| Copyright | © 2022 Julian Ospald |
|---|---|
| License | MIT |
| Maintainer | Julian Ospald <hasufell@posteo.de> |
| Stability | experimental |
| Portability | portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell2010 |
System.OsPath.Data.ByteString.Short.Word16
Description
ShortByteStrings encoded as UTF16-LE, suitable for windows FFI calls.
Word16s are *always* in BE encoding (both input and output), so e.g. pack
takes a list of BE encoded [Word16] and produces a UTF16-LE encoded ShortByteString.
Likewise, unpack takes a UTF16-LE encoded ShortByteString and produces a list of BE encoded [Word16].
Indices and lengths are always in respect to Word16, not Word8.
All functions will error out if the input string is not a valid UTF16 stream (uneven number of bytes). So use this module with caution.
Synopsis
- data ShortByteString = SBS ByteArray#
- empty :: ShortByteString
- singleton :: Word16 -> ShortByteString
- pack :: [Word16] -> ShortByteString
- unpack :: ShortByteString -> [Word16]
- fromShort :: ShortByteString -> ByteString
- toShort :: ByteString -> ShortByteString
- snoc :: ShortByteString -> Word16 -> ShortByteString
- cons :: Word16 -> ShortByteString -> ShortByteString
- append :: ShortByteString -> ShortByteString -> ShortByteString
- last :: HasCallStack => ShortByteString -> Word16
- tail :: HasCallStack => ShortByteString -> ShortByteString
- uncons :: ShortByteString -> Maybe (Word16, ShortByteString)
- uncons2 :: ShortByteString -> Maybe (Word16, Word16, ShortByteString)
- head :: HasCallStack => ShortByteString -> Word16
- init :: HasCallStack => ShortByteString -> ShortByteString
- unsnoc :: ShortByteString -> Maybe (ShortByteString, Word16)
- null :: ShortByteString -> Bool
- length :: ShortByteString -> Int
- numWord16 :: ShortByteString -> Int
- map :: (Word16 -> Word16) -> ShortByteString -> ShortByteString
- reverse :: ShortByteString -> ShortByteString
- intercalate :: ShortByteString -> [ShortByteString] -> ShortByteString
- foldl :: (a -> Word16 -> a) -> a -> ShortByteString -> a
- foldl' :: (a -> Word16 -> a) -> a -> ShortByteString -> a
- foldl1 :: HasCallStack => (Word16 -> Word16 -> Word16) -> ShortByteString -> Word16
- foldl1' :: HasCallStack => (Word16 -> Word16 -> Word16) -> ShortByteString -> Word16
- foldr :: (Word16 -> a -> a) -> a -> ShortByteString -> a
- foldr' :: (Word16 -> a -> a) -> a -> ShortByteString -> a
- foldr1 :: HasCallStack => (Word16 -> Word16 -> Word16) -> ShortByteString -> Word16
- foldr1' :: HasCallStack => (Word16 -> Word16 -> Word16) -> ShortByteString -> Word16
- all :: (Word16 -> Bool) -> ShortByteString -> Bool
- any :: (Word16 -> Bool) -> ShortByteString -> Bool
- concat :: [ShortByteString] -> ShortByteString
- replicate :: Int -> Word16 -> ShortByteString
- unfoldr :: (a -> Maybe (Word16, a)) -> a -> ShortByteString
- unfoldrN :: forall a. Int -> (a -> Maybe (Word16, a)) -> a -> (ShortByteString, Maybe a)
- take :: Int -> ShortByteString -> ShortByteString
- takeEnd :: Int -> ShortByteString -> ShortByteString
- takeWhileEnd :: (Word16 -> Bool) -> ShortByteString -> ShortByteString
- takeWhile :: (Word16 -> Bool) -> ShortByteString -> ShortByteString
- drop :: Int -> ShortByteString -> ShortByteString
- dropEnd :: Int -> ShortByteString -> ShortByteString
- dropWhile :: (Word16 -> Bool) -> ShortByteString -> ShortByteString
- dropWhileEnd :: (Word16 -> Bool) -> ShortByteString -> ShortByteString
- breakEnd :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString)
- break :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString)
- span :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString)
- spanEnd :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString)
- splitAt :: Int -> ShortByteString -> (ShortByteString, ShortByteString)
- split :: Word16 -> ShortByteString -> [ShortByteString]
