| Copyright | (c) Duncan Coutts 2012-2013 |
|---|---|
| License | BSD-style |
| Maintainer | duncan@community.haskell.org |
| Stability | stable |
| Portability | ghc only |
| Safe Haskell | Unsafe |
| Language | Haskell98 |
Data.ByteString.Short.Internal
Description
Internal representation of ShortByteString
Synopsis
- data ShortByteString = SBS ByteArray#
- toShort :: ByteString -> ShortByteString
- fromShort :: ShortByteString -> ByteString
- pack :: [Word8] -> ShortByteString
- unpack :: ShortByteString -> [Word8]
- empty :: ShortByteString
- null :: ShortByteString -> Bool
- length :: ShortByteString -> Int
- index :: ShortByteString -> Int -> Word8
- unsafeIndex :: ShortByteString -> Int -> Word8
- createFromPtr :: Ptr a -> Int -> IO ShortByteString
- copyToPtr :: ShortByteString -> Int -> Ptr a -> Int -> IO ()
- packCString :: CString -> IO ShortByteString
- packCStringLen :: CStringLen -> IO ShortByteString
- useAsCString :: ShortByteString -> (CString -> IO a) -> IO a
- useAsCStringLen :: ShortByteString -> (CStringLen -> IO a) -> IO a
The ShortByteString type and representation
data ShortByteString #
A compact representation of a Word8 vector.
It has a lower memory overhead than a ByteString and and does not
contribute to heap fragmentation. It can be converted to or from a
ByteString (at the cost of copying the string data). It supports very few
other operations.
It is suitable for use as an internal representation for code that needs
to keep many short strings in memory, but it should not be used as an
interchange type. That is, it should not generally be used in public APIs.
The ByteString type is usually more suitable for use in interfaces; it is
more flexible and it supports a wide range of operations.
Constructors
| SBS ByteArray# |
Instances
Conversions
toShort :: ByteString -> ShortByteString #
O(n). Convert a ByteString into a ShortByteString.
This makes a copy, so does not retain the input string.
fromShort :: ShortByteString -> ByteString #
O(n). Convert a ShortByteString into a ByteString.
pack :: [Word8] -> ShortByteString #
O(n). Convert a list into a ShortByteString
unpack :: ShortByteString -> [Word8] #
O(n). Convert a ShortByteString into a list.
Other operations
O(1). The empty ShortByteString.
null :: ShortByteString -> Bool #
O(1) Test whether a ShortByteString is empty.
length :: ShortByteString -> Int #
O(1) The length of a ShortByteString.
index :: ShortByteString -> Int -> Word8 #
O(1) ShortByteString index (subscript) operator, starting from 0.
unsafeIndex :: ShortByteString -> Int -> Word8 #
Low level operations
Arguments
| :: Ptr a | source data |
| -> Int | number of bytes to copy |
| -> IO ShortByteString |
Arguments
| :: ShortByteString | source data |
| -> Int | offset into source |
| -> Ptr a | destination |
| -> Int | number of bytes to copy |
| -> IO () |
Low level conversions
Packing CStrings and pointers
packCString :: CString -> IO ShortByteString #
O(n). Construct a new ShortByteString from a CString. The
resulting ShortByteString is an immutable copy of the original
CString, and is managed on the Haskell heap. The original
CString must be null terminated.
Since: bytestring-0.10.10.0
packCStringLen :: CStringLen -> IO ShortByteString #
O(n). Construct a new ShortByteString from a CStringLen. The
resulting ShortByteString is an immutable copy of the original CStringLen.
The ShortByteString is a normal Haskell value and will be managed on the
Haskell heap.
Since: bytestring-0.10.10.0
Using ByteStrings as CStrings
useAsCString :: ShortByteString -> (CString -> IO a) -> IO a #
O(n) construction. Use a ShortByteString with a function requiring a
null-terminated CString. The CString is a copy and will be freed
automatically; it must not be stored or used after the
subcomputation finishes.
Since: bytestring-0.10.10.0
useAsCStringLen :: ShortByteString -> (CStringLen -> IO a) -> IO a #
O(n) construction. Use a ShortByteString with a function requiring a CStringLen.
As for useAsCString this function makes a copy of the original ShortByteString.
It must not be stored or used after the subcomputation finishes.
Since: bytestring-0.10.10.0