mirror of
https://github.com/c-cube/ocaml-containers.git
synced 2025-12-06 03:05:28 -05:00
simplify CCHash
- remove functor - use `Hashtbl.seeded_hash` to combine values
This commit is contained in:
Simon Cruanes
parent
2c00983262
commit
192f315f53
2 changed files with 55 additions and 202 deletions
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@ -9,135 +9,61 @@ type 'a sequence = ('a -> unit) -> unit
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type 'a gen = unit -> 'a option
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type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
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let _r = 47
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let _m = 0xc6a4a7935bd1e995L
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type state = int
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let init = _m
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type 'a hash_fun = 'a -> state -> state
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(* combine key [k] with the current state [s] *)
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let combine_murmur_ s k =
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let k = Int64.mul _m k in
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let k = Int64.logxor k (Int64.shift_right k _r) in
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let k = Int64.mul _m k in
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let s = Int64.logxor s k in
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let s = Int64.mul _m s in
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s
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let combine f x s = Hashtbl.seeded_hash s (f x)
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let finish s =
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let s = Int64.logxor s (Int64.shift_right s _r) in
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let s = Int64.mul s _m in
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let s = Int64.logxor s (Int64.shift_right s _r) in
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(Int64.to_int s) land max_int
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let combine2 a b = Hashtbl.seeded_hash a b
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let apply f x = finish (f x init)
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let init : state = 0
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let finish i = i
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let apply f x = f x init
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(** {2 Combinators} *)
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(** {2 Generic Hashing} *)
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let int i s = combine2 s (Int64.of_int i)
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let bool x s = combine2 s (if x then 1L else 2L)
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let char x s = combine2 s (Int64.of_int (Char.code x))
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let int32 x s = combine2 s (Int64.of_int32 x)
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let int64 x s = combine2 s x
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let nativeint x s = combine2 s (Int64.of_nativeint x)
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module type HASH = sig
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type state
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let slice x i len s =
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let j=i+len in
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let rec aux i s =
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if i=j then s else aux (i+1) (char x.[i] s)
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in
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aux i s
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val int : int -> state -> state
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val bool : bool -> state -> state
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val char : char -> state -> state
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val int32 : int32 -> state -> state
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val int64 : int64 -> state -> state
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val nativeint : nativeint -> state -> state
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val slice : string -> int -> int -> state -> state
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(** [slice s i len state] hashes the slice [[i, ... i+len)] of [s]
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into [state] *)
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end
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let rec list f l s = match l with
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| [] -> s
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| x::l' -> list f l' (f x s)
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module type S = sig
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include HASH
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let array f a s = Array.fold_right f a s
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type 'a hash_fun = 'a -> state -> state
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let opt f o h = match o with
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| None -> h
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| Some x -> f x h
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let pair h1 h2 (x,y) s = h2 y (h1 x s)
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let triple h1 h2 h3 (x,y,z) s = h3 z (h2 y (h1 x s))
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val string : string hash_fun
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let string x s = slice x 0 (String.length x) s
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val list : 'a hash_fun -> 'a list hash_fun
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let if_ b then_ else_ h =
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if b then then_ h else else_ h
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val array : 'a hash_fun -> 'a array hash_fun
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let seq f seq s =
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let s = ref s in
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seq (fun x -> s := f x !s);
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!s
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val opt : 'a hash_fun -> 'a option hash_fun
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val pair : 'a hash_fun -> 'b hash_fun -> ('a * 'b) hash_fun
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val triple : 'a hash_fun -> 'b hash_fun -> 'c hash_fun -> ('a * 'b * 'c) hash_fun
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let rec gen f g s = match g () with
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| None -> s
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| Some x -> gen f g (f x s)
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val if_ : bool -> 'a hash_fun -> 'a hash_fun -> 'a hash_fun
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(** Decide which hash function to use depending on the boolean *)
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(** {2 Iterators} *)
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val seq : 'a hash_fun -> 'a sequence hash_fun
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val gen : 'a hash_fun -> 'a gen hash_fun
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val klist : 'a hash_fun -> 'a klist hash_fun
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end
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module Base = struct
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type state = int64
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let int i s = combine_murmur_ s (Int64.of_int i)
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let bool x s = combine_murmur_ s (if x then 1L else 2L)
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let char x s = combine_murmur_ s (Int64.of_int (Char.code x))
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let int32 x s = combine_murmur_ s (Int64.of_int32 x)
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let int64 x s = combine_murmur_ s x
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let nativeint x s = combine_murmur_ s (Int64.of_nativeint x)
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let slice x i len s =
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let j=i+len in
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let rec aux i s =
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if i=j then s else aux (i+1) (char x.[i] s)
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in
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aux i s
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end
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module Make(H : HASH) : S with type state = H.state = struct
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include H
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type 'a hash_fun = 'a -> state -> state
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let rec list f l s = match l with
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| [] -> s
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| x::l' -> list f l' (f x s)
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let array f a s = Array.fold_right f a s
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let opt f o h = match o with
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| None -> h
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| Some x -> f x h
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let pair h1 h2 (x,y) s = h2 y (h1 x s)
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let triple h1 h2 h3 (x,y,z) s = h3 z (h2 y (h1 x s))
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let string x s = slice x 0 (String.length x) s
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let if_ b then_ else_ h =
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if b then then_ h else else_ h
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let seq f seq s =
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let s = ref s in
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seq (fun x -> s := f x !s);
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!s
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let rec gen f g s = match g () with
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| None -> s
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| Some x -> gen f g (f x s)
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let rec klist f l s = match l () with
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| `Nil -> s
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| `Cons (x,l') -> klist f l' (f x s)
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end
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include Make(Base)
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(* deprecated aliases *)
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let int_ = int
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let bool_ = bool
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let char_ = char
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let int32_ = int32
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let int64_ = int64
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let nativeint_ = nativeint
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let string_ = string
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let list_ = list
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let array_ = array
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let rec klist f l s = match l () with
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| `Nil -> s
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| `Cons (x,l') -> klist f l' (f x s)
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@ -9,15 +9,11 @@ type t = int
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(** A hash value is a positive integer *)
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type state
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(** State required by the hash function.
