Copyright	(c) Duncan Coutts 2012-2013
License	BSD-style
Maintainer	[email protected]
Stability	stable
Portability	ghc only
Safe Haskell	Unsafe
Language	Haskell98

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 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.

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

createFromPtr Source

copyToPtr Source

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: 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 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: 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