mirror of
https://github.com/c-cube/ocaml-containers.git
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448 lines
12 KiB
OCaml
448 lines
12 KiB
OCaml
(*
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* CCRingBuffer - Polymorphic circular buffer with
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* deque semantics for accessing both the head and tail.
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*
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* Copyright (C) 2014 Simon Cruanes
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version,
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* with the special exception on linking described in file LICENSE.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*)
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(** Polymorphic Circular Buffer for IO *)
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module Array = struct
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module type S = sig
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type elt
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type t
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val empty : t
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val make: int -> elt -> t
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val length: t -> int
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val get: t -> int -> elt
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val set: t -> int -> elt -> unit
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val sub: t -> int -> int -> t
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val copy : t -> t
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val blit : t -> int -> t -> int -> int -> unit
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val iter : (elt -> unit) -> t -> unit
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end
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module ByteArray :
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S with type elt = char and type t = bytes = struct
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type elt = char
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include Bytes
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end
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module FloatArray :
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S with type elt = float and type t = float array = struct
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type t = float array
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type elt = float
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let make = Array.make
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let length = Array.length
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let get = Array.get
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let set = Array.set
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let copy = Array.copy
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let blit = Array.blit
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let iter = Array.iter
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let sub = Array.sub
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let empty = Array.of_list []
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end
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module IntArray :
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S with type elt = int and type t = int array = struct
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type t = int array
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type elt = int
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let make = Array.make
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let length = Array.length
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let get = Array.get
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let set = Array.set
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let copy = Array.copy
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let blit = Array.blit
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let iter = Array.iter
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let sub = Array.sub
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let empty = Array.of_list []
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end
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module BoolArray :
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S with type elt = bool and type t = bool array = struct
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type t = bool array
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type elt = bool
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let make = Array.make
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let length = Array.length
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let get = Array.get
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let set = Array.set
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let copy = Array.copy
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let blit = Array.blit
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let iter = Array.iter
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let sub = Array.sub
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let empty = Array.of_list []
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end
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module Make(Elt:sig type t end) :
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S with type elt = Elt.t and type t = Elt.t array = struct
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type elt = Elt.t
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type t = Elt.t array
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let make = Array.make
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let length = Array.length
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let get = Array.get
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let set = Array.set
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let copy = Array.copy
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let blit = Array.blit
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let iter = Array.iter
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let sub = Array.sub
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let empty = Array.of_list []
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end
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end
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module type S =
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sig
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module Array : Array.S
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type t = private {
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mutable start : int;
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mutable stop : int; (* excluded *)
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mutable buf : Array.t;
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bounded: bool;
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size : int
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}
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exception Empty
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val create : ?bounded:bool -> int -> t
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(** [create ?bounded size] creates a new buffer with given size.
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Defaults to [bounded=false]. *)
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val copy : t -> t
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(** fresh copy of the buffer *)
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val capacity : t -> int
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(** length of the inner buffer *)
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val max_capacity : t -> int option
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(** maximum length of the inner buffer, or [None] if unbounded. *)
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val length : t -> int
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(** number of elements currently stored in the buffer *)
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val blit_from : t -> Array.t -> int -> int -> unit
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(** [blit_from buf from_buf o len] copies the slice [o, ... o + len - 1] from
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a input buffer [from_buf] to the end of the buffer.
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@raise Invalid_argument if [o,len] is not a valid slice of [s] *)
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val blit_into : t -> Array.t -> int -> int -> int
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(** [blit_into buf to_buf o len] copies at most [len] elements from [buf]
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into [to_buf] starting at offset [o] in [s].
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@return the number of elements actually copied ([min len (length buf)]).
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@raise Invalid_argument if [o,len] is not a valid slice of [s] *)
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val to_list : t -> Array.elt list
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(** extract the current content into a list *)
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val clear : t -> unit
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(** clear the content of the buffer. Doesn't actually destroy the content. *)
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val reset : t -> unit
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(** clear the content of the buffer, and also resize it to a default size *)
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val is_empty :t -> bool
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(** is the buffer empty (i.e. contains no elements)? *)
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val next : t -> Array.elt
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(** obtain next element (the first one of the buffer)
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@raise Empty if the buffer is empty *)
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val junk : t -> unit
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(** Drop next element.
