UUIDs
v3 ns n
is a V3 UUID (named based with MD5 hashing) named by n
and namespaced by ns
.
v5 ns n
is a V5 UUID (named based with SHA-1 hashing) named by n
and namespaced by ns
.
val v4 : bytes -> t
v4 b
is a V4 UUID (random based) that uses the first 16 bytes of b
for randomness. Be aware that most of these 128 bits are seen literally in the result.
val v4_gen : Stdlib.Random.State.t -> unit -> t
v4_gen seed
is a function that generates random V4 UUIDs (random based) with the given seed
.
Warning. Sequences of UUIDs generated using Stdlib.Random
are suitably random but predictable by an observer. If that is an issue for you, use v4
with random bytes generated by a CSPRNG.
Informally deprecated
type version = [
| `V3 of t * string | Name based with MD5 hashing |
| `V4 | Random based |
| `V5 of t * string | Name based with SHA-1 hasing |
]
The type for UUID versions and generation parameters.
`V3
and`V5
specify a namespace and a name for the generation.`V4
is random based with a private state seeded withStdlib.Random.State.make_self_init
. Usev4_gen
to specify your own seed. Usev4
to specify your own randomness.Warning. The sequence resulting from repeatedly calling
v `V4
is random but predictable seev4_gen
.
Constants
val nil : t
nil
is the nil UUID.
val ns_dns : t
ns_dns
is the DNS namespace UUID.
val ns_url : t
ns_url
is the URL namespace UUID.
val ns_oid : t
ns_oid
is the ISO OID namespace UUID.
val ns_X500 : t
ns_dn
is the X.500 DN namespace UUID.
Comparing
Standard binary format
val of_bytes : ?pos:int -> string -> t option
of_bytes pos s
is the UUID represented by the 16 bytes starting at pos
(defaults to 0
) in s
. The result is None
if the string is not long enough.
val to_bytes : t -> string
to_bytes u
is u
as a 16 bytes long string.
Mixed-endian binary format
val of_mixed_endian_bytes : ?pos:int -> string -> t option
of_mixed_endian_bytes
is like of_bytes
but decodes the mixed endian serialization.
val to_mixed_endian_bytes : t -> string
to_mixed_endian_bytes
is like to_bytes
but encodes the mixed endian serialization.
US-ASCII format
val of_string : ?pos:int -> string -> t option
of_string pos s
converts the substring of s
starting at pos
(defaults to 0
) of the form "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX"
where X is a lower or upper case hexadecimal number to an UUID. The result is None
if a parse error occurs.
val to_string : ?upper:bool -> t -> string
to_string u
is u
as a string of the form "XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX"
where X is a lower (or upper if upper
is true
) case hexadecimal number.
Pretty-printing
val pp : Stdlib.Format.formatter -> t -> unit
pp ppf u
formats a representation based on to_string
of u
on ppf
.
val pp_string : ?upper:bool -> Stdlib.Format.formatter -> t -> unit
pp_string ?upper ppf u
formats u
on ppf
like to_string
would do.