Data.StorableVector
 Contents The Vector type Introducing and eliminating Vectors Basic interface Transformating Vectors Reducing Vectors (folds) Special folds Building Vectors Scans Accumulating maps Unfolding Vectors Substrings Breaking strings Breaking into many substrings Joining strings Predicates Searching Vectors Searching by equality Searching with a predicate Indexing Vectors Zipping and unzipping Vectors IO
Description

A time and space-efficient implementation of vectors using packed arrays, suitable for high performance use, both in terms of large data quantities, or high speed requirements. Vectors are encoded as strict arrays, held in a ForeignPtr, and can be passed between C and Haskell with little effort.

This module is intended to be imported qualified, to avoid name clashes with Prelude functions. eg.

``` import qualified Data.StorableVector as V
```

Original GHC implementation by Bryan O'Sullivan. Rewritten to use UArray by Simon Marlow. Rewritten to support slices and use ForeignPtr by David Roundy. Polished and extended by Don Stewart. Generalized to any Storable value by Spencer Janssen. Chunky lazy stream and mutable access in ST monad by Henning Thieleman.

Synopsis
 data Vector a empty :: Storable a => Vector a singleton :: Storable a => a -> Vector a pack :: Storable a => [a] -> Vector a unpack :: Storable a => Vector a -> [a] packWith :: Storable b => (a -> b) -> [a] -> Vector b unpackWith :: Storable a => (a -> b) -> Vector a -> [b] cons :: Storable a => a -> Vector a -> Vector a snoc :: Storable a => Vector a -> a -> Vector a append :: Storable a => Vector a -> Vector a -> Vector a head :: Storable a => Vector a -> a last :: Storable a => Vector a -> a tail :: Storable a => Vector a -> Vector a init :: Vector a -> Vector a null :: Vector a -> Bool length :: Vector a -> Int viewL :: Storable a => Vector a -> Maybe (a, Vector a) viewR :: Storable a => Vector a -> Maybe (Vector a, a) map :: (Storable a, Storable b) => (a -> b) -> Vector a -> Vector b reverse :: Storable a => Vector a -> Vector a intersperse :: Storable a => a -> Vector a -> Vector a transpose :: Storable a => [Vector a] -> [Vector a] foldl :: Storable a => (b -> a -> b) -> b -> Vector a -> b foldl' :: Storable a => (b -> a -> b) -> b -> Vector a -> b foldl1 :: Storable a => (a -> a -> a) -> Vector a -> a foldl1' :: Storable a => (a -> a -> a) -> Vector a -> a foldr :: Storable a => (a -> b -> b) -> b -> Vector a -> b foldr1 :: Storable a => (a -> a -> a) -> Vector a -> a concat :: Storable a => [Vector a] -> Vector a concatMap :: (Storable a, Storable b) => (a -> Vector b) -> Vector a -> Vector b any :: Storable a => (a -> Bool) -> Vector a -> Bool all :: Storable a => (a -> Bool) -> Vector a -> Bool maximum :: (Storable a, Ord a) => Vector a -> a minimum :: (Storable a, Ord a) => Vector a -> a scanl :: (Storable a, Storable b) => (a -> b -> a) -> a -> Vector b -> Vector a scanl1 :: Storable a => (a -> a -> a) -> Vector a -> Vector a scanr :: (Storable a, Storable b) => (a -> b -> b) -> b -> Vector a -> Vector b scanr1 :: Storable a => (a -> a -> a) -> Vector a -> Vector a mapAccumL :: (Storable a, Storable b) => (acc -> a -> (acc, b)) -> acc -> Vector a -> (acc, Vector b) mapAccumR :: (Storable a, Storable b) => (acc -> a -> (acc, b)) -> acc -> Vector a -> (acc, Vector b) mapIndexed :: (Storable a, Storable b) => (Int -> a -> b) -> Vector a -> Vector b replicate :: Storable a => Int -> a -> Vector a unfoldr :: Storable b => (a -> Maybe (b, a)) -> a -> Vector b unfoldrN :: Storable b => Int -> (a -> Maybe (b, a)) -> a -> (Vector b, Maybe a) take :: Storable a => Int -> Vector a -> Vector a drop :: Storable a => Int -> Vector a -> Vector a splitAt :: Storable a => Int -> Vector a -> (Vector a, Vector a) takeWhile :: Storable a => (a -> Bool) -> Vector a -> Vector a dropWhile :: Storable a => (a -> Bool) -> Vector a -> Vector a span :: Storable a => (a -> Bool) -> Vector a -> (Vector a, Vector a) spanEnd :: Storable a => (a -> Bool) -> Vector a -> (Vector a, Vector a) break :: Storable a => (a -> Bool) -> Vector a -> (Vector a, Vector a) breakEnd :: Storable a => (a -> Bool) -> Vector a -> (Vector a, Vector a) group :: (Storable a, Eq a) => Vector a -> [Vector a] groupBy :: Storable a => (a -> a -> Bool) -> Vector a -> [Vector a] inits :: Storable a => Vector a -> [Vector a] tails :: Storable a => Vector a -> [Vector a] split :: (Storable a, Eq a) => a -> Vector a -> [Vector a] splitWith :: Storable a => (a -> Bool) -> Vector a -> [Vector a] tokens :: Storable a => (a -> Bool) -> Vector a -> [Vector a] join :: Storable a => Vector a -> [Vector a] -> Vector a isPrefixOf :: (Storable a, Eq a) => Vector a -> Vector a -> Bool isSuffixOf :: (Storable a, Eq a) => Vector a -> Vector a -> Bool elem :: (Storable a, Eq a) => a -> Vector a -> Bool notElem :: (Storable a, Eq a) => a -> Vector a -> Bool find :: Storable a => (a -> Bool) -> Vector a -> Maybe a filter :: Storable a => (a -> Bool) -> Vector a -> Vector a index :: Storable a => Vector a -> Int -> a elemIndex :: (Storable a, Eq a) => a -> Vector a -> Maybe Int elemIndices :: (Storable a, Eq a) => a -> Vector a -> [Int] elemIndexEnd :: (Storable a, Eq a) => a -> Vector a -> Maybe Int findIndex :: Storable a => (a -> Bool) -> Vector a -> Maybe Int findIndices :: Storable a => (a -> Bool) -> Vector a -> [Int] count :: (Storable a, Eq a) => a -> Vector a -> Int findIndexOrEnd :: Storable a => (a -> Bool) -> Vector a -> Int zip :: (Storable a, Storable b) => Vector a -> Vector b -> [(a, b)] zipWith :: (Storable a, Storable b, Storable c) => (a -> b -> c) -> Vector a -> Vector b -> Vector c unzip :: (Storable a, Storable b) => [(a, b)] -> (Vector a, Vector b) copy :: Storable a => Vector a -> Vector a hGet :: Storable a => Handle -> Int -> IO (Vector a) hPut :: Storable a => Handle -> Vector a -> IO () readFile :: Storable a => FilePath -> IO (Vector a) writeFile :: Storable a => FilePath -> Vector a -> IO () appendFile :: Storable a => FilePath -> Vector a -> IO ()
The Vector type
 data Vector a Source

A space-efficient representation of a vector, supporting many efficient operations.

