dlist.h

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/*
 * Copyright (c) 2013-2015 Wind River Systems, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef ZEPHYR_INCLUDE_SYS_DLIST_H_
#define ZEPHYR_INCLUDE_SYS_DLIST_H_
 
#include <stddef.h>
#include <stdbool.h>
#include <zephyr/toolchain.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
struct _dnode {
        union {
                struct _dnode *head; /* ptr to head of list (sys_dlist_t) */
                struct _dnode *next; /* ptr to next node    (sys_dnode_t) */
        };
        union {
                struct _dnode *tail; /* ptr to tail of list (sys_dlist_t) */
                struct _dnode *prev; /* ptr to previous node (sys_dnode_t) */
        };
};
 
typedef struct _dnode sys_dlist_t;
typedef struct _dnode sys_dnode_t;
 
 
#define SYS_DLIST_FOR_EACH_NODE(__dl, __dn)                             \
        for (__dn = sys_dlist_peek_head(__dl); __dn != NULL;            \
             __dn = sys_dlist_peek_next(__dl, __dn))
 
#define SYS_DLIST_ITERATE_FROM_NODE(__dl, __dn) \
        for (__dn = __dn ? sys_dlist_peek_next_no_check(__dl, __dn) \
                         : sys_dlist_peek_head(__dl); \
             __dn != NULL; \
             __dn = sys_dlist_peek_next(__dl, __dn))
 
#define SYS_DLIST_FOR_EACH_NODE_SAFE(__dl, __dn, __dns)                 \
        for (__dn = sys_dlist_peek_head(__dl),                          \
                     __dns = sys_dlist_peek_next(__dl, __dn);           \
             __dn != NULL; __dn = __dns,                                \
                     __dns = sys_dlist_peek_next(__dl, __dn))
 
/*
 * @brief Provide the primitive to resolve the container of a list node
 * Note: it is safe to use with NULL pointer nodes
 *
 * @param __dn A pointer on a sys_dnode_t to get its container
 * @param __cn Container struct type pointer
 * @param __n The field name of sys_dnode_t within the container struct
 */
#define SYS_DLIST_CONTAINER(__dn, __cn, __n) \
        ((__dn != NULL) ? CONTAINER_OF(__dn, __typeof__(*__cn), __n) : NULL)
/*
 * @brief Provide the primitive to peek container of the list head
 *
 * @param __dl A pointer on a sys_dlist_t to peek
 * @param __cn Container struct type pointer
 * @param __n The field name of sys_dnode_t within the container struct
 */
#define SYS_DLIST_PEEK_HEAD_CONTAINER(__dl, __cn, __n) \
        SYS_DLIST_CONTAINER(sys_dlist_peek_head(__dl), __cn, __n)
 
/*
 * @brief Provide the primitive to peek the next container
 *
 * @param __dl A pointer on a sys_dlist_t to peek
 * @param __cn Container struct type pointer
 * @param __n The field name of sys_dnode_t within the container struct
 */
#define SYS_DLIST_PEEK_NEXT_CONTAINER(__dl, __cn, __n) \
        ((__cn != NULL) ? \
         SYS_DLIST_CONTAINER(sys_dlist_peek_next(__dl, &(__cn->__n)),   \
                                      __cn, __n) : NULL)
 
#define SYS_DLIST_FOR_EACH_CONTAINER(__dl, __cn, __n)                   \
        for (__cn = SYS_DLIST_PEEK_HEAD_CONTAINER(__dl, __cn, __n);     \
             __cn != NULL;                                              \
             __cn = SYS_DLIST_PEEK_NEXT_CONTAINER(__dl, __cn, __n))
 
#define SYS_DLIST_FOR_EACH_CONTAINER_SAFE(__dl, __cn, __cns, __n)       \
        for (__cn = SYS_DLIST_PEEK_HEAD_CONTAINER(__dl, __cn, __n),     \
             __cns = SYS_DLIST_PEEK_NEXT_CONTAINER(__dl, __cn, __n);    \
             __cn != NULL; __cn = __cns,                                \
             __cns = SYS_DLIST_PEEK_NEXT_CONTAINER(__dl, __cn, __n))
 
static inline void sys_dlist_init(sys_dlist_t *list)
{
        list->head = (sys_dnode_t *)list;
        list->tail = (sys_dnode_t *)list;
}
 
