{-# LANGUAGE BangPatterns, MagicHash, UnboxedTuples #-}
{-# OPTIONS_GHC -O2 #-}
-- We always optimise this, otherwise performance of a non-optimised
-- compiler is severely affected

-- -----------------------------------------------------------------------------
--
-- (c) The University of Glasgow, 1997-2006
--
-- Character encodings
--
-- -----------------------------------------------------------------------------

module Encoding (
        -- * UTF-8
        utf8DecodeChar#,
        utf8PrevChar,
        utf8CharStart,
        utf8DecodeChar,
        utf8DecodeByteString,
        utf8DecodeStringLazy,
        utf8EncodeChar,
        utf8EncodeString,
        utf8EncodedLength,
        countUTF8Chars,

        -- * Z-encoding
        zEncodeString,
        zDecodeString,

        -- * Base62-encoding
        toBase62,
        toBase62Padded
  ) where

import GhcPrelude

import Foreign
import Foreign.ForeignPtr.Unsafe
import Data.Char
import qualified Data.Char as Char
import Numeric
import GHC.IO

import Data.ByteString (ByteString)
import qualified Data.ByteString.Internal as BS

import GHC.Exts

-- -----------------------------------------------------------------------------
-- UTF-8

-- We can't write the decoder as efficiently as we'd like without
-- resorting to unboxed extensions, unfortunately.  I tried to write
-- an IO version of this function, but GHC can't eliminate boxed
-- results from an IO-returning function.
--
-- We assume we can ignore overflow when parsing a multibyte character here.
-- To make this safe, we add extra sentinel bytes to unparsed UTF-8 sequences
-- before decoding them (see StringBuffer.hs).

{-# INLINE utf8DecodeChar# #-}
utf8DecodeChar# :: Addr# -> (# Char#, Int# #)
utf8DecodeChar# :: Addr# -> (# Char#, Int# #)
utf8DecodeChar# a# :: Addr#
a# =
  let !ch0 :: Int#
ch0 = Word# -> Int#
word2Int# (Addr# -> Int# -> Word#
indexWord8OffAddr# Addr#
a# 0#) in
  case () of
    _ | Int# -> Bool
isTrue# (Int#
ch0 Int# -> Int# -> Int#
<=# 0x7F#) -> (# Int# -> Char#
chr# Int#
ch0, 1# #)

      | Int# -> Bool
isTrue# ((Int#
ch0 Int# -> Int# -> Int#
>=# 0xC0#) Int# -> Int# -> Int#
`andI#` (Int#
ch0 Int# -> Int# -> Int#
<=# 0xDF#)) ->
        let !ch1 :: Int#
ch1 = Word# -> Int#
word2Int# (Addr# -> Int# -> Word#
indexWord8OffAddr# Addr#
a# 1#) in
        if Int# -> Bool
isTrue# ((Int#
ch1 Int# -> Int# -> Int#
<# 0x80#) Int# -> Int# -> Int#
`orI#` (Int#
ch1 Int# -> Int# -> Int#
>=# 0xC0#)) then Int# -> (# Char#, Int# #)
fail 1# else
        (# Int# -> Char#
chr# (((Int#
ch0 Int# -> Int# -> Int#
-# 0xC0#) Int# -> Int# -> Int#
`uncheckedIShiftL#` 6#) Int# -> Int# -> Int#
+#
                  (Int#
ch1 Int# -> Int# -> Int#
-# 0x80#)),
           2# #)

      | Int# -> Bool
isTrue# ((Int#
ch0 Int# -> Int# -> Int#
>=# 0xE0#) Int# -> Int# -> Int#
`andI#` (Int#
ch0 Int# -> Int# -> Int#
<=# 0xEF#)) ->
        let !ch1 :: Int#
ch1 = Word# -> Int#
word2Int# (Addr# -> Int# -> Word#
indexWord8OffAddr# Addr#
a# 1#) in
        if Int# -> Bool
isTrue# ((Int#
ch1 Int# -> Int# -> Int#
<# 0x80#) Int# -> Int# -> Int#
`orI#` (Int#
ch1 Int# -> Int# -> Int#
>=# 0xC0#)) then Int# -> (# Char#, Int# #)
fail 1# else
        let !ch2 :: Int#
ch2 = Word# -> Int#
word2Int# (Addr# -> Int# -> Word#
indexWord8OffAddr# Addr#
a# 2#) in
        if Int# -> Bool
isTrue# ((Int#
ch2 Int# -> Int# -> Int#
<# 0x80#) Int# -> Int# -> Int#
`orI#` (Int#
ch2 Int# -> Int# -> Int#
>=# 0xC0#)) then Int# -> (# Char#, Int# #)
fail 2# else
        (# Int# -> Char#
chr# (((Int#
ch0 Int# -> Int# -> Int#
-# 0xE0#) Int# -> Int# -> Int#
`uncheckedIShiftL#` 12#) Int# -> Int# -> Int#
+#
                 ((Int#
ch1 Int# -> Int# -> Int#
-# 0x80#) Int# -> Int# -> Int#
`uncheckedIShiftL#` 6#)  Int# -> Int# -> Int#
+#
                  (Int#
ch2 Int# -> Int# -> Int#
-# 0x80#)),
           3# #)

