try to reorganize modules per os

We should make better split os specify code for FreeBSD and Linux.
Idea comes from @liskin.

19 files changed, 966 insertions, 702 deletions

diff --git a/src/Xmobar/Plugins/Monitors/Batt.hs b/src/Xmobar/Plugins/Monitors/Batt.hs
index af932ae..52600d8 100644
--- a/src/Xmobar/Plugins/Monitors/Batt.hs
+++ b/src/Xmobar/Plugins/Monitors/Batt.hs
@@ -17,44 +17,18 @@
 
 module Xmobar.Plugins.Monitors.Batt ( battConfig, runBatt, runBatt' ) where
 
-import System.Process (system)
-import Control.Monad (void, unless)
+import Xmobar.Plugins.Monitors.Batt.Common (BattOpts(..)
+                                           , Result(..)
+                                           , Status(..))
 import Xmobar.Plugins.Monitors.Common
-import Control.Exception (SomeException, handle)
-import System.FilePath ((</>))
-import System.IO (IOMode(ReadMode), hGetLine, withFile)
-import System.Posix.Files (fileExist)
-#ifdef FREEBSD
-import System.BSD.Sysctl (sysctlReadInt)
-#endif
 import System.Console.GetOpt
-import Data.List (sort, sortBy, group)
-import Data.Maybe (fromMaybe)
-import Data.Ord (comparing)
-import Text.Read (readMaybe)
 
-data BattOpts = BattOpts
-  { onString :: String
-  , offString :: String
-  , idleString :: String
-  , posColor :: Maybe String
-  , lowWColor :: Maybe String
-  , mediumWColor :: Maybe String
-  , highWColor :: Maybe String
-  , lowThreshold :: Float
-  , highThreshold :: Float
-  , onLowAction :: Maybe String
-  , actionThreshold :: Float
-  , onlineFile :: FilePath
-  , scale :: Float
-  , onIconPattern :: Maybe IconPattern
-  , offIconPattern :: Maybe IconPattern
-  , idleIconPattern :: Maybe IconPattern
-  , lowString :: String
-  , mediumString :: String
-  , highString :: String
-  , incPerc :: Bool
-  }
+#if defined(freebsd_HOST_OS)
+import qualified Xmobar.Plugins.Monitors.Batt.FreeBSD as MB
+#else
+import qualified Xmobar.Plugins.Monitors.Batt.Linux as MB
+#endif
+
 
 defaultOpts :: BattOpts
 defaultOpts = BattOpts
@@ -108,34 +82,11 @@ options =
   , Option "" ["highs"] (ReqArg (\x o -> o { highString = x }) "") ""
   ]
 
-data Status = Charging | Discharging | Full | Idle | Unknown deriving (Read, Eq)
--- Result perc watts time-seconds Status
-data Result = Result Float Float Float Status | NA
-
-sysDir :: FilePath
-sysDir = "/sys/class/power_supply"
-
 battConfig :: IO MConfig
 battConfig = mkMConfig
        "Batt: <watts>, <left>% / <timeleft>" -- template
        ["leftbar", "leftvbar", "left", "acstatus", "timeleft", "watts", "leftipat"] -- replacements
 
-data Files = Files
-  { fFull :: String
-  , fNow :: String
-  , fVoltage :: String
-  , fCurrent :: String
-  , fStatus :: String
-  , isCurrent :: Bool
-  } | NoFiles deriving Eq
-
-data Battery = Battery
-  { full :: !Float
-  , now :: !Float
-  , power :: !Float
-  , status :: !String
-  }
-
 data BatteryStatus
   = BattHigh
   | BattMedium
@@ -153,130 +104,13 @@ getBattStatus charge opts
  where
    c = 100 * min 1 charge
 
-maybeAlert :: BattOpts -> Float -> IO ()
-maybeAlert opts left =
-  case onLowAction opts of
-    Nothing -> return ()
-    Just x -> unless (isNaN left || actionThreshold opts < 100 * left)
-                $ void $ system x
-
--- | FreeBSD battery query
-#ifdef FREEBSD
-battStatusFbsd :: Int -> Status
-battStatusFbsd x
-  | x == 1 = Discharging
-  | x == 2 = Charging
-  | otherwise = Unknown
-
-readBatteriesFbsd :: BattOpts -> IO Result
-readBatteriesFbsd opts = do
-  lf <- sysctlReadInt "hw.acpi.battery.life"
-  rt <- sysctlReadInt "hw.acpi.battery.rate"
-  tm <- sysctlReadInt "hw.acpi.battery.time"
-  st <- sysctlReadInt "hw.acpi.battery.state"
-  acline <- sysctlReadInt "hw.acpi.acline"
-  let p = fromIntegral lf / 100
-      w = fromIntegral rt
-      t = fromIntegral tm * 60
-      ac = acline == 1
-      -- battery full when rate is 0 and on ac.
-      sts = if (w == 0 && ac) then Full else (battStatusFbsd $ fromIntegral st)
-  unless ac (maybeAlert opts p)
-  return (Result p w t sts)
-
-#else
--- | query linux battery
-safeFileExist :: String -> String -> IO Bool
-safeFileExist d f = handle noErrors $ fileExist (d </> f)
-  where noErrors = const (return False) :: SomeException -> IO Bool
-
-batteryFiles :: String -> IO Files
-batteryFiles bat =
-  do is_charge <- exists "charge_now"
-     is_energy <- if is_charge then return False else exists "energy_now"
-     is_power <- exists "power_now"
-     plain <- exists (if is_charge then "charge_full" else "energy_full")
-     let cf = if is_power then "power_now" else "current_now"
-         sf = if plain then "" else "_design"
-     return $ case (is_charge, is_energy) of
-       (True, _) -> files "charge" cf sf is_power
-       (_, True) -> files "energy" cf sf is_power
-       _ -> NoFiles
-  where prefix = sysDir </> bat
-        exists = safeFileExist prefix
-        files ch cf sf ip = Files { fFull = prefix </> ch ++ "_full" ++ sf
-                                  , fNow = prefix </> ch ++ "_now"
-                                  , fCurrent = prefix </> cf
-                                  , fVoltage = prefix </> "voltage_now"
-                                  , fStatus = prefix </> "status"
-                                  , isCurrent = not ip}
-
-haveAc :: FilePath -> IO Bool
-haveAc f =
-  handle onError $ withFile (sysDir </> f) ReadMode (fmap (== "1") . hGetLine)
-  where onError = const (return False) :: SomeException -> IO Bool
-
-readBattery :: Float -> Files -> IO Battery
-readBattery _ NoFiles = return $ Battery 0 0 0 "Unknown"
-readBattery sc files =
-    do a <- grab $ fFull files
-       b <- grab $ fNow files
-       d <- grab $ fCurrent files
-       s <- grabs $ fStatus files
-       let sc' = if isCurrent files then sc / 10 else sc
-           a' = max a b -- sometimes the reported max charge is lower than
-       return $ Battery (3600 * a' / sc') -- wattseconds
-                        (3600 * b / sc') -- wattseconds
-                        (abs d / sc') -- watts
-                        s -- string: Discharging/Charging/Full
-    where grab f = handle onError $ withFile f ReadMode (fmap read . hGetLine)
-          onError = const (return (-1)) :: SomeException -> IO Float
-          grabs f = handle onError' $ withFile f ReadMode hGetLine
-          onError' = const (return "Unknown") :: SomeException -> IO String
-
--- sortOn is only available starting at ghc 7.10
-sortOn :: Ord b => (a -> b) -> [a] -> [a]
-sortOn f =
-  map snd . sortBy (comparing fst) . map (\x -> let y = f x in y `seq` (y, x))
-
-mostCommonDef :: Eq a => a -> [a] -> a
-mostCommonDef x xs = head $ last $ [x] : sortOn length (group xs)
-
-readBatteriesLinux :: BattOpts -> [Files] -> IO Result
-readBatteriesLinux opts bfs =
-    do let bfs' = filter (/= NoFiles) bfs
-       bats <- mapM (readBattery (scale opts)) (take 3 bfs')
-       ac <- haveAc (onlineFile opts)
-       let sign = if ac then 1 else -1
-           ft = sum (map full bats)
-           left = if ft > 0 then sum (map now bats) / ft else 0
-           watts = sign * sum (map power bats)
-           time = if watts == 0 then 0 else max 0 (sum $ map time' bats)
-           mwatts = if watts == 0 then 1 else sign * watts
-           time' b = (if ac then full b - now b else now b) / mwatts
-           statuses :: [Status]
-           statuses = map (fromMaybe Unknown . readMaybe)
-                          (sort (map status bats))
-           acst = mostCommonDef Unknown $ filter (Unknown/=) statuses
-           racst | acst /= Unknown = acst
-                 | time == 0 = Idle
-                 | ac = Charging
-                 | otherwise = Discharging
-       unless ac (maybeAlert opts left)
-       return $ if isNaN left then NA else Result left watts time racst
-#endif
-
 runBatt :: [String] -> Monitor String
 runBatt = runBatt' ["BAT", "BAT0", "BAT1", "BAT2"]
 
