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iter.h
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172
iter.h
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/*
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* Copyright 2008-2013 Various Authors
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* Copyright 2005 Timo Hirvonen
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef CMUS_ITER_H
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#define CMUS_ITER_H
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#include <stddef.h> /* NULL */
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struct iter {
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/* this usually points to the list head */
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void *data0;
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/* these point to the list item, for simple lists data2 is usually NULL */
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void *data1;
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void *data2;
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};
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static inline void iter_init(struct iter *iter)
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{
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iter->data0 = NULL;
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iter->data1 = NULL;
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iter->data2 = NULL;
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}
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static inline void iter_head(struct iter *iter)
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{
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iter->data1 = NULL;
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iter->data2 = NULL;
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}
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static inline int iters_equal(struct iter *a, struct iter *b)
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{
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return a->data0 == b->data0 &&
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a->data1 == b->data1 &&
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a->data2 == b->data2;
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}
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static inline int iter_is_head(struct iter *iter)
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{
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return iter->data0 != NULL &&
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iter->data1 == NULL &&
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iter->data2 == NULL;
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}
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static inline int iter_is_null(struct iter *iter)
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{
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return iter->data0 == NULL &&
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iter->data1 == NULL &&
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iter->data2 == NULL;
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}
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static inline int iter_is_empty(struct iter *iter)
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{
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return iter->data0 == NULL || (iter->data1 == NULL && iter->data2 == NULL);
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}
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#define GENERIC_ITER_PREV(FUNC, TYPE, MEMBER) \
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int FUNC(struct iter *iter) \
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{ \
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struct list_head *head = iter->data0; \
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TYPE *e = iter->data1; \
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\
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if (head == NULL) \
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return 0; \
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if (e == NULL) { \
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/* head, get last */ \
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if (head->prev == head) { \
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/* empty, iter points to the head already */ \
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return 0; \
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} \
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iter->data1 = container_of(head->prev, TYPE, MEMBER); \
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return 1; \
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} \
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if (e->MEMBER.prev == head) { \
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iter->data1 = NULL; \
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return 0; \
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} \
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iter->data1 = container_of(e->MEMBER.prev, TYPE, MEMBER); \
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return 1; \
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}
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#define GENERIC_ITER_NEXT(FUNC, TYPE, MEMBER) \
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int FUNC(struct iter *iter) \
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{ \
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struct list_head *head = iter->data0; \
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TYPE *e = iter->data1; \
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\
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if (head == NULL) \
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return 0; \
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if (e == NULL) { \
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/* head, get first */ \
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if (head->next == head) { \
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/* empty, iter points to the head already */ \
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return 0; \
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} \
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iter->data1 = container_of(head->next, TYPE, MEMBER); \
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return 1; \
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} \
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if (e->MEMBER.next == head) { \
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iter->data1 = NULL; \
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return 0; \
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} \
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iter->data1 = container_of(e->MEMBER.next, TYPE, MEMBER); \
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return 1; \
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}
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#define GENERIC_TREE_ITER_PREV(FUNC, TYPE, MEMBER) \
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int FUNC(struct iter *iter) \
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{ \
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struct rb_root *root = iter->data0; \
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TYPE *e = iter->data1; \
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\
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if (root == NULL) \
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return 0; \
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if (e == NULL) { \
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/* head, get last */ \
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if (rb_root_empty(root)) { \
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/* empty, iter points to the head already */ \
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return 0; \
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} \
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iter->data1 = container_of(rb_last(root), TYPE, MEMBER); \
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return 1; \
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} \
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if (rb_prev(&e->MEMBER) == NULL) { \
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iter->data1 = NULL; \
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return 0; \
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} \
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iter->data1 = container_of(rb_prev(&e->MEMBER), TYPE, MEMBER); \
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return 1; \
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}
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#define GENERIC_TREE_ITER_NEXT(FUNC, TYPE, MEMBER) \
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int FUNC(struct iter *iter) \
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{ \
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struct rb_root *root = iter->data0; \
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TYPE *e = iter->data1; \
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\
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if (root == NULL) \
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return 0; \
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if (e == NULL) { \
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/* head, get first */ \
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if (rb_root_empty(root)) { \
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/* empty, iter points to the head already */ \
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return 0; \
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} \
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iter->data1 = container_of(rb_first(root), TYPE, MEMBER); \
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return 1; \
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} \
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if (rb_next(&e->MEMBER) == NULL) { \
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iter->data1 = NULL; \
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return 0; \
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} \
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iter->data1 = container_of(rb_next(&e->MEMBER), TYPE, MEMBER); \
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return 1; \
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}
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#endif
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