- splitWith :: (Word16 -> Bool) -> ShortByteString -> [ShortByteString]
- stripSuffix :: ShortByteString -> ShortByteString -> Maybe ShortByteString
- stripPrefix :: ShortByteString -> ShortByteString -> Maybe ShortByteString
- isInfixOf :: ShortByteString -> ShortByteString -> Bool
- isPrefixOf :: ShortByteString -> ShortByteString -> Bool
- isSuffixOf :: ShortByteString -> ShortByteString -> Bool
- breakSubstring :: ShortByteString -> ShortByteString -> (ShortByteString, ShortByteString)
- elem :: Word16 -> ShortByteString -> Bool
- find :: (Word16 -> Bool) -> ShortByteString -> Maybe Word16
- filter :: (Word16 -> Bool) -> ShortByteString -> ShortByteString
- partition :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString)
- index :: HasCallStack => ShortByteString -> Int -> Word16
- indexMaybe :: ShortByteString -> Int -> Maybe Word16
- (!?) :: ShortByteString -> Int -> Maybe Word16
- elemIndex :: Word16 -> ShortByteString -> Maybe Int
- elemIndices :: Word16 -> ShortByteString -> [Int]
- count :: Word16 -> ShortByteString -> Int
- findIndex :: (Word16 -> Bool) -> ShortByteString -> Maybe Int
- findIndices :: (Word16 -> Bool) -> ShortByteString -> [Int]
- packCWString :: Ptr Word16 -> IO ShortByteString
- packCWStringLen :: (Ptr Word16, Int) -> IO ShortByteString
- newCWString :: ShortByteString -> IO (Ptr Word16)
- useAsCWString :: ShortByteString -> (Ptr Word16 -> IO a) -> IO a
- useAsCWStringLen :: ShortByteString -> ((Ptr Word16, Int) -> 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 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
Introducing and eliminating ShortByteStrings
O(1). The empty ShortByteString.
singleton :: Word16 -> ShortByteString Source #
O(1) Convert a Word16 into a ShortByteString
pack :: [Word16] -> ShortByteString Source #
O(n). Convert a list into a ShortByteString
unpack :: ShortByteString -> [Word16] Source #
O(n). Convert a ShortByteString into a list.
fromShort :: ShortByteString -> ByteString #
O(n). Convert a ShortByteString into a ByteString.
toShort :: ByteString -> ShortByteString #
O(n). Convert a ByteString into a ShortByteString.
This makes a copy, so does not retain the input string.
Basic interface
snoc :: ShortByteString -> Word16 -> ShortByteString infixl 5 Source #
O(n) Append a Word16 to the end of a ShortByteString
Note: copies the entire byte array
cons :: Word16 -> ShortByteString -> ShortByteString infixr 5 Source #
O(n) cons is analogous to (:) for lists.
Note: copies the entire byte array
append :: ShortByteString -> ShortByteString -> ShortByteString #
last :: HasCallStack => ShortByteString -> Word16 Source #
O(1) Extract the last element of a ShortByteString, which must be finite and at least one Word16. An exception will be thrown in the case of an empty ShortByteString.
tail :: HasCallStack => ShortByteString -> ShortByteString Source #
O(n) Extract the elements after the head of a ShortByteString, which must at least one Word16. An exception will be thrown in the case of an empty ShortByteString.
Note: copies the entire byte array
uncons :: ShortByteString -> Maybe (Word16, ShortByteString) Source #
O(n) Extract the head and tail of a ByteString, returning Nothing if it is empty.
uncons2 :: ShortByteString -> Maybe (Word16, Word16, ShortByteString) Source #
O(n) Extract first two elements and the rest of a ByteString, returning Nothing if it is shorter than two elements.
head :: HasCallStack => ShortByteString -> Word16 Source #
O(1) Extract the first element of a ShortByteString, which must be at least one Word16. An exception will be thrown in the case of an empty ShortByteString.
init :: HasCallStack => ShortByteString -> ShortByteString Source #
O(n) Return all the elements of a ShortByteString except the last one.
An exception will be thrown in the case of an empty ShortByteString.
