openldap/libraries/liblutil/csn.c

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/* csn.c - Change Sequence Number routines */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
*
* Copyright 2000-2003 The OpenLDAP Foundation.
* Portions Copyright 2000-2003 Kurt D. Zeilenga.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
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*/
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/* Portions Copyright 2000, John E. Schimmel, All rights reserved.
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* This software is not subject to any license of Mirapoint, Inc.
*
* This is free software; you can redistribute and use it
* under the same terms as OpenLDAP itself.
*/
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/* This work was developed by John E. Schimmel and adapted for
* inclusion in OpenLDAP Software by Kurt D. Zeilenga.
*/
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/* This file contains routines to generate a change sequence number.
* Every add, delete, and modification is given a unique identifier
* for use in resolving conflicts during replication operations.
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*
* These routines are (loosly) based upon draft-ietf-ldup-model-03.txt,
* A WORK IN PROGRESS. The format will likely change.
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*
* The format of a CSN string is: yyyymmddhhmmssz#s#r#c
* where s is a counter of operations within a timeslice, r is
* the replica id (normally zero), and c is a counter of
* modifications within this operation. s, r, and c are
* represented in hex and zero padded to lengths of 6, 2, and
* 6, respectively.
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*
* Calls to this routine MUST be serialized with other calls
* to gmtime().
*/
#include "portable.h"
#include <stdio.h>
#include <ac/time.h>
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#include <lutil.h>
size_t
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lutil_csnstr(char *buf, size_t len, unsigned int replica, unsigned int mod)
{
static time_t csntime;
static unsigned int csnop;
time_t t;
unsigned int op;
struct tm *ltm;
int n;
time( &t );
if ( t > csntime ) {
csntime = t;
csnop = 0;
}
op = ++csnop;
ltm = gmtime( &t );
n = snprintf( buf, len,
"%4d%02d%02d%02d%02d%02dZ#%06x#%02x#%06x",
ltm->tm_year + 1900, ltm->tm_mon + 1, ltm->tm_mday, ltm->tm_hour,
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ltm->tm_min, ltm->tm_sec, op, replica, mod );
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if( n < 0 ) return 0;
return ( (size_t) n < len ) ? n : 0;
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}
#ifdef TEST
int
main(int argc, char **argv)
{
char buf[ LDAP_LUTIL_CSNSTR_BUFSIZE ];
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if ( ! lutil_csnstr( buf, (size_t) 10, 0, 0 ) ) {
fprintf(stderr, "failed lutil_csnstr\n");
}
if ( ! lutil_csnstr( buf, sizeof(buf), 0, 0 ) ) {
fprintf(stderr, "failed lutil_csnstr\n");
}
}
#endif