 runBatt' :: [String] -> [String] -> Monitor String
 runBatt' bfs args = do
   opts <- io $ parseOptsWith options defaultOpts args
-#ifdef FREEBSD
-  c <- io $ readBatteriesFbsd opts
-#else
-  c <- io $ readBatteriesLinux opts =<< mapM batteryFiles bfs
-#endif
+  c <- io $ MB.readBatteries opts bfs
   formatResult c opts
 
 formatResult :: Result -> BattOpts -> Monitor String
diff --git a/src/Xmobar/Plugins/Monitors/Batt/Common.hs b/src/Xmobar/Plugins/Monitors/Batt/Common.hs
new file mode 100644
index 0000000..3262b78
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Batt/Common.hs
@@ -0,0 +1,57 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Batt.Common
+-- Copyright   :  (c) 2010, 2011, 2012, 2013, 2015, 2016, 2018, 2019 Jose A Ortega
+--                (c) 2010 Andrea Rossato, Petr Rockai
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A battery monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Batt.Common (BattOpts(..)
+                                           , Result(..)
+                                           , Status(..)
+                                           , maybeAlert) where
+
+import System.Process (system)
+import Control.Monad (unless, void)
+import Xmobar.Plugins.Monitors.Common
+
+data Status = Charging | Discharging | Full | Idle | Unknown deriving (Read, Eq)
+-- Result perc watts time-seconds Status
+data Result = Result Float Float Float Status | NA
+
+data BattOpts = BattOpts
+  { onString :: String
+  , offString :: String
+  , idleString :: String
+  , posColor :: Maybe String
+  , lowWColor :: Maybe String
+  , mediumWColor :: Maybe String
+  , highWColor :: Maybe String
+  , lowThreshold :: Float
+  , highThreshold :: Float
+  , onLowAction :: Maybe String
+  , actionThreshold :: Float
+  , onlineFile :: FilePath
+  , scale :: Float
+  , onIconPattern :: Maybe IconPattern
+  , offIconPattern :: Maybe IconPattern
+  , idleIconPattern :: Maybe IconPattern
+  , lowString :: String
+  , mediumString :: String
+  , highString :: String
+  , incPerc :: Bool
+  }
+
+maybeAlert :: BattOpts -> Float -> IO ()
+maybeAlert opts left =
+  case onLowAction opts of
+    Nothing -> return ()
+    Just x -> unless (isNaN left || actionThreshold opts < 100 * left)
+                $ void $ system x
diff --git a/src/Xmobar/Plugins/Monitors/Batt/FreeBSD.hs b/src/Xmobar/Plugins/Monitors/Batt/FreeBSD.hs
new file mode 100644
index 0000000..2bb8618
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Batt/FreeBSD.hs
@@ -0,0 +1,46 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Batt.FreeBSD
+-- Copyright   :  (c) 2010, 2011, 2012, 2013, 2015, 2016, 2018, 2019 Jose A Ortega
+--                (c) 2010 Andrea Rossato, Petr Rockai
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A battery monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Batt.FreeBSD (readBatteries) where
+
+import Xmobar.Plugins.Monitors.Batt.Common (BattOpts(..)
+                                           , Result(..)
+                                           , Status(..)
+                                           , maybeAlert)
+
+import Control.Monad (unless)
+import System.BSD.Sysctl (sysctlReadInt)
+
+battStatus :: Int -> Status
+battStatus x
+  | x == 1 = Discharging
+  | x == 2 = Charging
+  | otherwise = Unknown
+
+readBatteries :: BattOpts -> [String] -> IO Result
+readBatteries opts _ = do
+  lf <- sysctlReadInt "hw.acpi.battery.life"
+  rt <- sysctlReadInt "hw.acpi.battery.rate"
+  tm <- sysctlReadInt "hw.acpi.battery.time"
+  st <- sysctlReadInt "hw.acpi.battery.state"
+  acline <- sysctlReadInt "hw.acpi.acline"
+  let p = fromIntegral lf / 100
+      w = fromIntegral rt
+      t = fromIntegral tm * 60
+      ac = acline == 1
+      -- battery full when rate is 0 and on ac.
+      sts = if w == 0 && ac then Full else battStatus $ fromIntegral st
+  unless ac (maybeAlert opts p)
+  return (Result p w t sts)
diff --git a/src/Xmobar/Plugins/Monitors/Batt/Linux.hs b/src/Xmobar/Plugins/Monitors/Batt/Linux.hs
new file mode 100644
index 0000000..454e7e9
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Batt/Linux.hs
@@ -0,0 +1,130 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Batt.Linux
+-- Copyright   :  (c) 2010, 2011, 2012, 2013, 2015, 2016, 2018, 2019 Jose A Ortega
+--                (c) 2010 Andrea Rossato, Petr Rockai
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A battery monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Batt.Linux (readBatteries) where
+
+import Xmobar.Plugins.Monitors.Batt.Common (BattOpts(..)
+                                           , Result(..)
+                                           , Status(..)
+                                           , maybeAlert)
+
+import Control.Monad (unless)
+import Control.Exception (SomeException, handle)
+import System.FilePath ((</>))
+import System.IO (IOMode(ReadMode), hGetLine, withFile)
+import System.Posix.Files (fileExist)
+import Data.List (sort, sortBy, group)
+import Data.Maybe (fromMaybe)
+import Data.Ord (comparing)
+import Text.Read (readMaybe)
+
+data Files = Files
+  { fFull :: String
+  , fNow :: String
+  , fVoltage :: String
+  , fCurrent :: String
+  , fStatus :: String
+  , isCurrent :: Bool
+  } | NoFiles deriving Eq
+
+data Battery = Battery
+  { full :: !Float
+  , now :: !Float
+  , power :: !Float
+  , status :: !String
+  }
+
+sysDir :: FilePath
+sysDir = "/sys/class/power_supply"
+
+safeFileExist :: String -> String -> IO Bool
+safeFileExist d f = handle noErrors $ fileExist (d </> f)
+  where noErrors = const (return False) :: SomeException -> IO Bool
+
+batteryFiles :: String -> IO Files
+batteryFiles bat =
+  do is_charge <- exists "charge_now"
+     is_energy <- if is_charge then return False else exists "energy_now"
+     is_power <- exists "power_now"
+     plain <- exists (if is_charge then "charge_full" else "energy_full")
+     let cf = if is_power then "power_now" else "current_now"
+         sf = if plain then "" else "_design"
+     return $ case (is_charge, is_energy) of
+       (True, _) -> files "charge" cf sf is_power
+       (_, True) -> files "energy" cf sf is_power
+       _ -> NoFiles
+  where prefix = sysDir </> bat
+        exists = safeFileExist prefix
+        files ch cf sf ip = Files { fFull = prefix </> ch ++ "_full" ++ sf
+                                  , fNow = prefix </> ch ++ "_now"
+                                  , fCurrent = prefix </> cf
+                                  , fVoltage = prefix </> "voltage_now"
+                                  , fStatus = prefix </> "status"
+                                  , isCurrent = not ip}
+
+haveAc :: FilePath -> IO Bool
+haveAc f =
+  handle onError $ withFile (sysDir </> f) ReadMode (fmap (== "1") . hGetLine)
+  where onError = const (return False) :: SomeException -> IO Bool
+
+readBattery :: Float -> Files -> IO Battery
+readBattery _ NoFiles = return $ Battery 0 0 0 "Unknown"
+readBattery sc files =
+    do a <- grab $ fFull files
+       b <- grab $ fNow files
+       d <- grab $ fCurrent files
+       s <- grabs $ fStatus files
+       let sc' = if isCurrent files then sc / 10 else sc
+           a' = max a b -- sometimes the reported max charge is lower than
+       return $ Battery (3600 * a' / sc') -- wattseconds
+                        (3600 * b / sc') -- wattseconds
+                        (abs d / sc') -- watts
+                        s -- string: Discharging/Charging/Full
+    where grab f = handle onError $ withFile f ReadMode (fmap read . hGetLine)
+          onError = const (return (-1)) :: SomeException -> IO Float
+          grabs f = handle onError' $ withFile f ReadMode hGetLine
+          onError' = const (return "Unknown") :: SomeException -> IO String
+
+-- sortOn is only available starting at ghc 7.10
+sortOn :: Ord b => (a -> b) -> [a] -> [a]
+sortOn f =
+  map snd . sortBy (comparing fst) . map (\x -> let y = f x in y `seq` (y, x))
+
+mostCommonDef :: Eq a => a -> [a] -> a
+mostCommonDef x xs = head $ last $ [x] : sortOn length (group xs)
+
+readBatteries :: BattOpts -> [String] -> IO Result
+readBatteries opts bfs =
+    do bfs' <- mapM batteryFiles bfs
+       let bfs'' = filter (/= NoFiles) bfs'
+       bats <- mapM (readBattery (scale opts)) (take 3 bfs'')
+       ac <- haveAc (onlineFile opts)
+       let sign = if ac then 1 else -1
+           ft = sum (map full bats)
+           left = if ft > 0 then sum (map now bats) / ft else 0
+           watts = sign * sum (map power bats)
+           time = if watts == 0 then 0 else max 0 (sum $ map time' bats)
+           mwatts = if watts == 0 then 1 else sign * watts
+           time' b = (if ac then full b - now b else now b) / mwatts
+           statuses :: [Status]
+           statuses = map (fromMaybe Unknown . readMaybe)
+                          (sort (map status bats))
+           acst = mostCommonDef Unknown $ filter (Unknown/=) statuses
+           racst | acst /= Unknown = acst
+                 | time == 0 = Idle
+                 | ac = Charging
+                 | otherwise = Discharging
+       unless ac (maybeAlert opts left)
+       return $ if isNaN left then NA else Result left watts time racst
diff --git a/src/Xmobar/Plugins/Monitors/Cpu.hs b/src/Xmobar/Plugins/Monitors/Cpu.hs
index cf1b1ec..d74e45c 100644
--- a/src/Xmobar/Plugins/Monitors/Cpu.hs
+++ b/src/Xmobar/Plugins/Monitors/Cpu.hs
@@ -20,22 +20,25 @@ module Xmobar.Plugins.Monitors.Cpu
   ( startCpu
   , runCpu
   , cpuConfig
-  , CpuDataRef
+  , MC.CpuDataRef
   , CpuOpts
   , CpuArguments
-  , parseCpu
+  , MC.parseCpu
   , getArguments
   ) where
 
