    {-# LANGUAGE ScopedTypeVariables, CPP, ForeignFunctionInterface,
                 MagicHash, UnboxedTuples #-}
    {-# OPTIONS_HADDOCK hide #-}
    #if __GLASGOW_HASKELL__ >= 701
    {-# LANGUAGE Trustworthy #-}
    #endif
    -- | Copyright : (c) 2010 - 2011 Simon Meier
    -- License     : BSD3-style (see LICENSE)
    --
    -- Maintainer  : Simon Meier <iridcode@gmail.com>
    -- Portability : GHC
    --
    -- Constructing 'Builder's using ASCII-based encodings.
    --
    module Data.ByteString.Builder.ASCII
        (
          -- ** Formatting numbers as text
          -- | Formatting of numbers as ASCII text.
          --
          -- Note that you can also use these functions for the ISO/IEC 8859-1 and
          -- UTF-8 encodings, as the ASCII encoding is equivalent on the
          -- codepoints 0-127.

          -- *** Decimal numbers
          -- | Decimal encoding of numbers using ASCII encoded characters.
          int8Dec
        , int16Dec
        , int32Dec
        , int64Dec
        , intDec
        , integerDec

        , word8Dec
        , word16Dec
        , word32Dec
        , word64Dec
        , wordDec

        , floatDec
        , doubleDec

          -- *** Hexadecimal numbers

          -- | Encoding positive integers as hexadecimal numbers using lower-case
          -- ASCII characters. The shortest
          -- possible representation is used. For example,
          --
          -- >>> toLazyByteString (word16Hex 0x0a10)
          -- Chunk "a10" Empty
          --
          -- Note that there is no support for using upper-case characters. Please
          -- contact the maintainer, if your application cannot work without
          -- hexadecimal encodings that use upper-case characters.
          --
        , word8Hex
        , word16Hex
        , word32Hex
        , word64Hex
        , wordHex

          -- *** Fixed-width hexadecimal numbers
          --
        , int8HexFixed
        , int16HexFixed
        , int32HexFixed
        , int64HexFixed
        , word8HexFixed
        , word16HexFixed
        , word32HexFixed
        , word64HexFixed

        , floatHexFixed
        , doubleHexFixed

        , byteStringHex
        , lazyByteStringHex

        ) where

    import           Data.ByteString                                as S
    import           Data.ByteString.Lazy                           as L
    import           Data.ByteString.Builder.Internal (Builder)
    import qualified Data.ByteString.Builder.Prim                   as P

    import           Foreign

    #if defined(INTEGER_GMP)

    #if !(MIN_VERSION_base(4,8,0))
    import           Data.Monoid (mappend)
    # endif
    import           Foreign.C.Types

    import qualified Data.ByteString.Builder.Prim.Internal          as P
    import           Data.ByteString.Builder.Prim.Internal.UncheckedShifts
                       ( caseWordSize_32_64 )

    # if __GLASGOW_HASKELL__ < 710
    import           GHC.Num     (quotRemInteger)
    # endif
    import           GHC.Types   (Int(..))

    # if __GLASGOW_HASKELL__ < 611
    import GHC.Integer.Internals
    # else
    import GHC.Integer.GMP.Internals
    # endif
    #endif

    ------------------------------------------------------------------------------
    -- Decimal Encoding
    ------------------------------------------------------------------------------

    -- | Encode a 'String' using 'P.char7'.
    {-# INLINE string7 #-}
    string7 :: String -> Builder
    string7 = P.primMapListFixed P.char7

    ------------------------------------------------------------------------------
    -- Decimal Encoding
    ------------------------------------------------------------------------------

    -- Signed integers
    ------------------

    -- | Decimal encoding of an 'Int8' using the ASCII digits.
    --
    -- e.g.
    --
    -- > toLazyByteString (int8Dec 42)   = "42"
    -- > toLazyByteString (int8Dec (-1)) = "-1"
    --
    {-# INLINE int8Dec #-}
    int8Dec :: Int8 -> Builder
    int8Dec = P.primBounded P.int8Dec

    -- | Decimal encoding of an 'Int16' using the ASCII digits.
    {-# INLINE int16Dec #-}
    int16Dec :: Int16 -> Builder
    int16Dec = P.primBounded P.int16Dec

    -- | Decimal encoding of an 'Int32' using the ASCII digits.
    {-# INLINE int32Dec #-}
    int32Dec :: Int32 -> Builder
    int32Dec = P.primBounded P.int32Dec

    -- | Decimal encoding of an 'Int64' using the ASCII digits.
    {-# INLINE int64Dec #-}
    int64Dec :: Int64 -> Builder
    int64Dec = P.primBounded P.int64Dec

    -- | Decimal encoding of an 'Int' using the ASCII digits.
    {-# INLINE intDec #-}
    intDec :: Int -> Builder
    intDec = P.primBounded P.intDec

