/*

  File: __acl_reorder_obj_p.c

  (Linux Access Control List Management, Posix Library Functions)

  Copyright (C) 1999, 2000

  Andreas Gruenbacher, <a.gruenbacher@bestbits.at>

  This program is free software; you can redistribute it and/or

  modify it under the terms of the GNU Lesser General Public

  License as published by the Free Software Foundation; either

  version 2.1 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

  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public

  License along with this library; if not, write to the Free Software

  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

*/

#include "config.h"

#include <alloca.h>

#include "libacl.h"

static inline int

__acl_entry_p_compare(const acl_entry_obj *a_p, const acl_entry_obj *b_p)

{

	if (a_p->etag < b_p->etag)

		return -1;

	else if (a_p->etag > b_p->etag)

		return 1;

	if (a_p->eid.qid < b_p->eid.qid)

		return -1;

	else if (a_p->eid.qid > b_p->eid.qid)

		return 1;

	else

		return 0;

}

static int

__acl_entry_pp_compare(const void *a, const void *b)

{

	return __acl_entry_p_compare(*(const acl_entry_obj **)a,

				   *(const acl_entry_obj **)b);

}

/*

  Take an ACL entry form its current place in the entry ring,

  and insert it at its proper place. Entries that are not valid

  (yet) are not reordered.

*/

int

__acl_reorder_entry_obj_p(acl_entry_obj *entry_obj_p)

{

	acl_obj *acl_obj_p = entry_obj_p->econtainer;

	acl_entry_obj *here_obj_p;

	if (acl_obj_p->aused <= 1)

		return 0;

	switch(entry_obj_p->etag) {

		case ACL_UNDEFINED_TAG:

			return 1;

		case ACL_USER:

		case ACL_GROUP:

			if (qualifier_obj_id(entry_obj_p->eid) ==

			    ACL_UNDEFINED_ID)

				return 1;

	}

	/* Remove entry from ring */

	entry_obj_p->eprev->enext = entry_obj_p->enext;

	entry_obj_p->enext->eprev = entry_obj_p->eprev;

	/* Search for next greater entry */

	FOREACH_ACL_ENTRY(here_obj_p, acl_obj_p) {

		if (__acl_entry_p_compare(here_obj_p, entry_obj_p) > 0)

			break;

	}

	/* Re-insert entry into ring */

	entry_obj_p->eprev = here_obj_p->eprev;

	entry_obj_p->enext = here_obj_p;

	entry_obj_p->eprev->enext = entry_obj_p;

	entry_obj_p->enext->eprev = entry_obj_p;

	return 0;

}

/*

  Sort all ACL entries at once, after initializing them. This function is

  only used when converting complete ACLs from external formats to ACLs;

  the ACL entries are always kept in canonical order while an ACL is

  manipulated.

*/

int

__acl_reorder_obj_p(acl_obj *acl_obj_p)

{

	acl_entry_obj **vector = alloca(sizeof(acl_entry_obj *) *

					acl_obj_p->aused), **v, *x;

	acl_entry_obj *entry_obj_p;

	if (acl_obj_p->aused <= 1)

		return 0;

	v = vector;

	FOREACH_ACL_ENTRY(entry_obj_p, acl_obj_p) {

		*v++ = entry_obj_p;

	}

	qsort(vector, acl_obj_p->aused, sizeof(acl_entry_obj *),

	       __acl_entry_pp_compare);

	x = (acl_entry_obj *)acl_obj_p;

	for (v = vector; v != vector + acl_obj_p->aused; v++) {

		(*v)->eprev = x;

		x = *v;

	}

	acl_obj_p->aprev = *(vector + acl_obj_p->aused - 1);

	x = (acl_entry_obj *)acl_obj_p;

	for (v = vector + acl_obj_p->aused - 1; v != vector - 1; v--) {

		(*v)->enext = x;

		x = *v;

	}

	acl_obj_p->anext = *vector;

	return 0;

}