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/*
* Copyright 2005 Timo Hirvonen
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
* 02111-1307, USA.
*/
#ifndef _ITER_H
#define _ITER_H
#include <stdlib.h>
struct iter {
/* this usually points to the list head */
void *data0;
/* these point to the list item, for simple lists data2 is usually NULL */
void *data1;
void *data2;
};
static inline void iter_init(struct iter *iter)
{
iter->data0 = NULL;
iter->data1 = NULL;
iter->data2 = NULL;
}
static inline void iter_head(struct iter *iter)
{
iter->data1 = NULL;
iter->data2 = NULL;
}
static inline int iters_equal(struct iter *a, struct iter *b)
{
return a->data0 == b->data0 &&
a->data1 == b->data1 &&
a->data2 == b->data2;
}
static inline int iter_is_head(struct iter *iter)
{
return iter->data0 != NULL &&
iter->data1 == NULL &&
iter->data2 == NULL;
}
static inline int iter_is_null(struct iter *iter)
{
return iter->data0 == NULL &&
iter->data1 == NULL &&
iter->data2 == NULL;
}
static inline int iter_is_empty(struct iter *iter)
{
return iter->data0 == NULL || (iter->data1 == NULL && iter->data2 == NULL);
}
#define GENERIC_ITER_PREV(FUNC, TYPE, MEMBER) \
int FUNC(struct iter *iter) \
{ \
struct list_head *head = iter->data0; \
TYPE *e = iter->data1; \
\
if (head == NULL) \
return 0; \
if (e == NULL) { \
/* head, get last */ \
if (head->prev == head) { \
/* empty, iter points to the head already */ \
return 0; \
} \
iter->data1 = container_of(head->prev, TYPE, MEMBER); \
return 1; \
} \
if (e->MEMBER.prev == head) { \
iter->data1 = NULL; \
return 0; \
} \
iter->data1 = container_of(e->MEMBER.prev, TYPE, MEMBER); \
return 1; \
}
#define GENERIC_ITER_NEXT(FUNC, TYPE, MEMBER) \
int FUNC(struct iter *iter) \
{ \
struct list_head *head = iter->data0; \
TYPE *e = iter->data1; \
\
if (head == NULL) \
return 0; \
if (e == NULL) { \
/* head, get first */ \
if (head->next == head) { \
/* empty, iter points to the head already */ \
return 0; \
} \
iter->data1 = container_of(head->next, TYPE, MEMBER); \
return 1; \
} \
if (e->MEMBER.next == head) { \
iter->data1 = NULL; \
return 0; \
} \
iter->data1 = container_of(e->MEMBER.next, TYPE, MEMBER); \
return 1; \
}
#endif
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