    -- Unsigned integers
    --------------------

    -- | Decimal encoding of a 'Word8' using the ASCII digits.
    {-# INLINE word8Dec #-}
    word8Dec :: Word8 -> Builder
    word8Dec = P.primBounded P.word8Dec

    -- | Decimal encoding of a 'Word16' using the ASCII digits.
    {-# INLINE word16Dec #-}
    word16Dec :: Word16 -> Builder
    word16Dec = P.primBounded P.word16Dec

    -- | Decimal encoding of a 'Word32' using the ASCII digits.
    {-# INLINE word32Dec #-}
    word32Dec :: Word32 -> Builder
    word32Dec = P.primBounded P.word32Dec

    -- | Decimal encoding of a 'Word64' using the ASCII digits.
    {-# INLINE word64Dec #-}
    word64Dec :: Word64 -> Builder
    word64Dec = P.primBounded P.word64Dec

    -- | Decimal encoding of a 'Word' using the ASCII digits.
    {-# INLINE wordDec #-}
    wordDec :: Word -> Builder
    wordDec = P.primBounded P.wordDec

    -- Floating point numbers
    -------------------------

    -- TODO: Use Bryan O'Sullivan's double-conversion package to speed it up.

    -- | /Currently slow./ Decimal encoding of an IEEE 'Float'.
    {-# INLINE floatDec #-}
    floatDec :: Float -> Builder
    floatDec = string7 . show

    -- | /Currently slow./ Decimal encoding of an IEEE 'Double'.
    {-# INLINE doubleDec #-}
    doubleDec :: Double -> Builder
    doubleDec = string7 . show

    ------------------------------------------------------------------------------
    -- Hexadecimal Encoding
    ------------------------------------------------------------------------------

    -- without lead
    ---------------

    -- | Shortest hexadecimal encoding of a 'Word8' using lower-case characters.
    {-# INLINE word8Hex #-}
    word8Hex :: Word8 -> Builder
    word8Hex = P.primBounded P.word8Hex

    -- | Shortest hexadecimal encoding of a 'Word16' using lower-case characters.
    {-# INLINE word16Hex #-}
    word16Hex :: Word16 -> Builder
    word16Hex = P.primBounded P.word16Hex

    -- | Shortest hexadecimal encoding of a 'Word32' using lower-case characters.
    {-# INLINE word32Hex #-}
    word32Hex :: Word32 -> Builder
    word32Hex = P.primBounded P.word32Hex

    -- | Shortest hexadecimal encoding of a 'Word64' using lower-case characters.
    {-# INLINE word64Hex #-}
    word64Hex :: Word64 -> Builder
    word64Hex = P.primBounded P.word64Hex

    -- | Shortest hexadecimal encoding of a 'Word' using lower-case characters.
    {-# INLINE wordHex #-}
    wordHex :: Word -> Builder
    wordHex = P.primBounded P.wordHex

    -- fixed width; leading zeroes
    ------------------------------

    -- | Encode a 'Int8' using 2 nibbles (hexadecimal digits).
    {-# INLINE int8HexFixed #-}
    int8HexFixed :: Int8 -> Builder
    int8HexFixed = P.primFixed P.int8HexFixed

    -- | Encode a 'Int16' using 4 nibbles.
    {-# INLINE int16HexFixed #-}
    int16HexFixed :: Int16 -> Builder
    int16HexFixed = P.primFixed P.int16HexFixed

    -- | Encode a 'Int32' using 8 nibbles.
    {-# INLINE int32HexFixed #-}
    int32HexFixed :: Int32 -> Builder
    int32HexFixed = P.primFixed P.int32HexFixed

    -- | Encode a 'Int64' using 16 nibbles.
    {-# INLINE int64HexFixed #-}
    int64HexFixed :: Int64 -> Builder
    int64HexFixed = P.primFixed P.int64HexFixed

    -- | Encode a 'Word8' using 2 nibbles (hexadecimal digits).
    {-# INLINE word8HexFixed #-}
    word8HexFixed :: Word8 -> Builder
    word8HexFixed = P.primFixed P.word8HexFixed

    -- | Encode a 'Word16' using 4 nibbles.
    {-# INLINE word16HexFixed #-}
    word16HexFixed :: Word16 -> Builder
    word16HexFixed = P.primFixed P.word16HexFixed

    -- | Encode a 'Word32' using 8 nibbles.
    {-# INLINE word32HexFixed #-}
    word32HexFixed :: Word32 -> Builder
    word32HexFixed = P.primFixed P.word32HexFixed

    -- | Encode a 'Word64' using 16 nibbles.
    {-# INLINE word64HexFixed #-}
    word64HexFixed :: Word64 -> Builder
    word64HexFixed = P.primFixed P.word64HexFixed

