| Copyright | (c) Don Stewart 2006-2008 (c) Duncan Coutts 2006-2012 |
|---|---|
| License | BSD-style |
| Maintainer | [email protected], [email protected] |
| Stability | unstable |
| Portability | non-portable |
| Safe Haskell | Unsafe |
| Language | Haskell98 |
A module containing semi-public ByteString internals. This exposes the ByteString representation and low level construction functions. As such all the functions in this module are unsafe. The API is also not stable.
Where possible application should instead use the functions from the normal public interface modules, such as Data.ByteString.Unsafe. Packages that extend the ByteString system at a low level will need to use this module.
data ByteString Source
A space-efficient representation of a Word8 vector, supporting many efficient operations.
A ByteString contains 8-bit bytes, or by using the operations from Data.ByteString.Char8 it can be interpreted as containing 8-bit characters.
| PS !(ForeignPtr Word8) !Int !Int |
packBytes :: [Word8] -> ByteString Source
packUptoLenBytes :: Int -> [Word8] -> (ByteString, [Word8]) Source
unsafePackLenBytes :: Int -> [Word8] -> ByteString Source
packChars :: [Char] -> ByteString Source
packUptoLenChars :: Int -> [Char] -> (ByteString, [Char]) Source
unsafePackLenChars :: Int -> [Char] -> ByteString Source
unpackBytes :: ByteString -> [Word8] Source
unpackAppendBytesLazy :: ByteString -> [Word8] -> [Word8] Source
unpackAppendBytesStrict :: ByteString -> [Word8] -> [Word8] Source
unpackChars :: ByteString -> [Char] Source
unpackAppendCharsLazy :: ByteString -> [Char] -> [Char] Source
unpackAppendCharsStrict :: ByteString -> [Char] -> [Char] Source
unsafePackAddress :: Addr# -> IO ByteString Source
O(n) Pack a null-terminated sequence of bytes, pointed to by an Addr# (an arbitrary machine address assumed to point outside the garbage-collected heap) into a ByteString. A much faster way to create an Addr# is with an unboxed string literal, than to pack a boxed string. A unboxed string literal is compiled to a static char
[] by GHC. Establishing the length of the string requires a call to strlen(3), so the Addr# must point to a null-terminated buffer (as is the case with "string"# literals in GHC). Use unsafePackAddressLen if you know the length of the string statically.
An example:
literalFS = unsafePackAddress "literal"#
This function is unsafe. If you modify the buffer pointed to by the original Addr# this modification will be reflected in the resulting ByteString, breaking referential transparency.
Note this also won't work if your Addr# has embedded '\0' characters in the string, as strlen will return too short a length.
create :: Int -> (Ptr Word8 -> IO ()) -> IO ByteString Source
Create ByteString of size l and use action f to fill it's contents.
createUptoN :: Int -> (Ptr Word8 -> IO Int) -> IO ByteString Source
Create ByteString of up to size size l and use action f to fill it's contents which returns its true size.
createAndTrim :: Int -> (Ptr Word8 -> IO Int) -> IO ByteString Source
Given the maximum size needed and a function to make the contents of a ByteString, createAndTrim makes the ByteString. The generating function is required to return the actual final size (<= the maximum size), and the resulting byte array is realloced to this size.
createAndTrim is the main mechanism for creating custom, efficient ByteString functions, using Haskell or C functions to fill the space.
createAndTrim' :: Int -> (Ptr Word8 -> IO (Int, Int, a)) -> IO (ByteString, a) Source
unsafeCreate :: Int -> (Ptr Word8 -> IO ()) -> ByteString Source
A way of creating ByteStrings outside the IO monad. The Int argument gives the final size of the ByteString.
unsafeCreateUptoN :: Int -> (Ptr Word8 -> IO Int) -> ByteString Source
Like unsafeCreate but instead of giving the final size of the ByteString, it is just an upper bound. The inner action returns the actual size. Unlike createAndTrim the ByteString is not reallocated if the final size is less than the estimated size.
mallocByteString :: Int -> IO (ForeignPtr a) Source
Wrapper of mallocForeignPtrBytes with faster implementation for GHC
| :: ForeignPtr Word8 | |
| -> Int | Offset |
| -> Int | Length |
| -> ByteString |
O(1) Build a ByteString from a ForeignPtr.
If you do not need the offset parameter then you do should be using unsafePackCStringLen or unsafePackCStringFinalizer instead.
| :: ByteString | |
| -> (ForeignPtr Word8, Int, Int) | (ptr, offset, length) |
O(1) Deconstruct a ForeignPtr from a ByteString
nullForeignPtr :: ForeignPtr Word8 Source
The 0 pointer. Used to indicate the empty Bytestring.
checkedAdd :: String -> Int -> Int -> Int Source
Add two non-negative numbers. Errors out on overflow.
c_strlen :: CString -> IO CSize Source
c_free_finalizer :: FunPtr (Ptr Word8 -> IO ()) Source
memchr :: Ptr Word8 -> Word8 -> CSize -> IO (Ptr Word8) Source
memcmp :: Ptr Word8 -> Ptr Word8 -> Int -> IO CInt Source
memcpy :: Ptr Word8 -> Ptr Word8 -> Int -> IO () Source
memset :: Ptr Word8 -> Word8 -> CSize -> IO (Ptr Word8) Source
c_reverse :: Ptr Word8 -> Ptr Word8 -> CULong -> IO () Source
c_intersperse :: Ptr Word8 -> Ptr Word8 -> CULong -> Word8 -> IO () Source
c_maximum :: Ptr Word8 -> CULong -> IO Word8 Source
c_minimum :: Ptr Word8 -> CULong -> IO Word8 Source
c_count :: Ptr Word8 -> CULong -> Word8 -> IO CULong Source
Conversion between Word8 and Char. Should compile to a no-op.
Unsafe conversion between Char and Word8. This is a no-op and silently truncates to 8 bits Chars > '255'. It is provided as convenience for ByteString construction.
isSpaceWord8 :: Word8 -> Bool Source
Selects words corresponding to white-space characters in the Latin-1 range ordered by frequency.
isSpaceChar8 :: Char -> Bool Source
Selects white-space characters in the Latin-1 range
accursedUnutterablePerformIO :: IO a -> a Source
This "function" has a superficial similarity to unsafePerformIO but it is in fact a malevolent agent of chaos. It unpicks the seams of reality (and the IO monad) so that the normal rules no longer apply. It lulls you into thinking it is reasonable, but when you are not looking it stabs you in the back and aliases all of your mutable buffers. The carcass of many a seasoned Haskell programmer lie strewn at its feet.
Witness the trail of destruction:
Do not talk about "safe"! You do not know what is safe!
Yield not to its blasphemous call! Flee traveller! Flee or you will be corrupted and devoured!
inlinePerformIO :: IO a -> a Source
Deprecated: If you think you know what you are doing, use unsafePerformIO. If you are sure you know what you are doing, use unsafeDupablePerformIO. If you enjoy sharing an address space with a malevolent agent of chaos, try accursedUnutterablePerformIO.
© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/8.8.3/docs/html/libraries/bytestring-0.10.10.0/Data-ByteString-Internal.html