitBuffer.
	--- @return number
	function meta:__len()
		return self._len
	end
	meta.Size = meta.__len

	--- Returns where we're reading/writing from.
	--- @return number
	function meta:Tell()
		return self._tell
	end

	--- Sets the tell to a position.
	--- @param num number
	--- @return self
	function meta:Seek( num )
		self._tell = brshift( blshift( num, 1 ), 1 )
		return self
	end

	--- Skips x bits ahead.
	--- @param num number
	--- @return BitBuffer self
	function meta:Skip( num )
		self._tell = self._tell + num
		return self
	end

	--- Returns true if we've reached the end of the bitbuffer.
	--- @return boolean
	function meta:EndOfData()
		return self._tell >= self._len
	end

	--- Clears all data from the BitBuffer.
	--- @return BitBuffer self
	function meta:Clear()
		self._data = {}
		self._len = 0
		self._tell = 0
		return self
	end

	--- Converts a number to bits. ( Big-Endian )
	--- @param num number
	--- @param bits number
	--- @return string
	local function toBits( num, bits, byte_space )
		local str = ""
		for i = bits, 1, -1 do
			if byte_space and i % 8 == 0 and i < 32 then
				str = str .. " "
			end
			local b = band( num, lshift( 0x1, i - 1 ) ) == 0
			str = str .. ( b and "0" or "1" )
		end
		return str
	end
	NikNaks.BitBuffer.ToBits = toBits

	--- Debug print function for the bitbuffer.
	function meta:Debug()
		local size = string.NiceSize( self._len / 8 )
		local rep = string.rep( "=", ( 32 - ( #size + 6 ) ) / 2 )
		print( "BitBuff	" .. rep .. " [" .. size  .. "] " .. ( self:IsLittleEndian() and "Le " or "Be " ) .. rep .. "\t= 0xHX =" )
		for i = 1, #self._data do
			print( i, toBits( self._data[i], 32 ), bit.tohex( self._data[i] ):upper() )
		end
	end

	--- Returns true if the bitbuffer is little-endian.
	--- @return boolean
	function meta:IsLittleEndian()
		return self._little_endian or false
	end

	--- Returns true if the bitbuffer is big-endian.
	--- @return boolean
	function meta:IsBigEndian()
		return not self._little_endian
	end

	--- Sets the bitbuffer to be little-endian.
	--- @return self BitBuffer The BitBuffer that was modified
	function meta:SetLittleEndian()
		self._little_endian = true
		return self
	end

	--- Sets the bitbuffer to be big-endian.
	--- @return self BitBuffer The BitBuffer that was modified
	function meta:SetBigEndian()
		self._little_endian = false
		return self
	end
end

-- Write / Read Raw
local writeraw, readraw
do
	-- Need to check endian type here.
	-- B |--|--|FF|11|
	-- L |--|--|11|FF|

	-- B |--|-F|FF|11| -- Input
	-- S |11|FF|-F|--| -- Swap
	-- > |--|11|FF|-F| -- rshift
	-- L |--|-1|1F|FF| -- Output

	-- B |00000000|00000000|00000000|00000000|
	local b_mask = 0xFFFFFFFF

	--- @param int number
	--- @param bits number
	--- @return number
	local function swap( int, bits )
		return brshift( bswap( int ), 32 - bits )
	end

	--- @param self BitBuffer
	--- @param int number
	--- @param bits number
	--- @return self BitBuffer The BitBuffer that was modified
	function writeraw( self, int, bits )
		if self._little_endian and bits % 8 == 0 then
			int = swap( int, bits )
		end

		local tell = self._tell
		self._tell = tell + bits
		self._len = max( self._len, self._tell )

		-- Retrive data pos
		local i_word = rshift( tell, 5 ) + 1  -- [ 1 - length ]
		local bitPos = tell % 32 -- [[ 0 - 31 ]]
		local ebitPos = bitPos + bits -- The end bit pos

		-- DataMask & Data
		local mask = bor( lshift( b_mask, 32 - bitPos ), rshift( b_mask, ebitPos ) )
		local data = band( self._data[ i_word ] or 0x0, mask )