 import Xmobar.Plugins.Monitors.Common
-import qualified Data.ByteString.Lazy.Char8 as B
-import Data.IORef (IORef, newIORef, readIORef, writeIORef)
-#ifdef FREEBSD
-import System.BSD.Sysctl (sysctlPeekArray)
-#endif
+import Data.IORef (newIORef)
 import System.Console.GetOpt
 import Xmobar.App.Timer (doEveryTenthSeconds)
 import Control.Monad (void)
+import Xmobar.Plugins.Monitors.Cpu.Common (CpuData(..))
+
+#if defined(freebsd_HOST_OS)
+import qualified Xmobar.Plugins.Monitors.Cpu.FreeBSD as MC
+#else
+import qualified Xmobar.Plugins.Monitors.Cpu.Linux as MC
+#endif
 
 newtype CpuOpts = CpuOpts
   { loadIconPattern :: Maybe IconPattern
@@ -94,83 +97,6 @@ cpuConfig =
     , iowaitField
     ]
 
-data CpuData = CpuData {
-      cpuUser :: !Float,
-      cpuNice :: !Float,
-      cpuSystem :: !Float,
-      cpuIdle :: !Float,
-      cpuIowait :: !Float,
-      cpuTotal :: !Float
-    }
-
-#ifdef FREEBSD
--- kern.cp_time data from the previous iteration for computing the difference
-type CpuDataRef = IORef [Word]
-
-cpuData :: IO [Word]
-cpuData = sysctlPeekArray "kern.cp_time" :: IO [Word]
-
-parseCpu :: CpuDataRef -> IO CpuData
-parseCpu cref = do
-    prev <- readIORef cref
-    curr <- cpuData
-    writeIORef cref curr
-    let diff = map fromIntegral $ zipWith (-) curr prev
-        user = diff !! 0
-        nice = diff !! 1
-        system = diff !! 2
-        intr = diff !! 3
-        idle = diff !! 4
-        total = user + nice + system + intr + idle
-    return CpuData
-      { cpuUser = user/total
-      , cpuNice = nice/total
-      , cpuSystem = (system+intr)/total
-      , cpuIdle = idle/total
-      , cpuIowait = 0
-      , cpuTotal = user/total
-      }
-#else
-type CpuDataRef = IORef [Int]
-
--- Details about the fields here: https://www.kernel.org/doc/Documentation/filesystems/proc.txt
-cpuData :: IO [Int]
-cpuData = cpuParser <$> B.readFile "/proc/stat"
-
-readInt :: B.ByteString -> Int
-readInt bs = case B.readInt bs of
-               Nothing -> 0
-               Just (i, _) -> i
-
-cpuParser :: B.ByteString -> [Int]
-cpuParser = map readInt . tail . B.words . head . B.lines
-
-convertToCpuData :: [Float] -> CpuData
-convertToCpuData (u:n:s:ie:iw:_) =
-  CpuData
-    { cpuUser = u
-    , cpuNice = n
-    , cpuSystem = s
-    , cpuIdle = ie
-    , cpuIowait = iw
-    , cpuTotal = sum [u, n, s]
-    }
-convertToCpuData args = error $ "convertToCpuData: Unexpected list" <> show args
-
-parseCpu :: CpuDataRef -> IO CpuData
-parseCpu cref =
-    do a <- readIORef cref
-       b <- cpuData
-       writeIORef cref b
-       let dif = zipWith (-) b a
-           tot = fromIntegral $ sum dif
-           safeDiv n = case tot of
-                         0 -> 0
-                         v -> fromIntegral n / v
-           percent = map safeDiv dif
-       return $ convertToCpuData percent
-#endif
-
 data Field = Field {
       fieldName :: !String,
       fieldCompute :: !ShouldCompute
@@ -235,7 +161,7 @@ optimizeAllTemplate args@CpuArguments {..} =
 
 data CpuArguments =
   CpuArguments
-    { cpuDataRef :: !CpuDataRef
+    { cpuDataRef :: !MC.CpuDataRef
     , cpuParams :: !MonitorConfig
     , cpuArgs :: ![String]
     , cpuOpts :: !CpuOpts
@@ -247,9 +173,9 @@ data CpuArguments =
 
 getArguments :: [String] -> IO CpuArguments
 getArguments cpuArgs = do
-  initCpuData <- cpuData
+  initCpuData <- MC.cpuData
   cpuDataRef <- newIORef initCpuData
-  void $ parseCpu cpuDataRef
+  void $ MC.parseCpu cpuDataRef
   cpuParams <- computeMonitorConfig cpuArgs cpuConfig
   cpuInputTemplate <- runTemplateParser cpuParams
   cpuAllTemplate <- runExportParser (pExport cpuParams)
@@ -270,7 +196,7 @@ getArguments cpuArgs = do
 
 runCpu :: CpuArguments -> IO String
 runCpu args@CpuArguments {..} = do
-  cpuValue <- parseCpu cpuDataRef
+  cpuValue <- MC.parseCpu cpuDataRef
   temMonitorValues <- formatCpu args cpuValue
   let templateInput =
         TemplateInput
diff --git a/src/Xmobar/Plugins/Monitors/Cpu/Common.hs b/src/Xmobar/Plugins/Monitors/Cpu/Common.hs
new file mode 100644
index 0000000..ccec535
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Cpu/Common.hs
@@ -0,0 +1,25 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Cpu.Common
+-- Copyright   :  (c) 2011, 2017 Jose Antonio Ortega Ruiz
+--                (c) 2007-2010 Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A cpu monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Cpu.Common (CpuData(..)) where
+
+data CpuData = CpuData {
+      cpuUser :: !Float,
+      cpuNice :: !Float,
+      cpuSystem :: !Float,
+      cpuIdle :: !Float,
+      cpuIowait :: !Float,
+      cpuTotal :: !Float
+    }
diff --git a/src/Xmobar/Plugins/Monitors/Cpu/FreeBSD.hs b/src/Xmobar/Plugins/Monitors/Cpu/FreeBSD.hs
new file mode 100644
index 0000000..7cb711a
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Cpu/FreeBSD.hs
@@ -0,0 +1,49 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Cpu.FreeBSD
+-- Copyright   :  (c) 2011, 2017 Jose Antonio Ortega Ruiz
+--                (c) 2007-2010 Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A cpu monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Cpu.FreeBSD (parseCpu
+                                           , CpuDataRef
+                                           , cpuData) where
+
+import Xmobar.Plugins.Monitors.Cpu.Common (CpuData(..))
+import Data.IORef (IORef, readIORef, writeIORef)
+import System.BSD.Sysctl (sysctlPeekArray)
+
+-- kern.cp_time data from the previous iteration for computing the difference
+type CpuDataRef = IORef [Word]
+
+cpuData :: IO [Word]
+cpuData = sysctlPeekArray "kern.cp_time" :: IO [Word]
+
+parseCpu :: CpuDataRef -> IO CpuData
+parseCpu cref = do
+    prev <- readIORef cref
+    curr <- cpuData
+    writeIORef cref curr
+    let diff = map fromIntegral $ zipWith (-) curr prev
+        user = head diff
+        nice = diff !! 1
+        system = diff !! 2
+        intr = diff !! 3
+        idle = diff !! 4
+        total = user + nice + system + intr + idle
+    return CpuData
+      { cpuUser = user/total
+      , cpuNice = nice/total
+      , cpuSystem = (system+intr)/total
+      , cpuIdle = idle/total
+      , cpuIowait = 0
+      , cpuTotal = user/total
+      }
diff --git a/src/Xmobar/Plugins/Monitors/Cpu/Linux.hs b/src/Xmobar/Plugins/Monitors/Cpu/Linux.hs
new file mode 100644
index 0000000..39baea6
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Cpu/Linux.hs
@@ -0,0 +1,61 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Cpu.Linux
+-- Copyright   :  (c) 2011, 2017 Jose Antonio Ortega Ruiz
+--                (c) 2007-2010 Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A cpu monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Cpu.Linux (parseCpu
+                                         , CpuDataRef
+                                         , cpuData) where
+
+import Xmobar.Plugins.Monitors.Cpu.Common (CpuData(..))
+import qualified Data.ByteString.Lazy.Char8 as B
+import Data.IORef (IORef, readIORef, writeIORef)
+
+type CpuDataRef = IORef [Int]
+
+-- Details about the fields here: https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+cpuData :: IO [Int]
+cpuData = cpuParser <$> B.readFile "/proc/stat"
+
+readInt :: B.ByteString -> Int
+readInt bs = case B.readInt bs of
+               Nothing -> 0
+               Just (i, _) -> i
+
+cpuParser :: B.ByteString -> [Int]
+cpuParser = map readInt . tail . B.words . head . B.lines
+
+convertToCpuData :: [Float] -> CpuData
+convertToCpuData (u:n:s:ie:iw:_) =
+  CpuData
+    { cpuUser = u
+    , cpuNice = n
+    , cpuSystem = s
+    , cpuIdle = ie
+    , cpuIowait = iw
+    , cpuTotal = sum [u, n, s]
+    }
+convertToCpuData args = error $ "convertToCpuData: Unexpected list" <> show args
+
+parseCpu :: CpuDataRef -> IO CpuData
+parseCpu cref =
+    do a <- readIORef cref
+       b <- cpuData
+       writeIORef cref b
+       let dif = zipWith (-) b a
+           tot = fromIntegral $ sum dif
+           safeDiv n = case tot of
+                         0 -> 0
+                         v -> fromIntegral n / v
+           percent = map safeDiv dif
+       return $ convertToCpuData percent
diff --git a/src/Xmobar/Plugins/Monitors/Mem.hs b/src/Xmobar/Plugins/Monitors/Mem.hs
index 6f3e383..6a863ce 100644
--- a/src/Xmobar/Plugins/Monitors/Mem.hs
+++ b/src/Xmobar/Plugins/Monitors/Mem.hs
@@ -17,12 +17,14 @@ module Xmobar.Plugins.Monitors.Mem (memConfig, runMem, totalMem, usedMem) where
 
