parse ip data by haskell -- in-complete

IP.hs

module IP where

import System.IO
import qualified Data.ByteString.Lazy as BL
import qualified Data.ByteString.Lazy.UTF8 as UTF8
import Data.Binary.Get
import Data.Word
import Data.Char
import Numeric
import Data.Bits
--import Text.Regex
import Data.Int
import Control.Monad (replicateM)

--dataFile = "e:/Program Files/cz88.net/ip/qqwry.dat"
dataFile = "F:/Program Files/cz88.net/ip/qqwry.dat"

--第一条IP的索引位置
firstIpOffset = 5712056
--最后一条IP的索引位置
lastIpOffset = 8576351

--共有多少条IP记录
--(firstIpOffse + lastIpOffset) / 7
totalRecord = 409185

--读取文件头共8字节
--前四个字节指示第一条ip的索引位置
--后四个字节指示最后一条IP的索引位置
readHeader :: BL.ByteString -> (Integer,Integer)
readHeader header = (fromIntegral left,fromIntegral right)
  where (left,right) = 
          runGet (
            getWord32le >>= \first -> 
             getWord32le >>= \last -> 
             return (first,last)
            ) header

dataFileHandle :: IO Handle
dataFileHandle = openFile dataFile ReadMode

readOneByte :: BL.ByteString -> Word8
readOneByte  =  runGet getWord8

-- read Bytes and return by little-endian
readBytes :: Int -> BL.ByteString -> [Word8]
readBytes n = runGet ( fmap reverse (Control.Monad.replicateM n getWord8 ))

-- Word32 to Word8 by little endian order
intToBytes :: Word32 -> [Word8]
intToBytes w = [ fromIntegral (w `shiftR` 24)
                 , fromIntegral (w `shiftR` 16)
                 , fromIntegral (w `shiftR` 8)
                 , fromIntegral w ]  
      
-- for test a region offset : 5712023
readRegion offset howMany = 
  dataFileHandle  >>= \h -> 
  readIt h offset >>= \(_,r) -> 
  (return . runGet getWord32be) (BL.pack r) >>= \p -> 
  -- +4 是因为跳过的这4个字节是这个ip段的结束地址
  (hSeek h AbsoluteSeek . fromIntegral) (p + 4) >>  
  fmap BL.unpack (BL.hGet h howMany) 
--  >>= return .  map (\i -> fromIntegral i :: Int8)
  

readIt h offset = do
  hSeek h AbsoluteSeek offset
  b <- BL.hGet h 7
  let (ippart,region) = BL.splitAt 4 b
  let ip = readBytes 4 ippart
  let regionOffset = 0 : readBytes 3 region
  return (ip,regionOffset)
  
main :: IO ()
main = do 
  h <- dataFileHandle
  --fileSize <- hFileSize h
  header <- BL.hGet h 8
  let addr@(first,last) = readHeader header
  print addr
  ip <- readIt h last
  print ip
  hClose h

gbkToUtf8 :: BL.ByteString  -> BL.ByteString
gbkToUtf8 binary = BL.pack []