		-- Write the data
		if ebitPos <= 32 then
			self._data[ i_word ] = bor( data, lshift( int, 32 - ebitPos ) )
			return
		end

		local overflow = ebitPos - 32 -- [[ 1, 31 ]]
		self._data[ i_word ] = bor( data, rshift( int, overflow ) )

		data = band( rshift( b_mask, overflow ), self._data[ i_word + 1 ] or 0x0 )
		self._data[ i_word + 1 ] = bor( data, lshift( int, 32 - overflow ) )

		return self
	end

	--- @param self BitBuffer
	--- @param bits number
	--- @return number # The read data
	function readraw( self, bits )
		local tell = self._tell
		self._tell = tell + bits

		-- Retrive data pos
		local i_word = rshift( tell, 5 ) + 1  -- [ 1 - length ]
		local bitPos = tell % 32 -- [[ 0 - 31 ]]
		local ebitPos = bitPos + bits -- The end bit pos

		-- DataMask & Data
		if ebitPos <= 32 then
			local data = brshift( self._data[ i_word ] or 0x0, 32 - ebitPos )
			if self._little_endian and bits % 8 == 0 then
				return swap( band( data, brshift( b_mask, 32 - bits ) ), bits )
			end
			return band( data, brshift( b_mask, 32 - bits ) )
		end

		local over = ebitPos - 32 -- How many bits we're over
		local data1 = lshift( band( self._data[ i_word ] or 0x0, rshift( b_mask, bitPos ) ), over )
		local data2 = rshift( self._data[ i_word + 1 ] or 0x0, 32 - over )

		if self._little_endian and bits % 8 == 0 then
			return swap( bor( data1, data2 ), bits  )
		end

		return bor( data1, data2 )
	end

	if not source:find( "niknak" ) then return end
end

--- Add raw (debug) functions
meta._writeraw = writeraw
meta._readraw = readraw

-- Boolean
do
	local b_mask = 0xFFFFFFFF
	--We don't need to call write/read raw. Since this is 1 bit.

	--- Writes a boolean.
	--- @param b boolean
	--- @return self BitBuffer
	function meta:WriteBoolean( b )
		local tell = self._tell
		self._tell = tell + 1
		self._len = max( self._len, self._tell )

		-- Retrive data pos
		local i_word = rshift( tell, 5 ) + 1  -- [ 1 - length ]
		local bitPos = tell % 32 -- [[ 0 - 31 ]]
		local ebitPos = bitPos + 1

		-- DataMask & Data
		local mask = bor( lshift( b_mask, 32 - bitPos ), rshift( b_mask, ebitPos ) )
		local data = band( self._data[ i_word ] or 0x0, mask )

		-- Write the data
		self._data[ i_word ] = bor( data, lshift( b and 1 or 0, 32 - ebitPos ) )

		return self
	end

	--- Reads a boolean.
	--- @return boolean
	function meta:ReadBoolean()
		local tell = self._tell
		self._tell = tell + 1

		-- Retrive data pos
		local i_word = rshift( tell, 5 ) + 1  -- [ 1 - length ]
		local bitPos = tell % 32 -- [[ 0 - 31 ]]
		local ebitPos = bitPos + 1 -- The end bit pos

		-- DataMask & Data
		local data = rshift( self._data[ i_word ] or 0x0, 32 - ebitPos )

		return band( data, rshift( b_mask, 32 - 1 ) ) == 1
	end
end

-- 32 bit Int
do
	meta.WriteInt = writeraw

	--- Reads an int.
	--- @param bits number
	--- @return number
	function meta:ReadInt( bits )
		return to_signed( readraw( self, bits ), bits )
	end
end

-- UInt
do
	meta.WriteUInt = writeraw

	local c = math.pow( 2, 32 )

	--- Reads an unsigned int.
	--- @param bits number
	--- @return number
	function meta:ReadUInt( bits )
		local n = readraw( self, bits )
		if n > -1 then return n end -- 32bit numbers could be negative when reading.
		return n + c
	end
end

-- Byte
do
	--- Writes a byte. ( 0 - 255 )
	--- @param byte number
	--- @return BitBuffer self
	function meta:WriteByte( byte )
		writeraw( self, byte, 8 )
		return self
	end

	--- Reads a byte. ( 0 - 255 )
	--- @return number
	function meta:ReadByte()
		return readraw( self, 8 )
	end
end