#define SYS_DLIST_STATIC_INIT(ptr_to_list) { {(ptr_to_list)}, {(ptr_to_list)} }
 
static inline void sys_dnode_init(sys_dnode_t *node)
{
        node->next = NULL;
        node->prev = NULL;
}
 
static inline bool sys_dnode_is_linked(const sys_dnode_t *node)
{
        return node->next != NULL;
}
 
static inline bool sys_dlist_is_head(sys_dlist_t *list, sys_dnode_t *node)
{
        return list->head == node;
}
 
static inline bool sys_dlist_is_tail(sys_dlist_t *list, sys_dnode_t *node)
{
        return list->tail == node;
}
 
static inline bool sys_dlist_is_empty(sys_dlist_t *list)
{
        return list->head == list;
}
 
static inline bool sys_dlist_has_multiple_nodes(sys_dlist_t *list)
{
        return list->head != list->tail;
}
 
static inline sys_dnode_t *sys_dlist_peek_head(sys_dlist_t *list)
{
        return sys_dlist_is_empty(list) ? NULL : list->head;
}
 
static inline sys_dnode_t *sys_dlist_peek_head_not_empty(sys_dlist_t *list)
{
        return list->head;
}
 
static inline sys_dnode_t *sys_dlist_peek_next_no_check(sys_dlist_t *list,
                                                        sys_dnode_t *node)
{
        return (node == list->tail) ? NULL : node->next;
}
 
static inline sys_dnode_t *sys_dlist_peek_next(sys_dlist_t *list,
                                               sys_dnode_t *node)
{
        return (node != NULL) ? sys_dlist_peek_next_no_check(list, node) : NULL;
}
 
static inline sys_dnode_t *sys_dlist_peek_prev_no_check(sys_dlist_t *list,
                                                        sys_dnode_t *node)
{
        return (node == list->head) ? NULL : node->prev;
}
 
static inline sys_dnode_t *sys_dlist_peek_prev(sys_dlist_t *list,
                                               sys_dnode_t *node)
{
        return (node != NULL) ? sys_dlist_peek_prev_no_check(list, node) : NULL;
}
 
static inline sys_dnode_t *sys_dlist_peek_tail(sys_dlist_t *list)
{
        return sys_dlist_is_empty(list) ? NULL : list->tail;
}
 
static inline void sys_dlist_append(sys_dlist_t *list, sys_dnode_t *node)
{
        sys_dnode_t *const tail = list->tail;
 
        node->next = list;
        node->prev = tail;
 
        tail->next = node;
        list->tail = node;
}
 
static inline void sys_dlist_prepend(sys_dlist_t *list, sys_dnode_t *node)
{
        sys_dnode_t *const head = list->head;
 
        node->next = head;
        node->prev = list;
 
        head->prev = node;
        list->head = node;
}
 
static inline void sys_dlist_insert(sys_dnode_t *successor, sys_dnode_t *node)
{
        sys_dnode_t *const prev = successor->prev;
 
        node->prev = prev;
        node->next = successor;
        prev->next = node;
        successor->prev = node;
}
 
static inline void sys_dlist_insert_at(sys_dlist_t *list, sys_dnode_t *node,
        int (*cond)(sys_dnode_t *node, void *data), void *data)
{
        if (sys_dlist_is_empty(list)) {
                sys_dlist_append(list, node);
        } else {
                sys_dnode_t *pos = sys_dlist_peek_head(list);
 
                while ((pos != NULL) && (cond(pos, data) == 0)) {
                        pos = sys_dlist_peek_next(list, pos);
                }
                if (pos != NULL) {
                        sys_dlist_insert(pos, node);
                } else {
                        sys_dlist_append(list, node);
                }
        }
}
 
static inline void sys_dlist_remove(sys_dnode_t *node)
{
        sys_dnode_t *const prev = node->prev;
        sys_dnode_t *const next = node->next;
 
        prev->next = next;
        next->prev = prev;
        sys_dnode_init(node);
}
 
static inline sys_dnode_t *sys_dlist_get(sys_dlist_t *list)
{
        sys_dnode_t *node = NULL;
 
        if (!sys_dlist_is_empty(list)) {
                node = list->head;
                sys_dlist_remove(node);
        }
 
        return node;
}
 
#ifdef __cplusplus
}
#endif
 
#endif /* ZEPHYR_INCLUDE_SYS_DLIST_H_ */