+++ /dev/null
--- -----------------------------------------------------------------------------
---
--- (c) The University of Glasgow, 1997-2006
---
--- Character encodings
---
--- -----------------------------------------------------------------------------
-
-module Encoding (
- -- * UTF-8
- utf8DecodeChar#,
- utf8PrevChar,
- utf8CharStart,
- utf8DecodeChar,
- utf8DecodeString,
- utf8EncodeChar,
- utf8EncodeString,
- utf8EncodedLength,
- countUTF8Chars,
-
- -- * Z-encoding
- zEncodeString,
- zDecodeString
- ) where
-
-#define COMPILING_FAST_STRING
-#include "HsVersions.h"
-import Foreign
-import Data.Char ( ord, chr, isDigit, digitToInt, isHexDigit )
-import Numeric ( showHex )
-
-import Data.Bits
-import GHC.Ptr ( Ptr(..) )
-import GHC.Base
-
--- -----------------------------------------------------------------------------
--- 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#, Addr# #)
-utf8DecodeChar# a# =
- let ch0 = word2Int# (indexWord8OffAddr# a# 0#) in
- case () of
- _ | ch0 <=# 0x7F# -> (# chr# ch0, a# `plusAddr#` 1# #)
-
- | ch0 >=# 0xC0# && ch0 <=# 0xDF# ->
- let ch1 = word2Int# (indexWord8OffAddr# a# 1#) in
- if ch1 <# 0x80# || ch1 >=# 0xC0# then fail 1# else
- (# chr# (((ch0 -# 0xC0#) `uncheckedIShiftL#` 6#) +#
- (ch1 -# 0x80#)),
- a# `plusAddr#` 2# #)
-
- | ch0 >=# 0xE0# && ch0 <=# 0xEF# ->
- let ch1 = word2Int# (indexWord8OffAddr# a# 1#) in
- if ch1 <# 0x80# || ch1 >=# 0xC0# then fail 1# else
- let ch2 = word2Int# (indexWord8OffAddr# a# 2#) in
- if ch2 <# 0x80# || ch2 >=# 0xC0# then fail 2# else
- (# chr# (((ch0 -# 0xE0#) `uncheckedIShiftL#` 12#) +#
- ((ch1 -# 0x80#) `uncheckedIShiftL#` 6#) +#
- (ch2 -# 0x80#)),
- a# `plusAddr#` 3# #)
-
- | ch0 >=# 0xF0# && ch0 <=# 0xF8# ->
- let ch1 = word2Int# (indexWord8OffAddr# a# 1#) in
- if ch1 <# 0x80# || ch1 >=# 0xC0# then fail 1# else
- let ch2 = word2Int# (indexWord8OffAddr# a# 2#) in
- if ch2 <# 0x80# || ch2 >=# 0xC0# then fail 2# else
- let ch3 = word2Int# (indexWord8OffAddr# a# 3#) in
- if ch3 <# 0x80# || ch3 >=# 0xC0# then fail 3# else
- (# chr# (((ch0 -# 0xF0#) `uncheckedIShiftL#` 18#) +#
- ((ch1 -# 0x80#) `uncheckedIShiftL#` 12#) +#
- ((ch2 -# 0x80#) `uncheckedIShiftL#` 6#) +#
- (ch3 -# 0x80#)),
- a# `plusAddr#` 4# #)
-
- | otherwise -> fail 1#
- where
- -- all invalid sequences end up here:
- fail n = (# '\0'#, a# `plusAddr#` n #)
- -- '\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, Ptr Word8)
-utf8DecodeChar (Ptr a#) =
- case utf8DecodeChar# a# of (# c#, b# #) -> ( C# c#, Ptr b# )
-
--- 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 p = utf8CharStart (p `plusPtr` (-1))
-
-utf8CharStart :: Ptr Word8 -> IO (Ptr Word8)
-utf8CharStart p = go p
- where go p = do w <- peek p
- if w >= 0x80 && w < 0xC0
- then go (p `plusPtr` (-1))
- else return p
-
-utf8DecodeString :: Ptr Word8 -> Int -> IO [Char]
-STRICT2(utf8DecodeString)
-utf8DecodeString (Ptr a#) (I# len#)
- = unpack a#
- where
- end# = addr2Int# (a# `plusAddr#` len#)
-
- unpack p#
- | addr2Int# p# >=# end# = return []
- | otherwise =
- case utf8DecodeChar# p# of
- (# c#, q# #) -> do
- chs <- unpack q#
- return (C# c# : chs)
-
-countUTF8Chars :: Ptr Word8 -> Int -> IO Int
-countUTF8Chars ptr bytes = go ptr 0
- where
- end = ptr `plusPtr` bytes
-
- STRICT2(go)
- go ptr n
- | ptr >= end = return n
- | otherwise = do
- case utf8DecodeChar# (unPtr ptr) of
- (# c, a #) -> go (Ptr a) (n+1)
-
-unPtr (Ptr a) = a
-
-utf8EncodeChar c ptr =
- let x = ord c in
- case () of
- _ | x > 0 && x <= 0x007f -> do
- poke ptr (fromIntegral x)
- return (ptr `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).