 import Xmobar.Plugins.Monitors.Common
 import System.Console.GetOpt
-#ifdef FREEBSD
-import System.BSD.Sysctl (sysctlReadUInt)
+
+#if defined(freebsd_HOST_OS)
+import qualified Xmobar.Plugins.Monitors.Mem.FreeBSD as MM
 #else
-import qualified Data.Map as M
+import qualified Xmobar.Plugins.Monitors.Mem.Linux as MM
 #endif
 
+
 data MemOpts = MemOpts
   { usedIconPattern :: Maybe IconPattern
   , freeIconPattern :: Maybe IconPattern
@@ -54,58 +56,11 @@ memConfig = mkMConfig
         "usedratio", "freeratio", "availableratio",
         "total", "free", "buffer", "cache", "available", "used"] -- available replacements
 
-#ifdef FREEBSD
-parseMEM :: IO [Float]
-parseMEM = do stats <- mapM sysctlReadUInt [
-                "vm.stats.vm.v_page_size"
-                , "vm.stats.vm.v_page_count"
-                , "vm.stats.vm.v_free_count"
-                , "vm.stats.vm.v_active_count"
-                , "vm.stats.vm.v_inactive_count"
-                , "vm.stats.vm.v_wire_count"
-                , "vm.stats.vm.v_cache_count"]
-
-              let [ pagesize, totalpages, freepages, activepages, inactivepages, wiredpages, cachedpages ] = fmap fromIntegral stats
-                  usedpages = activepages + wiredpages + cachedpages
-                  availablepages = inactivepages + cachedpages + freepages
-                  bufferedpages = activepages + inactivepages + wiredpages
-
-                  available = availablepages * pagesize
-                  used = usedpages * pagesize
-                  free = freepages * pagesize
-                  cache = cachedpages * pagesize
-                  buffer = bufferedpages * pagesize
-                  total = totalpages * pagesize
-
-                  usedratio = usedpages / totalpages
-                  freeratio = freepages / totalpages
-                  availableratio = availablepages / totalpages
-
-              return [usedratio, freeratio, availableratio, total, free, buffer, cache, available, used]
-
-#else
-fileMEM :: IO String
-fileMEM = readFile "/proc/meminfo"
-
-parseMEM :: IO [Float]
-parseMEM =
-    do file <- fileMEM
-       let content = map words $ take 8 $ lines file
-           info = M.fromList $ map (\line -> (head line, (read $ line !! 1 :: Float) / 1024)) content
-           [total, free, buffer, cache] = map (info M.!) ["MemTotal:", "MemFree:", "Buffers:", "Cached:"]
-           available = M.findWithDefault (free + buffer + cache) "MemAvailable:" info
-           used = total - available
-           usedratio = used / total
-           freeratio = free / total
-           availableratio = available / total
-       return [usedratio, freeratio, availableratio, total, free, buffer, cache, available, used]
-#endif
-
 totalMem :: IO Float
-totalMem = fmap ((*1024) . (!!1)) parseMEM
+totalMem = fmap ((*1024) . (!!1)) MM.parseMEM
 
 usedMem :: IO Float
-usedMem = fmap ((*1024) . (!!6)) parseMEM
+usedMem = fmap ((*1024) . (!!6)) MM.parseMEM
 
 formatMem :: MemOpts -> [Float] -> Monitor [String]
 formatMem opts (r:fr:ar:xs) =
@@ -120,7 +75,7 @@ formatMem _ _ = replicate 10 `fmap` getConfigValue naString
 
