stackoverflow with LuaJIT 2.0.0-beta6 (but not with lua 5.1.4)

[Valerio Schiavoni <valerio.schiavoni@...>]

Hello,

the following code throws a stack overflow error with luajit, but it
works fine (although slowly) with lua 5.1.4.

Also, if you have suggestions on how to improve the running time of it
that'd be nice.


--save as : test-bench-luajit.lua
-- convert big or small number in scientific notation into a decimal string
function to_dec_string(s)
	s = tostring(s)
	local start, stop = string.find(s, "e", 1, true)
	-- not scientific
	if not start then return s end

	local positif = true
	if string.sub(s, 1, 1) == "-" then
		s = tonumber(string.sub(s, 2))
		positif = false
	end

	local t = split(s, "e")
	local m, e = t[1], t[2]
	local t = split(m, ".")
	if t[2] then
		m = t[1]..t[2]
	end

	if string.sub(e, 1, 1) == "-" then
		e = tonumber(string.sub(e, 2))
		for i = 1, e - 1 do
			m = "0"..m
		end
		m = "0."..m
	else
		e = tonumber(e) - #m + 1
		for i = 1, e do
			m = m.."0"
		end
	end
	if not positif then m = "-"..m end
	return m
end

function encode(data)
	local t = type(data)

	if t == 'table' then -- list(array) or hash
		local i = 1
		local list = true
		for k, v in pairs(data) do
			if k ~= i then
				list = false
				break
			end
			i = i + 1
		end
		local out = ''
		if list then
			out = 'l'
			for k, v in pairs(data) do
				out = out..encode(v)
			end
		else -- hash
			out = 'd'
			for k, v in pairs(data) do
				out = out..encode(k)..encode(v)
			end
		end
		return out..'e'
	elseif t == 'string' then
		return #data..':'..data
	elseif t == 'number' then
		-- we need to convert scientific notation to decimal
		return 'i'..to_dec_string(data)..'e'
	elseif t == 'nil' then -- extension of benc
		return 'n'
	elseif t == 'boolean' then -- extension of benc
		if data then
			return 't'
		else
			return 'f'
		end
	end
end

data_sizes={1000,10000,100000,1000000}

print("Bench nested arrays with fixed-size string")
for k,v in pairs(data_sizes) do
	
	local gen="a"
	for i=1,(v/100) do --to avoid stackoverlow
		gen={gen}
	end
	
	start=os.clock()
	enc_data=encode(gen)
	print((v/100), os.clock()-start)
end


best regards,
Valerio