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@since 0.16 the state is abstract, for more flexibility *)
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type 'a hash_fun = 'a -> state -> state
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(** Hash function for values of type ['a], merging a fingerprint of the
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value into the state of type [t] *)
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(** {2 Applying Hash} *)
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val init : state
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(** Initial value *)
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@ -28,41 +24,23 @@ val apply : 'a hash_fun -> 'a -> int
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(** Apply a hash function to a value.
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[apply f x] is the same as [finish (f x init)] *)
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(** {2 Basic Combinators}
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val int : int hash_fun
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val bool : bool hash_fun
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val char : char hash_fun
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val int32 : int32 hash_fun
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val int64 : int64 hash_fun
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val nativeint : nativeint hash_fun
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val slice : string -> int -> int hash_fun
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(** [slice s i len state] hashes the slice [i, ... i+len-1] of [s]
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into [state] *)
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Those combinators have been renamed in 0.13, so as to
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remove the trailing "_".
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They are now defined by the application of {!Make}
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val combine : ('a -> int) -> 'a hash_fun
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*)
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val string : string hash_fun
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val bool_ : bool hash_fun
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(** @deprecated use {!bool} *)
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val list : 'a hash_fun -> 'a list hash_fun
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val char_ : char hash_fun
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(** @deprecated use {!char} *)
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val int_ : int hash_fun
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(** @deprecated use {!int} *)
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val string_ : string hash_fun
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(** @deprecated use {!string} *)
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val int32_ : int32 hash_fun
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(** @deprecated use {!int32} *)
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val int64_ : int64 hash_fun
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(** @deprecated use {!int64} *)
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val nativeint_ : nativeint hash_fun
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(** @deprecated use {!nativeint} *)
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val list_ : 'a hash_fun -> 'a list hash_fun
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(** Hash a list. Each element is hashed using [f].
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@deprecated use {!list} *)
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val array_ : 'a hash_fun -> 'a array hash_fun
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(** @deprecated use {!array} *)
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val array : 'a hash_fun -> 'a array hash_fun
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val opt : 'a hash_fun -> 'a option hash_fun
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val pair : 'a hash_fun -> 'b hash_fun -> ('a * 'b) hash_fun
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@ -80,54 +58,3 @@ type 'a klist = unit -> [`Nil | `Cons of 'a * 'a klist]
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val seq : 'a hash_fun -> 'a sequence hash_fun
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val gen : 'a hash_fun -> 'a gen hash_fun
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val klist : 'a hash_fun -> 'a klist hash_fun
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(** {2 Generic Hashing}
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Parametrize over the state, and some primitives to hash basic types.
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This can for instance be used for cryptographic hashing or
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checksums such as MD5.
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@since 0.13 *)
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module type HASH = sig
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type state
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val int : int -> state -> state
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val bool : bool -> state -> state
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val char : char -> state -> state
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val int32 : int32 -> state -> state
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val int64 : int64 -> state -> state
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val nativeint : nativeint -> state -> state
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val slice : string -> int -> int -> state -> state
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(** [slice s i len state] hashes the slice [i, ... i+len-1] of [s]
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into [state] *)
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end
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module type S = sig
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include HASH
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type 'a hash_fun = 'a -> state -> state
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val string : string hash_fun
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val list : 'a hash_fun -> 'a list hash_fun
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val array : 'a hash_fun -> 'a array hash_fun
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val opt : 'a hash_fun -> 'a option hash_fun
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val pair : 'a hash_fun -> 'b hash_fun -> ('a * 'b) hash_fun
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val triple : 'a hash_fun -> 'b hash_fun -> 'c hash_fun -> ('a * 'b * 'c) hash_fun
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val if_ : bool -> 'a hash_fun -> 'a hash_fun -> 'a hash_fun
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(** Decide which hash function to use depending on the boolean *)
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(** {2 Iterators} *)
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val seq : 'a hash_fun -> 'a sequence hash_fun
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val gen : 'a hash_fun -> 'a gen hash_fun
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val klist : 'a hash_fun -> 'a klist hash_fun
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end
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module Make(H : HASH) : S with type state = H.state
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include S with type state := state and type 'a hash_fun := 'a hash_fun
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