     | Int# -> Bool
isTrue# ((Int#
ch0 Int# -> Int# -> Int#
>=# 0xF0#) Int# -> Int# -> Int#
`andI#` (Int#
ch0 Int# -> Int# -> Int#
<=# 0xF8#)) ->
        let !ch1 :: Int#
ch1 = Word# -> Int#
word2Int# (Addr# -> Int# -> Word#
indexWord8OffAddr# Addr#
a# 1#) in
        if Int# -> Bool
isTrue# ((Int#
ch1 Int# -> Int# -> Int#
<# 0x80#) Int# -> Int# -> Int#
`orI#` (Int#
ch1 Int# -> Int# -> Int#
>=# 0xC0#)) then Int# -> (# Char#, Int# #)
fail 1# else
        let !ch2 :: Int#
ch2 = Word# -> Int#
word2Int# (Addr# -> Int# -> Word#
indexWord8OffAddr# Addr#
a# 2#) in
        if Int# -> Bool
isTrue# ((Int#
ch2 Int# -> Int# -> Int#
<# 0x80#) Int# -> Int# -> Int#
`orI#` (Int#
ch2 Int# -> Int# -> Int#
>=# 0xC0#)) then Int# -> (# Char#, Int# #)
fail 2# else
        let !ch3 :: Int#
ch3 = Word# -> Int#
word2Int# (Addr# -> Int# -> Word#
indexWord8OffAddr# Addr#
a# 3#) in
        if Int# -> Bool
isTrue# ((Int#
ch3 Int# -> Int# -> Int#
<# 0x80#) Int# -> Int# -> Int#
`orI#` (Int#
ch3 Int# -> Int# -> Int#
>=# 0xC0#)) then Int# -> (# Char#, Int# #)
fail 3# else
        (# Int# -> Char#
chr# (((Int#
ch0 Int# -> Int# -> Int#
-# 0xF0#) Int# -> Int# -> Int#
`uncheckedIShiftL#` 18#) Int# -> Int# -> Int#
+#
                 ((Int#
ch1 Int# -> Int# -> Int#
-# 0x80#) Int# -> Int# -> Int#
`uncheckedIShiftL#` 12#) Int# -> Int# -> Int#
+#
                 ((Int#
ch2 Int# -> Int# -> Int#
-# 0x80#) Int# -> Int# -> Int#
`uncheckedIShiftL#` 6#)  Int# -> Int# -> Int#
+#
                  (Int#
ch3 Int# -> Int# -> Int#
-# 0x80#)),
           4# #)

      | Bool
otherwise -> Int# -> (# Char#, Int# #)
fail 1#
  where
        -- all invalid sequences end up here:
        fail :: Int# -> (# Char#, Int# #)
        fail :: Int# -> (# Char#, Int# #)
fail nBytes# :: Int#
nBytes# = (# '\0'#, Int#
nBytes# #)
        -- '\xFFFD' would be the usual replacement character, but
        -- that's a valid symbol in Haskell, so will result in a
        -- confusing parse error later on.  Instead we use '\0' which
        -- will signal a lexer error immediately.

utf8DecodeChar :: Ptr Word8 -> (Char, Int)
utf8DecodeChar :: Ptr Word8 -> (Char, Int)
utf8DecodeChar (Ptr a# :: Addr#
a#) =
  case Addr# -> (# Char#, Int# #)
utf8DecodeChar# Addr#
a# of (# c# :: Char#
c#, nBytes# :: Int#
nBytes# #) -> ( Char# -> Char
C# Char#
c#, Int# -> Int
I# Int#
nBytes# )

-- UTF-8 is cleverly designed so that we can always figure out where
-- the start of the current character is, given any position in a
-- stream.  This function finds the start of the previous character,
-- assuming there *is* a previous character.
utf8PrevChar :: Ptr Word8 -> IO (Ptr Word8)
utf8PrevChar :: Ptr Word8 -> IO (Ptr Word8)
utf8PrevChar p :: Ptr Word8
p = Ptr Word8 -> IO (Ptr Word8)
utf8CharStart (Ptr Word8
p Ptr Word8 -> Int -> Ptr Word8
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` (-1))

