ByteString.hs

{-----------------------------------------------------------------
 
  (c) 2008-2009 Markus Dittrich 
 
  This program is free software; you can redistribute it 
  and/or modify it under the terms of the GNU General Public 
  License Version 3 as published by the Free Software Foundation. 
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License Version 3 for more details.
 
  You should have received a copy of the GNU General Public 
  License along with this program; if not, write to the Free 
  Software Foundation, Inc., 59 Temple Place - Suite 330, 
  Boston, MA 02111-1307, USA.

--------------------------------------------------------------------}


-- | this module contains some helper function for ByteString
-- related functionality
module Helpers.ByteString ( andStr
                          , colonW
                          , dashW
                          , exclMarkW
                          , globW
                          , newlineW
                          , newline
                          , periodW
                          , plusW
                          , questMark
                          , slashW
                          , spaceCharW
                          , underscoreW
                          , binStr
                          , closeBracket
                          , dash
                          , docStr
                          , equalSign
                          , etcStr
                          , exclMark
                          , glob
                          , greater
                          , gr_eq
                          , includeStr
                          , libStr
                          , lib64Str
                          , low_eq
                          , orSymbol
                          , openBracket
                          , plus
                          , sbinStr
                          , shareStr
                          , smaller
                          , spaceChar
                          , tilde
                          , usrStr
                          , char_to_Word8
                          , remove_last_newline
                          , tokenize_BS
                          ) where 


-- imports
import Char(ord)
import qualified Data.ByteString as B(ByteString, init, last, split)
import qualified Data.ByteString.Char8 as BC(pack)
import Prelude
import Word(Word8)


--
-- some useful constants
--

-- Word8
colonW :: Word8
colonW = char_to_Word8 ':'

dashW :: Word8
dashW = char_to_Word8 '-'

exclMarkW :: Word8
exclMarkW = char_to_Word8 '!'

globW :: Word8
globW = char_to_Word8 '*'

newlineW :: Word8
newlineW = char_to_Word8 '\n' 

periodW :: Word8
periodW = char_to_Word8 '.'

plusW :: Word8
plusW = char_to_Word8 '+'

spaceCharW :: Word8
spaceCharW = char_to_Word8 ' '

slashW :: Word8
slashW = char_to_Word8 '/'

underscoreW :: Word8
underscoreW = char_to_Word8 '_'


-- ByteString
andStr :: B.ByteString
andStr = BC.pack "&"

binStr :: B.ByteString
binStr = BC.pack "bin"

closeBracket :: B.ByteString
closeBracket = BC.pack ")"

dash :: B.ByteString
dash = BC.pack "-"

docStr :: B.ByteString
docStr = BC.pack "doc"

equalSign :: B.ByteString
equalSign = BC.pack "="

etcStr :: B.ByteString
etcStr = BC.pack "etc"

exclMark :: B.ByteString
exclMark = BC.pack "!"

glob :: B.ByteString
glob = BC.pack "*"

greater :: B.ByteString
greater = BC.pack ">"

gr_eq :: B.ByteString
gr_eq = BC.pack ">="

includeStr :: B.ByteString
includeStr = BC.pack "include"

libStr :: B.ByteString
libStr = BC.pack "lib"

lib64Str :: B.ByteString
lib64Str = BC.pack "lib64"

low_eq :: B.ByteString
low_eq = BC.pack "<="

newline :: B.ByteString
newline = BC.pack "\n"

orSymbol :: B.ByteString
orSymbol = BC.pack "||"  -- "||"

openBracket :: B.ByteString
openBracket = BC.pack "("

plus :: B.ByteString
plus = BC.pack "+"

questMark :: B.ByteString
questMark = BC.pack "?"

sbinStr :: B.ByteString
sbinStr = BC.pack "sbin"

shareStr :: B.ByteString
shareStr = BC.pack "share"

smaller :: B.ByteString
smaller = BC.pack "<"

spaceChar :: B.ByteString
spaceChar = BC.pack " "         -- " "

tilde :: B.ByteString
tilde = BC.pack "~"

usrStr :: B.ByteString
usrStr = BC.pack "usr"


-- | convert char into Word8
char_to_Word8 :: Char -> Word8
char_to_Word8 = fromIntegral . ord


-- | if the last element in a ByteString is a newline,
-- discard it, otherwise splitting the ByteString by
-- newlines will result in an empty last element
remove_last_newline :: B.ByteString -> B.ByteString 
remove_last_newline string = if ( B.last string == newlineW ) then 
                               B.init string 
                             else 
                               string  


-- | split ByteString into tokens separated by whitespace 
-- (currently only spaces) making sure to remove any trailing
-- newlines
tokenize_BS :: B.ByteString -> [B.ByteString]
tokenize_BS = B.split spaceCharW . remove_last_newline