Skip to content

Instantly share code, notes, and snippets.

@snegovick snegovick/sutil.lua
Created Sep 10, 2015

Embed
What would you like to do?
Serial utils for 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
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.