    -- | Encode an IEEE 'Float' using 8 nibbles.
    {-# INLINE floatHexFixed #-}
    floatHexFixed :: Float -> Builder
    floatHexFixed = P.primFixed P.floatHexFixed

    -- | Encode an IEEE 'Double' using 16 nibbles.
    {-# INLINE doubleHexFixed #-}
    doubleHexFixed :: Double -> Builder
    doubleHexFixed = P.primFixed P.doubleHexFixed

    -- | Encode each byte of a 'S.ByteString' using its fixed-width hex encoding.
    {-# NOINLINE byteStringHex #-} -- share code
    byteStringHex :: S.ByteString -> Builder
    byteStringHex = P.primMapByteStringFixed P.word8HexFixed

    -- | Encode each byte of a lazy 'L.ByteString' using its fixed-width hex encoding.
    {-# NOINLINE lazyByteStringHex #-} -- share code
    lazyByteStringHex :: L.ByteString -> Builder
    lazyByteStringHex = P.primMapLazyByteStringFixed P.word8HexFixed

    ------------------------------------------------------------------------------
    -- Fast decimal 'Integer' encoding.
    ------------------------------------------------------------------------------

    #if defined(INTEGER_GMP)
    -- An optimized version of the integer serialization code
    -- in blaze-textual (c) 2011 MailRank, Inc. Bryan O'Sullivan
    -- <bos@mailrank.com>. It is 2.5x faster on Int-sized integers and 4.5x faster
    -- on larger integers.

    # define PAIR(a,b) (# a,b #)

    -- | Maximal power of 10 fitting into an 'Int' without using the MSB.
    --     10 ^ 9  for 32 bit ints  (31 * log 2 / log 10 =  9.33)
    --     10 ^ 18 for 64 bit ints  (63 * log 2 / log 10 = 18.96)
    --
    -- FIXME: Think about also using the MSB. For 64 bit 'Int's this makes a
    -- difference.
    maxPow10 :: Integer
    maxPow10 = toInteger $ (10 :: Int) ^ caseWordSize_32_64 (9 :: Int) 18

    -- | Decimal encoding of an 'Integer' using the ASCII digits.
    integerDec :: Integer -> Builder
    integerDec (S# i#) = intDec (I# i#)
    integerDec i
        | i < 0     = P.primFixed P.char8 '-' `mappend` go (-i)
        | otherwise =                                   go ( i)
      where
        errImpossible fun =
            error $ "integerDec: " ++ fun ++ ": the impossible happened."

        go :: Integer -> Builder
        go n | n < maxPow10 = intDec (fromInteger n)
             | otherwise    =
                 case putH (splitf (maxPow10 * maxPow10) n) of
                   (x:xs) -> intDec x `mappend` P.primMapListBounded intDecPadded xs
                   []     -> errImpossible "integerDec: go"

        splitf :: Integer -> Integer -> [Integer]
        splitf pow10 n0
          | pow10 > n0  = [n0]
          | otherwise   = splith (splitf (pow10 * pow10) n0)
          where
            splith []     = errImpossible "splith"
            splith (n:ns) =
                case n `quotRemInteger` pow10 of
                    PAIR(q,r) | q > 0     -> q : r : splitb ns
                              | otherwise ->     r : splitb ns

            splitb []     = []
            splitb (n:ns) = case n `quotRemInteger` pow10 of
                                PAIR(q,r) -> q : r : splitb ns

        putH :: [Integer] -> [Int]
        putH []     = errImpossible "putH"
        putH (n:ns) = case n `quotRemInteger` maxPow10 of
                        PAIR(x,y)
                            | q > 0     -> q : r : putB ns
                            | otherwise ->     r : putB ns
                            where q = fromInteger x
                                  r = fromInteger y

        putB :: [Integer] -> [Int]
        putB []     = []
        putB (n:ns) = case n `quotRemInteger` maxPow10 of
                        PAIR(q,r) -> fromInteger q : fromInteger r : putB ns

    foreign import ccall unsafe "static _hs_bytestring_int_dec_padded9"
        c_int_dec_padded9 :: CInt -> Ptr Word8 -> IO ()

    foreign import ccall unsafe "static _hs_bytestring_long_long_int_dec_padded18"
        c_long_long_int_dec_padded18 :: CLLong -> Ptr Word8 -> IO ()

    {-# INLINE intDecPadded #-}
    intDecPadded :: P.BoundedPrim Int
    intDecPadded = P.liftFixedToBounded $ caseWordSize_32_64
        (P.fixedPrim  9 $ c_int_dec_padded9            . fromIntegral)
        (P.fixedPrim 18 $ c_long_long_int_dec_padded18 . fromIntegral)

    #else
    -- compilers other than GHC

    -- | Decimal encoding of an 'Integer' using the ASCII digits. Implemented
    -- using via the 'Show' instance of 'Integer's.
    integerDec :: Integer -> Builder
    integerDec = string7 . show
    #endif