-- Signed Byte
do
	--- Writes a signed byte. ( -128 - 127 )
	--- @param byte number
	--- @return BitBuffer self
	function meta:WriteSignedByte( byte )
		self:WriteInt( byte, 8 )
		return self
	end

	--- Writes a signed byte. ( -128 - 127 )
	--- @return number
	function meta:ReadSignedByte()
		return self:ReadInt( 8 )
	end
end

-- Ushort
do
	--- Writes an unsigned 2 byte number. ( 0 - 65535 )
	--- @param num number
	--- @return BitBuffer self
	function meta:WriteUShort( num )
		self:WriteUInt( num, 16 )
		return self
	end

	--- Reads an unsigned 2 byte number. ( 0 - 65535 )
	--- @return number
	function meta:ReadUShort()
		return self:ReadUInt( 16 )
	end
end

-- Short
do
	--- Writes a 2 byte number. ( -32768 - 32767 )
	--- @param num number
	--- @return BitBuffer self
	function meta:WriteShort( num )
		self:WriteInt( num, 16 )
		return self
	end

	--- Reads an 2 byte number. ( -32768 - 32767 )
	--- @return number
	function meta:ReadShort()
		return self:ReadInt( 16 )
	end
end

-- ULong
do
	--- Writes an unsigned 4 byte number. ( 0 - 4294967295 )
	--- @param num number
	--- @return self BitBuffer
	function meta:WriteULong( num )
		self:WriteUInt( num, 32 )
		return self
	end

	--- Reads an unsigned 4 byte number ( 0 - 4294967295 )
	--- @return number
	function meta:ReadULong()
		return self:ReadUInt( 32 )
	end
end

-- Long
do
	--- Writes a 4 byte number. ( -2147483648 - 2147483647 )
	--- @param num number
	--- @return BitBuffer self
	function meta:WriteLong( num )
		self:WriteInt( num, 32 )
		return self
	end

	--- Reads a 4 byte number. ( -2147483648 - 2147483647 )
	--- @return number
	function meta:ReadLong()
		return self:ReadInt( 32 )
	end
end

-- Nibble
do
	--- Writes a 4 bit unsigned number. ( 0 - 15 )
	--- @param num number
	--- @return BitBuffer self
	function meta:WriteNibble( num )
		self:WriteUInt( num, 4 )
		return self
	end

	--- Reads a 4 bit unsigned number. ( 0 - 15 )
	--- @return number
	function meta:ReadNibble()
		return self:ReadUInt( 4 )
	end
end

-- Snort ( 2bit number )
do
	--- Writes a 2 bit unsigned number. ( 0 - 3 )
	--- @param num number
	--- @return BitBuffer self
	function meta:WriteSnort( num )
		self:WriteUInt( num, 2 )
		return self
	end

	--- Reads a 2 bit unsigned number. ( 0 - 3 )
	--- @return number
	function meta:ReadSnort()
		return self:ReadUInt( 2 )
	end
end

--- @param n number
--- @return boolean
local function isNegative( n ) return 1 / n == -math.huge end

-- Float
do
	--- Writes an IEEE 754 little-endian float.
	--- @param num number
	--- @return self BitBuffer
	function meta:WriteFloat( num )
		local sign = 0
		local man = 0
		local ex = 0

		-- Mark negative numbers.
		if num < 0 then
			sign = 0x80000000
			num = -num
		end

		if num ~= num then -- Nan
			ex = 0xFF
			man = 1
		elseif num == math.huge then -- Infintiy
			ex = 0xFF
			man = 0
		elseif num ~= 0 then -- Anything but 0's
			man, ex = frexp( num )
			ex = ex + 0x7F

			if ex <= 0 then
				man = ldexp( man, ex - 1 )
				ex = 0
			elseif ex >= 0xFF then -- Reached infinity
				ex = 0xFF
				man = 0
			elseif ex == 1 then
				ex = 0
			else
				man = man * 2 - 1
				ex = ex - 1
			end

			man = floor( ldexp( man, 23 ) + 0.5 )
		elseif isNegative( num ) then -- Minus 0 support
			sign = 0x80000000
			man = 0
		end

