package containers

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Module CCHashSource

Hash combinators

The API of this module is stable as per semantic versioning, like the rest of containers. However the exact implementation of hashing function can change and should not be relied on (i.e. hashing a value always returns the same integer within a run of a program, not across versions of OCaml and Containers).

Definitions

Sourcetype hash = int

A hash value is a positive integer.

Sourcetype 'a t = 'a -> hash

A hash function for values of type 'a.

Sourceval const : hash -> _ t

const h hashes any value into h. Use with caution!.

Sourceval const0 : _ t

Always return 0. Useful for ignoring elements. Example: Hash.(pair string const0) will map pairs ("a", 1) and ("a", 2) to the same hash, but not the same as ("b", 1).

  • since 1.5
Sourceval int : int t
Sourceval bool : bool t
Sourceval char : char t
Sourceval int32 : int32 t
Sourceval int64 : int64 t
Sourceval nativeint : nativeint t
Sourceval slice : string -> int -> int t

slice s i len state hashes the slice i, …, i+len-1 of s into state.

Sourceval bytes : bytes t

Hash a byte array.

  • since 3.5
Sourceval string : string t
Sourceval list : 'a t -> 'a list t
Sourceval array : 'a t -> 'a array t
Sourceval opt : 'a t -> 'a option t
Sourceval pair : 'a t -> 'b t -> ('a * 'b) t
Sourceval triple : 'a t -> 'b t -> 'c t -> ('a * 'b * 'c) t
Sourceval quad : 'a t -> 'b t -> 'c t -> 'd t -> ('a * 'b * 'c * 'd) t
Sourceval map : ('a -> 'b) -> 'b t -> 'a t

map f h is the hasher that takes x, and uses h to hash f x.

For example:

  module Str_set = Set.Make(String)

  let hash_str_set : Str_set.t CCHash.t = CCHash.(map Str_set.to_seq @@ seq string)
  • since 3.5
Sourceval if_ : bool -> 'a t -> 'a t -> 'a t

Decide which hash function to use depending on the boolean.

Sourceval poly : 'a t

poly x is Hashtbl.hash x. The regular polymorphic hash function.

Sourceval list_comm : 'a t -> 'a list t

Commutative version of list. Lists that are equal up to permutation will have the same hash.

  • since 1.0
Sourceval array_comm : 'a t -> 'a array t

Commutative version of array. Arrays that are equal up to permutation will have the same hash.

  • since 1.0

Base hash combinators

Sourceval combine : 'a t -> hash -> 'a -> hash
Sourceval combine2 : hash -> hash -> hash
Sourceval combine3 : hash -> hash -> hash -> hash
Sourceval combine4 : hash -> hash -> hash -> hash -> hash
Sourceval combine5 : hash -> hash -> hash -> hash -> hash -> hash
  • since 2.1
Sourceval combine6 : hash -> hash -> hash -> hash -> hash -> hash -> hash
  • since 2.1

Iterators

Sourcetype 'a iter = ('a -> unit) -> unit
Sourcetype 'a gen = unit -> 'a option
Sourceval seq : 'a t -> 'a Seq.t t
Sourceval iter : 'a t -> 'a iter t
Sourceval gen : 'a t -> 'a gen t
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