utf8CharStart :: Ptr Word8 -> IO (Ptr Word8)
utf8CharStart :: Ptr Word8 -> IO (Ptr Word8)
utf8CharStart p :: Ptr Word8
p = Ptr Word8 -> IO (Ptr Word8)
forall b. (Storable b, Ord b, Num b) => Ptr b -> IO (Ptr b)
go Ptr Word8
p
 where go :: Ptr b -> IO (Ptr b)
go p :: Ptr b
p = do b
w <- Ptr b -> IO b
forall a. Storable a => Ptr a -> IO a
peek Ptr b
p
                 if b
w b -> b -> Bool
forall a. Ord a => a -> a -> Bool
>= 0x80 Bool -> Bool -> Bool
&& b
w b -> b -> Bool
forall a. Ord a => a -> a -> Bool
< 0xC0
                        then Ptr b -> IO (Ptr b)
go (Ptr b
p Ptr b -> Int -> Ptr b
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` (-1))
                        else Ptr b -> IO (Ptr b)
forall (m :: * -> *) a. Monad m => a -> m a
return Ptr b
p

utf8DecodeByteString :: ByteString -> [Char]
utf8DecodeByteString :: ByteString -> [Char]
utf8DecodeByteString (BS.PS ptr :: ForeignPtr Word8
ptr offset :: Int
offset len :: Int
len)
  = ForeignPtr Word8 -> Int -> Int -> [Char]
utf8DecodeStringLazy ForeignPtr Word8
ptr Int
offset Int
len

utf8DecodeStringLazy :: ForeignPtr Word8 -> Int -> Int -> [Char]
utf8DecodeStringLazy :: ForeignPtr Word8 -> Int -> Int -> [Char]
utf8DecodeStringLazy fptr :: ForeignPtr Word8
fptr offset :: Int
offset len :: Int
len
  = IO [Char] -> [Char]
forall a. IO a -> a
unsafeDupablePerformIO (IO [Char] -> [Char]) -> IO [Char] -> [Char]
forall a b. (a -> b) -> a -> b
$ Ptr Any -> IO [Char]
forall a. Ptr a -> IO [Char]
unpack Ptr Any
forall b. Ptr b
start
  where
    !start :: Ptr b
start = ForeignPtr Word8 -> Ptr Word8
forall a. ForeignPtr a -> Ptr a
unsafeForeignPtrToPtr ForeignPtr Word8
fptr Ptr Word8 -> Int -> Ptr b
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` Int
offset
    !end :: Ptr b
end = Ptr Any
forall b. Ptr b
start Ptr Any -> Int -> Ptr b
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` Int
len

    unpack :: Ptr a -> IO [Char]
unpack p :: Ptr a
p
        | Ptr a
p Ptr a -> Ptr a -> Bool
forall a. Ord a => a -> a -> Bool
>= Ptr a
forall b. Ptr b
end  = ForeignPtr Word8 -> IO ()
forall a. ForeignPtr a -> IO ()
touchForeignPtr ForeignPtr Word8
fptr IO () -> IO [Char] -> IO [Char]
forall (m :: * -> *) a b. Monad m => m a -> m b -> m b
>> [Char] -> IO [Char]
forall (m :: * -> *) a. Monad m => a -> m a
return []
        | Bool
otherwise =
            case Addr# -> (# Char#, Int# #)
utf8DecodeChar# (Ptr a -> Addr#
forall a. Ptr a -> Addr#
unPtr Ptr a
p) of
                (# c# :: Char#
c#, nBytes# :: Int#
nBytes# #) -> do
                  [Char]
rest <- IO [Char] -> IO [Char]
forall a. IO a -> IO a
unsafeDupableInterleaveIO (IO [Char] -> IO [Char]) -> IO [Char] -> IO [Char]
forall a b. (a -> b) -> a -> b
$ Ptr a -> IO [Char]
unpack (Ptr a
p Ptr a -> Int# -> Ptr a
forall a. Ptr a -> Int# -> Ptr a
`plusPtr#` Int#
nBytes#)
                  [Char] -> IO [Char]
forall (m :: * -> *) a. Monad m => a -> m a
return (Char# -> Char
C# Char#
c# Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: [Char]
rest)

countUTF8Chars :: Ptr Word8 -> Int -> IO Int
countUTF8Chars :: Ptr Word8 -> Int -> IO Int
countUTF8Chars ptr :: Ptr Word8
ptr len :: Int
len = Ptr Word8 -> Int -> IO Int
forall (m :: * -> *) t a. (Monad m, Num t) => Ptr a -> t -> m t
go Ptr Word8
ptr 0
  where
        !end :: Ptr b
end = Ptr Word8
ptr Ptr Word8 -> Int -> Ptr b
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` Int
len

