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/*
Unix SMB/CIFS implementation.
Copyright (C) Stefan Metzmacher 2015
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _LIB_UTIL_DNS_CMP_H_
#define _LIB_UTIL_DNS_CMP_H_ 1
#define DNS_CMP_FIRST_IS_CHILD -2
#define DNS_CMP_FIRST_IS_LESS -1
#define DNS_CMP_MATCH 0
#define DNS_CMP_SECOND_IS_LESS 1
#define DNS_CMP_SECOND_IS_CHILD 2
#define DNS_CMP_IS_NO_MATCH(__cmp) \
((__cmp == DNS_CMP_FIRST_IS_LESS) || (__cmp == DNS_CMP_SECOND_IS_LESS))
/*
* this function assumes names are well formed DNS names.
* it doesn't validate them
*
* It allows strings up to a length of UINT16_MAX - 1
* with up to UINT8_MAX components. On overflow this
* just returns the result of strcasecmp_m().
*
* Trailing dots (only one) are ignored.
*
* The DNS names are compared per component, starting from
* the last one.
*
* The function is usable in a sort, but the return value contains more
* information than a simple comparison. There are 5 return values, defined
* above.
*
* DNS_CMP_FIRST_IS_CHILD (-2) means the first argument is a sub-domain of the
* second. e.g. dns_cmp("foo.example.org", "example.org")
*
* DNS_CMP_FIRST_IS_LESS (-1) means the first argument sorts before the
* second, but is not a sub-domain. e.g. dns_cmp("eggsample.org", "example.org").
*
* DNS_CMP_SECOND_IS_CHILD (+2) and DNS_CMP_SECOND_IS_LESS (+1) have the
* similar expected meanings. DNS_CMP_MATCH (0) means equality.
*
* NULL values are the parent of all addresses, which means comparisons
* between a string and NULL will return +2 or -2.
*/
int dns_cmp(const char *s1, const char *s2);
#endif /* _LIB_UTIL_DNS_CMP_H_ */
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