package vector

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package vector
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Vectors (aka resizable arrays, growing arrays, dynamic arrays, etc.)

This module implements arrays that automatically expand as necessary. Its implementation uses a traditional array and replaces it with a larger array when needed (and elements are copied from the old array to the new one). The current implementation doubles the capacity when growing the array (and shrinks it whenever the number of elements comes to one fourth of the capacity).

The unused part of the internal array is filled with a dummy value, which is user-provided at creation time (and referred to below as ``the dummy value''). Consequently, vectors do not retain pointers to values that are not used anymore after a shrinking.

Vectors provide an efficient implementation of stacks, with a better locality of reference than list-based implementations (such as standard library Stack). A stack interface is provided, similar to that of Stack (though Vector.push have arguments in the other way round). Inserting n elements with Vector.push has overall complexity O(n) i.e. each insertion has amortized constant time complexity.

type 'a t

The polymorphic type of vectors. This is a mutable data type.

Operations proper to vectors, or with a different type and/or semantics than those of module Array

val make : int -> dummy:'a -> 'a t

Vector.make n dummy returns a fresh vector of length n. All the elements of this new vector are initially physically equal to dummy (in the sense of the == predicate).

Raise Invalid_argument if n < 0 or n > Sys.max_array_length. If the value of dummy is a floating-point number, then the maximum size is only Sys.max_array_length / 2.

val create : dummy:'a -> 'a t

Vector.create dummy returns a fresh vector of length 0.

val init : int -> dummy:'a -> (int -> 'a) -> 'a t

Vector.init n f returns a fresh vector of length n, with element number i initialized to the result of f i. In other terms, Vector.init n f tabulates the results of f applied to the integers 0 to n-1.

Raise Invalid_argument if n < 0 or n > Sys.max_array_length. If the return type of f is float, then the maximum size is only Sys.max_array_length / 2.

val resize : 'a t -> int -> unit

Vector.resize a n sets the length of vector a to n.

The elements that are no longer part of the vector, if any, are internally replaced by the dummy value of vector a, so that they can be garbage collected when possible.

Raise Invalid_argument if n < 0 or n > Sys.max_array_length.

Stack interface

Contrary to standard library's Stack, module Vector uses less space (between N and 2N words, instead of 3N) and has better data locality.

val push : 'a t -> 'a -> unit

Vector.push a x appends x at the end of vector a, i.e., increases the size of a by one and stores x at the rightmost position.

Note: the order of the arguments is not that of Stack.push.

exception Empty

Raised when Vector.pop or Vector.top is applied to an empty vector.

val pop : 'a t -> 'a

Vector.pop a removes and returns the rightmost element in vector a, or raises Empty if the stack is empty.

val top : 'a t -> 'a

Vector.top a returns the rightmost element in vector a, or raises Empty if the vector is empty.

val clear : 'a t -> unit

Discard all elements from a vector. This is equivalent to setting the size to 0 with resize.

val is_empty : 'a t -> bool

Return true if the given vector is empty, false otherwise.

Array interface

val length : 'a t -> int

Return the length (number of elements) of the given vector. Note: the number of memory words occupiedby the vector can be larger.

val get : 'a t -> int -> 'a

Vector.get a n returns the element number n of vector a. The first element has number 0. The last element has number Vector.length a - 1.

Raise Invalid_argument "Vector.get" if n is outside the range 0 to Vector.length a - 1.

val set : 'a t -> int -> 'a -> unit

Vector.set a n x modifies vector a in place, replacing element number n with x.

Raise Invalid_argument "Vector.set" if n is outside the range 0 to Vector.length a - 1.

val append : 'a t -> 'a t -> unit

Vector.append a1 a2 appends the elements of vector a2 to the end of vector a1. It works correctly even if a1 and a2 are the same vector.

val sub : 'a t -> int -> int -> 'a t

Vector.sub a start len returns a fresh vector of length len, containing the elements number start to start + len - 1 of vector a.

val copy : 'a t -> 'a t

Vector.copy a returns a copy of a, that is, a fresh vector containing the same elements as a.

val fill : 'a t -> int -> int -> 'a -> unit

Vector.fill a ofs len x modifies the vector a in place, storing x in elements number ofs to ofs + len - 1.

Raise Invalid_argument "Vector.fill" if ofs and len do not designate a valid subvector of a.

val blit : 'a t -> int -> 'a t -> int -> int -> unit

Vector.blit v1 o1 v2 o2 len copies len elements from vector v1, starting at element number o1, to vector v2, starting at element number o2. It works correctly even if v1 and v2 are the same vector, and the source and destination chunks overlap.

Raise Invalid_argument "Vector.blit" if o1 and len do not designate a valid subvector of v1, or if o2 and len do not designate a valid subvector of v2.

val to_list : 'a t -> 'a list

Vector.to_list a returns the list of all the elements of a.

val of_list : dummy:'a -> 'a list -> 'a t

Vector.of_list dummy l returns a fresh vector containing the elements of l.

val to_array : 'a t -> 'a array

Vector.to_array a returns the array of all the elements of a.

val of_array : dummy:'a -> 'a array -> 'a t

Vector.of_array dummy a returns a fresh vector containing the elements of a.

val iter : ('a -> unit) -> 'a t -> unit

Vector.iter f a applies function f in turn to all the elements of a. It is equivalent to f (get a 0); f (get a 1); ...; f (get a (Vector.length a - 1)).

val map : ('a -> 'b) -> 'a t -> 'b t

Vector.map f a applies function f to all the elements of a, and builds a fresh vector with the results returned by f.

Note: the dummy value of the returned vector is obtained by applying f to the dummy value of a. If this is not what you want, first create a new vector and then fill it with the value f (get a 0), f (get a 1), etc.

val iteri : (int -> 'a -> unit) -> 'a t -> unit

Same as Vector.iter, but the function is applied to the index of the element as first argument, and the element itself as second argument.

val mapi : (int -> 'a -> 'b) -> 'a t -> 'b t

Same as Vector.map, but the function is applied to the index of the element as first argument, and the element itself as second argument.

Note: the dummy value of the returned vector is obtained by applying f 0 to the dummy value of a.

val fold_left : ('a -> 'b -> 'a) -> 'a -> 'b t -> 'a

Vector.fold_left f x a computes f (... (f (f x (get a 0)) (get a 1)) ...) (get a (n-1)), where n is the length of the vector a.

val fold_right : ('b -> 'a -> 'a) -> 'b t -> 'a -> 'a

Vector.fold_right f a x computes f (get a 0) (f (get a 1) ( ... (f (get a (n-1)) x) ...)), where n is the length of the vector a.

Only if you know what you are doing...

val unsafe_get : 'a t -> int -> 'a
val unsafe_set : 'a t -> int -> 'a -> unit