        go :: Ptr a -> t -> m t
go p :: Ptr a
p !t
n
           | Ptr a
p Ptr a -> Ptr a -> Bool
forall a. Ord a => a -> a -> Bool
>= Ptr a
forall b. Ptr b
end = t -> m t
forall (m :: * -> *) a. Monad m => a -> m a
return t
n
           | Bool
otherwise  = do
                case Addr# -> (# Char#, Int# #)
utf8DecodeChar# (Ptr a -> Addr#
forall a. Ptr a -> Addr#
unPtr Ptr a
p) of
                  (# _, nBytes# :: Int#
nBytes# #) -> Ptr a -> t -> m t
go (Ptr a
p Ptr a -> Int# -> Ptr a
forall a. Ptr a -> Int# -> Ptr a
`plusPtr#` Int#
nBytes#) (t
nt -> t -> t
forall a. Num a => a -> a -> a
+1)

unPtr :: Ptr a -> Addr#
unPtr :: Ptr a -> Addr#
unPtr (Ptr a :: Addr#
a) = Addr#
a

plusPtr# :: Ptr a -> Int# -> Ptr a
plusPtr# :: Ptr a -> Int# -> Ptr a
plusPtr# ptr :: Ptr a
ptr nBytes# :: Int#
nBytes# = Ptr a
ptr Ptr a -> Int -> Ptr a
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` (Int# -> Int
I# Int#
nBytes#)

utf8EncodeChar :: Char -> Ptr Word8 -> IO (Ptr Word8)
utf8EncodeChar :: Char -> Ptr Word8 -> IO (Ptr Word8)
utf8EncodeChar c :: Char
c ptr :: Ptr Word8
ptr =
  let x :: Int
x = Char -> Int
ord Char
c in
  case () of
    _ | Int
x Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
> 0 Bool -> Bool -> Bool
&& Int
x Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= 0x007f -> do
          Ptr Word8 -> Word8 -> IO ()
forall a. Storable a => Ptr a -> a -> IO ()
poke Ptr Word8
ptr (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral Int
x)
          Ptr Word8 -> IO (Ptr Word8)
forall (m :: * -> *) a. Monad m => a -> m a
return (Ptr Word8
ptr Ptr Word8 -> Int -> Ptr Word8
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` 1)
        -- NB. '\0' is encoded as '\xC0\x80', not '\0'.  This is so that we
        -- can have 0-terminated UTF-8 strings (see GHC.Base.unpackCStringUtf8).
      | Int
x Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= 0x07ff -> do
          Ptr Word8 -> Word8 -> IO ()
forall a. Storable a => Ptr a -> a -> IO ()
poke Ptr Word8
ptr (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0xC0 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. ((Int
x Int -> Int -> Int
forall a. Bits a => a -> Int -> a
`shiftR` 6) Int -> Int -> Int
forall a. Bits a => a -> a -> a
.&. 0x1F)))
          Ptr Word8 -> Int -> Word8 -> IO ()
forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr Word8
ptr 1 (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0x80 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. (Int
x Int -> Int -> Int
forall a. Bits a => a -> a -> a
.&. 0x3F)))
          Ptr Word8 -> IO (Ptr Word8)
forall (m :: * -> *) a. Monad m => a -> m a
return (Ptr Word8
ptr Ptr Word8 -> Int -> Ptr Word8
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` 2)
      | Int
x Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= 0xffff -> do
          Ptr Word8 -> Word8 -> IO ()
forall a. Storable a => Ptr a -> a -> IO ()
poke Ptr Word8
ptr (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0xE0 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. (Int
x Int -> Int -> Int
forall a. Bits a => a -> Int -> a
`shiftR` 12) Int -> Int -> Int
forall a. Bits a => a -> a -> a
.&. 0x0F))
          Ptr Word8 -> Int -> Word8 -> IO ()
forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr Word8
ptr 1 (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0x80 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. (Int
x Int -> Int -> Int
forall a. Bits a => a -> Int -> a
`shiftR` 6) Int -> Int -> Int
forall a. Bits a => a -> a -> a
.&. 0x3F))
          Ptr Word8 -> Int -> Word8 -> IO ()
forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr Word8
ptr 2 (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0x80 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. (Int
x Int -> Int -> Int
forall a. Bits a => a -> a -> a
.&. 0x3F)))
          Ptr Word8 -> IO (Ptr Word8)
forall (m :: * -> *) a. Monad m => a -> m a
return (Ptr Word8
ptr Ptr Word8 -> Int -> Ptr Word8
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` 3)
      | Bool
otherwise -> do
          Ptr Word8 -> Word8 -> IO ()
forall a. Storable a => Ptr a -> a -> IO ()
poke Ptr Word8
ptr (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0xF0 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. (Int
x Int -> Int -> Int
forall a. Bits a => a -> Int -> a
`shiftR` 18)))
          Ptr Word8 -> Int -> Word8 -> IO ()
forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr Word8
ptr 1 (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0x80 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. ((Int
x Int -> Int -> Int
forall a. Bits a => a -> Int -> a
`shiftR` 12) Int -> Int -> Int
forall a. Bits a => a -> a -> a
.&. 0x3F)))
          Ptr Word8 -> Int -> Word8 -> IO ()
forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr Word8
ptr 2 (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0x80 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. ((Int
x Int -> Int -> Int
forall a. Bits a => a -> Int -> a
`shiftR` 6) Int -> Int -> Int
forall a. Bits a => a -> a -> a
.&. 0x3F)))
          Ptr Word8 -> Int -> Word8 -> IO ()
forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr Word8
ptr 3 (Int -> Word8
forall a b. (Integral a, Num b) => a -> b
fromIntegral (0x80 Int -> Int -> Int
forall a. Bits a => a -> a -> a
.|. (Int
x Int -> Int -> Int
forall a. Bits a => a -> a -> a
.&. 0x3F)))
          Ptr Word8 -> IO (Ptr Word8)
forall (m :: * -> *) a. Monad m => a -> m a
return (Ptr Word8
ptr Ptr Word8 -> Int -> Ptr Word8
forall a b. Ptr a -> Int -> Ptr b
`plusPtr` 4)