 runMem :: [String] -> Monitor String
 runMem argv =
-    do m <- io parseMEM
+    do m <- io MM.parseMEM
        opts <- io $ parseOptsWith options defaultOpts argv
        l <- formatMem opts m
        parseTemplate l
diff --git a/src/Xmobar/Plugins/Monitors/Mem/FreeBSD.hs b/src/Xmobar/Plugins/Monitors/Mem/FreeBSD.hs
new file mode 100644
index 0000000..787cace
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Mem/FreeBSD.hs
@@ -0,0 +1,45 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Mem.FreeBSD
+-- Copyright   :  (c) Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A memory monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Mem.FreeBSD (parseMEM) where
+
+import System.BSD.Sysctl (sysctlReadUInt)
+
+parseMEM :: IO [Float]
+parseMEM = do stats <- mapM sysctlReadUInt [
+                "vm.stats.vm.v_page_size"
+                , "vm.stats.vm.v_page_count"
+                , "vm.stats.vm.v_free_count"
+                , "vm.stats.vm.v_active_count"
+                , "vm.stats.vm.v_inactive_count"
+                , "vm.stats.vm.v_wire_count"
+                , "vm.stats.vm.v_cache_count"]
+
+              let [ pagesize, totalpages, freepages, activepages, inactivepages, wiredpages, cachedpages ] = fmap fromIntegral stats
+                  usedpages = activepages + wiredpages + cachedpages
+                  availablepages = inactivepages + cachedpages + freepages
+                  bufferedpages = activepages + inactivepages + wiredpages
+
+                  available = availablepages * pagesize
+                  used = usedpages * pagesize
+                  free = freepages * pagesize
+                  cache = cachedpages * pagesize
+                  buffer = bufferedpages * pagesize
+                  total = totalpages * pagesize
+
+                  usedratio = usedpages / totalpages
+                  freeratio = freepages / totalpages
+                  availableratio = availablepages / totalpages
+
+              return [usedratio, freeratio, availableratio, total, free, buffer, cache, available, used]
diff --git a/src/Xmobar/Plugins/Monitors/Mem/Linux.hs b/src/Xmobar/Plugins/Monitors/Mem/Linux.hs
new file mode 100644
index 0000000..9e48d22
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Mem/Linux.hs
@@ -0,0 +1,33 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Mem.Linux
+-- Copyright   :  (c) Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A memory monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Mem.Linux (parseMEM) where
+
+import qualified Data.Map as M
+
+fileMEM :: IO String
+fileMEM = readFile "/proc/meminfo"
+
+parseMEM :: IO [Float]
+parseMEM =
+    do file <- fileMEM
+       let content = map words $ take 8 $ lines file
+           info = M.fromList $ map (\line -> (head line, (read $ line !! 1 :: Float) / 1024)) content
+           [total, free, buffer, cache] = map (info M.!) ["MemTotal:", "MemFree:", "Buffers:", "Cached:"]
+           available = M.findWithDefault (free + buffer + cache) "MemAvailable:" info
+           used = total - available
+           usedratio = used / total
+           freeratio = free / total
+           availableratio = available / total
+       return [usedratio, freeratio, availableratio, total, free, buffer, cache, available, used]
diff --git a/src/Xmobar/Plugins/Monitors/Net.hs b/src/Xmobar/Plugins/Monitors/Net.hs
new file mode 100644
index 0000000..23b3dc3
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Net.hs
@@ -0,0 +1,171 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Net
+-- Copyright   :  (c) 2011, 2012, 2013, 2014, 2017, 2020 Jose Antonio Ortega Ruiz
+--                (c) 2007-2010 Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A net device monitor for Xmobar
+--
+
+-----------------------------------------------------------------------------
+
+{-# LANGUAGE CPP #-}
+
+module Xmobar.Plugins.Monitors.Net (
+                        startNet
+                      , startDynNet
+                      ) where
+
+import Xmobar.Plugins.Monitors.Common
+import Xmobar.Plugins.Monitors.Net.Common (NetDev(..), NetDevInfo(..), NetDevRate, NetDevRef)
+import Data.IORef (newIORef, readIORef, writeIORef)
+import Data.Time.Clock (getCurrentTime, diffUTCTime)
+import System.Console.GetOpt
+
+#if defined(freebsd_HOST_OS)
+import qualified Xmobar.Plugins.Monitors.Net.FreeBSD as MN
+#else
+import qualified Xmobar.Plugins.Monitors.Net.Linux as MN
+#endif
+
+import Control.Monad (forM)
+
+type DevList = [String]
+
+parseDevList :: String -> DevList
+parseDevList = splitOnComma
+  where splitOnComma [] = [[]]
+        splitOnComma (',':xs) = [] : splitOnComma xs
+        splitOnComma (x:xs) =
+           let rest = splitOnComma xs
+           in (x : head rest) : tail rest
+
+data NetOpts = NetOpts
+  { rxIconPattern :: Maybe IconPattern
+  , txIconPattern :: Maybe IconPattern
+  , onlyDevList :: Maybe DevList
+  , upIndicator :: String
+  }
+
+defaultOpts :: NetOpts
+defaultOpts = NetOpts
+  { rxIconPattern = Nothing
+  , txIconPattern = Nothing
+  , onlyDevList = Nothing
+  , upIndicator = "+"
+  }
+
+options :: [OptDescr (NetOpts -> NetOpts)]
+options =
+  [ Option "" ["rx-icon-pattern"] (ReqArg (\x o ->
+     o { rxIconPattern = Just $ parseIconPattern x }) "") ""
+  , Option "" ["tx-icon-pattern"] (ReqArg (\x o ->
+     o { txIconPattern = Just $ parseIconPattern x }) "") ""
+  , Option "" ["up"] (ReqArg (\x o -> o { upIndicator = x }) "") ""
+  , Option "" ["devices"] (ReqArg (\x o ->
+     o { onlyDevList = Just $ parseDevList x }) "") ""
+  ]
+
+data UnitPerSec = Bs | KBs | MBs | GBs deriving (Eq,Enum,Ord)
+data NetValue = NetValue Float UnitPerSec deriving (Eq,Show)
+
+instance Show UnitPerSec where
+    show Bs  = "B/s"
+    show KBs = "KB/s"
+    show MBs = "MB/s"
+    show GBs = "GB/s"
+
+netConfig :: IO MConfig
+netConfig = mkMConfig
+    "<dev>: <rx>KB|<tx>KB"      -- template
+    ["dev", "rx", "tx", "rxbar", "rxvbar", "rxipat", "txbar", "txvbar", "txipat", "up"]     -- available replacements
+
+formatNet :: Maybe IconPattern -> Float -> Monitor (String, String, String, String)
+formatNet mipat d = do
+    s <- getConfigValue useSuffix
+    dd <- getConfigValue decDigits
+    let str True v = showDigits dd d' ++ show u
+            where (NetValue d' u) = byteNetVal v
+        str False v = showDigits dd $ v / 1024
+    b <- showLogBar 0.9 d
+    vb <- showLogVBar 0.9 d
+    ipat <- showLogIconPattern mipat 0.9 d
+    x <- showWithColors (str s) d
+    return (x, b, vb, ipat)
+
+printNet :: NetOpts -> NetDevRate -> Monitor String
+printNet opts nd =
+  case nd of
+    N d (ND r t) -> do
+        (rx, rb, rvb, ripat) <- formatNet (rxIconPattern opts) r
+        (tx, tb, tvb, tipat) <- formatNet (txIconPattern opts) t
+        parseTemplate [d,rx,tx,rb,rvb,ripat,tb,tvb,tipat, upIndicator opts]
+    N _ NI -> return ""
+    NA -> getConfigValue naString
+
+parseNet :: NetDevRef -> String -> IO NetDevRate
+parseNet nref nd = do
+  (n0, t0) <- readIORef nref
+  n1 <- MN.findNetDev nd
+  t1 <- getCurrentTime
+  writeIORef nref (n1, t1)
+  let scx = realToFrac (diffUTCTime t1 t0)
+      scx' = if scx > 0 then scx else 1
+      rate da db = takeDigits 2 $ fromIntegral (db - da) / scx'
+      diffRate (N d (ND ra ta)) (N _ (ND rb tb)) = N d (ND (rate ra rb) (rate ta tb))
+      diffRate (N d NI) _ = N d NI
+      diffRate _ (N d NI) = N d NI
+      diffRate _ _ = NA
+  return $ diffRate n0 n1
+
+runNet :: NetDevRef -> String -> [String] -> Monitor String
+runNet nref i argv = do
+  dev <- io $ parseNet nref i
+  opts <- io $ parseOptsWith options defaultOpts argv
+  printNet opts dev
+
+parseNets :: [(NetDevRef, String)] -> IO [NetDevRate]
+parseNets = mapM $ uncurry parseNet
+
+runNets :: [(NetDevRef, String)] -> [String] -> Monitor String
+runNets refs argv = do
+  opts <- io $ parseOptsWith options defaultOpts argv
+  dev <- io $ parseActive $ filterRefs opts refs
+  printNet opts dev
+    where parseActive refs' = fmap selectActive (parseNets refs')
+          refInDevList opts' (_, refname') = case onlyDevList opts' of
+            Just theList -> refname' `elem` theList
+            Nothing -> True
+          filterRefs opts' refs' = case filter (refInDevList opts') refs' of
+            [] -> refs'
+            xs -> xs
+          selectActive = maximum
+
+startNet :: String -> [String] -> Int -> (String -> IO ()) -> IO ()
+startNet i a r cb = do
+  t0 <- getCurrentTime
+  nref <- newIORef (NA, t0)
+  _ <- parseNet nref i
+  runM a netConfig (runNet nref i) r cb
+
+startDynNet :: [String] -> Int -> (String -> IO ()) -> IO ()
+startDynNet a r cb = do
+  devs <- MN.existingDevs
+  refs <- forM devs $ \d -> do
+            t <- getCurrentTime
+            nref <- newIORef (NA, t)
+            _ <- parseNet nref d
+            return (nref, d)
+  runM a netConfig (runNets refs) r cb
+
+byteNetVal :: Float -> NetValue
+byteNetVal v
+    | v < 1024**1 = NetValue v Bs
+    | v < 1024**2 = NetValue (v/1024**1) KBs
+    | v < 1024**3 = NetValue (v/1024**2) MBs
+    | otherwise   = NetValue (v/1024**3) GBs
diff --git a/src/Xmobar/Plugins/Monitors/Net.hsc b/src/Xmobar/Plugins/Monitors/Net.hsc
deleted file mode 100644
index 53a1a9e..0000000
--- a/src/Xmobar/Plugins/Monitors/Net.hsc
+++ /dev/null
@@ -1,334 +0,0 @@
------------------------------------------------------------------------------
--- |
--- Module      :  Plugins.Monitors.Net
--- Copyright   :  (c) 2011, 2012, 2013, 2014, 2017, 2020 Jose Antonio Ortega Ruiz
---                (c) 2007-2010 Andrea Rossato
