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https://github.com/c-cube/ocaml-containers.git
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97 lines
3 KiB
OCaml
97 lines
3 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 Hash combinators} *)
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type t = int
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type state = int64
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type 'a hash_fun = 'a -> state -> state
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let _r = 47
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let _m = 0xc6a4a7935bd1e995L
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let init = _m (* TODO? *)
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(* combine key [k] with the current state [s] *)
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let _combine 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 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 apply f x = finish (f x init)
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(** {2 Combinators} *)
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let int_ i s = _combine s (Int64.of_int i)
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let bool_ x s = _combine s (if x then 1L else 2L)
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let char_ x s = _combine s (Int64.of_int (Char.code x))
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let int32_ x s = _combine s (Int64.of_int32 x)
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let int64_ x s = _combine s x
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let nativeint_ x s = _combine s (Int64.of_nativeint x)
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let string_ x s =
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let s = ref s in
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String.iter (fun c -> s := char_ c !s) x;
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!s
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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 if_ b then_ else_ h =
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if b then then_ h else else_ h
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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 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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