utf8EncodeString :: Ptr Word8 -> String -> IO ()
utf8EncodeString :: Ptr Word8 -> [Char] -> IO ()
utf8EncodeString ptr :: Ptr Word8
ptr str :: [Char]
str = Ptr Word8 -> [Char] -> IO ()
go Ptr Word8
ptr [Char]
str
  where go :: Ptr Word8 -> [Char] -> IO ()
go !Ptr Word8
_   []     = () -> IO ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
        go ptr :: Ptr Word8
ptr (c :: Char
c:cs :: [Char]
cs) = do
          Ptr Word8
ptr' <- Char -> Ptr Word8 -> IO (Ptr Word8)
utf8EncodeChar Char
c Ptr Word8
ptr
          Ptr Word8 -> [Char] -> IO ()
go Ptr Word8
ptr' [Char]
cs

utf8EncodedLength :: String -> Int
utf8EncodedLength :: [Char] -> Int
utf8EncodedLength str :: [Char]
str = Int -> [Char] -> Int
forall a. Num a => a -> [Char] -> a
go 0 [Char]
str
  where go :: a -> [Char] -> a
go !a
n [] = a
n
        go n :: a
n (c :: Char
c:cs :: [Char]
cs)
          | Char -> Int
ord Char
c Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
> 0 Bool -> Bool -> Bool
&& Char -> Int
ord Char
c Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= 0x007f = a -> [Char] -> a
go (a
na -> a -> a
forall a. Num a => a -> a -> a
+1) [Char]
cs
          | Char -> Int
ord Char
c Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= 0x07ff = a -> [Char] -> a
go (a
na -> a -> a
forall a. Num a => a -> a -> a
+2) [Char]
cs
          | Char -> Int
ord Char
c Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
<= 0xffff = a -> [Char] -> a
go (a
na -> a -> a
forall a. Num a => a -> a -> a
+3) [Char]
cs
          | Bool
otherwise       = a -> [Char] -> a
go (a
na -> a -> a
forall a. Num a => a -> a -> a
+4) [Char]
cs

-- -----------------------------------------------------------------------------
-- The Z-encoding

{-
This is the main name-encoding and decoding function.  It encodes any
string into a string that is acceptable as a C name.  This is done
right before we emit a symbol name into the compiled C or asm code.
Z-encoding of strings is cached in the FastString interface, so we
never encode the same string more than once.

The basic encoding scheme is this.

* Tuples (,,,) are coded as Z3T

* Alphabetic characters (upper and lower) and digits
        all translate to themselves;
        except 'Z', which translates to 'ZZ'
        and    'z', which translates to 'zz'
  We need both so that we can preserve the variable/tycon distinction

* Most other printable characters translate to 'zx' or 'Zx' for some
        alphabetic character x

* The others translate as 'znnnU' where 'nnn' is the decimal number
        of the character

        Before          After
        --------------------------
        Trak            Trak
        foo_wib         foozuwib
        >               zg
        >1              zg1
        foo#            foozh
        foo##           foozhzh
        foo##1          foozhzh1
        fooZ            fooZZ
        :+              ZCzp
        ()              Z0T     0-tuple
        (,,,,)          Z5T     5-tuple
        (# #)           Z1H     unboxed 1-tuple (note the space)
        (#,,,,#)        Z5H     unboxed 5-tuple
                (NB: There is no Z1T nor Z0H.)
-}

type UserString = String        -- As the user typed it
type EncodedString = String     -- Encoded form


