package core_kernel

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This module implements the MD5 message-digest algorithm as described IETF RFC 1321. t is the result type and val digest_string : string -> t is the implementation of the algorithm itself.

This is currently a thin wrapper over the Digest module in INRIA's standard library.

module Stable : sig ... end
module As_binary_string : sig ... end

Both bin_io and sexp serializations produce a binary 16-character string.

type t = Stable.V1.t

Intended to represent a 16-byte string that is the output of MD5 algorithm.

Note that any 16-byte string can be converted to this type, so a value of type t is not an evidence of someone having found an input corresponding to this output.

include Bin_prot.Binable.S with type t := t
include Ppx_sexp_conv_lib.Sexpable.S with type t := t
val t_of_sexp : Sexplib0.Sexp.t -> t
val sexp_of_t : t -> Sexplib0.Sexp.t
include Interfaces.Comparable with type t := t
include Base.Comparable.S with type t := t
val (>=) : t -> t -> bool
val (<=) : t -> t -> bool
val (=) : t -> t -> bool
val (>) : t -> t -> bool
val (<) : t -> t -> bool
val (<>) : t -> t -> bool
val equal : t -> t -> bool
val min : t -> t -> t
val max : t -> t -> t
val ascending : t -> t -> int
val descending : t -> t -> int
val between : t -> low:t -> high:t -> bool
val clamp_exn : t -> min:t -> max:t -> t
val clamp : t -> min:t -> max:t -> t Base__.Or_error.t
type comparator_witness
val comparator : (t, comparator_witness) Base__.Comparator.comparator
val validate_lbound : min:t Base__.Maybe_bound.t -> t Base__.Validate.check
val validate_ubound : max:t Base__.Maybe_bound.t -> t Base__.Validate.check
val validate_bound : min:t Base__.Maybe_bound.t -> max:t Base__.Maybe_bound.t -> t Base__.Validate.check
module Replace_polymorphic_compare = Md5.Replace_polymorphic_compare
module Map : sig ... end
module Set : sig ... end
include Interfaces.Binable with type t := t
val bin_size_t : t Bin_prot.Size.sizer
val bin_write_t : t Bin_prot.Write.writer
val bin_read_t : t Bin_prot.Read.reader
val __bin_read_t__ : (int -> t) Bin_prot.Read.reader
val bin_shape_t : Bin_prot.Shape.t
val bin_writer_t : t Bin_prot.Type_class.writer
val bin_reader_t : t Bin_prot.Type_class.reader
val bin_t : t Bin_prot.Type_class.t
include Interfaces.Hashable with type t := t
include Hashable.Common with type t := t
val compare : t -> t -> Base.Int.t
val hash_fold_t : Ppx_hash_lib.Std.Hash.state -> t -> Ppx_hash_lib.Std.Hash.state
val hash : t -> Ppx_hash_lib.Std.Hash.hash_value
val hashable : t Core_kernel__.Hashtbl.Hashable.t
module Table : sig ... end
module Hash_set : sig ... end
module Hash_queue : sig ... end
val digest_num_bytes : int

digest_num_bytes = 16 is the size of the digest in bytes.

val to_binary : t -> string

Binary representations are 16 bytes long, and not human readable.

val of_binary_exn : string -> t
val to_hex : t -> string

to_hex prints each byte of t as a big-endian sequence of 2 hex digits (e.g. byte 31 is written as "1f") and then concatenates them. For example,

Md5.to_hex (Md5.digest_string "a") =
Md5.to_hex (
  Md5.of_binary_exn
    "\x0c\xc1\x75\xb9\xc0\xf1\xb6\xa8\x31\xc3\x99\xe2\x69\x77\x26\x61") =
"0cc175b9c0f1b6a831c399e269772661"
val of_hex_exn : string -> t

The inverse of to_hex. This function ignores case. It will raise an exception if the string is not a 32-byte-long string of hex digits.

val digest_string : string -> t
val digest_bytes : bytes -> t
val digest_subbytes : bytes -> pos:int -> len:int -> t

digest_subbytes m ~pos ~len computes Md5 digest of the substring of m of length len starting at pos.

val digest_file_blocking : string -> t

digest_file_blocking filename reads the contents of file filename and computes its digest.

val digest_channel_blocking_without_releasing_runtime_lock : Stdlib.in_channel -> len:int -> t

Reads len bytes from the given channel and computes md5 digest of that.

WARNING: This function does digest computation with OCaml global lock held, so it can be slow and make the other threads starve. See digest_file_blocking.

val input_blocking : Stdlib.in_channel -> t

Reads an Md5 digest from the given channel (in a format written by output_blocking)

val output_blocking : t -> Stdlib.out_channel -> unit

Writes the Md5 digest to the given channel.

val string : string -> t
  • deprecated [since 2017-07] use [Md5.digest_string].
val bytes : bytes -> t
  • deprecated [since 2017-07] use [Md5.digest_bytes].
val subbytes : bytes -> int -> int -> t
  • deprecated [since 2017-07] use [Md5.digest_subbytes].
val from_hex : string -> t
  • deprecated [since 2017-07] use [of_hex_exn].
val file : string -> t
  • deprecated [since 2017-07] blocking functions should be avoided. Use [file_blocking] if you really want this.
val channel : Stdlib.in_channel -> int -> t
  • deprecated [since 2017-07] blocking functions should be avoided. Use [channel_blocking] if you really want this.
val output : Stdlib.out_channel -> t -> unit
  • deprecated [since 2017-07] Use [to_binary] together with [Out_channel.output_string]
val input : Stdlib.in_channel -> t
  • deprecated [since 2017-07] blocking functions should be avoided. Use [input_blocking] if you really want this.
val digest_bin_prot : 'a Bin_prot.Type_class.writer -> 'a -> t

digest_bin_prot w x digests the serialization of x by w. It is a cheap way (in dev time) to compute the digest of an ocaml value, for a fixed and deterministic serialization function. It is currently implemented inefficiently and allocates large strings.

For a more efficient and resource-aware version, use Bigbuffer.add_bin_prot and Bigbuffer_blocking.md5.

val digest_bigstring : Bigstring.t -> t
val digest_subbigstring : Bigstring.t -> pos:int -> len:int -> t
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