		-- Not tested, but I guess it is faster to write 1 32bit number, than 3x others.
		self:WriteULong( bor( sign, lshift( band( ex, 0xFF ), 23 ), man ), 32 )

		return self
	end

	local _23pow = 2 ^ 23

	--- Reads an IEEE 754 little-endian float.
	--- @return number
	function meta:ReadFloat()
		local n = self:ReadULong()
		local sign = band( 0x80000000, n ) == 0 and 1 or -1
		local ex = band( rshift( n, 23 ), 0xFF )
		local man = band( n, 0x007FFFFF ) / _23pow

		if ex == 0 and man == 0 then return 0 * sign				-- Number 0
		elseif ex == 255 and man == 0 then return math.huge * sign 	-- -+inf
		elseif ex == 255 and man ~= 0 then return 0 / 0				-- nan
		else return ldexp ( 1 + man, ex - 127 ) * sign end
	end
end

-- Double
do
	--[[
		|FFFFFFFF|FFFFFFFF|
		|Fa|Fb|Fc|Fd| |Fe|Ff|Fg|Fh|
		|Fh|Fg|Ff|Fe| |Fd|Fc|Fb|Fa| -> Data input

		|Fh|Fg|Ff|Fe| |Fd|Fc|Fb|Fa|
		|Fe|Ff|Fg|Fh| |Fa|Fb|Fc|Fd|
		|Fa|Fb|Fc|Fd| |Fe|Ff|Fg|Fh|
	]]
	local _52pow = 2 ^ 52
	local _32pow = 2 ^ 32
	local _log = math.log( 2 )

	--- Writes an IEEE 754 little-endian double.
	--- @param num number
	--- @return BitBuffer self
	function meta:WriteDouble( num )
		-- Calculate sign, ex and man
		local sign = 0
		if num < 0 or ( num == 0 and isNegative( num ) ) then
			num = -num
			sign = 0x80000000
		end
		local ex	= ceil( log( num ) / _log ) - 1
		local man	= num / ( 2 ^ ex ) - 1

		-- If clamp or reach math.huge
		if ( ex < -1023 ) then
			ex = -1023
			man = num / ( 2 ^ ex )
		elseif ( ex > 1024 ) then
			ex = 1024
			man = 0
		end
		if ( num == 0 ) then -- Zero
			ex = 0
			man = 0
		elseif ( num == math.huge ) then --Infinity
			ex = 2047
			man = 0
		elseif ( num ~= num ) then  -- Nan
			ex = 2047
			man = 1
		else
			ex = ex + 1023
			man = man * _52pow
		end

		if self._little_endian then
			self:WriteULong( band( man, 0xFFFFFFFF ) )
			self:WriteULong( bor( sign, lshift( ex, 20 ), band( man / _32pow, 0x001FFFFF ) ) )
		else
			self:WriteULong( bor( sign, lshift( ex, 20 ), band( man / _32pow, 0x001FFFFF ) ) )
			self:WriteULong( band( man, 0xFFFFFFFF ) )
		end

		return self
	end

	--- Reads an IEEE 754 little-endian double.
	--- @return number
	function meta:ReadDouble()
		local a, b
		if self._little_endian then
			b, a = self:ReadUInt( 32 ), self:ReadUInt( 32 )
		else
			a, b = self:ReadUInt( 32 ), self:ReadUInt( 32 )
		end
		local sign = band( 0x80000000, a ) == 0 and 1 or -1
		local ex = rshift( band( 0x7FF00000, a ), 20 )
		local man = band( a, 0x000FFFFF ) * _32pow + b
		if ex == 0 and man == 0 then return 0 * sign					-- Number 0
		elseif ex == 0x7FF and man == 0 then return math.huge * sign 	-- -+inf
		elseif ex == 0x7FF and man ~= 0 then return 0 / 0					-- nan
		else return math.pow( 2, ex - 0x3FF ) * ( man / _52pow + 1 ) * sign end
	end
end

