| Copyright | (c) The University of Glasgow 2001 David Roundy 2003-2005 |
|---|---|
| License | GPL (I'm happy to also license this file BSD style but don't want to bother distributing two license files with darcs. |
| Maintainer | droundy@abridgegame.org |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | None |
| Language | Haskell2010 |
Darcs.Util.ByteString
Description
GZIp and MMap IO for ByteStrings, encoding utilities, and miscellaneous functions for Data.ByteString
Synopsis
- gzReadFilePS :: FilePath -> IO ByteString
- mmapFilePS :: FilePath -> IO ByteString
- gzWriteFilePS :: FilePath -> ByteString -> IO ()
- gzWriteFilePSs :: FilePath -> [ByteString] -> IO ()
- gzReadStdin :: IO ByteString
- gzWriteHandle :: Handle -> [ByteString] -> IO ()
- type FileSegment = (FilePath, Maybe (Int64, Int))
- readSegment :: FileSegment -> IO ByteString
- isGZFile :: FilePath -> IO (Maybe Int)
- gzDecompress :: Maybe Int -> ByteString -> ([ByteString], Bool)
- dropSpace :: ByteString -> ByteString
- linesPS :: ByteString -> [ByteString]
- unlinesPS :: [ByteString] -> ByteString
- hashPS :: ByteString -> Int32
- breakFirstPS :: Char -> ByteString -> Maybe (ByteString, ByteString)
- breakLastPS :: Char -> ByteString -> Maybe (ByteString, ByteString)
- substrPS :: ByteString -> ByteString -> Maybe Int
- isFunky :: ByteString -> Bool
- fromHex2PS :: ByteString -> ByteString
- fromPS2Hex :: ByteString -> ByteString
- betweenLinesPS :: ByteString -> ByteString -> ByteString -> Maybe ByteString
- intercalate :: ByteString -> [ByteString] -> ByteString
- isAscii :: ByteString -> Bool
- decodeLocale :: ByteString -> String
- encodeLocale :: String -> ByteString
- unpackPSFromUTF8 :: ByteString -> String
- packStringToUTF8 :: String -> ByteString
- prop_unlinesPS_linesPS_left_inverse :: ByteString -> Bool
- prop_linesPS_length :: ByteString -> Bool
- prop_unlinesPS_length :: [ByteString] -> Bool
- propHexConversion :: ByteString -> Bool
- spec_betweenLinesPS :: ByteString -> ByteString -> ByteString -> Maybe ByteString
IO with mmap or gzip
gzReadFilePS :: FilePath -> IO ByteString Source #
Read an entire file, which may or may not be gzip compressed, directly
into a ByteString.
mmapFilePS :: FilePath -> IO ByteString Source #
Like readFilePS, this reads an entire file directly into a
ByteString, but it is even more efficient. It involves directly
mapping the file to memory. This has the advantage that the contents of
the file never need to be copied. Also, under memory pressure the page
may simply be discarded, wile in the case of readFilePS it would need to
be written to swap. If you read many small files, mmapFilePS will be
less memory-efficient than readFilePS, since each mmapFilePS takes up a
separate page of memory. Also, you can run into bus errors if the file
is modified.
gzWriteFilePS :: FilePath -> ByteString -> IO () Source #
gzWriteFilePSs :: FilePath -> [ByteString] -> IO () Source #
gzReadStdin :: IO ByteString Source #
Read standard input, which may or may not be gzip compressed, directly
into a ByteString.
gzWriteHandle :: Handle -> [ByteString] -> IO () Source #
type FileSegment = (FilePath, Maybe (Int64, Int)) Source #
Pointer to a filesystem, possibly with start/end offsets. Supposed to be fed to (uncurry mmapFileByteString) or similar.
readSegment :: FileSegment -> IO ByteString Source #
Read in a FileSegment into a Lazy ByteString. Implemented using mmap.
gzip handling
gzDecompress :: Maybe Int -> ByteString -> ([ByteString], Bool) Source #
Decompress the given bytestring into a lazy list of chunks, along with a boolean flag indicating (if True) that the CRC was corrupted. Inspecting the flag will cause the entire list of chunks to be evaluated (but if you throw away the list immediately this should run in constant space).
list utilities
dropSpace :: ByteString -> ByteString Source #
Drop leading white space, where white space is defined as consisting of ' ', '\t', '\n', or '\r'.
linesPS :: ByteString -> [ByteString] Source #
unlinesPS :: [ByteString] -> ByteString Source #
hashPS :: ByteString -> Int32 Source #
breakFirstPS :: Char -> ByteString -> Maybe (ByteString, ByteString) Source #
breakLastPS :: Char -> ByteString -> Maybe (ByteString, ByteString) Source #
substrPS :: ByteString -> ByteString -> Maybe Int Source #
isFunky :: ByteString -> Bool Source #
fromHex2PS :: ByteString -> ByteString Source #
fromPS2Hex :: ByteString -> ByteString Source #
betweenLinesPS :: ByteString -> ByteString -> ByteString -> Maybe ByteString Source #
Return the B.ByteString between the two lines given, or Nothing if they do not appear.
intercalate :: ByteString -> [ByteString] -> ByteString #
O(n) The intercalate function takes a ByteString and a list of
ByteStrings and concatenates the list after interspersing the first
argument between each element of the list.
encoding and unicode utilities
isAscii :: ByteString -> Bool Source #
Test if a ByteString is made of ascii characters
decodeLocale :: ByteString -> String Source #
Decode a ByteString to a String according to the current locale,
using lone surrogates for un-decodable bytes.
encodeLocale :: String -> ByteString Source #
Encode a String to a ByteString according to the current locale,
converting lone surrogates back to the original byte. If that
fails (because the locale does not support the full unicode range)
then encode using utf-8, assuming that the un-ecodable characters
come from patch meta data.
See also setEnvCautiously.
unpackPSFromUTF8 :: ByteString -> String Source #
Decode a ByteString containing UTF-8 to a String. Decoding errors
are flagged with the U+FFFD character.
packStringToUTF8 :: String -> ByteString Source #
Encode a String to a ByteString using UTF-8.
properties
prop_linesPS_length :: ByteString -> Bool Source #
prop_unlinesPS_length :: [ByteString] -> Bool Source #
propHexConversion :: ByteString -> Bool Source #
spec_betweenLinesPS :: ByteString -> ByteString -> ByteString -> Maybe ByteString Source #
Simpler but less efficient variant of betweenLinesPS.