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@raise Empty if the buffer is already empty *)
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val skip : t -> int -> unit
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(** [skip b len] removes [len] elements from [b].
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@raise Invalid_argument if [len > length b]. *)
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val iteri : t -> (int -> Array.elt -> unit) -> unit
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(** [iteri b f] calls [f i t] for each element [t] in [buf], with [i]
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being its relative index within [buf]. *)
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val get : t -> int -> Array.elt
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(** [get buf i] returns the [i]-th element of [buf], ie the one that
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is returned by [next buf] after [i-1] calls to [junk buf].
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@raise Invalid_argument if the index is invalid (> [length buf]) *)
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val push_back : t -> Array.elt -> unit
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(** Push value at the back *)
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val peek_front : t -> Array.elt
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(** First value, or Empty *)
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val peek_back : t -> Array.elt
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(** Last value, or Empty *)
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val take_back : t -> Array.elt
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(** Take last value, or raise Empty *)
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val take_front : t -> Array.elt
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(** Take first value, or raise Empty *)
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end
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module Make_array(Array:Array.S) =
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struct
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module Array = Array
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type t = {
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mutable start : int;
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mutable stop : int; (* excluded *)
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mutable buf : Array.t;
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bounded : bool;
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size : int
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}
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exception Empty
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let create ?(bounded=false) size =
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{ start=0;
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stop=0;
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bounded;
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size;
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buf = Array.empty
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}
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let copy b =
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{ b with buf=Array.copy b.buf; }
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let capacity b = Array.length b.buf
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let max_capacity b = if b.bounded then Some b.size else None
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let length b =
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if b.stop >= b.start
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then b.stop - b.start
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else (Array.length b.buf - b.start) + b.stop
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(* resize [b] so that inner capacity is [cap] *)
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let resize b cap elem =
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assert (cap >= Array.length b.buf);
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let buf' = Array.make cap elem in
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(* copy into buf' *)
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let _:int =
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if b.stop >= b.start
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then begin
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Array.blit b.buf b.start buf' 0 (b.stop - b.start);
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b.stop - b.start
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end else begin
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let len_end = Array.length b.buf - b.start in
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Array.blit b.buf b.start buf' 0 len_end;
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Array.blit b.buf 0 buf' len_end b.stop;
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len_end + b.stop
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end
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in
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b.buf <- buf'
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let blit_from_bounded b from_buf o len =
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let cap = capacity b - len in
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(* resize if needed, with a constant to amortize *)
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if cap < len then begin
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let new_size =
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let desired = Array.length b.buf + len + 24 in
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min (b.size+1) desired in
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resize b new_size from_buf.(0)
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end;
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let sub = Array.sub from_buf o len in
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let iter x =
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let capacity = capacity b in
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Array.set b.buf b.stop x;
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if b.stop = capacity-1 then b.stop <- 0 else b.stop <- b.stop + 1;
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if b.start = b.stop then
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begin
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if b.start = capacity-1 then b.start <- 0 else b.start <- b.start + 1
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end
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in
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Array.iter iter sub
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let blit_from_unbounded b from_buf o len =
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let cap = capacity b - len in
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(* resize if needed, with a constant to amortize *)
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if cap < len then resize b (max b.size (Array.length b.buf + len + 24)) from_buf.(0);
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assert (capacity b - length b >= len);
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if b.stop >= b.start
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then (* [_______ start xxxxxxxxx stop ______] *)
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let len_end = Array.length b.buf - b.stop in
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if len_end >= len
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then (Array.blit from_buf o b.buf b.stop len;
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b.stop <- b.stop + len)
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else (Array.blit from_buf o b.buf b.stop len_end;
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Array.blit from_buf (o+len_end) b.buf 0 (len-len_end);
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b.stop <- len-len_end)
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else begin (* [xxxxx stop ____________ start xxxxxx] *)
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let len_middle = b.start - b.stop in
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assert (len_middle >= len);
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Array.blit from_buf o b.buf b.stop len;
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b.stop <- b.stop + len
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end;
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()
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let blit_from b from_buf o len =
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if (Array.length from_buf) = 0 then () else
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if b.bounded then
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blit_from_bounded b from_buf o len
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else