Instances of Eq, Ord, Read, Show, Data, Typeable

Instances
 Typeable1 Vector (Storable a, Eq a) => Eq (Vector a) Typeable a => Data (Vector a) Storable a => Monoid (Vector a)
Introducing and eliminating Vectors
 empty :: Storable a => Vector a Source
O(1) The empty Vector
 singleton :: Storable a => a -> Vector a Source
O(1) Construct a Vector containing a single element
 pack :: Storable a => [a] -> Vector a Source
O(n) Convert a '[a]' into a 'Vector a'.
 unpack :: Storable a => Vector a -> [a] Source
O(n) Converts a 'Vector a' to a '[a]'.
 packWith :: Storable b => (a -> b) -> [a] -> Vector b Source
O(n) Convert a list into a Vector using a conversion function
 unpackWith :: Storable a => (a -> b) -> Vector a -> [b] Source
O(n) Convert a Vector into a list using a conversion function
Basic interface
 cons :: Storable a => a -> Vector a -> Vector a Source
O(n) cons is analogous to (:) for lists, but of different complexity, as it requires a memcpy.
 snoc :: Storable a => Vector a -> a -> Vector a Source
O(n) Append an element to the end of a Vector
 append :: Storable a => Vector a -> Vector a -> Vector a Source
O(n) Append two Vectors
 head :: Storable a => Vector a -> a Source
O(1) Extract the first element of a Vector, which must be non-empty. An exception will be thrown in the case of an empty Vector.
 last :: Storable a => Vector a -> a Source
O(1) Extract the last element of a Vector, which must be finite and non-empty. An exception will be thrown in the case of an empty Vector.
 tail :: Storable a => Vector a -> Vector a Source
O(1) Extract the elements after the head of a Vector, which must be non-empty. An exception will be thrown in the case of an empty Vector.
 init :: Vector a -> Vector a Source
O(1) Return all the elements of a Vector except the last one. An exception will be thrown in the case of an empty Vector.
 null :: Vector a -> Bool Source
O(1) Test whether a Vector is empty.
 length :: Vector a -> Int Source
O(1) length returns the length of a Vector as an Int.
 viewL :: Storable a => Vector a -> Maybe (a, Vector a) Source
 viewR :: Storable a => Vector a -> Maybe (Vector a, a) Source
Transformating Vectors
 map :: (Storable a, Storable b) => (a -> b) -> Vector a -> Vector b Source
O(n) map f xs is the Vector obtained by applying f to each element of xs.
 reverse :: Storable a => Vector a -> Vector a Source
O(n) reverse xs efficiently returns the elements of xs in reverse order.
 intersperse :: Storable a => a -> Vector a -> Vector a Source
O(n) The intersperse function takes a element and a Vector and `intersperses' that element between the elements of the Vector. It is analogous to the intersperse function on Lists.
 transpose :: Storable a => [Vector a] -> [Vector a] Source
The transpose function transposes the rows and columns of its Vector argument.
Reducing Vectors (folds)
 foldl :: Storable a => (b -> a -> b) -> b -> Vector a -> b Source
foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a Vector, reduces the Vector using the binary operator, from left to right. This function is subject to array fusion.
 foldl' :: Storable a => (b -> a -> b) -> b -> Vector a -> b Source
'foldl\'' is like foldl, but strict in the accumulator. Though actually foldl is also strict in the accumulator.
 foldl1 :: Storable a => (a -> a -> a) -> Vector a -> a Source
foldl1 is a variant of foldl that has no starting value argument, and thus must be applied to non-empty Vectors. This function is subject to array fusion. An exception will be thrown in the case of an empty Vector.
 foldl1' :: Storable a => (a -> a -> a) -> Vector a -> a Source
'foldl1\'' is like foldl1, but strict in the accumulator. An exception will be thrown in the case of an empty Vector.
 foldr :: Storable a => (a -> b -> b) -> b -> Vector a -> b Source
foldr, applied to a binary operator, a starting value (typically the right-identity of the operator), and a Vector, reduces the Vector using the binary operator, from right to left.
 foldr1 :: Storable a => (a -> a -> a) -> Vector a -> a Source
foldr1 is a variant of foldr that has no starting value argument, and thus must be applied to non-empty Vectors An exception will be thrown in the case of an empty Vector.
Special folds
 concat :: Storable a => [Vector a] -> Vector a Source
O(n) Concatenate a list of Vectors.
 concatMap :: (Storable a, Storable b) => (a -> Vector b) -> Vector a -> Vector b Source
Map a function over a Vector and concatenate the results
 any :: Storable a => (a -> Bool) -> Vector a -> Bool Source
O(n) Applied to a predicate and a Vector, any determines if any element of the Vector satisfies the predicate.
 all :: Storable a => (a -> Bool) -> Vector a -> Bool Source
O(n) Applied to a predicate and a Vector, all determines if all elements of the Vector satisfy the predicate.
 maximum :: (Storable a, Ord a) => Vector a -> a Source
O(n) maximum returns the maximum value from a Vector This function will fuse. An exception will be thrown in the case of an empty Vector.
 minimum :: (Storable a, Ord a) => Vector a -> a Source
O(n) minimum returns the minimum value from a Vector This function will fuse. An exception will be thrown in the case of an empty Vector.
Building Vectors
Scans
 scanl :: (Storable a, Storable b) => (a -> b -> a) -> a -> Vector b -> Vector a Source

