/[dtapublic]/to_be_filed/webprojs/php_libraries/php_library/pamc_gen_a/unique_id/sguid.inc
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Revision 35 - (show annotations) (download)
Sat Oct 8 23:35:33 2016 UTC (8 years, 1 month ago) by dashley
File size: 4121 byte(s)
Initial commit.
1 <?php
2 //$Header: /hl/cvsroots/gpl01/gpl01/webprojs/pamc/gen_a/sw/phplib/unique_id/sguid.inc,v 1.2 2007/06/24 19:40:01 dashley Exp $
3 //--------------------------------------------------------------------------------
4 //sguid.inc -- Server globally-unique identifiers.
5 //Copyright (C) 2007 David T. Ashley
6 //--------------------------------------------------------------------------------
7 //This program is free software; you can redistribute it and/or
8 //modify it under the terms of the GNU General Public License
9 //as published by the Free Software Foundation; either version 2
10 //of the License, or (at your option) any later version.
11 //
12 //This program is distributed in the hope that it will be useful,
13 //but WITHOUT ANY WARRANTY; without even the implied warranty of
14 //MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 //GNU General Public License for more details.
16 //
17 //You should have received a copy of the GNU General Public License
18 //along with this program; if not, write to the Free Software
19 //Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
20 //--------------------------------------------------------------------------------
21 //Author contact information:
22 // David T. Ashley
23 // P.O. Box 918
24 // Marshall, Michigan, 49068
25 // dta@e3ft.com
26 //--------------------------------------------------------------------------------
27 require_once("string/strfunc_charset.inc");
28 require_once("time/timeraw.inc");
29 require_once("time/autime.inc");
30 //--------------------------------------------------------------------------------
31 //Returns an SGUID. Leap seconds situations are avoided.
32 //
33 //Unit-tested 20070624.
34 //
35 function SGUID_sguid()
36 {
37 //Get the reference timestamp.
38 $reftime = TIMERAW_time_precision_mixed_array_2_noleap();
39
40 //Get the PID. This may also chew up some time and hopefully let the
41 //server time change.
42 $pid = getmypid();
43
44 //Add the number of seconds between Jan 1, 1900 and Jan 1, 1970. This
45 //time is based from beginning of the century, whereas Unix time is
46 //based from the Unix epoch (Jan 1, 1970).
47 $reftime[0] = bcadd($reftime[0], "2208988800");
48
49 //Form the SGUID proper. Hopefully this will also chew up more time.
50 $reftime_whole = $reftime[0];
51 $reftime_frac = sprintf("%d", $reftime[1]);
52 $pid_string = sprintf("%d", $pid );
53 $rv = STRFUNC_pad_left_zero($reftime_whole, 10)
54 . STRFUNC_pad_left_zero($reftime_frac, 9)
55 . STRFUNC_pad_left_zero($pid_string, 10);
56
57 //Spin-lock until the time has changed. With any luck, the statements
58 //above have done that for us. It is hard to judge without some data
59 //whether microsleep would make things more efficient ... let's just leave
60 //it as a pure spin-lock.
61 do
62 {
63 $comptime = TIMERAW_time_precision_mixed_array_2_noleap();
64 }
65 while (($reftime[1] == $comptime[1]) && ($reftime[0] == $comptime[0]));
66
67 //Return the value to the caller.
68 return($rv);
69 }
70 //
71 //
72 //--------------------------------------------------------------------------------
73 //Returns the length of a SGUID (in characters).
74 //
75 //Unit-tested 20070624.
76 //
77 function SGUID_sguid_len()
78 {
79 return(29);
80 }
81 //
82 //
83 //--------------------------------------------------------------------------------
84 //Returns 1 if the SGUID is syntactically valid or 0 otherwise.
85 //
86 //Unit-tested 20070624.
87 //
88 function SGUID_is_syntactically_valid($sguid_to_check)
89 {
90 //Must be a string data type.
91 if (! is_string($sguid_to_check))
92 return(0);
93
94 //Must be of appropriate length.
95 if (strlen($sguid_to_check) != 29)
96 return(0);
97
98 //The string must be digits only.
99 if (! STRFUNC_is_pure_digits($sguid_to_check))
100 return(0);
101
102 //If we're here, nothing obvious wrong with it.
103 return(1);
104 }
105 //--------------------------------------------------------------------------------
106 //End of $RCSfile: sguid.inc,v $.
107 //--------------------------------------------------------------------------------
108 ?>

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