--- License     :  BSD-style (see LICENSE)
---
--- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
--- Stability   :  unstable
--- Portability :  unportable
---
--- A net device monitor for Xmobar
---
-
------------------------------------------------------------------------------
-
-{-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE ForeignFunctionInterface #-}
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE CApiFFI #-}
-
-module Xmobar.Plugins.Monitors.Net (
-                        startNet
-                      , startDynNet
-                      ) where
-
-import Xmobar.Plugins.Monitors.Common
-
-import Data.IORef (IORef, newIORef, readIORef, writeIORef)
-import Data.Time.Clock (UTCTime, getCurrentTime, diffUTCTime)
-import Data.Word (Word64)
-import System.Console.GetOpt
-
-#ifdef FREEBSD
-import Control.Monad (forM)
-import Foreign (Int32, plusPtr)
-import Foreign.C.Types (CUIntMax, CUChar)
-import Foreign.C.String (peekCString)
-import Foreign.ForeignPtr ()
-import Foreign.Storable (Storable, alignment, sizeOf, peek, poke)
-import System.BSD.Sysctl (OID, sysctlPrepareOid, sysctlReadInt, sysctlPeek)
-#else
-import Control.Monad (forM, filterM)
-import System.Directory (getDirectoryContents, doesFileExist)
-import System.FilePath ((</>))
-import System.IO.Error (catchIOError)
-import System.IO.Unsafe (unsafeInterleaveIO)
-
-import qualified Data.ByteString.Char8 as B
-#endif
-
-type DevList = [String]
-
-parseDevList :: String -> DevList
-parseDevList = splitOnComma
-  where splitOnComma [] = [[]]
-        splitOnComma (',':xs) = [] : splitOnComma xs
-        splitOnComma (x:xs) =
-           let rest = splitOnComma xs
-           in (x : head rest) : tail rest
-
-data NetOpts = NetOpts
-  { rxIconPattern :: Maybe IconPattern
-  , txIconPattern :: Maybe IconPattern
-  , onlyDevList :: Maybe DevList
-  , upIndicator :: String
-  }
-
-defaultOpts :: NetOpts
-defaultOpts = NetOpts
-  { rxIconPattern = Nothing
-  , txIconPattern = Nothing
-  , onlyDevList = Nothing
-  , upIndicator = "+"
-  }
-
-options :: [OptDescr (NetOpts -> NetOpts)]
-options =
-  [ Option "" ["rx-icon-pattern"] (ReqArg (\x o ->
-     o { rxIconPattern = Just $ parseIconPattern x }) "") ""
-  , Option "" ["tx-icon-pattern"] (ReqArg (\x o ->
-     o { txIconPattern = Just $ parseIconPattern x }) "") ""
-  , Option "" ["up"] (ReqArg (\x o -> o { upIndicator = x }) "") ""
-  , Option "" ["devices"] (ReqArg (\x o ->
-     o { onlyDevList = Just $ parseDevList x }) "") ""
-  ]
-
-data UnitPerSec = Bs | KBs | MBs | GBs deriving (Eq,Enum,Ord)
-data NetValue = NetValue Float UnitPerSec deriving (Eq,Show)
-
-instance Show UnitPerSec where
-    show Bs  = "B/s"
-    show KBs = "KB/s"
-    show MBs = "MB/s"
-    show GBs = "GB/s"
-
-data NetDev num = N String (NetDevInfo num) | NA deriving (Eq,Show,Read)
-data NetDevInfo num = NI | ND num num deriving (Eq,Show,Read)
-
-type NetDevRawTotal = NetDev Word64
-type NetDevRate = NetDev Float
-
-type NetDevRef = IORef (NetDevRawTotal, UTCTime)
-
--- The more information available, the better.
--- Note that names don't matter. Therefore, if only the names differ,
--- a compare evaluates to EQ while (==) evaluates to False.
-instance Ord num => Ord (NetDev num) where
-    compare NA NA             = EQ
-    compare NA _              = LT
-    compare _  NA             = GT
-    compare (N _ i1) (N _ i2) = i1 `compare` i2
-
-instance Ord num => Ord (NetDevInfo num) where
-    compare NI NI                 = EQ
-    compare NI ND {}              = LT
-    compare ND {} NI              = GT
-    compare (ND x1 y1) (ND x2 y2) = x1 `compare` x2 <> y1 `compare` y2
-
-netConfig :: IO MConfig
-netConfig = mkMConfig
-    "<dev>: <rx>KB|<tx>KB"      -- template
-    ["dev", "rx", "tx", "rxbar", "rxvbar", "rxipat", "txbar", "txvbar", "txipat", "up"]     -- available replacements
-
-
-#ifdef FREEBSD
-
-#include <sys/sysctl.h>
-#include <net/if.h>
-#include <net/if_mib.h>
-
-data IfData = IfData {
-  name :: String
-  , txBytes :: CUIntMax
-  , rxBytes :: CUIntMax
-  , isUp :: Bool
-  }
-  deriving (Show, Read, Eq)
-
-instance Storable IfData where
-  alignment _ = #{alignment struct ifmibdata}
-  sizeOf _    = #{size struct ifmibdata}
-  peek ptr    = do
-    cname <- peekCString (ptr `plusPtr` (#offset struct ifmibdata, ifmd_name))
-    tx <- peek ((ifmd_data_ptr ptr) `plusPtr` (#offset struct if_data, ifi_obytes)) :: IO CUIntMax
-    rx <- peek ((ifmd_data_ptr ptr) `plusPtr` (#offset struct if_data, ifi_ibytes)) :: IO CUIntMax
-    state <- peek ((ifmd_data_ptr ptr) `plusPtr` (#offset struct if_data, ifi_link_state)) :: IO CUChar
-    return $ IfData {name = cname, txBytes = tx, rxBytes = rx, isUp = up state}
-      where
-        up state = state == (#const LINK_STATE_UP)
-        ifmd_data_ptr p = p `plusPtr` (#offset struct ifmibdata, ifmd_data)
-
-  poke _ _    = pure ()
-
-getNetIfCountOID :: IO OID
-getNetIfCountOID = sysctlPrepareOid [
-  #const CTL_NET
-  , #const PF_LINK
-  , #const NETLINK_GENERIC
-  , #const IFMIB_SYSTEM
-  , #const IFMIB_IFCOUNT]
-
-getNetIfDataOID :: Int32 -> IO OID
-getNetIfDataOID i = sysctlPrepareOid [
-  #const CTL_NET
-  , #const PF_LINK
-  , #const NETLINK_GENERIC
-  , #const IFMIB_IFDATA
-  , i
-  , #const IFDATA_GENERAL]
-
-getNetIfCount :: IO Int32
-getNetIfCount = do
-  oid <- getNetIfCountOID
-  sysctlReadInt oid
-
-getNetIfData :: Int32 -> IO IfData
-getNetIfData i = do
-  oid <- getNetIfDataOID i
-  res <- sysctlPeek oid :: IO IfData
-  return res
-
-getAllNetworkData :: IO [IfData]
-getAllNetworkData = do
-  count <- getNetIfCount
-  result <- mapM getNetIfData [1..count]
-  return $ result
-
-existingDevs :: IO [String]
-existingDevs = getAllNetworkData >>= (\xs -> return $ filter (/= "lo0") $ fmap name xs)
-
-convertIfDataToNetDev :: IfData -> IO NetDevRawTotal
-convertIfDataToNetDev ifData = do
-  let up = isUp ifData
-      rx = fromInteger . toInteger $ rxBytes ifData
-      tx = fromInteger . toInteger $ txBytes ifData
-      d = name ifData
-  return $ N d (if up then ND rx tx else NI)
-
-netConvertIfDataToNetDev :: [IfData] -> IO [NetDevRawTotal]
-netConvertIfDataToNetDev = mapM convertIfDataToNetDev
-
-findNetDev :: String -> IO NetDevRawTotal
-findNetDev dev = do
-  nds <- getAllNetworkData >>= netConvertIfDataToNetDev
-  case filter isDev nds of
-    x:_ -> return x
-    _ -> return NA
-  where isDev (N d _) = d == dev
-        isDev NA = False
-
-#else
-operstateDir :: String -> FilePath
-operstateDir d = "/sys/class/net" </> d </> "operstate"
-
-existingDevs :: IO [String]
-existingDevs = getDirectoryContents "/sys/class/net" >>= filterM isDev
-  where isDev d | d `elem` excludes = return False
-                | otherwise = doesFileExist (operstateDir d)
-        excludes = [".", "..", "lo"]
-
-isUp :: String -> IO Bool
-isUp d = flip catchIOError (const $ return False) $ do
-  operstate <- B.readFile (operstateDir d)
-  return $! (head . B.lines) operstate `elem` ["up", "unknown"]
-
-readNetDev :: [String] -> IO NetDevRawTotal
-readNetDev ~[d, x, y] = do
-  up <- unsafeInterleaveIO $ isUp d
-  return $ N d (if up then ND (r x) (r y) else NI)
-    where r s | s == "" = 0
-              | otherwise = read s
-
-netParser :: B.ByteString -> IO [NetDevRawTotal]
-netParser = mapM (readNetDev . splitDevLine) . readDevLines
-  where readDevLines = drop 2 . B.lines
-        splitDevLine = map B.unpack . selectCols . filter (not . B.null) . B.splitWith (`elem` [' ',':'])
-        selectCols cols = map (cols!!) [0,1,9]
-
-findNetDev :: String -> IO NetDevRawTotal
-findNetDev dev = do
-  nds <- B.readFile "/proc/net/dev" >>= netParser
-  case filter isDev nds of
-    x:_ -> return x
-    _ -> return NA
-  where isDev (N d _) = d == dev
-        isDev NA = False
-
-#endif
-
-formatNet :: Maybe IconPattern -> Float -> Monitor (String, String, String, String)
-formatNet mipat d = do
-    s <- getConfigValue useSuffix
-    dd <- getConfigValue decDigits
-    let str True v = showDigits dd d' ++ show u
-            where (NetValue d' u) = byteNetVal v
-        str False v = showDigits dd $ v / 1024
-    b <- showLogBar 0.9 d
-    vb <- showLogVBar 0.9 d
-    ipat <- showLogIconPattern mipat 0.9 d
-    x <- showWithColors (str s) d
-    return (x, b, vb, ipat)
-
-printNet :: NetOpts -> NetDevRate -> Monitor String
-printNet opts nd =
-  case nd of
-    N d (ND r t) -> do
-        (rx, rb, rvb, ripat) <- formatNet (rxIconPattern opts) r
-        (tx, tb, tvb, tipat) <- formatNet (txIconPattern opts) t
-        parseTemplate [d,rx,tx,rb,rvb,ripat,tb,tvb,tipat, upIndicator opts]
-    N _ NI -> return ""
-    NA -> getConfigValue naString
-
-parseNet :: NetDevRef -> String -> IO NetDevRate
-parseNet nref nd = do
-  (n0, t0) <- readIORef nref
-  n1 <- findNetDev nd
-  t1 <- getCurrentTime
-  writeIORef nref (n1, t1)
-  let scx = realToFrac (diffUTCTime t1 t0)
-      scx' = if scx > 0 then scx else 1
-      rate da db = takeDigits 2 $ fromIntegral (db - da) / scx'
-      diffRate (N d (ND ra ta)) (N _ (ND rb tb)) = N d (ND (rate ra rb) (rate ta tb))
-      diffRate (N d NI) _ = N d NI
-      diffRate _ (N d NI) = N d NI
-      diffRate _ _ = NA
-  return $ diffRate n0 n1
-
-runNet :: NetDevRef -> String -> [String] -> Monitor String
-runNet nref i argv = do
-  dev <- io $ parseNet nref i
-  opts <- io $ parseOptsWith options defaultOpts argv
-  printNet opts dev
-
-parseNets :: [(NetDevRef, String)] -> IO [NetDevRate]
-parseNets = mapM $ uncurry parseNet
-
-runNets :: [(NetDevRef, String)] -> [String] -> Monitor String
