46 lines
1.7 KiB
OCaml
46 lines
1.7 KiB
OCaml
(**************************************************************************)
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(* *)
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(* Copyright (c) 2014 - 2017. *)
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(* Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
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(* *)
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(* All rights reserved. No warranty, explicit or implicit, provided. *)
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(* *)
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(**************************************************************************)
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(** Imperative Ring Buffer *)
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(** An imperative ring buffer: a mutable structure that holds at most
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a fixed number of values of a same type. Values are never removed,
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once the limit is reached, adding a value replaces the oldest one
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in the ring buffer. *)
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type 'a t
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(** Allocates a ring buffer for a given number of values. *)
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val create : int -> 'a t
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(** Adds a value, dropping the oldest present one if full. *)
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val add : 'a t -> 'a -> unit
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(** Same as {!add}, but returns the dropped value if any. *)
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val add_and_return_erased : 'a t -> 'a -> 'a option
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(** Adds the values of a list, in order. *)
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val add_list : 'a t -> 'a list -> unit
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(** Removes all values in the ring buffer. *)
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val clear : 'a t -> unit
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(** Retrieves the most recent value, or [None] when empty. *)
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val last : 'a t -> 'a option
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exception Empty
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(** Same as {!last}, but raises {!Empty} when empty. *)
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val last_exn : 'a t -> 'a
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(** Iterates over the elements, oldest to newest. *)
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val fold : 'a t -> init:'b -> f:('b -> 'a -> 'b) -> 'b
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(** Retrieves the elements as a list, oldest first.. *)
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val elements : 'a t -> 'a list
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