zEncodeString :: UserString -> EncodedString
zEncodeString :: [Char] -> [Char]
zEncodeString cs :: [Char]
cs = case [Char] -> Maybe [Char]
maybe_tuple [Char]
cs of
                Just n :: [Char]
n  -> [Char]
n            -- Tuples go to Z2T etc
                Nothing -> [Char] -> [Char]
go [Char]
cs
          where
                go :: [Char] -> [Char]
go []     = []
                go (c :: Char
c:cs :: [Char]
cs) = Char -> [Char]
encode_digit_ch Char
c [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ [Char] -> [Char]
go' [Char]
cs
                go' :: [Char] -> [Char]
go' []     = []
                go' (c :: Char
c:cs :: [Char]
cs) = Char -> [Char]
encode_ch Char
c [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ [Char] -> [Char]
go' [Char]
cs

unencodedChar :: Char -> Bool   -- True for chars that don't need encoding
unencodedChar :: Char -> Bool
unencodedChar 'Z' = Bool
False
unencodedChar 'z' = Bool
False
unencodedChar c :: Char
c   =  Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
>= 'a' Bool -> Bool -> Bool
&& Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
<= 'z'
                  Bool -> Bool -> Bool
|| Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
>= 'A' Bool -> Bool -> Bool
&& Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
<= 'Z'
                  Bool -> Bool -> Bool
|| Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
>= '0' Bool -> Bool -> Bool
&& Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
<= '9'

-- If a digit is at the start of a symbol then we need to encode it.
-- Otherwise package names like 9pH-0.1 give linker errors.
encode_digit_ch :: Char -> EncodedString
encode_digit_ch :: Char -> [Char]
encode_digit_ch c :: Char
c | Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
>= '0' Bool -> Bool -> Bool
&& Char
c Char -> Char -> Bool
forall a. Ord a => a -> a -> Bool
<= '9' = Char -> [Char]
encode_as_unicode_char Char
c
encode_digit_ch c :: Char
c | Bool
otherwise            = Char -> [Char]
encode_ch Char
c

encode_ch :: Char -> EncodedString
encode_ch :: Char -> [Char]
encode_ch c :: Char
c | Char -> Bool
unencodedChar Char
c = [Char
c]     -- Common case first

-- Constructors
encode_ch '('  = "ZL"   -- Needed for things like (,), and (->)
encode_ch ')'  = "ZR"   -- For symmetry with (
encode_ch '['  = "ZM"
encode_ch ']'  = "ZN"
encode_ch ':'  = "ZC"
encode_ch 'Z'  = "ZZ"

-- Variables
encode_ch 'z'  = "zz"
encode_ch '&'  = "za"
encode_ch '|'  = "zb"
encode_ch '^'  = "zc"
encode_ch '$'  = "zd"
encode_ch '='  = "ze"
encode_ch '>'  = "zg"
encode_ch '#'  = "zh"
encode_ch '.'  = "zi"
encode_ch '<'  = "zl"
encode_ch '-'  = "zm"
encode_ch '!'  = "zn"
encode_ch '+'  = "zp"
encode_ch '\'' = "zq"
encode_ch '\\' = "zr"
encode_ch '/'  = "zs"
encode_ch '*'  = "zt"
encode_ch '_'  = "zu"
encode_ch '%'  = "zv"
encode_ch c :: Char
c    = Char -> [Char]
encode_as_unicode_char Char
c

encode_as_unicode_char :: Char -> EncodedString
encode_as_unicode_char :: Char -> [Char]
encode_as_unicode_char c :: Char
c = 'z' Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: if Char -> Bool
isDigit ([Char] -> Char
forall a. [a] -> a
head [Char]
hex_str) then [Char]
hex_str
                                                           else '0'Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
:[Char]
hex_str
  where hex_str :: [Char]
hex_str = Int -> [Char] -> [Char]
forall a. (Integral a, Show a) => a -> [Char] -> [Char]
showHex (Char -> Int
ord Char
c) "U"
  -- ToDo: we could improve the encoding here in various ways.
  -- eg. strings of unicode characters come out as 'z1234Uz5678U', we
  -- could remove the 'U' in the middle (the 'z' works as a separator).

zDecodeString :: EncodedString -> UserString
zDecodeString :: [Char] -> [Char]
zDecodeString [] = []
zDecodeString ('Z' : d :: Char
d : rest :: [Char]
rest)
  | Char -> Bool
isDigit Char
d = Char -> [Char] -> [Char]
decode_tuple   Char
d [Char]
rest
  | Bool
otherwise = Char -> Char
decode_upper   Char
d Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: [Char] -> [Char]
zDecodeString [Char]
rest
zDecodeString ('z' : d :: Char
d : rest :: [Char]
rest)
  | Char -> Bool
isDigit Char
d = Char -> [Char] -> [Char]
decode_num_esc Char
d [Char]
rest
  | Bool
otherwise = Char -> Char
decode_lower   Char
d Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: [Char] -> [Char]
zDecodeString [Char]
rest
zDecodeString (c :: Char
c   : rest :: [Char]
rest) = Char
c Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: [Char] -> [Char]
zDecodeString [Char]
rest

