Module `B0_std.Hash`

Hash values and functions.

The property we want from these functions is speed and collision resistance. Build correctness depends on the latter.

Hash values

type t: The type for hash values. All hash functions use this representation. It is not possible to distinguish them, except for their length which might vary, or not.

val nil : t: nil is the only hash value of length 0.

val length : t -> int: length h is the length of h in bytes.

Predicate and comparisons

val is_nil : t -> bool: is_nil h is true iff h is nil.

val equal : t -> t -> bool: equal h0 h1 is true iff h0 and h1 are equal.

val compare : t -> t -> int: compare h0 h1 is a total order on hashes compatible with equal.

Converting

val to_bytes : t -> string: to_bytes h is the sequence of bytes of h.

val of_bytes : string -> t: of_bytes s is the sequences of bytes of s as a hash value.

val to_hex : t -> string: to_hex h is String.Ascii.to_hex (to_bytes h).

val of_hex : string -> (t, int) Stdlib.result: of_hex s is Result.map of_bytes (String.Ascii.of_hex s).

val conv : t Conv.t: conv converts using Conv.string_bytes.

val pp : t Fmt.t: pp formats using to_hex or, if the hash is nil, formats "nil".

Hash functions

module type T = sig ... end: The type for hash functions.

module Murmur3_128 : T: Murmur3_128 is the MurmurHash3 128-bit hash.

module Xxh_64 : T: Xxh_64 is the xxHash 64-bit hash.

val funs : unit -> (module T) list: funs () is the list of available hash functions.

val add_fun : (module T) -> unit: add_fun m adds m to the list returned by funs.