{-| Module : Geometry.Shapefile.Internal Description : Some functions for reuse inside the library Author : Sam van Herwaarden -} module Geometry.Shapefile.Internal where import Control.Monad ( replicateM ) import Data.Binary.Get import Data.Binary.IEEE754 ( getFloat64le ) import qualified Data.ByteString.Char8 as C -- | 8-bit Int value getInt8 :: Get Int getInt8 = fromIntegral <\$> getWord8 -- | 32-bit big-endian Int getIntBE :: Get Int getIntBE = fromIntegral <\$> getWord32be -- | 16-bit big-endian Int getInt16BE :: Get Int getInt16BE = fromIntegral <\$> getWord16be -- | 32-bit little-endian Int getIntLE :: Get Int getIntLE = fromIntegral <\$> getWord32le -- | 16-bit little-endian Int getInt16LE :: Get Int getInt16LE = fromIntegral <\$> getWord16le -- | String of length `l` getString :: Int -> Get String getString l = filter (/= '\NUL') . C.unpack <\$> getByteString l -- | Char (presumably 8-bit) getCharVal :: Get Char getCharVal = C.head <\$> getByteString 1 type Point = (Double, Double) -- | Two doubles making up a point with two coordinates getPoint :: Get Point getPoint = do x <- getFloat64le y <- getFloat64le return (x, y) -- | Get the increments between list values steps :: Num a => [a] -> [a] steps [] = [] steps (_:[]) = [] steps (x1:x2:xs) = x2 - x1 : steps (x2:xs) -- | List of points of length `numPoints` getPointList :: Int -> Get [Point] getPointList numPoints = replicateM numPoints getPoint