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blit_from_unbounded b from_buf o len
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let blit_into b to_buf o len =
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if o+len > Array.length to_buf
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then raise (Invalid_argument "BufferIO.blit_into");
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if b.stop >= b.start
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then
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let n = min (b.stop - b.start) len in
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let _ = Array.blit b.buf b.start to_buf o n in
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n
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else begin
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let len_end = Array.length b.buf - b.start in
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Array.blit b.buf b.start to_buf o (min len_end len);
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if len_end >= len
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then len (* done *)
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else begin
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let n = min b.stop (len - len_end) in
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Array.blit b.buf 0 to_buf (o+len_end) n;
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n + len_end
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end
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end
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let add b s = blit_from b s 0 (Array.length s)
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(*$Q
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(Q.pair Q.printable_string Q.printable_string) (fun (s,s') -> \
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let b = create 24 in add b s; add_string b s'; \
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Array.length s + String.length s' = length b)
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*)
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let clear b =
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b.stop <- 0;
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b.start <- 0;
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()
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let reset b =
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clear b;
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b.buf <- Array.empty
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let is_empty b = b.start = b.stop
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let next b =
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if b.start = b.stop then raise Empty;
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b.buf.(b.start)
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let take_front b =
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if b.start = b.stop then raise Empty;
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let c = b.buf.(b.start) in
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if b.start + 1 = Array.length b.buf
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then b.start <- 0
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else b.start <- b.start + 1;
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c
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let take_back b =
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if b.start = b.stop then raise Empty;
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if b.stop - 1 = 0
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then b.stop <- Array.length b.buf - 1
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else b.stop <- b.stop - 1;
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b.buf.(b.stop)
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let junk b =
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if b.start = b.stop then raise Empty;
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if b.start + 1 = Array.length b.buf
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then b.start <- 0
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else b.start <- b.start + 1
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let skip b len =
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if len > length b then raise (Invalid_argument "BufferIO.skip");
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if b.stop >= b.start
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then b.start <- b.start + len
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else
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let len_end = Array.length b.buf - b.start in
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if len > len_end
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then b.start <- len-len_end (* wrap to the beginning *)
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else b.start <- b.start + len
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(*$Q
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(Q.pair Q.printable_string Q.printable_string) (fun (s,s') -> \
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let b = create 24 in add_string b s; add_string b s'; \
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add_string b "hello world"; (* big enough *) \
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let l = length b in let l' = l/2 in skip b l'; \
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length b + l' = l)
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*)
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let iteri b f =
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if b.stop >= b.start
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then for i = b.start to b.stop - 1 do f i b.buf.(i) done
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else (
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for i = b.start to Array.length b.buf -1 do f i b.buf.(i) done;
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for i = 0 to b.stop - 1 do f i b.buf.(i) done;
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)
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(*$T
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let s = "hello world" in \
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let b = of_string s in \
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try iteri b (fun i c -> if s.[i] <> c then raise Exit); true with Exit -> false
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*)
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let get b i =
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if b.stop >= b.start
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then
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if i >= b.stop - b.start
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then raise (Invalid_argument "BufferIO.get")
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else b.buf.(b.start + i)
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else
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let len_end = Array.length b.buf - b.start in
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if i < len_end
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then b.buf.(b.start + i)
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else if i - len_end > b.stop
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then raise (Invalid_argument "BufferIO.get")
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else b.buf.(i - len_end)
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let to_list b =
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let len = length b in
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let rec build l i =
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if i < 0 then l else
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build ((get b i)::l) (i-1) in
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build [] (len-1)
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let push_back b e = add b (Array.make 1 e)
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let peek_front b = if is_empty b then
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raise Empty else Array.get b.buf b.start
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let peek_back b = if is_empty b then
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raise Empty else Array.get b.buf
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(if b.stop = 0 then capacity b - 1 else b.stop-1)
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end
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module Bytes = Make_array(Array.ByteArray)
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module Floats = Make_array(Array.FloatArray)
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module Ints = Make_array(Array.IntArray)
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module Bools = Make_array(Array.BoolArray)
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module Make(Elt:sig type t end) = Make_array(Array.Make(Elt))
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