{-# LANGUAGE BangPatterns, CPP, MagicHash, OverloadedStrings, UnboxedTuples #-}
-- Module: Blaze.Text.Int
-- Copyright: (c) 2011 MailRank, Inc.
-- License: BSD3
-- Maintainer: Bryan O'Sullivan <bos@serpentine.com>
-- Stability: experimental
-- Portability: portable
--
-- Efficiently serialize an integral value as a lazy 'L.ByteString'.
module Blaze.Text.Int
(
digit
, integral
, minus
) where
import Blaze.ByteString.Builder
import Blaze.ByteString.Builder.Char8
import Data.ByteString.Char8 ()
import Data.Int (Int8, Int16, Int32, Int64)
import Data.Monoid (mappend, mempty)
import Data.Word (Word, Word8, Word16, Word32, Word64)
import GHC.Base (quotInt, remInt)
#if MIN_VERSION_base(4,15,0)
#else
import GHC.Num (quotRemInteger)
#endif
import GHC.Types (Int(..))
#if defined(INTEGER_GMP)
import GHC.Integer.GMP.Internals
#elif defined(INTEGER_SIMPLE)
import GHC.Integer.Simple.Internals
#endif
#define PAIR(a,b) (# a,b #)
integral :: (Integral a, Show a) => a -> Builder
{-# RULES "integral/Int" integral = bounded :: Int -> Builder #-}
{-# RULES "integral/Int8" integral = bounded :: Int8 -> Builder #-}
{-# RULES "integral/Int16" integral = bounded :: Int16 -> Builder #-}
{-# RULES "integral/Int32" integral = bounded :: Int32 -> Builder #-}
{-# RULES "integral/Int64" integral = bounded :: Int64 -> Builder #-}
{-# RULES "integral/Word" integral = nonNegative :: Word -> Builder #-}
{-# RULES "integral/Word8" integral = nonNegative :: Word8 -> Builder #-}
{-# RULES "integral/Word16" integral = nonNegative :: Word16 -> Builder #-}
{-# RULES "integral/Word32" integral = nonNegative :: Word32 -> Builder #-}
{-# RULES "integral/Word64" integral = nonNegative :: Word64 -> Builder #-}
{-# RULES "integral/Integer" integral = integer :: Integer -> Builder #-}
-- This definition of the function is here PURELY to be used by ghci
-- and those rare cases where GHC is being invoked without
-- optimization, as otherwise the rewrite rules above should fire. The
-- test for `(-i) == i` catches when we render minBound, in which case
-- using `-i` would be wrong. An example is `-(-128 :: Int8) == -128`.
integral i
| i >= 0 = nonNegative i
| (-i) == i = fromString (show i)
| otherwise = b
where b = minus `mappend` nonNegative (-i)
{-# NOINLINE integral #-}
bounded :: (Bounded a, Integral a) => a -> Builder
{-# SPECIALIZE bounded :: Int -> Builder #-}
{-# SPECIALIZE bounded :: Int8 -> Builder #-}
{-# SPECIALIZE bounded :: Int16 -> Builder #-}
{-# SPECIALIZE bounded :: Int32 -> Builder #-}
{-# SPECIALIZE bounded :: Int64 -> Builder #-}
bounded i
| i >= 0 = nonNegative i
| i > minBound = minus `mappend` nonNegative (-i)
| otherwise = minus `mappend`
nonNegative (negate (k `quot` 10)) `mappend`
digit (negate (k `rem` 10))
where k = minBound `asTypeOf` i
nonNegative :: Integral a => a -> Builder
{-# SPECIALIZE nonNegative :: Int -> Builder #-}
{-# SPECIALIZE nonNegative :: Int8 -> Builder #-}
{-# SPECIALIZE nonNegative :: Int16 -> Builder #-}
{-# SPECIALIZE nonNegative :: Int32 -> Builder #-}
{-# SPECIALIZE nonNegative :: Int64 -> Builder #-}
{-# SPECIALIZE nonNegative :: Word -> Builder #-}
{-# SPECIALIZE nonNegative :: Word8 -> Builder #-}
{-# SPECIALIZE nonNegative :: Word16 -> Builder #-}
{-# SPECIALIZE nonNegative :: Word32 -> Builder #-}
{-# SPECIALIZE nonNegative :: Word64 -> Builder #-}
nonNegative x
| x < 0 = error $ "nonNegative: Called with negative number " ++ show (fromIntegral x :: Integer)
| otherwise = go x
where
go n | n < 10 = digit n
| otherwise = go (n `quot` 10) `mappend` digit (n `rem` 10)
digit :: Integral a => a -> Builder
digit n = fromWord8 $! fromIntegral n + 48
{-# INLINE digit #-}
minus :: Builder
minus = fromWord8 45
int :: Int -> Builder
int = integral
{-# INLINE int #-}
integer :: Integer -> Builder
#if defined(INTEGER_GMP)
integer (S# i#) = int (I# i#)
#endif
integer i
| i < 0 = minus `mappend` go (-i)
| otherwise = go i
where
go n | n < maxInt = int (fromInteger n)
| otherwise = putH (splitf (maxInt * maxInt) n)
splitf p n
| p > n = [n]
| otherwise = splith p (splitf (p*p) n)
splith p (n:ns) = case n `quotRemInteger` p of
PAIR(q,r) | q > 0 -> q : r : splitb p ns
| otherwise -> r : splitb p ns
splith _ _ = error "splith: the impossible happened."
splitb p (n:ns) = case n `quotRemInteger` p of
PAIR(q,r) -> q : r : splitb p ns
splitb _ _ = []
data T = T !Integer !Int
fstT :: T -> Integer
fstT (T a _) = a
maxInt :: Integer
maxDigits :: Int
T maxInt maxDigits =
until ((>mi) . (*10) . fstT) (\(T n d) -> T (n*10) (d+1)) (T 10 1)
where mi = fromIntegral (maxBound :: Int)
putH :: [Integer] -> Builder
putH (n:ns) = case n `quotRemInteger` maxInt of
PAIR(x,y)
| q > 0 -> int q `mappend` pblock r `mappend` putB ns
| otherwise -> int r `mappend` putB ns
where q = fromInteger x
r = fromInteger y
putH _ = error "putH: the impossible happened"
putB :: [Integer] -> Builder
putB (n:ns) = case n `quotRemInteger` maxInt of
PAIR(x,y) -> pblock q `mappend` pblock r `mappend` putB ns
where q = fromInteger x
r = fromInteger y
putB _ = mempty
pblock :: Int -> Builder
pblock = go maxDigits
where
go !d !n
| d == 1 = digit n
| otherwise = go (d-1) q `mappend` digit r
where q = n `quotInt` 10
r = n `remInt` 10