-runNets refs argv = do
-  opts <- io $ parseOptsWith options defaultOpts argv
-  dev <- io $ parseActive $ filterRefs opts refs
-  printNet opts dev
-    where parseActive refs' = fmap selectActive (parseNets refs')
-          refInDevList opts' (_, refname') = case onlyDevList opts' of
-            Just theList -> refname' `elem` theList
-            Nothing -> True
-          filterRefs opts' refs' = case filter (refInDevList opts') refs' of
-            [] -> refs'
-            xs -> xs
-          selectActive = maximum
-
-startNet :: String -> [String] -> Int -> (String -> IO ()) -> IO ()
-startNet i a r cb = do
-  t0 <- getCurrentTime
-  nref <- newIORef (NA, t0)
-  _ <- parseNet nref i
-  runM a netConfig (runNet nref i) r cb
-
-startDynNet :: [String] -> Int -> (String -> IO ()) -> IO ()
-startDynNet a r cb = do
-  devs <- existingDevs
-  refs <- forM devs $ \d -> do
-            t <- getCurrentTime
-            nref <- newIORef (NA, t)
-            _ <- parseNet nref d
-            return (nref, d)
-  runM a netConfig (runNets refs) r cb
-
-byteNetVal :: Float -> NetValue
-byteNetVal v
-    | v < 1024**1 = NetValue v Bs
-    | v < 1024**2 = NetValue (v/1024**1) KBs
-    | v < 1024**3 = NetValue (v/1024**2) MBs
-    | otherwise   = NetValue (v/1024**3) GBs
diff --git a/src/Xmobar/Plugins/Monitors/Net/Common.hs b/src/Xmobar/Plugins/Monitors/Net/Common.hs
new file mode 100644
index 0000000..16ed865
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Net/Common.hs
@@ -0,0 +1,50 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Net.Common
+-- Copyright   :  (c) 2011, 2012, 2013, 2014, 2017, 2020 Jose Antonio Ortega Ruiz
+--                (c) 2007-2010 Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A net device monitor for Xmobar
+--
+
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Net.Common (
+                        NetDev(..)
+                      , NetDevInfo(..)
+                      , NetDevRawTotal
+                      , NetDevRate
+                      , NetDevRef
+                      ) where
+
+import Data.IORef (IORef)
+import Data.Time.Clock (UTCTime)
+import Data.Word (Word64)
+
+data NetDev num = N String (NetDevInfo num) | NA deriving (Eq,Show,Read)
+data NetDevInfo num = NI | ND num num deriving (Eq,Show,Read)
+
+type NetDevRawTotal = NetDev Word64
+type NetDevRate = NetDev Float
+
+type NetDevRef = IORef (NetDevRawTotal, UTCTime)
+
+-- The more information available, the better.
+-- Note that names don't matter. Therefore, if only the names differ,
+-- a compare evaluates to EQ while (==) evaluates to False.
+instance Ord num => Ord (NetDev num) where
+    compare NA NA             = EQ
+    compare NA _              = LT
+    compare _  NA             = GT
+    compare (N _ i1) (N _ i2) = i1 `compare` i2
+
+instance Ord num => Ord (NetDevInfo num) where
+    compare NI NI                 = EQ
+    compare NI ND {}              = LT
+    compare ND {} NI              = GT
+    compare (ND x1 y1) (ND x2 y2) = x1 `compare` x2 <> y1 `compare` y2
diff --git a/src/Xmobar/Plugins/Monitors/Net/FreeBSD.hsc b/src/Xmobar/Plugins/Monitors/Net/FreeBSD.hsc
new file mode 100644
index 0000000..ab446e3
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Net/FreeBSD.hsc
@@ -0,0 +1,118 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ForeignFunctionInterface #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE CApiFFI #-}
+
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Net.FreeBSD
+-- Copyright   :  (c) 2011, 2012, 2013, 2014, 2017, 2020 Jose Antonio Ortega Ruiz
+--                (c) 2007-2010 Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A net device monitor for Xmobar
+--
+
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Net.FreeBSD (
+  existingDevs
+  , findNetDev
+  ) where
+
+import Xmobar.Plugins.Monitors.Net.Common (NetDevRawTotal, NetDev(..), NetDevInfo(..))
+import Control.Exception (catch, SomeException(..))
+import Foreign (Int32, plusPtr)
+import Foreign.C.Types (CUIntMax, CUChar)
+import Foreign.C.String (peekCString)
+import Foreign.ForeignPtr ()
+import Foreign.Storable (Storable, alignment, sizeOf, peek, poke)
+import System.BSD.Sysctl (OID, sysctlPrepareOid, sysctlReadInt, sysctlPeek)
+
+#include <sys/sysctl.h>
+#include <net/if.h>
+#include <net/if_mib.h>
+
+data IfData = AvailableIfData {
+  name :: String
+  , txBytes :: CUIntMax
+  , rxBytes :: CUIntMax
+  , isUp :: Bool
+  } | NotAvailableIfData
+  deriving (Show, Read, Eq)
+
+instance Storable IfData where
+  alignment _ = #{alignment struct ifmibdata}
+  sizeOf _    = #{size struct ifmibdata}
+  peek ptr    = do
+    cname <- peekCString (ptr `plusPtr` (#offset struct ifmibdata, ifmd_name))
+    tx <- peek ((ifmd_data_ptr ptr) `plusPtr` (#offset struct if_data, ifi_obytes)) :: IO CUIntMax
+    rx <- peek ((ifmd_data_ptr ptr) `plusPtr` (#offset struct if_data, ifi_ibytes)) :: IO CUIntMax
+    state <- peek ((ifmd_data_ptr ptr) `plusPtr` (#offset struct if_data, ifi_link_state)) :: IO CUChar
+    return $ AvailableIfData {name = cname, txBytes = tx, rxBytes = rx, isUp = up state}
+      where
+        up state = state == (#const LINK_STATE_UP)
+        ifmd_data_ptr p = p `plusPtr` (#offset struct ifmibdata, ifmd_data)
+
+  poke _ _    = pure ()
+
+getNetIfCountOID :: IO OID
+getNetIfCountOID = sysctlPrepareOid [
+  #const CTL_NET
+  , #const PF_LINK
+  , #const NETLINK_GENERIC
+  , #const IFMIB_SYSTEM
+  , #const IFMIB_IFCOUNT]
+
+getNetIfDataOID :: Int32 -> IO OID
+getNetIfDataOID i = sysctlPrepareOid [
+  #const CTL_NET
+  , #const PF_LINK
+  , #const NETLINK_GENERIC
+  , #const IFMIB_IFDATA
+  , i
+  , #const IFDATA_GENERAL]
+
+getNetIfCount :: IO Int32
+getNetIfCount = do
+  oid <- getNetIfCountOID
+  sysctlReadInt oid
+
+getNetIfData :: Int32 -> IO IfData
+getNetIfData i = do
+  oid <- getNetIfDataOID i
+  res <- catch (sysctlPeek oid) (\(SomeException _) -> return NotAvailableIfData)
+  return res
+
+getAllNetworkData :: IO [IfData]
+getAllNetworkData = do
+  count <- getNetIfCount
+  result <- mapM getNetIfData [1..count]
+  return result
+
+existingDevs :: IO [String]
+existingDevs = getAllNetworkData >>= (\xs -> return $ filter (/= "lo0") $ fmap name xs)
+
+convertIfDataToNetDev :: IfData -> IO NetDevRawTotal
+convertIfDataToNetDev ifData = do
+  let up = isUp ifData
+      rx = fromInteger . toInteger $ rxBytes ifData
+      tx = fromInteger . toInteger $ txBytes ifData
+      d = name ifData
+  return $ N d (if up then ND rx tx else NI)
+
+netConvertIfDataToNetDev :: [IfData] -> IO [NetDevRawTotal]
+netConvertIfDataToNetDev = mapM convertIfDataToNetDev
+
+findNetDev :: String -> IO NetDevRawTotal
+findNetDev dev = do
+  nds <- getAllNetworkData >>= netConvertIfDataToNetDev
+  case filter isDev nds of
+    x:_ -> return x
+    _ -> return NA
+  where isDev (N d _) = d == dev
+        isDev NA = False
diff --git a/src/Xmobar/Plugins/Monitors/Net/Linux.hs b/src/Xmobar/Plugins/Monitors/Net/Linux.hs
new file mode 100644
index 0000000..9306497
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Net/Linux.hs
@@ -0,0 +1,69 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Net.Linux
+-- Copyright   :  (c) 2011, 2012, 2013, 2014, 2017, 2020 Jose Antonio Ortega Ruiz
+--                (c) 2007-2010 Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A net device monitor for Xmobar
+--
+
+-----------------------------------------------------------------------------
+
+{-# LANGUAGE OverloadedStrings #-}
+
+module Xmobar.Plugins.Monitors.Net.Linux (
+  existingDevs
+  , findNetDev
+  ) where
+
+import Xmobar.Plugins.Monitors.Net.Common (NetDevRawTotal, NetDev(..), NetDevInfo(..))
+
+import Control.Monad (filterM)
+import System.Directory (getDirectoryContents, doesFileExist)
+import System.FilePath ((</>))
+import System.IO.Error (catchIOError)
+import System.IO.Unsafe (unsafeInterleaveIO)
+
+import qualified Data.ByteString.Char8 as B
+
+
+operstateDir :: String -> FilePath
+operstateDir d = "/sys/class/net" </> d </> "operstate"
+
+existingDevs :: IO [String]
+existingDevs = getDirectoryContents "/sys/class/net" >>= filterM isDev
+  where isDev d | d `elem` excludes = return False
+                | otherwise = doesFileExist (operstateDir d)
+        excludes = [".", "..", "lo"]
+
+isUp :: String -> IO Bool
+isUp d = flip catchIOError (const $ return False) $ do
+  operstate <- B.readFile (operstateDir d)
+  return $! (head . B.lines) operstate `elem` ["up", "unknown"]
+
+readNetDev :: [String] -> IO NetDevRawTotal
+readNetDev ~[d, x, y] = do
+  up <- unsafeInterleaveIO $ isUp d
+  return $ N d (if up then ND (r x) (r y) else NI)
+    where r s | s == "" = 0
+              | otherwise = read s
+
+netParser :: B.ByteString -> IO [NetDevRawTotal]
+netParser = mapM (readNetDev . splitDevLine) . readDevLines
+  where readDevLines = drop 2 . B.lines
+        splitDevLine = map B.unpack . selectCols . filter (not . B.null) . B.splitWith (`elem` [' ',':'])
+        selectCols cols = map (cols!!) [0,1,9]
+
+findNetDev :: String -> IO NetDevRawTotal
+findNetDev dev = do
+  nds <- B.readFile "/proc/net/dev" >>= netParser
+  case filter isDev nds of
+    x:_ -> return x
+    _ -> return NA
+  where isDev (N d _) = d == dev
+        isDev NA = False
diff --git a/src/Xmobar/Plugins/Monitors/Swap.hs b/src/Xmobar/Plugins/Monitors/Swap.hs
index ca46010..e8b2f54 100644
--- a/src/Xmobar/Plugins/Monitors/Swap.hs
+++ b/src/Xmobar/Plugins/Monitors/Swap.hs
@@ -17,10 +17,10 @@ module Xmobar.Plugins.Monitors.Swap where
 