- | x <= 0x07ff -> do
- poke ptr (fromIntegral (0xC0 .|. ((x `shiftR` 6) .&. 0x1F)))
- pokeElemOff ptr 1 (fromIntegral (0x80 .|. (x .&. 0x3F)))
- return (ptr `plusPtr` 2)
- | x <= 0xffff -> do
- poke ptr (fromIntegral (0xE0 .|. (x `shiftR` 12) .&. 0x0F))
- pokeElemOff ptr 1 (fromIntegral (0x80 .|. (x `shiftR` 6) .&. 0x3F))
- pokeElemOff ptr 2 (fromIntegral (0x80 .|. (x .&. 0x3F)))
- return (ptr `plusPtr` 3)
- | otherwise -> do
- poke ptr (fromIntegral (0xF0 .|. (x `shiftR` 18)))
- pokeElemOff ptr 1 (fromIntegral (0x80 .|. ((x `shiftR` 12) .&. 0x3F)))
- pokeElemOff ptr 2 (fromIntegral (0x80 .|. ((x `shiftR` 6) .&. 0x3F)))
- pokeElemOff ptr 3 (fromIntegral (0x80 .|. (x .&. 0x3F)))
- return (ptr `plusPtr` 4)
-
-utf8EncodeString :: Ptr Word8 -> String -> IO ()
-utf8EncodeString ptr str = go ptr str
- where STRICT2(go)
- go ptr [] = return ()
- go ptr (c:cs) = do
- ptr' <- utf8EncodeChar c ptr
- go ptr' cs
-
-utf8EncodedLength :: String -> Int
-utf8EncodedLength str = go 0 str
- where STRICT2(go)
- go n [] = n
- go n (c:cs)
- | ord c > 0 && ord c <= 0x007f = go (n+1) cs
- | ord c <= 0x07ff = go (n+2) cs
- | ord c <= 0xffff = go (n+3) cs
- | otherwise = go (n+4) 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 cs = case maybe_tuple cs of
- Just n -> n -- Tuples go to Z2T etc
- Nothing -> go cs
- where
- go [] = []
- go (c:cs) = encode_ch c ++ go cs
-
-unencodedChar :: Char -> Bool -- True for chars that don't need encoding
-unencodedChar 'Z' = False
-unencodedChar 'z' = False
-unencodedChar c = c >= 'a' && c <= 'z'
- || c >= 'A' && c <= 'Z'
- || c >= '0' && c <= '9'
-
-encode_ch :: Char -> EncodedString
-encode_ch c | unencodedChar c = [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 '$' = "zd"
-encode_ch '=' = "ze"
-encode_ch '>' = "zg"
-encode_ch '#' = "zh"
-encode_ch '.' = "zi"
-encode_ch '<' = "zl"
-encode_ch '-' = "zm"
-encode_ch '!' = "zn"
-encode_ch '+' = "zp"
-encode_ch '\'' = "zq"
-encode_ch '\\' = "zr"
-encode_ch '/' = "zs"
-encode_ch '*' = "zt"
-encode_ch '_' = "zu"
-encode_ch '%' = "zv"
-encode_ch c = 'z' : if isDigit (head hex_str) then hex_str
- else '0':hex_str
- where hex_str = showHex (ord c) "U"
- -- ToDo: we could improve the encoding here in various ways.
- -- eg. strings of unicode characters come out as 'z1234Uz5678U', we
- -- could remove the 'U' in the middle (the 'z' works as a separator).
-
-zDecodeString :: EncodedString -> UserString
-zDecodeString [] = []
-zDecodeString ('Z' : d : rest)
- | isDigit d = decode_tuple d rest
- | otherwise = decode_upper d : zDecodeString rest
-zDecodeString ('z' : d : rest)
- | isDigit d = decode_num_esc d rest
- | otherwise = decode_lower d : zDecodeString rest
-zDecodeString (c : rest) = c : zDecodeString rest
-
-decode_upper, decode_lower :: Char -> Char
-
-decode_upper 'L' = '('
-decode_upper 'R' = ')'
-decode_upper 'M' = '['
-decode_upper 'N' = ']'
-decode_upper 'C' = ':'
-decode_upper 'Z' = 'Z'
-decode_upper ch = {-pprTrace "decode_upper" (char ch)-} ch
-
-decode_lower 'z' = 'z'
-decode_lower 'a' = '&'
-decode_lower 'b' = '|'
-decode_lower 'c' = '^'
-decode_lower 'd' = '$'
-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 = {-pprTrace "decode_lower" (char ch)-} ch
-
--- Characters not having a specific code are coded as z224U (in hex)
-decode_num_esc d rest
- = go (digitToInt d) rest
- where
- go n (c : rest) | isHexDigit c = go (16*n + digitToInt c) rest
- go n ('U' : rest) = chr n : zDecodeString rest
- go n other = error ("decode_num_esc: " ++ show n ++ ' ':other)
-
-decode_tuple :: Char -> EncodedString -> UserString
-decode_tuple d rest
- = go (digitToInt d) rest
- where
- -- NB. recurse back to zDecodeString after decoding the tuple, because
- -- the tuple might be embedded in a longer name.
- go n (c : rest) | isDigit c = go (10*n + digitToInt c) rest
- go 0 ('T':rest) = "()" ++ zDecodeString rest
- go n ('T':rest) = '(' : replicate (n-1) ',' ++ ")" ++ zDecodeString rest
- go 1 ('H':rest) = "(# #)" ++ zDecodeString rest
- go n ('H':rest) = '(' : '#' : replicate (n-1) ',' ++ "#)" ++ zDecodeString rest
- go n other = error ("decode_tuple: " ++ show n ++ ' ':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 "(# #)" = Just("Z1H")
-maybe_tuple ('(' : '#' : cs) = case count_commas (0::Int) cs of
- (n, '#' : ')' : cs) -> Just ('Z' : shows (n+1) "H")
- other -> Nothing
-maybe_tuple "()" = Just("Z0T")
-maybe_tuple ('(' : cs) = case count_commas (0::Int) cs of
- (n, ')' : cs) -> Just ('Z' : shows (n+1) "T")
- other -> Nothing
-maybe_tuple other = Nothing
-
-count_commas :: Int -> String -> (Int, String)
-count_commas n (',' : cs) = count_commas (n+1) cs
-count_commas n cs = (n,cs)
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