scanl is similar to foldl, but returns a list of successive reduced values from the left. This function will fuse.

``` scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]
```

Note that

``` last (scanl f z xs) == foldl f z xs.
```
 scanl1 :: Storable a => (a -> a -> a) -> Vector a -> Vector a Source

scanl1 is a variant of scanl that has no starting value argument. This function will fuse.

``` scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]
```
 scanr :: (Storable a, Storable b) => (a -> b -> b) -> b -> Vector a -> Vector b Source
scanr is the right-to-left dual of scanl.
 scanr1 :: Storable a => (a -> a -> a) -> Vector a -> Vector a Source
scanr1 is a variant of scanr that has no starting value argument.
Accumulating maps
 mapAccumL :: (Storable a, Storable b) => (acc -> a -> (acc, b)) -> acc -> Vector a -> (acc, Vector b) Source
The mapAccumL function behaves like a combination of map and foldl; it applies a function to each element of a Vector, passing an accumulating parameter from left to right, and returning a final value of this accumulator together with the new list.
 mapAccumR :: (Storable a, Storable b) => (acc -> a -> (acc, b)) -> acc -> Vector a -> (acc, Vector b) Source
The mapAccumR function behaves like a combination of map and foldr; it applies a function to each element of a Vector, passing an accumulating parameter from right to left, and returning a final value of this accumulator together with the new Vector.
 mapIndexed :: (Storable a, Storable b) => (Int -> a -> b) -> Vector a -> Vector b Source
O(n) map functions, provided with the index at each position
Unfolding Vectors
 replicate :: Storable a => Int -> a -> Vector a Source
O(n) replicate n x is a Vector of length n with x the value of every element.
 unfoldr :: Storable b => (a -> Maybe (b, a)) -> a -> Vector b Source

O(n), where n is the length of the result. The unfoldr function is analogous to the List 'unfoldr'. unfoldr builds a Vector from a seed value. The function takes the element and returns Nothing if it is done producing the 'Vector or returns Just (a,b), in which case, a is the next element in the Vector, and b is the seed value for further production.

Examples:

```    unfoldr (\x -> if x <= 5 then Just (x, x + 1) else Nothing) 0
== pack [0, 1, 2, 3, 4, 5]
```
 unfoldrN :: Storable b => Int -> (a -> Maybe (b, a)) -> a -> (Vector b, Maybe a) Source

O(n) Like unfoldr, unfoldrN builds a Vector 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
 take :: Storable a => Int -> Vector a -> Vector a Source
O(1) take n, applied to a Vector xs, returns the prefix of xs of length n, or xs itself if n > length xs.
 drop :: Storable a => Int -> Vector a -> Vector a Source
O(1) drop n xs returns the suffix of xs after the first n elements, or [] if n > length xs.
 splitAt :: Storable a => Int -> Vector a -> (Vector a, Vector a) Source
O(1) splitAt n xs is equivalent to (take n xs, drop n xs).
 takeWhile :: Storable a => (a -> Bool) -> Vector a -> Vector a Source
takeWhile, applied to a predicate p and a Vector xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p.
 dropWhile :: Storable a => (a -> Bool) -> Vector a -> Vector a Source
dropWhile p xs returns the suffix remaining after takeWhile p xs.
 span :: Storable a => (a -> Bool) -> Vector a -> (Vector a, Vector a) Source
span p xs breaks the Vector into two segments. It is equivalent to (takeWhile p xs, dropWhile p xs)
 spanEnd :: Storable a => (a -> Bool) -> Vector a -> (Vector a, Vector a) Source

