list.h

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/* SPDX-License-Identifier: BSD-2-Clause */
 
/*
 * Copyright (c) 2010 Isilon Systems, Inc.
 * Copyright (c) 2010 iX Systems, Inc.
 * Copyright (c) 2010 Panasas, Inc.
 * Copyright (c) 2013-2016 Mellanox Technologies, Ltd.
 * Copyright (c) 2021-2024 by Antonio Borneo <borneo.antonio@gmail.com>
 * All rights reserved.
 */
 
/*
 * Circular doubly linked list implementation.
 *
 * The content of this file is mainly copied/inspired from FreeBSD code in:
 * https://cgit.freebsd.org/src/tree/
 * files:
 * sys/compat/linuxkpi/common/include/linux/list.h
 * sys/compat/linuxkpi/common/include/linux/types.h
 *
 * Last aligned with release/13.3.0:
 *
 * - Skip 'hlist_*' double linked lists with a single pointer list head.
 * - Expand WRITE_ONCE().
 * - Use TAB for indentation.
 * - Put macro arguments within parenthesis.
 * - Remove blank lines after an open brace '{'.
 * - Remove multiple assignment.
 *
 * There is an example of using this file in contrib/list_example.c.
 */
 
#ifndef OPENOCD_HELPER_LIST_H
#define OPENOCD_HELPER_LIST_H
 
/* begin OpenOCD changes */
 
#include <assert.h>
#include <stddef.h>
 
struct list_head {
    struct list_head *next;
    struct list_head *prev;
};
 
/* end OpenOCD changes */
 
#define LIST_HEAD_INIT(name) { &(name), &(name) }
 
#define OOCD_LIST_HEAD(name) \
    struct list_head name = LIST_HEAD_INIT(name)
 
static inline void
INIT_LIST_HEAD(struct list_head *list)
{
    list->next = list;
    list->prev = list;
}
 
static inline int
list_empty(const struct list_head *head)
{
    return (head->next == head);
}
 
static inline int
list_empty_careful(const struct list_head *head)
{
    struct list_head *next = head->next;
 
    return ((next == head) && (next == head->prev));
}
 
static inline void
__list_del(struct list_head *prev, struct list_head *next)
{
    next->prev = prev;
    prev->next = next;
}
 
static inline void
__list_del_entry(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
}
 
static inline void
list_del(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
}
 
static inline void
list_replace(struct list_head *old, struct list_head *new)
{
    new->next = old->next;
    new->next->prev = new;
    new->prev = old->prev;
    new->prev->next = new;
}
 
static inline void
list_replace_init(struct list_head *old, struct list_head *new)
{
    list_replace(old, new);
    INIT_LIST_HEAD(old);
}
 
static inline void
linux_list_add(struct list_head *new, struct list_head *prev,
    struct list_head *next)
{
    assert(next);
    assert(prev);
 
    next->prev = new;
    new->next = next;
    new->prev = prev;
    prev->next = new;
}
 
static inline void
list_del_init(struct list_head *entry)
{
    list_del(entry);
    INIT_LIST_HEAD(entry);
}
 
#define list_entry(ptr, type, field)    container_of(ptr, type, field)
 
#define list_first_entry(ptr, type, member) \
    list_entry((ptr)->next, type, member)
 
#define list_last_entry(ptr, type, member)  \
    list_entry((ptr)->prev, type, member)
 
#define list_first_entry_or_null(ptr, type, member) \
    (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL)
 
#define list_next_entry(ptr, member)                    \
    list_entry(((ptr)->member.next), typeof(*(ptr)), member)
 
#define list_safe_reset_next(ptr, n, member) \
    (n) = list_next_entry(ptr, member)
 
#define list_prev_entry(ptr, member)                    \
    list_entry(((ptr)->member.prev), typeof(*(ptr)), member)
 
#define list_for_each(p, head)                      \
    for (p = (head)->next; p != (head); p = (p)->next)
 
#define list_for_each_safe(p, n, head)                  \
    for (p = (head)->next, n = (p)->next; p != (head); p = n, n = (p)->next)
 
#define list_for_each_entry(p, h, field)                \
    for (p = list_entry((h)->next, typeof(*p), field); &(p)->field != (h); \
        p = list_entry((p)->field.next, typeof(*p), field))
 
#define list_for_each_entry_safe(p, n, h, field)            \
    for (p = list_entry((h)->next, typeof(*p), field),      \
        n = list_entry((p)->field.next, typeof(*p), field); &(p)->field != (h);\
        p = n, n = list_entry(n->field.next, typeof(*n), field))
 
#define list_for_each_entry_from(p, h, field) \
    for ( ; &(p)->field != (h); \
        p = list_entry((p)->field.next, typeof(*p), field))
 
#define list_for_each_entry_continue(p, h, field)           \
    for (p = list_next_entry((p), field); &(p)->field != (h);   \
        p = list_next_entry((p), field))
 
#define list_for_each_entry_safe_from(pos, n, head, member)         \
    for (n = list_entry((pos)->member.next, typeof(*pos), member);      \
         &(pos)->member != (head);                      \
         pos = n, n = list_entry(n->member.next, typeof(*n), member))
 
