Serial utils for lua

sutil.lua

local sutil = {}

function sutil.getchar(ttyfile)
   return ttyfile:read(1)
end

function sutil.readall_timeout(ttyfile, n, time)
   local data = ""
   local ret = true
   local ctr = 0
   local start = os.time()
   local timeout = false
   while (ctr<n) do
      local current = os.time()
      if (current-start>time) then
         print("Timeout [current: "..tostring(current).." start: "..tostring(start).." diff: "..tostring(current-start).."]")
         timeout = true
         break
      end
      local char = ttyfile:read(n-ctr)
      if char ~= nil then
         ctr=ctr+char:len()
         -- print ("ret: "..tostring(ret).." char: "..tostring(char))
         data = data..char
      end
   end
   return data, timeout
end

function sutil.set_line_params(dev, speed)
   speed = tostring(speed)
   os.execute("stty -F "..dev.." -echo cbreak ispeed "..speed.." ospeed "..speed.." min 0 time 3")
end

-- convert a 64-bit unsigned integer into a 8 bytes (network order)
function sutil.int64_to_bytes(n)
  -- adjust for 2's complement
   --n = (n < 0) and (4294967296 + n) or n
   return string.char((math.modf(n/0x100000000000000))%256)..string.char((math.modf(n/0x1000000000000))%256)..string.char((math.modf(n/0x10000000000))%256)..string.char((math.modf(n/4294967296))%256)..string.char((math.modf(n/16777216))%256)..string.char((math.modf(n/65536))%256)..string.char((math.modf(n/256))%256)..string.char(n%256)
end

-- convert bytes (network order) to a 64-bit unsigned integer
function sutil.bytes_to_int64(s)
   local n = string.byte(s, 1)*0x100000000000000 + string.byte(s, 2)*0x1000000000000 + string.byte(s, 3)*0x10000000000 + string.byte(s, 4)*0x100000000 + string.byte(s, 5)*0x1000000 + string.byte(s, 6)*0x10000 + string.byte(s, 7)*0x100 + string.byte(s, 8)
   return n
end

-- convert a 64-bit two's complement integer into a 8 bytes (network order)
function sutil.int32_to_bytes(n)
  -- adjust for 2's complement
   --n = (n < 0) and (4294967296 + n) or n
   return string.char((math.modf(n/16777216))%256)..string.char((math.modf(n/65536))%256)..string.char((math.modf(n/256))%256)..string.char(n%256)
end

-- convert bytes (network order) to a 64-bit two's complement integer
function sutil.bytes_to_int32(s)
   local n = string.byte(s, 1)*0x1000000 + string.byte(s, 2)*0x10000 + string.byte(s, 3)*0x100 + string.byte(s, 4)
   return n
end

function sutil.htonl(int_str)
   return string.sub(int_str, 4, 4)..string.sub(int_str, 3, 3)..string.sub(int_str, 2, 2)..string.sub(int_str, 1, 1)
end

return sutil