example.lua

-- `*` prefix means list. 
-- e.g. `*ui6` would be a list of 6 bit wide unsigned integers.
local Schema = [[
	Version ui
	Thing *i
	Items *s
	Test i4
	pi f64
	e f32
]]
-- This is the table encoded in the Base64 string below.
local Data = {
	Version = 2,
	Thing = { 1, 2, 3, 5, 100 },
	Items = { 'hey', 'hello', 'test' },
	Test = -2,
	pi = 3.14159,
	e = 2.71828
}
local B = b.MakeBuffer()
B.Schema = Schema
B:FromSchema(Data)
print(B:ToBase64())
B:FromBase64('CHdYhFf0HyiLTR8AQLrY0BuTL/YwH8n6mhbAf+hkFgNhfrCA')
local Data = B:ToSchema()
print(Data.Items[1], Data.Items[2], Data.Items[3])
print(Data.Version, Data.Test, Data.pi, Data.e)

FastBuffer.lua

-- FastBuffer
-- @BadccVoid
-- Tell me if you have optimizations!

local pow,log,ceil,floor=math.pow,math.log,math.ceil,math.floor
local insert,concat=table.insert,table.concat
local char,byte=string.char,string.byte
local abs=math.abs
local frexp,ldexp=math.frexp,math.ldexp
local log2=log(2)

local ntb,btn do
	ntb,btn={},{}
	local b = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
	for i = 1,#b do
		local j=b:sub(i,i)
		ntb[i-1],btn[j]=j,i-1
	end
end