Note: copies the entire byte array
unsnoc :: ShortByteString -> Maybe (ShortByteString, Word16) Source #
null :: ShortByteString -> Bool #
O(1) Test whether a ShortByteString is empty.
length :: ShortByteString -> Int #
O(1) The length of a ShortByteString.
numWord16 :: ShortByteString -> Int Source #
Transforming ShortByteStrings
map :: (Word16 -> Word16) -> ShortByteString -> ShortByteString Source #
O(n) map f xs is the ShortByteString obtained by applying f to each
element of xs.
reverse :: ShortByteString -> ShortByteString Source #
O(n) reverse xs efficiently returns the elements of xs in reverse order.
intercalate :: ShortByteString -> [ShortByteString] -> ShortByteString #
O(n) The intercalate function takes a ShortByteString and a list of
ShortByteStrings and concatenates the list after interspersing the first
argument between each element of the list.
Since: bytestring-0.11.3.0
Reducing ShortByteStrings (folds)
foldl :: (a -> Word16 -> a) -> a -> ShortByteString -> a Source #
foldl, applied to a binary operator, a starting value (typically
the left-identity of the operator), and a ShortByteString, reduces the
ShortByteString using the binary operator, from left to right.
foldl' :: (a -> Word16 -> a) -> a -> ShortByteString -> a Source #
foldl1 :: HasCallStack => (Word16 -> Word16 -> Word16) -> ShortByteString -> Word16 Source #
foldl1 is a variant of foldl that has no starting value
argument, and thus must be applied to non-empty ShortByteStrings.
An exception will be thrown in the case of an empty ShortByteString.
foldl1' :: HasCallStack => (Word16 -> Word16 -> Word16) -> ShortByteString -> Word16 Source #
foldr :: (Word16 -> a -> a) -> a -> ShortByteString -> a Source #
foldr, applied to a binary operator, a starting value
(typically the right-identity of the operator), and a ShortByteString,
reduces the ShortByteString using the binary operator, from right to left.
foldr' :: (Word16 -> a -> a) -> a -> ShortByteString -> a Source #
foldr1 :: HasCallStack => (Word16 -> Word16 -> Word16) -> ShortByteString -> Word16 Source #
foldr1 is a variant of foldr that has no starting value argument,
and thus must be applied to non-empty ShortByteStrings
An exception will be thrown in the case of an empty ShortByteString.
foldr1' :: HasCallStack => (Word16 -> Word16 -> Word16) -> ShortByteString -> Word16 Source #
Special folds
all :: (Word16 -> Bool) -> ShortByteString -> Bool Source #
O(n) Applied to a predicate and a ShortByteString, all determines
if all elements of the ShortByteString satisfy the predicate.
any :: (Word16 -> Bool) -> ShortByteString -> Bool Source #
O(n) Applied to a predicate and a ByteString, any determines if
any element of the ByteString satisfies the predicate.
concat :: [ShortByteString] -> ShortByteString #
Generating and unfolding ByteStrings
replicate :: Int -> Word16 -> ShortByteString Source #
O(n) replicate n x is a ByteString of length n with x
the value of every element. The following holds:
replicate w c = unfoldr w (\u -> Just (u,u)) c
unfoldr :: (a -> Maybe (Word16, a)) -> a -> ShortByteString Source #
O(n), where n is the length of the result. The unfoldr
function is analogous to the List 'unfoldr'. unfoldr builds a
ShortByteString from a seed value. The function takes the element and
returns Nothing if it is done producing the ShortByteString or returns
Just (a,b), in which case, a is the next byte in the string,
and b is the seed value for further production.
This function is not efficient/safe. It will build a list of [Word16]
and run the generator until it returns Nothing, otherwise recurse infinitely,
then finally create a ShortByteString.
Examples:
unfoldr (\x -> if x <= 5 then Just (x, x + 1) else Nothing) 0 == pack [0, 1, 2, 3, 4, 5]
Arguments
| :: forall a. Int | number of |
| -> (a -> Maybe (Word16, a)) | |
| -> a | |
| -> (ShortByteString, Maybe a) |
O(n) Like unfoldr, unfoldrN builds a ShortByteString from a seed
value. However, the length of the result is limited by the first
argument to unfoldrN. This function is more efficient than unfoldr
when the maximum length of the result is known.