decode_upper, decode_lower :: Char -> Char

decode_upper :: Char -> Char
decode_upper 'L' = '('
decode_upper 'R' = ')'
decode_upper 'M' = '['
decode_upper 'N' = ']'
decode_upper 'C' = ':'
decode_upper 'Z' = 'Z'
decode_upper ch :: Char
ch  = {-pprTrace "decode_upper" (char ch)-} Char
ch

decode_lower :: Char -> Char
decode_lower 'z' = 'z'
decode_lower 'a' = '&'
decode_lower 'b' = '|'
decode_lower 'c' = '^'
decode_lower 'd' = '$'
decode_lower 'e' = '='
decode_lower 'g' = '>'
decode_lower 'h' = '#'
decode_lower 'i' = '.'
decode_lower 'l' = '<'
decode_lower 'm' = '-'
decode_lower 'n' = '!'
decode_lower 'p' = '+'
decode_lower 'q' = '\''
decode_lower 'r' = '\\'
decode_lower 's' = '/'
decode_lower 't' = '*'
decode_lower 'u' = '_'
decode_lower 'v' = '%'
decode_lower ch :: Char
ch  = {-pprTrace "decode_lower" (char ch)-} Char
ch

-- Characters not having a specific code are coded as z224U (in hex)
decode_num_esc :: Char -> EncodedString -> UserString
decode_num_esc :: Char -> [Char] -> [Char]
decode_num_esc d :: Char
d rest :: [Char]
rest
  = Int -> [Char] -> [Char]
go (Char -> Int
digitToInt Char
d) [Char]
rest
  where
    go :: Int -> [Char] -> [Char]
go n :: Int
n (c :: Char
c : rest :: [Char]
rest) | Char -> Bool
isHexDigit Char
c = Int -> [Char] -> [Char]
go (16Int -> Int -> Int
forall a. Num a => a -> a -> a
*Int
n Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Char -> Int
digitToInt Char
c) [Char]
rest
    go n :: Int
n ('U' : rest :: [Char]
rest)           = Int -> Char
chr Int
n Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: [Char] -> [Char]
zDecodeString [Char]
rest
    go n :: Int
n other :: [Char]
other = [Char] -> [Char]
forall a. HasCallStack => [Char] -> a
error ("decode_num_esc: " [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ Int -> [Char]
forall a. Show a => a -> [Char]
show Int
n [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++  ' 'Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
:[Char]
other)

decode_tuple :: Char -> EncodedString -> UserString
decode_tuple :: Char -> [Char] -> [Char]
decode_tuple d :: Char
d rest :: [Char]
rest
  = Int -> [Char] -> [Char]
go (Char -> Int
digitToInt Char
d) [Char]
rest
  where
        -- NB. recurse back to zDecodeString after decoding the tuple, because
        -- the tuple might be embedded in a longer name.
    go :: Int -> [Char] -> [Char]
go n :: Int
n (c :: Char
c : rest :: [Char]
rest) | Char -> Bool
isDigit Char
c = Int -> [Char] -> [Char]
go (10Int -> Int -> Int
forall a. Num a => a -> a -> a
*Int
n Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Char -> Int
digitToInt Char
c) [Char]
rest
    go 0 ('T':rest :: [Char]
rest)     = "()" [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ [Char] -> [Char]
zDecodeString [Char]
rest
    go n :: Int
n ('T':rest :: [Char]
rest)     = '(' Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: Int -> Char -> [Char]
forall a. Int -> a -> [a]
replicate (Int
nInt -> Int -> Int
forall a. Num a => a -> a -> a
-1) ',' [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ ")" [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ [Char] -> [Char]
zDecodeString [Char]
rest
    go 1 ('H':rest :: [Char]
rest)     = "(# #)" [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ [Char] -> [Char]
zDecodeString [Char]
rest
    go n :: Int
n ('H':rest :: [Char]
rest)     = '(' Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: '#' Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: Int -> Char -> [Char]
forall a. Int -> a -> [a]
replicate (Int
nInt -> Int -> Int
forall a. Num a => a -> a -> a
-1) ',' [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ "#)" [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ [Char] -> [Char]
zDecodeString [Char]
rest
    go n :: Int
n other :: [Char]
other = [Char] -> [Char]
forall a. HasCallStack => [Char] -> a
error ("decode_tuple: " [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ Int -> [Char]
forall a. Show a => a -> [Char]
show Int
n [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ ' 'Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
:[Char]
other)

{-
Tuples are encoded as
        Z3T or Z3H
for 3-tuples or unboxed 3-tuples respectively.  No other encoding starts
        Z<digit>

* "(# #)" is the tycon for an unboxed 1-tuple (not 0-tuple)
  There are no unboxed 0-tuples.