#define list_for_each_entry_reverse(p, h, field)            \
    for (p = list_entry((h)->prev, typeof(*p), field); &(p)->field != (h); \
        p = list_entry((p)->field.prev, typeof(*p), field))
 
#define list_for_each_entry_safe_reverse(p, n, h, field)        \
    for (p = list_entry((h)->prev, typeof(*p), field),      \
        n = list_entry((p)->field.prev, typeof(*p), field); &(p)->field != (h); \
        p = n, n = list_entry(n->field.prev, typeof(*n), field))
 
#define list_for_each_entry_continue_reverse(p, h, field) \
    for (p = list_entry((p)->field.prev, typeof(*p), field); &(p)->field != (h); \
        p = list_entry((p)->field.prev, typeof(*p), field))
 
#define list_for_each_prev(p, h) for (p = (h)->prev; p != (h); p = (p)->prev)
 
#define list_for_each_entry_from_reverse(p, h, field)   \
    for (; &p->field != (h);            \
         p = list_prev_entry(p, field))
 
static inline void
list_add(struct list_head *new, struct list_head *head)
{
    linux_list_add(new, head, head->next);
}
 
static inline void
list_add_tail(struct list_head *new, struct list_head *head)
{
    linux_list_add(new, head->prev, head);
}
 
static inline void
list_move(struct list_head *list, struct list_head *head)
{
    list_del(list);
    list_add(list, head);
}
 
static inline void
list_move_tail(struct list_head *entry, struct list_head *head)
{
    list_del(entry);
    list_add_tail(entry, head);
}
 
static inline void
list_rotate_to_front(struct list_head *entry, struct list_head *head)
{
    list_move_tail(entry, head);
}
 
static inline void
list_bulk_move_tail(struct list_head *head, struct list_head *first,
    struct list_head *last)
{
    first->prev->next = last->next;
    last->next->prev = first->prev;
    head->prev->next = first;
    first->prev = head->prev;
    last->next = head;
    head->prev = last;
}
 
static inline void
linux_list_splice(const struct list_head *list, struct list_head *prev,
    struct list_head *next)
{
    struct list_head *first;
    struct list_head *last;
 
    if (list_empty(list))
        return;
    first = list->next;
    last = list->prev;
    first->prev = prev;
    prev->next = first;
    last->next = next;
    next->prev = last;
}
 
static inline void
list_splice(const struct list_head *list, struct list_head *head)
{
    linux_list_splice(list, head, head->next);
}
 
static inline void
list_splice_tail(struct list_head *list, struct list_head *head)
{
    linux_list_splice(list, head->prev, head);
}
 
static inline void
list_splice_init(struct list_head *list, struct list_head *head)
{
    linux_list_splice(list, head, head->next);
    INIT_LIST_HEAD(list);
}
 
static inline void
list_splice_tail_init(struct list_head *list, struct list_head *head)
{
    linux_list_splice(list, head->prev, head);
    INIT_LIST_HEAD(list);
}
 
/*
 * Double linked lists with a single pointer list head.
 * IGNORED
 */
 
static inline int list_is_singular(const struct list_head *head)
{
    return !list_empty(head) && (head->next == head->prev);
}
 
static inline void __list_cut_position(struct list_head *list,
        struct list_head *head, struct list_head *entry)
{
    struct list_head *new_first = entry->next;
    list->next = head->next;
    list->next->prev = list;
    list->prev = entry;
    entry->next = list;
    head->next = new_first;
    new_first->prev = head;
}
 
static inline void list_cut_position(struct list_head *list,
        struct list_head *head, struct list_head *entry)
{
    if (list_empty(head))
        return;
    if (list_is_singular(head) &&
        (head->next != entry && head != entry))
        return;
    if (entry == head)
        INIT_LIST_HEAD(list);
    else
        __list_cut_position(list, head, entry);
}
 
static inline int list_is_first(const struct list_head *list,
                const struct list_head *head)
{
    return (list->prev == head);
}
 
static inline int list_is_last(const struct list_head *list,
                const struct list_head *head)
{
    return list->next == head;
}
 
static inline size_t
list_count_nodes(const struct list_head *list)
{
    const struct list_head *lh;
    size_t count;
 
    count = 0;
    list_for_each(lh, list) {
        count++;
    }
 
    return (count);
}
 
/*
 * Double linked lists with a single pointer list head.
 * IGNORED
 */
 
/* begin OpenOCD extensions */
 
#define list_for_each_entry_direction(is_fwd, p, h, field)                  \
    for (p = list_entry(is_fwd ? (h)->next : (h)->prev, typeof(*p), field); \
        &(p)->field != (h);                                                 \
        p = list_entry(is_fwd ? (p)->field.next : (p)->field.prev, typeof(*p), field))
 
static inline void list_rotate_left(struct list_head *h)
{
    struct list_head *first;
 
    if (!list_empty(h)) {
        first = h->next;
        list_move_tail(first, h);
    }
}
 
/* end OpenOCD extensions */
 
#endif /* OPENOCD_HELPER_LIST_H */