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158 lines
4.8 KiB
OCaml
158 lines
4.8 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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Combination of hashes based on the Murmur Hash (64 bits). See
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{{: https://sites.google.com/site/murmurhash/MurmurHash2_64.cpp?attredirects=0} this page}
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*)
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(** {2 Definitions} *)
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type t = int
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(** A hash value is a positive integer *)
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type state = int64
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(** State required by the hash function *)
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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 Murmur Hash} *)
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val init : state
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(** Initial value *)
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val finish : state -> int
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(** Extract a usable hash value *)
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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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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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*)
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val bool_ : bool hash_fun
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(** @deprecated use {!bool} *)
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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 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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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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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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