ULID-Ada

Implementation of ULID (Universally Unique Lexicographically Sortable Identifier) in Ada.

In a nutshell, a ULID code (Universally Unique Lexicographically Sortable Identifier) is a combination of a 48-bit time stamp (most significant part, with a millisecond accuracy), and a 80-bit random number (least significant part), totalling 128 bits, that is 16 bytes (octets).

Usage

The package ULID provides two functions Generate. One function produces a 128-bit number that can be output (for instance) in the UUID format. One function produces a string in the Base32 format (Crockford variant) - the preferred (canonical) representation of a ULID. Additionally, the Generate_Monotonic function enables the production of a monotonically increasing sequence of ULID numbers within the same millisecond. The function Encode_as_8_4_4_4_12 outputs a text representation of a ULID number in the usual UUID 8-4-4-4-12 format (like: 01920161-d64d-5a3e-589e-c45df155547b). Both formats (Base32 and 8-4-4-4-12) are also recognized by the Decode function.

All functions are task-safe (several Ada tasks can call Generate at the same time without messing the pseudo-random generator) and you can optionally set a time zone offset.

Generating ULID's

Here is an example for generating ULID's:

with Ada.Text_IO;
with ULID;

procedure ULID_Test is
  use Ada.Text_IO, ULID;
  gen : Random_Generator;
begin
  Reset (gen);  --  Randomize
  for i in 1 .. 10 loop
    Put_Line (ULID.Generate (gen));
  end loop;
  Put ("Press Return");
  Skip_Line;
end ULID_Test;

With AdaCore's GNAT you can build and run the test using the ulid.gpr project file.

Here is an example of ULIDs in their canonical text representation (Base32):

  01J8ZGFCTBGE4X4ZG1G5MVJQQQ
  01J8ZGFCTB35CA4YGH0RD25R5B
  01J8ZGFCTCZE7YSRQWAQNQHFAC
  01J8ZGFCTC4E3PBBJ3ASYZRBB4

Another bunch of ULIDs in the usual UUID/GUID 8-4-4-4-12 format:

  {01923f07-b34c-7693-6d40-a3844156c1ae}
  {01923f07-b34c-efde-95e7-08decfe60c07}
  {01923f07-b34c-dc69-2ef1-2ac4b7c9bc84}
  {01923f07-b34c-81d0-667c-43694d2f740a}

License

ULID-Ada is released under the MIT license. See the LICENSE file for more info.