* "()" is the tycon for a boxed 0-tuple.
  There are no boxed 1-tuples.
-}

maybe_tuple :: UserString -> Maybe EncodedString

maybe_tuple :: [Char] -> Maybe [Char]
maybe_tuple "(# #)" = [Char] -> Maybe [Char]
forall a. a -> Maybe a
Just("Z1H")
maybe_tuple ('(' : '#' : cs :: [Char]
cs) = case Int -> [Char] -> (Int, [Char])
count_commas (0::Int) [Char]
cs of
                                 (n :: Int
n, '#' : ')' : _) -> [Char] -> Maybe [Char]
forall a. a -> Maybe a
Just ('Z' Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: Int -> [Char] -> [Char]
forall a. Show a => a -> [Char] -> [Char]
shows (Int
nInt -> Int -> Int
forall a. Num a => a -> a -> a
+1) "H")
                                 _                  -> Maybe [Char]
forall a. Maybe a
Nothing
maybe_tuple "()" = [Char] -> Maybe [Char]
forall a. a -> Maybe a
Just("Z0T")
maybe_tuple ('(' : cs :: [Char]
cs)       = case Int -> [Char] -> (Int, [Char])
count_commas (0::Int) [Char]
cs of
                                 (n :: Int
n, ')' : _) -> [Char] -> Maybe [Char]
forall a. a -> Maybe a
Just ('Z' Char -> [Char] -> [Char]
forall a. a -> [a] -> [a]
: Int -> [Char] -> [Char]
forall a. Show a => a -> [Char] -> [Char]
shows (Int
nInt -> Int -> Int
forall a. Num a => a -> a -> a
+1) "T")
                                 _            -> Maybe [Char]
forall a. Maybe a
Nothing
maybe_tuple _                = Maybe [Char]
forall a. Maybe a
Nothing

count_commas :: Int -> String -> (Int, String)
count_commas :: Int -> [Char] -> (Int, [Char])
count_commas n :: Int
n (',' : cs :: [Char]
cs) = Int -> [Char] -> (Int, [Char])
count_commas (Int
nInt -> Int -> Int
forall a. Num a => a -> a -> a
+1) [Char]
cs
count_commas n :: Int
n cs :: [Char]
cs         = (Int
n,[Char]
cs)


{-
************************************************************************
*                                                                      *
                        Base 62
*                                                                      *
************************************************************************

Note [Base 62 encoding 128-bit integers]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Instead of base-62 encoding a single 128-bit integer
(ceil(21.49) characters), we'll base-62 a pair of 64-bit integers
(2 * ceil(10.75) characters).  Luckily for us, it's the same number of
characters!
-}

--------------------------------------------------------------------------
-- Base 62

-- The base-62 code is based off of 'locators'
-- ((c) Operational Dynamics Consulting, BSD3 licensed)

-- | Size of a 64-bit word when written as a base-62 string
word64Base62Len :: Int
word64Base62Len :: Int
word64Base62Len = 11

-- | Converts a 64-bit word into a base-62 string
toBase62Padded :: Word64 -> String
toBase62Padded :: Word64 -> [Char]
toBase62Padded w :: Word64
w = [Char]
pad [Char] -> [Char] -> [Char]
forall a. [a] -> [a] -> [a]
++ [Char]
str
  where
    pad :: [Char]
pad = Int -> Char -> [Char]
forall a. Int -> a -> [a]
replicate Int
len '0'
    len :: Int
len = Int
word64Base62Len Int -> Int -> Int
forall a. Num a => a -> a -> a
- [Char] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length [Char]
str -- 11 == ceil(64 / lg 62)
    str :: [Char]
str = Word64 -> [Char]
toBase62 Word64
w

toBase62 :: Word64 -> String
toBase62 :: Word64 -> [Char]
toBase62 w :: Word64
w = Word64 -> (Int -> Char) -> Word64 -> [Char] -> [Char]
forall a.
(Integral a, Show a) =>
a -> (Int -> Char) -> a -> [Char] -> [Char]
showIntAtBase 62 Int -> Char
represent Word64
w ""
  where
    represent :: Int -> Char
    represent :: Int -> Char
represent x :: Int
x
        | Int
x Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
< 10 = Int -> Char
Char.chr (48 Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
x)
        | Int
x Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
< 36 = Int -> Char
Char.chr (65 Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
x Int -> Int -> Int
forall a. Num a => a -> a -> a
- 10)
        | Int
x Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
< 62 = Int -> Char
Char.chr (97 Int -> Int -> Int
forall a. Num a => a -> a -> a
+ Int
x Int -> Int -> Int
forall a. Num a => a -> a -> a
- 36)
        | Bool
otherwise = [Char] -> Char
forall a. HasCallStack => [Char] -> a
error "represent (base 62): impossible!"