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    1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2012-2023, VU University Amsterdam
    7                              SWI-Prolog Solutions b.v.
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module(uuid,
   37          [ uuid/1,                     % -UUID
   38            uuid/2,                     % -UUID, +Options
   39            uuid_property/2             % +UUID, ?Property
   40          ]).   41
   42/** <module> Universally Unique Identifier (UUID) Library
   43
   44The library provides operations on UUIDs.   Please consult other sources
   45for understanding UUIDs and  the  implications   of  the  different UUID
   46versions.  Some typical calls are given below:
   47
   48  ==
   49  ?- uuid(X).
   50  X = 'ea6589fa-19dd-11e2-8a49-001d92e1879d'.
   51
   52  ?- uuid(X, [url('http://www.swi-prolog.org')]).
   53  X = '73a07870-6a90-3f2e-ae2b-ffa538dc7c2c'.
   54  ==
   55
   56@tbd Compare UUIDs, extract time and version from UUIDs
   57@see http://www.ossp.org/pkg/lib/uuid/
   58@see https://en.wikipedia.org/wiki/Universally_unique_identifier
   59*/
   60
   61link_uuid :-
   62    catch(load_foreign_library(foreign(uuid)), _, true).
   63
   64:- initialization(link_uuid, now).   65
   66%!  uuid(-UUID) is det.
   67%
   68%   UUID is an atom representing a  new   UUID.  This is the same as
   69%   calling uuid(UUID, []).  See uuid/2 for options.
   70
   71uuid(UUID) :-
   72    uuid(UUID, []).
   73
   74%!  uuid(-UUID, +Options) is det.
   75%
   76%   Create a new UUID according to   Options.  The following options
   77%   are defined:
   78%
   79%     * version(+Versions)
   80%     Integer in the range 1..5, which specifies the UUID version
   81%     that is created.  Default is 1.
   82%
   83%     * dns(DNS)
   84%     * url(URL)
   85%     * oid(OID)
   86%     * x500(X500)
   87%     Provide additional context information for UUIDs using version
   88%     3 or 5.  If there is no explicit version option, UUID version
   89%     3 is used.
   90%
   91%     * format(+Format)
   92%     Representation of the UUID.  Default is =atom=, yielding atoms
   93%     such as =|8304efdd-bd6e-5b7c-a27f-83f3f05c64e0|=. The
   94%     alternative is =integer=, returning a large integer that
   95%     represents the 128 bits of the UUID.
   96%
   97%   If SWI-Prolog was not built with the  OSSP UUID dependency library a
   98%   simple Prolog alternative that  only   implements  version  4 random
   99%   UUIDs is provided. In this case  the   default  version is 4 and the
  100%   only admissible options are version(4) and format(Format).
  101
  102:- if(current_predicate(ossp_uuid/2)).  103uuid(UUID, Options) :-
  104    ossp_uuid(UUID, Options).
  105
  106:- else.  107
  108uuid(UUID, []) :-
  109    !,
  110    random_uuid(UUID).
  111uuid(UUID, Options) :-
  112    option(version(4), Options, 4),
  113    option(format(Format), Options, atom),
  114    (   Format == atom
  115    ->  !, random_uuid(UUID)
  116    ;   Format == integer
  117    ->  !, random_int_uuid(UUID)
  118    ).
  119uuid(_UUID, Options) :-
  120    domain_error(uuid_options, Options).
  121
  122random_uuid(UUID) :-
  123    Version = 4,
  124    A is random(0xffffffff),
  125    B is random(0xffff),
  126    C is random(0x0fff) \/ Version<<12,
  127    D is random(0x3fff) \/ 0x8000,
  128    E is random(0xffffffffffff),
  129    format(atom(UUID),
  130           '~`0t~16r~8+-~|\c
  131            ~`0t~16r~4+-~|\c
  132            ~`0t~16r~4+-~|\c
  133            ~`0t~16r~4+-~|\c
  134            ~`0t~16r~12+', [A,B,C,D,E]).
  135
  136random_int_uuid(UUID) :-
  137    Version = 4,
  138    A is random(0xffffffff),
  139    B is random(0xffff),
  140    C is random(0x0fff) \/ Version<<12,
  141    D is random(0x3fff) \/ 0x8000,
  142    E is random(0xffffffffffff),
  143    UUID is (A<<96)+(B<<80)+(C<<84)+(D<<48)+E.
  144
  145:- endif.  146
  147%!  uuid_property(+UUID, ?Property)
  148%
  149%   True when UUID is a property of the given UUID. Supported properties
  150%   are:
  151%
  152%     - version(V)
  153%       Return the version of the UUID (1..5)
  154%     - time(-Stamp)
  155%       Time using SWI-Prolog's time stamp (float with seconds
  156%       since January 1, 1970, UTC).  Only for version 1 and 2
  157%       UUIDs
  158%
  159%   @tbd Implement more properties.
  160
  161uuid_property(UUID, P) :-
  162    property_uuid(P, UUID).
  163
  164property_uuid(version(V), UUID) :-
  165    split_string(UUID, "-", "", [_A,_B,C,_D,_E]),
  166    sub_string(C, 0, 1, _, F),
  167    char_type(F, xdigit(V)).
  168property_uuid(time(Time), UUID) :-
  169    split_string(UUID, "-", "", [A,B,C,_D,_E]),
  170    sub_atom(C, 0, 1, _, F),
  171    has_time(F),
  172    sub_string(C, 1, _, 0, T),
  173    atomics_to_string(["0x",T,B,A], Hex),
  174    number_string(Nanos, Hex),
  175    Offset is 24*60*60*141427*10 000 000,
  176    Time is (Nanos-Offset)/10000000.0.
  177
  178has_time('1').
  179has_time('2')