OC-PsychOS2/lib/interminitel.lua

64 lines
1.5 KiB
Lua

local imt = {}
imt.ttypes = {}
imt.ttypes.string=1
imt.ttypes.number=2
imt.ftypes = {tostring,tonumber}
function imt.to16bn(n)
return string.char(math.floor(n/256))..string.char(math.floor(n%256))
end
function imt.from16bn(s)
return (string.byte(s,1,1)*256)+string.byte(s,2,2)
end
function imt.encodePacket(...)
local tArgs = {...}
local packet = string.char(#tArgs%256)
for _,segment in ipairs(tArgs) do
local segtype = type(segment)
segment = tostring(segment)
packet = packet .. imt.to16bn(segment:len()) .. string.char(imt.ttypes[segtype]) .. tostring(segment)
end
packet = imt.to16bn(packet:len()) .. packet
return packet
end
function imt.decodePacket(s)
local function getfirst(n)
local ns = s:sub(1,n)
s=s:sub(n+1)
return ns
end
if s:len() < 2 then return false end
local plen = imt.from16bn(getfirst(2))
local segments = {}
if s:len() < plen then return false end
local nsegments = string.byte(getfirst(1))
--print(tostring(plen).." bytes, "..tostring(nsegments).." segments")
for i = 1, nsegments do
local seglen = imt.from16bn(getfirst(2))
local segtype = imt.ftypes[string.byte(getfirst(1))]
local segment = segtype(getfirst(seglen))
--print(seglen,segtype,segment,type(segment))
segments[#segments+1] = segment
end
return table.unpack(segments)
end
function imt.getRemainder(s)
local function getfirst(n)
local ns = s:sub(1,n)
s=s:sub(n+1)
return ns
end
local plen = imt.from16bn(getfirst(2))
if s:len() > plen then
getfirst(plen)
return s
end
return nil
end
return imt