 import Xmobar.Plugins.Monitors.Common
 
-#ifdef FREEBSD
-import System.BSD.Sysctl (sysctlReadUInt, sysctlReadULong)
+#if defined(freebsd_HOST_OS)
+import qualified Xmobar.Plugins.Monitors.Swap.FreeBSD as MS
 #else
-import qualified Data.ByteString.Lazy.Char8 as B
+import qualified Xmobar.Plugins.Monitors.Swap.Linux as MS
 #endif
 
 swapConfig :: IO MConfig
@@ -28,53 +28,6 @@ swapConfig = mkMConfig
         "Swap: <usedratio>%"                    -- template
         ["usedratio", "total", "used", "free"] -- available replacements
 
-#ifdef FREEBSD
-
-isEnabled :: IO Bool
-isEnabled = do
-  enabled <- sysctlReadUInt "vm.swap_enabled"
-  return $ enabled == 1
-
-parseMEM' :: Bool -> IO [Float]
-parseMEM' False = return $ []
-parseMEM' True = do
-  swapIn <- sysctlReadUInt "vm.stats.vm.v_swapin"
-  swapTotal <- sysctlReadULong "vm.swap_total"
-  let tot = toInteger swapTotal
-      free = tot - (toInteger swapIn)
-
-  return $ res (fromInteger tot) (fromInteger free)
-  where
-    res :: Float -> Float -> [Float]
-    res _ 0 = []
-    res tot free = [(tot - free) / tot, tot, tot - free, free]
-
-parseMEM :: IO [Float]
-parseMEM = do
-  enabled <- isEnabled
-  parseMEM' enabled
-
-#else
-fileMEM :: IO B.ByteString
-fileMEM = B.readFile "/proc/meminfo"
-
-parseMEM :: IO [Float]
-parseMEM =
-    do file <- fileMEM
-       let li i l
-               | l /= [] = head l !! i
-               | otherwise = B.empty
-           fs s l
-               | null l    = False
-               | otherwise = head l == B.pack s
-           get_data s = flip (/) 1024 . read . B.unpack . li 1 . filter (fs s)
-           st   = map B.words . B.lines $ file
-           tot  = get_data "SwapTotal:" st
-           free = get_data "SwapFree:" st
-       return [(tot - free) / tot, tot, tot - free, free]
-
-#endif
-
 formatSwap :: [Float] -> Monitor [String]
 formatSwap (r:xs) = do
   d <- getConfigValue decDigits
@@ -85,6 +38,6 @@ formatSwap _ = return $ replicate 4 "N/A"
 
 runSwap :: [String] -> Monitor String
 runSwap _ =
-    do m <- io parseMEM
+    do m <- io MS.parseMEM
        l <- formatSwap m
        parseTemplate l
diff --git a/src/Xmobar/Plugins/Monitors/Swap/FreeBSD.hs b/src/Xmobar/Plugins/Monitors/Swap/FreeBSD.hs
new file mode 100644
index 0000000..0e0c03d
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Swap/FreeBSD.hs
@@ -0,0 +1,41 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Swap.FreeBSD
+-- Copyright   :  (c) Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A  swap usage monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Swap.FreeBSD (parseMEM) where
+
+import System.BSD.Sysctl (sysctlReadUInt, sysctlReadULong)
+
+isEnabled :: IO Bool
+isEnabled = do
+  enabled <- sysctlReadUInt "vm.swap_enabled"
+  return $ enabled == 1
+
+parseMEM' :: Bool -> IO [Float]
+parseMEM' False = return []
+parseMEM' True = do
+  swapIn <- sysctlReadUInt "vm.stats.vm.v_swapin"
+  swapTotal <- sysctlReadULong "vm.swap_total"
+  let tot = toInteger swapTotal
+      free = tot - toInteger swapIn
+
+  return $ res (fromInteger tot) (fromInteger free)
+  where
+    res :: Float -> Float -> [Float]
+    res _ 0 = []
+    res tot free = [(tot - free) / tot, tot, tot - free, free]
+
+parseMEM :: IO [Float]
+parseMEM = do
+  enabled <- isEnabled
+  parseMEM' enabled
diff --git a/src/Xmobar/Plugins/Monitors/Swap/Linux.hs b/src/Xmobar/Plugins/Monitors/Swap/Linux.hs
new file mode 100644
index 0000000..0af0f5d
--- /dev/null
+++ b/src/Xmobar/Plugins/Monitors/Swap/Linux.hs
@@ -0,0 +1,35 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Plugins.Monitors.Swap.Linux
+-- Copyright   :  (c) Andrea Rossato
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  Jose A. Ortega Ruiz <jao@gnu.org>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+-- A  swap usage monitor for Xmobar
+--
+-----------------------------------------------------------------------------
+
+module Xmobar.Plugins.Monitors.Swap.Linux (parseMEM) where
+
+import qualified Data.ByteString.Lazy.Char8 as B
+
+fileMEM :: IO B.ByteString
+fileMEM = B.readFile "/proc/meminfo"
+
+parseMEM :: IO [Float]
+parseMEM =
+    do file <- fileMEM
+       let li i l
+               | l /= [] = head l !! i
+               | otherwise = B.empty
+           fs s l
+               | null l    = False
+               | otherwise = head l == B.pack s
+           get_data s = flip (/) 1024 . read . B.unpack . li 1 . filter (fs s)
+           st   = map B.words . B.lines $ file
+           tot  = get_data "SwapTotal:" st
+           free = get_data "SwapFree:" st
+       return [(tot - free) / tot, tot, tot - free, free]