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107 lines
3.5 KiB
OCaml
107 lines
3.5 KiB
OCaml
(*
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Copyright (c) 2013, Simon Cruanes
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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Redistributions of source code must retain the above copyright notice, this
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list of conditions and the following disclaimer. Redistributions in binary
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form must reproduce the above copyright notice, this list of conditions and the
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following disclaimer in the documentation and/or other materials provided with
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the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*)
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(** {1 Memoization caches} *)
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(** {2 Signatures} *)
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module type EQ = sig
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type t
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val equal : t -> t -> bool
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end
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module type HASH = sig
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include EQ
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val hash : t -> int
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end
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(** Signature of a cache for values *)
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module type S = sig
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type 'a t
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type key
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val create : int -> 'a t
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(** Create a new cache of the given size. *)
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val clear : 'a t -> unit
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(** Clear content of the cache *)
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val with_cache : 'a t -> (key -> 'a) -> key -> 'a
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(** Wrap the function with the cache. This means that
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[with_cache cache f x] always returns the same value as
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[f x], if [f x] returns, or raise the same exception.
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However, [f] may not be called if [x] is in the cache. *)
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val with_cache_rec : 'a t -> ((key -> 'a) -> key -> 'a) -> key -> 'a
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(** Partially apply the given function with a cached version of itself.
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It returns the specialized function.
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[with_cache_rec cache f] applies [f] to a cached version of [f],
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called [f'], so that [f' x = f f' x]. *)
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end
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(** Signature of a cache for pairs of values *)
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module type S2 = sig
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type 'a t
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type key1
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type key2
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val create : int -> 'a t
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(** Create a new cache of the given size. *)
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val clear : 'a t -> unit
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(** Clear content of the cache *)
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val with_cache : 'a t -> (key1 -> key2 -> 'a) -> key1 -> key2 -> 'a
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(** Wrap the function with the cache *)
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end
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(** {2 Dummy cache (no caching)} *)
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module Dummy(X : sig type t end) : S with type key = X.t
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module Dummy2(X : sig type t end)(Y : sig type t end) : S2 with type key1 = X.t and type key2 = Y.t
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(** {2 Small linear cache} *)
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(** This cache stores (key,value) pairs in an array, that is traversed
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linearily. It is therefore only reasonable for small sizes (like 5). *)
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module Linear(X : EQ) : S with type key = X.t
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module Linear2(X : EQ)(Y : EQ) : S2 with type key1 = X.t and type key2 = Y.t
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(** {2 Hashtables that resolve collisions by replacing} *)
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module Replacing(X : HASH) : S with type key = X.t
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module Replacing2(X : HASH)(Y : HASH) : S2 with type key1 = X.t and type key2 = Y.t
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(** {2 Hashtables with Least Recently Used eviction policy} *)
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module LRU(X : HASH) : S with type key = X.t
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(* TODO exception handling in LRU *)
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(* TODO LRU2 *)
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