| 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
Contents
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 Source #
A compact representation of a Word8 vector.
It has a lower memory overhead than a ByteString 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 Source #
O(n). Convert a ByteString into a ShortByteString.
This makes a copy, so does not retain the input string.
fromShort :: ShortByteString -> ByteString Source #
O(n). Convert a ShortByteString into a ByteString.
pack :: [Word8] -> ShortByteString Source #
O(n). Convert a list into a ShortByteString
unpack :: ShortByteString -> [Word8] Source #
O(n). Convert a ShortByteString into a list.
Other operations
empty :: ShortByteString Source #
O(1). The empty ShortByteString.
null :: ShortByteString -> Bool Source #
O(1) Test whether a ShortByteString is empty.
length :: ShortByteString -> Int Source #
O(1) The length of a ShortByteString.
index :: ShortByteString -> Int -> Word8 Source #
O(1) ShortByteString index (subscript) operator, starting from 0.
unsafeIndex :: ShortByteString -> Int -> Word8 Source #
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 Source #
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: 0.10.10.0
packCStringLen :: CStringLen -> IO ShortByteString Source #
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: 0.10.10.0
Using ByteStrings as CStrings
useAsCString :: ShortByteString -> (CString -> IO a) -> IO a Source #
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: 0.10.10.0
useAsCStringLen :: ShortByteString -> (CStringLen -> IO a) -> IO a Source #
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: 0.10.10.0