local p2m do
	p2m = {}
	for i = 0,64 do
		p2m[i]=2^i
	end
end

local b = {}
b.__index = b
function b.MakeBuffer()
	return setmetatable({
		d = {},
		i = 0
	}, b)
end
local function NextPower(n)
	if (n==0) then return 1 end
	for i=0,64 do
		if (n<p2m[i]) then return i end
	end
end
local function NextPowerOf2(n)
	return p2m[NextPower(n)]
end
local function Write(b,v)
	local i=b.i+1
	b.i=i
	b.d[i]=v
end
local function Read(b)
	local i=b.i+1
	b.i=i
	return b.d[i]
end
function b:WriteBool(v)
	Write(self,v and 1 or 0)
	return true
end
function b:ReadBool(v)
	return Read(self) == 1
end
function b:WriteUnsignedW(w,v)
	assert(v>=0,v..' signed') -- Unsigned
	assert(floor(v)==v,v..' not integer') -- Integer
	assert(v<=p2m[w],v..' too big')
	for i=1,w do
		Write(self,v%2)
		v=floor(v*0.5)
	end
	return true
end
function b:ReadUnsignedW(w)
	local r=0
	for i=1,w do
		r=r+p2m[i-1]*Read(self)
	end
	return r
end
function b:WriteUnsigned(v)
	local w=NextPower(v)
	self:WriteUnsignedW(5,w)
	self:WriteUnsignedW(w,v)
	return true
end
function b:ReadUnsigned()
	local w=self:ReadUnsignedW(5)
	return self:ReadUnsignedW(w)
end
function b:WriteSignedW(w,v)
	self:WriteBool(v>=0)
	return self:WriteUnsignedW(w-1,abs(v))
end
function b:ReadSignedW(w)
	local s=self:ReadBool() and 1 or -1
	return self:ReadUnsignedW(w-1)*s
end
function b:WriteSigned(v)
	self:WriteBool(v>=0)
	return self:WriteUnsigned(abs(v))
end
function b:ReadSigned()
	local s=self:ReadBool() and 1 or -1
	return self:ReadUnsigned()*s
end
function b:WriteFloatW(wm,we,f)
	local s=f>=0
	self:WriteBool(s)
	if (not s) then f=-f end
	local m,e=frexp(f)
	m=(m-0.5)/0.5*p2m[wm]
	m=floor(m+0.5)
	self:WriteUnsignedW(wm,m)
	return self:WriteSignedW(we,e)
end
function b:ReadFloatW(wm,we)
	local s=self:ReadBool() and 1 or -1
	local m,e=self:ReadUnsignedW(wm),self:ReadSignedW(we)
	m=m/p2m[wm]*0.5+0.5
	return s*ldexp(m,e)
end
function b:WriteFloat32(f)
	return self:WriteFloatW(23,8,f)
end
function b:ReadFloat32()
	return self:ReadFloatW(23,8)
end
function b:WriteFloat64(f)
	return self:WriteFloatW(52,11,f)
end
function b:ReadFloat64()
	return self:ReadFloatW(52,11)
end
function b:WriteString(s)
	local mi,ma
	for i=1,#s do
		local c=byte(s:sub(i,i))
		if (not mi or c<mi) then mi=c end
		if (not ma or c>ma) then ma=c end
	end
	-- min,range,n,bytes[]
	self:WriteUnsignedW(7,mi)
	self:WriteUnsignedW(7,ma-mi)
	self:WriteUnsigned(#s)
	-- Optimial case: Minimize range and minimum
	local w=NextPower(ma-mi)
	for i=1,#s do
		local c=s:sub(i,i):byte()-mi
		self:WriteUnsignedW(w,c)
	end
	return true
end
function b:ReadString()
	local mi=self:ReadUnsignedW(7)
	local r=self:ReadUnsignedW(7)
	local l=self:ReadUnsigned()
	local w=NextPower(r)
	local s={}
	for i=1,l do
		local u=self:ReadUnsignedW(w)
		local c=u+mi
		insert(s,char(c))
	end
	return concat(s)
end
function b:ToBase64()
	local t={}
	local a,i,d=0,self.i,self.d
	for j=1,i do
		local jm6=(j-1)%6 -- 2^6=64
		a=a+p2m[jm6]*d[j]
		if (jm6==5 or j==i) then
			insert(t,ntb[a])
			a=0
		end
	end
	return concat(t)
end
function b:FromBase64(s)
	self.i=0
	self.d={}
	for i=1,#s do
		local c=btn[s:sub(i,i)]
		for j=1,6 do
			Write(self,c%2)
			c=floor(c*0.5)
		end
	end
	self.i=0
end
function SchemaAction(self,t,w,v)
	local a=v and 'Write' or 'Read'
	if (t=='ui') then
		return w and self[a..'UnsignedW'](self,w,v) or self[a..'Unsigned'](self,v)
	elseif (t=='i') then
		return w and self[a..'SignedW'](self,w,v) or self[a..'Signed'](self,v)
	elseif (t=='f') then
		assert(w==32 or w==64, 'invalid float width')
		return self[a..'Float'..w](self,v)
	elseif (t=='s') then
		return self[a..'String'](self,v)
	elseif (t:sub(1,1)=='*') then
		local l = not v and {}
		if (v) then self['WriteUnsigned'](self,#v) end
		for i=1,v and #v or self[a..'Unsigned'](self) do
			local r=SchemaAction(self,t:sub(2),w,v and v[i])
			if (not v) then insert(l,r) end
		end
		return l
	end
end
function b:FromSchema(Data)
	for n,t,w in self.Schema:gmatch('(%w+)%s*([%*%a]+)(%d*)') do
		w=tonumber(w)
		local v=Data[n]
		SchemaAction(self,t,w,v)
	end
end
function b:ToSchema()
	local d={}
	for n,t,w in self.Schema:gmatch('(%w+)%s*([%*%a]+)(%d*)') do
		w=tonumber(w)
		d[n]=SchemaAction(self,t,w)
	end
	return d
end
function b.TrimSchema(Schema)
	return Schema:gsub('%s*(%w+)%s*([^\n]+)','%1 %2 '):sub(0,-2)
end
function b:Dump()
	local s = ''
	for i=1,self.i do
		-- Print MSB
		s=tostring(self.d[i])..s
		if (i%8==0 and i~=self.i) then s=' '..s end
	end
	print(s)
end