spanEnd behaves like span but from the end of the Vector. 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)
```
 break :: Storable a => (a -> Bool) -> Vector a -> (Vector a, Vector a) Source
break p is equivalent to span (not . p).
 breakEnd :: Storable a => (a -> Bool) -> Vector a -> (Vector a, Vector a) Source

breakEnd behaves like break but from the end of the Vector

breakEnd p == spanEnd (not.p)

 group :: (Storable a, Eq a) => Vector a -> [Vector a] Source

The group function takes a Vector and returns a list of Vectors such that the concatenation of the result is equal to the argument. Moreover, each sublist in the result contains only equal elements. For example,

``` group "Mississippi" = ["M","i","ss","i","ss","i","pp","i"]
```

It is a special case of groupBy, which allows the programmer to supply their own equality test. It is about 40% faster than groupBy (==)

 groupBy :: Storable a => (a -> a -> Bool) -> Vector a -> [Vector a] Source
The groupBy function is the non-overloaded version of group.
 inits :: Storable a => Vector a -> [Vector a] Source
O(n) Return all initial segments of the given Vector, shortest first.
 tails :: Storable a => Vector a -> [Vector a] Source
O(n) Return all final segments of the given Vector, longest first.
Breaking into many substrings
 split :: (Storable a, Eq a) => a -> Vector a -> [Vector a] Source

O(n) Break a Vector into pieces separated by the argument, consuming the delimiter. I.e.

``` split '\n' "a\nb\nd\ne" == ["a","b","d","e"]
split 'a'  "aXaXaXa"    == ["","X","X","X"]
split 'x'  "x"          == ["",""]
```

and

``` join [c] . split c == id
split == splitWith . (==)
```

As for all splitting functions in this library, this function does not copy the substrings, it just constructs new Vectors that are slices of the original.

 splitWith :: Storable a => (a -> Bool) -> Vector a -> [Vector a] Source

O(n) Splits a Vector 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 (=='a') "aabbaca" == ["","","bb","c",""]
splitWith (=='a') []        == []
```
 tokens :: Storable a => (a -> Bool) -> Vector a -> [Vector a] Source

Like splitWith, except that sequences of adjacent separators are treated as a single separator. eg.

``` tokens (=='a') "aabbaca" == ["bb","c"]
```
Joining strings
 join :: Storable a => Vector a -> [Vector a] -> Vector a Source
O(n) The join function takes a Vector and a list of Vectors and concatenates the list after interspersing the first argument between each element of the list.
Predicates
 isPrefixOf :: (Storable a, Eq a) => Vector a -> Vector a -> Bool Source
O(n) The isPrefixOf function takes two Vector and returns True iff the first is a prefix of the second.
 isSuffixOf :: (Storable a, Eq a) => Vector a -> Vector a -> Bool Source

O(n) The isSuffixOf function takes two Vectors and returns True iff the first is a suffix of the second.