The following equation relates unfoldrN and unfoldr:
fst (unfoldrN n f s) == take n (unfoldr f s)
Substrings
Breaking strings
Arguments
| :: Int | number of Word16 |
| -> ShortByteString | |
| -> ShortByteString |
Arguments
| :: Int | number of |
| -> ShortByteString | |
| -> ShortByteString |
takeWhileEnd :: (Word16 -> Bool) -> ShortByteString -> ShortByteString Source #
Returns the longest (possibly empty) suffix of elements satisfying the predicate.
is equivalent to takeWhileEnd p.reverse . takeWhile p . reverse
takeWhile :: (Word16 -> Bool) -> ShortByteString -> ShortByteString Source #
Similar to takeWhile,
returns the longest (possibly empty) prefix of elements
satisfying the predicate.
Arguments
| :: Int | number of |
| -> ShortByteString | |
| -> ShortByteString |
Arguments
| :: Int | number of |
| -> ShortByteString | |
| -> ShortByteString |
dropWhile :: (Word16 -> Bool) -> ShortByteString -> ShortByteString Source #
Similar to dropWhile,
drops the longest (possibly empty) prefix of elements
satisfying the predicate and returns the remainder.
Note: copies the entire byte array
dropWhileEnd :: (Word16 -> Bool) -> ShortByteString -> ShortByteString Source #
Similar to dropWhileEnd,
drops the longest (possibly empty) suffix of elements
satisfying the predicate and returns the remainder.
is equivalent to dropWhileEnd p.reverse . dropWhile p . reverse
Since: 0.10.12.0
breakEnd :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString) Source #
Returns the longest (possibly empty) suffix of elements which do not satisfy the predicate and the remainder of the string.
breakEnd p is equivalent to and to spanEnd (not . p)(.takeWhileEnd (not . p) &&& dropWhileEnd (not . p))
break :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString) Source #
span :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString) Source #
spanEnd :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString) Source #
Returns the longest (possibly empty) suffix of elements satisfying the predicate and the remainder of the string.
spanEnd p is equivalent to and to breakEnd (not . p)(.takeWhileEnd p &&& dropWhileEnd p)
We have
spanEnd (not . isSpace) "x y z" == ("x y ", "z")and
spanEnd (not . isSpace) ps == let (x, y) = span (not . isSpace) (reverse ps) in (reverse y, reverse x)
Arguments
| :: Int | number of Word16 |
| -> ShortByteString | |
| -> (ShortByteString, ShortByteString) |
split :: Word16 -> ShortByteString -> [ShortByteString] Source #
O(n) Break a ShortByteString into pieces separated by the byte
argument, consuming the delimiter. I.e.
split 10 "a\nb\nd\ne" == ["a","b","d","e"] -- fromEnum '\n' == 10 split 97 "aXaXaXa" == ["","X","X","X",""] -- fromEnum 'a' == 97 split 120 "x" == ["",""] -- fromEnum 'x' == 120 split undefined "" == [] -- and not [""]
and
intercalate [c] . split c == id split == splitWith . (==)
Note: copies the substrings
splitWith :: (Word16 -> Bool) -> ShortByteString -> [ShortByteString] Source #
O(n) Splits a ShortByteString into components delimited by
separators, where the predicate returns True for a separator element.
The resulting components do not contain the separators. Two adjacent
separators result in an empty component in the output. eg.
splitWith (==97) "aabbaca" == ["","","bb","c",""] -- fromEnum 'a' == 97 splitWith undefined "" == [] -- and not [""]
stripSuffix :: ShortByteString -> ShortByteString -> Maybe ShortByteString #
O(n) The stripSuffix function takes two ShortByteStrings and returns Just
the remainder of the second iff the first is its suffix, and otherwise
Nothing.
Since: bytestring-0.11.3.0
stripPrefix :: ShortByteString -> ShortByteString -> Maybe ShortByteString #
O(n) The stripPrefix function takes two ShortByteStrings and returns Just
the remainder of the second iff the first is its prefix, and otherwise
Nothing.