-- Data
do
	--- Writes raw string-data.
	--- @param str string
	--- @return BitBuffer self
	function meta:Write( str )
		local len = #str
		local q = lshift( rshift( len, 2 ), 2 )

		for i = 1, q, 4 do
			local a, b, c, d = s_byte( str, i, i + 3 )
			self:WriteUInt( bor( lshift( a, 24 ), lshift( b, 16 ), lshift( c, 8 ), d ), 32 )
		end

		for i = q + 1, len do
			self:WriteUInt( s_byte( str, i ), 8 )
		end

		return self
	end

	--- Reads raw string-data. Default bytes are the length of the bitbuffer.
	--- @param bytes number
	--- @return string
	function meta:Read( bytes )
		bytes = bytes or math.ceil( ( self:Size() - self:Tell() ) / 8 )

		local ReadByte = meta.ReadByte
		local c, s = lshift( rshift( bytes, 2 ), 2 ), ""

		for _ = 1, c, 4 do
			s = s .. s_char( ReadByte( self ), ReadByte( self ), ReadByte( self ), ReadByte( self ) )
		end

		for _ = c + 1, bytes do
			s = s .. s_char( ReadByte( self ) )
		end

		return s
	end
end

-- Special Types
do
	local Write, Read = meta.Write, meta.Read

	--- Writes a string. Max string length: 65535
	--- @param str string
	--- @return BitBuffer self
	function meta:WriteString( str )
		local l = #str
		if l > 65535 then
			str = str:sub( 0, 65535 )
			l = 65535
		end

		self:WriteUShort( l )
		Write( self, str )

		return self
	end

	--- Reads a string. Max string length: 65535
	--- @return string
	function meta:ReadString()
		return Read( self, self:ReadUShort() or 0 )
	end

	local z = '\0'

	--- Writes a string using a nullbyte at the end. Note: Will remove all nullbytes given.
	--- @param str string
	--- @return BitBuffer self
	function meta:WriteStringNull( str )
		Write( self, string.gsub( str, z, '' ) .. z )
		return self
	end

	--- Reads a string using a nullbyte at the end. Note: ReadStringNull is a bit slower than ReadString.
	--- @param maxLength? number
	--- @return string
	function meta:ReadStringNull( maxLength )
		maxLength = maxLength or ceil( self:Size() - self:Tell() ) / 8

		local str = ""
		if maxLength < 1 then return str end

		local c = self:ReadByte()
		while c ~= 0 and maxLength > 0 do
			str = str .. s_char( c )
			c = self:ReadByte()
			maxLength = maxLength - 1
		end

		return str
	end

	--- Writes a Vector.
	--- @param vector Vector
	--- @return BitBuffer self
	function meta:WriteVector( vector )
		self:WriteFloat( vector.x )
		self:WriteFloat( vector.y )
		self:WriteFloat( vector.z )
		return self
	end

	--- Reads a Vector.
	--- @return Vector
	function meta:ReadVector()
		return Vector( self:ReadFloat(), self:ReadFloat(), self:ReadFloat() )
	end

	--- Writes an Angle.
	--- @param angle Angle
	--- @return BitBuffer self
	function meta:WriteAngle( angle )
		self:WriteFloat( angle.p )
		self:WriteFloat( angle.y )
		self:WriteFloat( angle.r )
		return self
	end

	--- Reads an Angle.
	--- @return Angle
	function meta:ReadAngle()
		return Angle( self:ReadFloat(), self:ReadFloat(), self:ReadFloat() )
	end

	--- Writes a 32bit Color.
	--- @param color Color
	--- @return self BitBuffer
	function meta:WriteColor( color )
		self:WriteByte( color.r )
		self:WriteByte( color.g )
		self:WriteByte( color.b )
		self:WriteByte( color.a or 255 )
		return self
	end

	--- Reads a 32bit color.
	--- @return Color
	function meta:ReadColor()
		return Color( self:ReadByte(), self:ReadByte(), self:ReadByte(), self:ReadByte() )
	end
end

-- Tables / Types
do
	local typeIDs = {
		["nil"] 	= 0,
		["boolean"]	= 1,
		["number"]	= 2,
		-- light userdata
		["string"]	= 4,
		["table"]	= 5,
		-- function
		-- userdata
		-- thread
		["Player"]	= 8,
		["Entity"]	= 9,
		["Vector"]	= 10,
		["Angle"]	= 11,
		-- physobj
		["IMaterial"]	= 21,
		["Color"]		= 255
	}

