Copyright | (c) Duncan Coutts 2012-2013 |
---|---|
License | BSD-style |
Maintainer | duncan@community.haskell.org |
Stability | stable |
Portability | ghc only |
Safe Haskell | Unsafe |
Language | Haskell98 |
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.
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
:: Ptr a | source data |
-> Int | number of bytes to copy |
-> IO ShortByteString |
:: ShortByteString | source data |
-> Int | offset into source |
-> Ptr a | destination |
-> Int | number of bytes to copy |
-> IO () |
Low level conversions
Packing CString
s 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: bytestring-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: bytestring-0.10.10.0
Using ByteStrings as CString
s
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: bytestring-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: bytestring-0.10.10.0