Since: bytestring-0.11.3.0
Predicates
isInfixOf :: ShortByteString -> ShortByteString -> Bool Source #
Check whether one string is a substring of another.
isPrefixOf :: ShortByteString -> ShortByteString -> Bool #
O(n) The isPrefixOf function takes two ShortByteStrings and returns True
Since: bytestring-0.11.3.0
isSuffixOf :: ShortByteString -> ShortByteString -> Bool #
O(n) The isSuffixOf function takes two ShortByteStrings and returns True
iff the first is a suffix of the second.
The following holds:
isSuffixOf x y == reverse x `isPrefixOf` reverse y
Since: bytestring-0.11.3.0
Search for arbitrary substrings
Arguments
| :: ShortByteString | String to search for |
| -> ShortByteString | String to search in |
| -> (ShortByteString, ShortByteString) | Head and tail of string broken at substring |
Searching ShortByteStrings
Searching by equality
elem :: Word16 -> ShortByteString -> Bool Source #
O(n) elem is the ShortByteString membership predicate.
Searching with a predicate
filter :: (Word16 -> Bool) -> ShortByteString -> ShortByteString Source #
O(n) filter, applied to a predicate and a ByteString,
returns a ByteString containing those characters that satisfy the
predicate.
partition :: (Word16 -> Bool) -> ShortByteString -> (ShortByteString, ShortByteString) Source #
O(n) The partition function takes a predicate a ByteString and returns
the pair of ByteStrings with elements which do and do not satisfy the
predicate, respectively; i.e.,
partition p bs == (filter p xs, filter (not . p) xs)
Indexing ShortByteStrings
Arguments
| :: HasCallStack | |
| => ShortByteString | |
| -> Int | number of |
| -> Word16 |
O(1) ShortByteString index (subscript) operator, starting from 0.
Arguments
| :: ShortByteString | |
| -> Int | number of |
| -> Maybe Word16 |
Arguments
| :: ShortByteString | |
| -> Int | number of |
| -> Maybe Word16 |
Arguments
| :: Word16 | |
| -> ShortByteString | |
| -> Maybe Int | number of |
O(n) The elemIndex function returns the index of the first
element in the given ShortByteString which is equal to the query
element, or Nothing if there is no such element.
elemIndices :: Word16 -> ShortByteString -> [Int] Source #
O(n) The elemIndices function extends elemIndex, by returning
the indices of all elements equal to the query element, in ascending order.
count :: Word16 -> ShortByteString -> Int Source #
count returns the number of times its argument appears in the ShortByteString
findIndex :: (Word16 -> Bool) -> ShortByteString -> Maybe Int Source #
O(n) The findIndex function takes a predicate and a ShortByteString and
returns the index of the first element in the ByteString
satisfying the predicate.
findIndices :: (Word16 -> Bool) -> ShortByteString -> [Int] Source #
O(n) The findIndices function extends findIndex, by returning the
indices of all elements satisfying the predicate, in ascending order.
Encoding validation
Low level conversions
Packing CStrings and pointers
packCWString :: Ptr Word16 -> IO ShortByteString Source #
O(n). Construct a new ShortByteString from a CWString. The
resulting ShortByteString is an immutable copy of the original
CWString, and is managed on the Haskell heap. The original
CWString must be null terminated.
Since: 0.10.10.0
packCWStringLen :: (Ptr Word16, Int) -> IO ShortByteString Source #
O(n). Construct a new ShortByteString from a CWStringLen. The
resulting ShortByteString is an immutable copy of the original CWStringLen.
The ShortByteString is a normal Haskell value and will be managed on the
Haskell heap.
Since: 0.10.10.0
newCWString :: ShortByteString -> IO (Ptr Word16) Source #
O(n) construction. Use a ShortByteString with a function requiring a CWStringLen.
As for useAsCWString 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
Using ShortByteStrings as CStrings
useAsCWString :: ShortByteString -> (Ptr Word16 -> IO a) -> IO a Source #
O(n) construction. Use a ShortByteString with a function requiring a
null-terminated CWString. The CWString is a copy and will be freed
automatically; it must not be stored or used after the
subcomputation finishes.
Since: 0.10.10.0
useAsCWStringLen :: ShortByteString -> ((Ptr Word16, Int) -> IO a) -> IO a Source #
O(n) construction. Use a ShortByteString with a function requiring a CWStringLen.
As for useAsCWString 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