	--- Writes a type using a byte as TYPE_ID.
	--- @param obj any
	--- @return BitBuffer self
	function meta:WriteType( obj )
		local id = typeIDs[ type( obj ) ]
		assert( id, "Trying to write invalid type [" .. type( obj ) .. "]" )

		if id == 5 and obj.r and obj.g and obj.b then
			id = 255
		end

		self:WriteByte( id )

		if id == 0 then return
		elseif id == 1 then self:WriteByte( obj and 1 or 0 )
		elseif id == 2 then self:WriteDouble( obj )
		elseif id == 4 then self:WriteString( obj )
		elseif id == 5 then	self:WriteTable( obj )
		elseif id == 8 then self:WriteString( obj:SteamID64() )
		elseif id == 9 then self:WriteULong( obj:EntIndex() )
		elseif id == 10 then self:WriteVector( obj )
		elseif id == 11 then self:WriteAngle( obj )
		elseif id == 21 then self:WriteString( obj:GetName() )
		elseif id == 255 then self:WriteColor( obj )
		end

		return self
	end

	--- Reads a type using a byte as TYPE_ID.
	--- @return any
	function meta:ReadType()
		local id = self:ReadByte()

		if id == 0 then return
		elseif id == 1 then return self:ReadByte( ) == 1
		elseif id == 2 then return self:ReadDouble( )
		elseif id == 4 then return self:ReadString( )
		elseif id == 5 then	return self:ReadTable( )
		elseif id == 8 then
			local steamID64 = self:ReadString()
			local plys = player.GetAll()

			for i = 1, #plys do
				if plys[i]:SteamID64() == steamID64 then
					return plys[i]
				end
			end
		elseif id == 9 then 	return Entity( self:ReadULong( ) )
		elseif id == 10 then 	return self:ReadVector( )
		elseif id == 11 then 	return self:ReadAngle( )
		elseif id == 21 then 	return Material( self:ReadString( ) )
		elseif id == 255 then 	return self:ReadColor( )
		end
	end

	--- Writes a table
	--- @param tab table
	--- @return self BitBuffer
	function meta:WriteTable( tab )
		for k, v in pairs( tab ) do
			self:WriteType( k )
			self:WriteType( v )
		end

		self:WriteByte( 0 )

		return self
	end

	--- Reads a table. Default maxValues is 150
	--- @param maxValues? number
	--- @return table
	function meta:ReadTable( maxValues )
		maxValues = maxValues or 150

		-- Table
		local tab = {}
		local k = self:ReadType()

		while k ~= nil and maxValues > 0 do
			tab[k] = self:ReadType()
			k = self:ReadType()
			maxValues = maxValues - 1
		end

		return tab
	end
end

-- File functions
do
	--- Same as file.Open, but returns it as a bitbuffer. little_endian is true by default.
	--- @param fileName string
	--- @param gamePath? string
	--- @param lzma? boolean
	--- @param little_endian? boolean
	--- @return BitBuffer
	function NikNaks.BitBuffer.OpenFile( fileName, gamePath, lzma, little_endian )
		if gamePath == true then gamePath = "GAME" end
		if gamePath == nil then gamePath = "DATA" end
		if gamePath == false then gamePath = "DATA" end

		local f = file.Open( fileName, "rb", gamePath )
		if not f or not NikNaks._source:find( "niknak" ) then return end

		-- Data
		local str = f:Read( f:Size() ) -- Is faster
		if lzma then
			str = util.Decompress( str ) or str
		end

		f:Close()

		--- @type BitBuffer
		local b = NikNaks.BitBuffer( str, little_endian )
		b:Seek( 0 )

		return b
	end

	--- Saves the bitbuffer to a file within the data folder. Returns true if it got saved.
	--- @param fileName string
	--- @param lzma? boolean
	--- @return boolean
	function meta:SaveToFile( fileName, lzma )
		local f = file.Open( fileName, "wb", "DATA" )
		if not f then return false end

		local s = self:Size()
		local t = self:Tell()

		if lzma then
			self:Seek( 0 )
			local data = self:Read()
			data = util.Compress( data ) or data
			f:Write( data )
		else
			local n = rshift( s, 5 ) -- Amount of "chunks"
			for i = 1, n do
				f:WriteULong( self._data[i] )
			end

			local p = lshift( n, 5 )
			local l = s - p -- How many bits left to write.

