| Copyright | (c) The University of Glasgow 2008 |
|---|---|
| License | see libraries/base/LICENSE |
| Maintainer | cvs-ghc@haskell.org |
| Stability | internal |
| Portability | non-portable (GHC Extensions) |
| Safe Haskell | Trustworthy |
| Language | Haskell2010 |
GHC.IO.Buffer
Contents
Description
Buffers used in the IO system
- data Buffer e = Buffer {}
- data BufferState
- type CharBuffer = Buffer Char
- type CharBufElem = Char
- newByteBuffer :: Int -> BufferState -> IO (Buffer Word8)
- newCharBuffer :: Int -> BufferState -> IO CharBuffer
- newBuffer :: Int -> Int -> BufferState -> IO (Buffer e)
- emptyBuffer :: RawBuffer e -> Int -> BufferState -> Buffer e
- bufferRemove :: Int -> Buffer e -> Buffer e
- bufferAdd :: Int -> Buffer e -> Buffer e
- slideContents :: Buffer Word8 -> IO (Buffer Word8)
- bufferAdjustL :: Int -> Buffer e -> Buffer e
- isEmptyBuffer :: Buffer e -> Bool
- isFullBuffer :: Buffer e -> Bool
- isFullCharBuffer :: Buffer e -> Bool
- isWriteBuffer :: Buffer e -> Bool
- bufferElems :: Buffer e -> Int
- bufferAvailable :: Buffer e -> Int
- summaryBuffer :: Buffer a -> String
- withBuffer :: Buffer e -> (Ptr e -> IO a) -> IO a
- withRawBuffer :: RawBuffer e -> (Ptr e -> IO a) -> IO a
- checkBuffer :: Buffer a -> IO ()
- type RawBuffer e = ForeignPtr e
- readWord8Buf :: RawBuffer Word8 -> Int -> IO Word8
- writeWord8Buf :: RawBuffer Word8 -> Int -> Word8 -> IO ()
- type RawCharBuffer = RawBuffer CharBufElem
- peekCharBuf :: RawCharBuffer -> Int -> IO Char
- readCharBuf :: RawCharBuffer -> Int -> IO (Char, Int)
- writeCharBuf :: RawCharBuffer -> Int -> Char -> IO Int
- readCharBufPtr :: Ptr CharBufElem -> Int -> IO (Char, Int)
- writeCharBufPtr :: Ptr CharBufElem -> Int -> Char -> IO Int
- charSize :: Int
Buffers of any element
A mutable array of bytes that can be passed to foreign functions.
The buffer is represented by a record, where the record contains the raw buffer and the start/end points of the filled portion. The buffer contents itself is mutable, but the rest of the record is immutable. This is a slightly odd mix, but it turns out to be quite practical: by making all the buffer metadata immutable, we can have operations on buffer metadata outside of the IO monad.
The "live" elements of the buffer are those between the bufL and
bufR offsets. In an empty buffer, bufL is equal to bufR, but
they might not be zero: for exmaple, the buffer might correspond to
a memory-mapped file and in which case bufL will point to the
next location to be written, which is not necessarily the beginning
of the file.
type CharBuffer = Buffer Char Source
type CharBufElem = Char Source
Creation
newByteBuffer :: Int -> BufferState -> IO (Buffer Word8) Source
newCharBuffer :: Int -> BufferState -> IO CharBuffer Source
emptyBuffer :: RawBuffer e -> Int -> BufferState -> Buffer e Source
Insertion/removal
bufferRemove :: Int -> Buffer e -> Buffer e Source
slideContents :: Buffer Word8 -> IO (Buffer Word8) Source
slides the contents of the buffer to the beginning
bufferAdjustL :: Int -> Buffer e -> Buffer e Source
Inspecting
isEmptyBuffer :: Buffer e -> Bool Source
isFullBuffer :: Buffer e -> Bool Source
isFullCharBuffer :: Buffer e -> Bool Source
isWriteBuffer :: Buffer e -> Bool Source
bufferElems :: Buffer e -> Int Source
bufferAvailable :: Buffer e -> Int Source
summaryBuffer :: Buffer a -> String Source
Operating on the raw buffer as a Ptr
Assertions
checkBuffer :: Buffer a -> IO () Source
Raw buffers
type RawBuffer e = ForeignPtr e Source
type RawCharBuffer = RawBuffer CharBufElem Source
peekCharBuf :: RawCharBuffer -> Int -> IO Char Source
readCharBuf :: RawCharBuffer -> Int -> IO (Char, Int) Source
writeCharBuf :: RawCharBuffer -> Int -> Char -> IO Int Source
readCharBufPtr :: Ptr CharBufElem -> Int -> IO (Char, Int) Source
writeCharBufPtr :: Ptr CharBufElem -> Int -> Char -> IO Int Source