The following holds:

``` isSuffixOf x y == reverse x `isPrefixOf` reverse y
```
Searching Vectors
Searching by equality
 elem :: (Storable a, Eq a) => a -> Vector a -> Bool Source
O(n) elem is the Vector membership predicate.
 notElem :: (Storable a, Eq a) => a -> Vector a -> Bool Source
O(n) notElem is the inverse of elem
Searching with a predicate
 find :: Storable a => (a -> Bool) -> Vector a -> Maybe a Source

O(n) The find function takes a predicate and a Vector, and returns the first element in matching the predicate, or Nothing if there is no such element.

``` find f p = case findIndex f p of Just n -> Just (p ! n) ; _ -> Nothing
```
 filter :: Storable a => (a -> Bool) -> Vector a -> Vector a Source
O(n) filter, applied to a predicate and a Vector, returns a Vector containing those elements that satisfy the predicate. This function is subject to array fusion.
Indexing Vectors
 index :: Storable a => Vector a -> Int -> a Source
O(1) Vector index (subscript) operator, starting from 0.
 elemIndex :: (Storable a, Eq a) => a -> Vector a -> Maybe Int Source
O(n) The elemIndex function returns the index of the first element in the given Vector which is equal to the query element, or Nothing if there is no such element. This implementation uses memchr(3).
 elemIndices :: (Storable a, Eq a) => a -> Vector a -> [Int] Source
O(n) The elemIndices function extends elemIndex, by returning the indices of all elements equal to the query element, in ascending order. This implementation uses memchr(3).
 elemIndexEnd :: (Storable a, Eq a) => a -> Vector a -> Maybe Int Source

O(n) The elemIndexEnd function returns the last index of the element in the given Vector which is equal to the query element, or Nothing if there is no such element. The following holds:

``` elemIndexEnd c xs ==
(-) (length xs - 1) `fmap` elemIndex c (reverse xs)
```
 findIndex :: Storable a => (a -> Bool) -> Vector a -> Maybe Int Source
The findIndex function takes a predicate and a Vector and returns the index of the first element in the Vector satisfying the predicate.
 findIndices :: Storable a => (a -> Bool) -> Vector a -> [Int] Source
The findIndices function extends findIndex, by returning the indices of all elements satisfying the predicate, in ascending order.
 count :: (Storable a, Eq a) => a -> Vector a -> Int Source

count returns the number of times its argument appears in the Vector

``` count = length . elemIndices
```

But more efficiently than using length on the intermediate list.

 findIndexOrEnd :: Storable a => (a -> Bool) -> Vector a -> Int Source
findIndexOrEnd is a variant of findIndex, that returns the length of the string if no element is found, rather than Nothing.
Zipping and unzipping Vectors
 zip :: (Storable a, Storable b) => Vector a -> Vector b -> [(a, b)] Source
O(n) zip takes two Vectors and returns a list of corresponding pairs of elements. If one input Vector is short, excess elements of the longer Vector are discarded. This is equivalent to a pair of unpack operations.
 zipWith :: (Storable a, Storable b, Storable c) => (a -> b -> c) -> Vector a -> Vector b -> Vector c Source
zipWith generalises zip by zipping with the function given as the first argument, instead of a tupling function. For example, zipWith (+) is applied to two Vectors to produce the list of corresponding sums.
 unzip :: (Storable a, Storable b) => [(a, b)] -> (Vector a, Vector b) Source
O(n) unzip transforms a list of pairs of elements into a pair of Vectors. Note that this performs two pack operations.
 copy :: Storable a => Vector a -> Vector a Source
O(n) Make a copy of the Vector with its own storage. This is mainly useful to allow the rest of the data pointed to by the Vector to be garbage collected, for example if a large string has been read in, and only a small part of it is needed in the rest of the program.
IO
 hGet :: Storable a => Handle -> Int -> IO (Vector a) Source
Read a Vector directly from the specified Handle. This is far more efficient than reading the characters into a list and then using pack.
 hPut :: Storable a => Handle -> Vector a -> IO () Source
Outputs a Vector to the specified Handle.
 readFile :: Storable a => FilePath -> IO (Vector a) Source
Read an entire file strictly into a Vector. This is far more efficient than reading the characters into a String and then using pack. It also may be more efficient than opening the file and reading it using hGet. Files are read using 'binary mode' on Windows.
 writeFile :: Storable a => FilePath -> Vector a -> IO () Source
Write a Vector to a file.
 appendFile :: Storable a => FilePath -> Vector a -> IO () Source
Append a Vector to a file.