			self:Seek( p )

			for i = 1, math.ceil( l / 8 ) do
				f:WriteByte( f:ReadByte() )
			end
		end

		self:Seek( t )
		f:Close()

		return true
	end
end

-- Net functions
function meta:ReadFromNet( bits )
	for i = 1, bits / 32 do
		self:WriteUInt( net.ReadUInt( 32 ), 32 )
	end

	local leftover = bits % 32
	if leftover > 0 then
		self:WriteUInt( net.ReadUInt( leftover ), leftover )
	end

	self:Seek( 0 )
	return self
end

function NikNaks.BitBuffer.FromNet( bits )
	return NikNaks.BitBuffer():ReadFromNet( bits )
end

function meta:WriteToNet()
	local tell = self:Tell()
	self:Seek( 0 )

	local l = self:Size()
	for _ = 1, l / 32 do
		net.WriteUInt( self:ReadULong(), 32 )
	end

	local leftover = l % 32
	if leftover > 0 then
		net.WriteUInt( self:ReadUInt( leftover ), leftover )
	end

	self:Seek( tell )
	return l
end

function NikNaks.BitBuffer.ToNet( buf )
	return buf:WriteToNet()
end


-- Debug BitBuffer
if true then return end
local function d_print( str, b )
	print( str, b and '✓' or '✗', b and "" or "<- !!!" )
end

local function o_print( self, str, obj, ex )
	local write = "Write" .. str
	local read = "Read" .. str
	self:Seek(0)
	self[write](self, obj)
	self:Seek(0)
	local r = self[read]( self )
	local p = r == obj
	str = ex and ex .. str or str
	if p then
		d_print( str .. string.rep(" ", 8 - #str), true)
	else
		print( str, '✗', r, "~=", obj )
	end
end

function NikNaks.BitBuffer.DebugTest()
	local b = create()
	print( "\n============= BitBuffer Test =============" )
	print( "State" )
		b:WriteInt(0, 8)
		b:WriteInt(0, 16)
		b:WriteInt(0x1234, 32)
		b:WriteInt(0, 8)
		d_print("	Tell", b._len == 8 + 16 + 32 + 8 )
		b:Seek( 8 + 16 )
		d_print("	Seek", b:ReadInt(32) == 0x1234 )
		b:ReadInt( 8 )
		d_print("	End", b:EndOfData())
		b:Seek( 0 )
	print("Boolean:")
		for i = 1, 64 do
			b:WriteBoolean( i % 3 == 0 )
		end
		b:Seek( 0 )
		local q = true
		for i = 1, 64 do
			q = q and (b:ReadBoolean( ) == (i % 3 == 0) )
		end
		d_print("	64x w/r", q)
		b:Seek( 0 )
	print("Data:")
		b:Seek(0)
		b:Write("abcdefghijk!pq")
		b:Seek(0)
		d_print("	w/r", b:Read(14) == "abcdefghijk!pq")
		b:Seek(0)
		local q = b:Read(4) == "abcd" and b:Read(10) == "efghijk!pq"
		d_print("	parts", q)
		b:Seek(0)
	print("UInt:")
		b:WriteUInt(1,1)
		b:WriteUInt(0,1)
		b:Seek(0)
		d_print("	Bit", b:ReadUInt(1) == 1 and b:ReadUInt(1) == 0)
		b:Seek(0)

		b:WriteUInt(0,32)
		b:WriteUInt(4294967295,32)
		b:Seek(0)
		d_print("	Max/Min", b:ReadUInt(32) == 0 and b:ReadUInt(32) == 4294967295)
		b:Seek(0)

