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(*                                                                     *)
(*                           Objective Caml                            *)
(*                                                                     *)
(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
(*                                                                     *)
(*  Copyright 1996 Institut National de Recherche en Informatique et   *)
(*  en Automatique.  All rights reserved.  This file is distributed    *)
(*  under the terms of the GNU Library General Public License.         *)
(*                                                                     *)
(***********************************************************************)

(* $Id$ *)

(** Array operations. *)

external length : 'a array -> int = "%array_length"
(** Return the length (number of elements) of the given array. *)

external get : 'a array -> int -> 'a = "%array_safe_get"
(** [Array.get a n] returns the element number [n] of array [a].
   The first element has number 0.
   The last element has number [Array.length a - 1].

   Raise [Invalid_argument "Array.get"]  if [n] is outside the range
   0 to [(Array.length a - 1)].
   You can also write [a.(n)] instead of [Array.get a n]. *)

external set : 'a array -> int -> 'a -> unit = "%array_safe_set"
(** [Array.set a n x] modifies array [a] in place, replacing
   element number [n] with [x].

   Raise [Invalid_argument "Array.set"] if [n] is outside the range
   0 to [Array.length a - 1].
   You can also write [a.(n) <- x] instead of [Array.set a n x]. *)
        
external make : int -> 'a -> 'a array = "make_vect"
(** [Array.make n x] returns a fresh array of length [n],
   initialized with [x].
   All the elements of this new array are initially
   physically equal to [x] (in the sense of the [==] predicate).
   Consequently, if [x] is mutable, it is shared among all elements
   of the array, and modifying [x] through one of the array entries
   will modify all other entries at the same time.

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

external create : int -> 'a -> 'a array = "make_vect"
(** @deprecated [Array.create] is an alias for {!Array.make}. *)

val init : int -> (int -> 'a) -> 'a array
(** [Array.init n f] returns a fresh array of length [n],
   with element number [i] initialized to the result of [f i].
   In other terms, [Array.init n f] tabulates the results of [f]
   applied to the integers [0] to [n-1]. *)

val make_matrix : int -> int -> 'a -> 'a array array
(** [Array.make_matrix dimx dimy e] returns a two-dimensional array
   (an array of arrays) with first dimension [dimx] and
   second dimension [dimy]. All the elements of this new matrix
   are initially physically equal to [e].
   The element ([x,y]) of a matrix [m] is accessed
   with the notation [m.(x).(y)].

   Raise [Invalid_argument] if [dimx] or [dimy] is less than 1 or
   greater than [Sys.max_array_length].
   If the value of [e] is a floating-point number, then the maximum
   size is only [Sys.max_array_length / 2]. *)

val create_matrix : int -> int -> 'a -> 'a array array
(** @deprecated [Array.create_matrix] is an alias for {!Array.make_matrix}. *)

val append : 'a array -> 'a array -> 'a array
(** [Array.append v1 v2] returns a fresh array containing the
   concatenation of the arrays [v1] and [v2]. *)

val concat : 'a array list -> 'a array
(** Same as [Array.append], but catenates a list of arrays. *)

val sub : 'a array -> int -> int -> 'a array
(** [Array.sub a start len] returns a fresh array of length [len],
   containing the elements number [start] to [start + len - 1]
   of array [a].

   Raise [Invalid_argument "Array.sub"] if [start] and [len] do not
   designate a valid subarray of [a]; that is, if
   [start < 0], or [len < 0], or [start + len > Array.length a]. *)

val copy : 'a array -> 'a array
(** [Array.copy a] returns a copy of [a], that is, a fresh array
   containing the same elements as [a]. *)

val fill : 'a array -> int -> int -> 'a -> unit
(** [Array.fill a ofs len x] modifies the array [a] in place,
   storing [x] in elements number [ofs] to [ofs + len - 1].

   Raise [Invalid_argument "Array.fill"] if [ofs] and [len] do not
   designate a valid subarray of [a]. *)

val blit : 'a array -> int -> 'a array -> int -> int -> unit
(** [Array.blit v1 o1 v2 o2 len] copies [len] elements
   from array [v1], starting at element number [o1], to array [v2],
   starting at element number [o2]. It works correctly even if
   [v1] and [v2] are the same array, and the source and
   destination chunks overlap.

   Raise [Invalid_argument "Array.blit"] if [o1] and [len] do not
   designate a valid subarray of [v1], or if [o2] and [len] do not
   designate a valid subarray of [v2]. *)

val to_list : 'a array -> 'a list
(** [Array.to_list a] returns the list of all the elements of [a]. *)

val of_list : 'a list -> 'a array
(** [Array.of_list l] returns a fresh array containing the elements
   of [l]. *)

val iter : ('a -> unit) -> 'a array -> unit
(** [Array.iter f a] applies function [f] in turn to all
   the elements of [a].  It is equivalent to
   [f a.(0); f a.(1); ...; f a.(Array.length a - 1); ()]. *)

val map : ('a -> 'b) -> 'a array -> 'b array
(** [Array.map f a] applies function [f] to all the elements of [a],
   and builds an array with the results returned by [f]:
   [[| f a.(0); f a.(1); ...; f a.(Array.length a - 1) |]]. *)

val iteri : (int -> 'a -> unit) -> 'a array -> unit
(** Same as {!Array.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 array -> 'b array
(** Same as {!Array.map}, but the
   function is applied to the index of the element as first argument,
   and the element itself as second argument. *)

val fold_left : ('a -> 'b -> 'a) -> 'a -> 'b array -> 'a
(** [Array.fold_left f x a] computes
   [f (... (f (f x a.(0)) a.(1)) ...) a.(n-1)],
   where [n] is the length of the array [a]. *)

val fold_right : ('b -> 'a -> 'a) -> 'b array -> 'a -> 'a
(** [Array.fold_right f a x] computes
   [f a.(0) (f a.(1) ( ... (f a.(n-1) x) ...))],
   where [n] is the length of the array [a]. *)


(** {2 Sorting} *)


val sort : ('a -> 'a -> int) -> 'a array -> unit
(** Sort an array in increasing order according to a comparison
   function.  The comparison function must return 0 if its arguments
   compare as equal, a positive integer if the first is greater,
   and a negative integer if the first is smaller.  For example,
   the {!Pervasives.compare} function is a suitable comparison function.
   After calling [Array.sort], the array is sorted in place in
   increasing order.
   [Array.sort] is guaranteed to run in constant heap space
   and logarithmic stack space.

   The current implementation uses Heap Sort.  It runs in constant
   stack space.
*)

val stable_sort : ('a -> 'a -> int) -> 'a array -> unit
(** Same as {!Array.sort}, but the sorting algorithm is stable and
   not guaranteed to use a fixed amount of heap memory.
   The current implementation is Merge Sort. It uses [n/2]
   words of heap space, where [n] is the length of the array.
   It is faster than the current implementation of {!Array.sort}.
*)

(**/**)
(** {2 Undocumented functions} *)

external unsafe_get : 'a array -> int -> 'a = "%array_unsafe_get"
external unsafe_set : 'a array -> int -> 'a -> unit = "%array_unsafe_set"