		b:WriteUInt(0x15555555,30)
		b:WriteUInt(7,3)
		b:WriteUInt(0,3)
		b:Seek(0)
		d_print("	Offset", b:ReadUInt(30) == 0x15555555 and b:ReadUInt(3) == 7 and b:ReadUInt(3) == 0 )
		b:Seek(0)
	print("Int:")
		b:WriteInt(0x15555555,31)
		b:Seek(0)
		d_print("	Negative", b:ReadUInt(31) == 0x15555555)
		b:Seek(0)
		b:WriteInt(2147483647,32)
		b:WriteInt(-2147483648,32)
		b:Seek(0)
		d_print("	Max/Min", b:ReadInt(32) == 2147483647 and b:ReadInt(32) == -2147483648)
		b:Seek(0)
	print("Float:")
		b:WriteFloat(22.33)
		b:WriteFloat(-3422.25)
		b:WriteFloat(0)
		b:WriteFloat(0 * -1)
		b:Seek(0)
		d_print( "	Num", math.Round( b:ReadFloat(), 2 ) == 22.33 and math.Round( b:ReadFloat(), 2 ) == -3422.25 and math.Round( b:ReadFloat(), 2) == 0 and math.Round( b:ReadFloat(), 2 ) == 0)
		b:Seek( 0 )
		b:WriteFloat( 1 / 0 )
		b:WriteFloat( -1 / 0 )
		b:Seek( 0 )
		d_print("	INF", tostring(b:ReadFloat()) == "inf" and tostring(b:ReadFloat()) == "-inf")
		b:Seek(0)
		b:WriteFloat(0/0)
		b:Seek(0)
		d_print("	NAN", tostring(b:ReadFloat()) == "nan")
		b:Seek( 0 )
	print( "Double:" )
		b:WriteDouble( 22.33 )
		b:WriteDouble( -3422.25 )
		b:WriteDouble( 233.25 )
		b:WriteDouble( 22.33, true )
		b:WriteDouble( 0)
		b:WriteDouble( 4 )
		b:WriteDouble( 0 / 0 )
		b:Seek(0)
		local f = math.Round(b:ReadDouble(), 2)
		local a = f == 22.33
		local g = math.Round(b:ReadDouble(), 2) == -3422.25
		local c = math.Round(b:ReadDouble(), 2) == 233.25
		local d = math.Round(b:ReadDouble(), 2) == 22.33
		local e = math.Round(b:ReadDouble(), 2) == 0 and math.Round(b:ReadDouble( true), 2) == 4 and tostring(b:ReadDouble( true)) == "nan"

		d_print("	Num", a and g and c and d and e )
		b:Seek(0)
		b:WriteDouble( 1 / 0 )
		b:WriteDouble( -1 / 0 )
		b:Seek(0)
		d_print("	INF", tostring(b:ReadDouble()) == "inf" and tostring(b:ReadDouble()) == "-inf")
		b:Seek(0)
		b:WriteDouble( 0 / 0 )
		b:Seek(0)
		d_print("	NAN", tostring(b:ReadDouble()) == "nan")
		b:Seek(0)
	print("Signed:")
	-- Signed Byte
	o_print(b, "Long", -214748364, "\t")
	-- Signed Byte
	o_print(b, "Short",  -32768, "\t")
	-- Signed Byte
	o_print(b, "SignedByte", -128, "\t")
	print("Unsigned:")
	-- Signed Byte
	o_print(b, "ULong", 4294967295, "\t" )
	-- Signed Byte
	o_print(b, "UShort", 0xF0F0, "\t")
	-- Byte
	o_print(b, "Byte", 255, "\t")
	-- Signed Byte
	o_print(b, "Nibble", 5, "\t")
	-- Signed Byte
	o_print(b, "Snort", 3, "\t")
	print("Objects:")
	-- string
	o_print(b, "String", "abcdefghijklmnopqrstuvwxyz !abcdefghijklmnopqrstuvwxyz!abcdefghijklmnopqrstuvwxyz!", "\t")
	-- stringnull
	o_print(b, "StringNull", "abcdefghijklmnopqrstuvwxyz !abcdefghijklmnopqrstuvwxyz!abcdefghijklmnopqrstuvwxyz!", "\t")
	-- vector
	o_print(b, "Vector", Vector(123,321,101), "\t")
	-- angle
	o_print(b, "Angle", Angle(3,22,13213), "\t")
	-- color
	o_print(b, "Color", Color(255,0,127, 55), "\t")
	-- HEX / BIT Display
	print()
	b = create()
	b:WriteUInt(0x00FFFFFF, 32)
	b:WriteUInt(0xFF00FFFF, 32)
	b:WriteUInt(0xFFFF00FF, 32)
	b:WriteUInt(0xFFFFFF00, 32)
	for i = 1, 5 do
		b:WriteUInt(1, 6)
	end
	b:WriteUInt(1,3)
	b:WriteUInt(1,31)
	b:Debug()
end

NikNaks.BitBuffer.DebugTest()