/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef prclist_h___
#define prclist_h___

#include "prtypes.h"

typedef struct PRCListStr PRCList;

/*
** Circular linked list
*/
struct PRCListStr {
    PRCList* next;
    PRCList* prev;
};

/*
** Insert element "_e" into the list, before "_l".
*/
#define PR_INSERT_BEFORE(_e, _l)     \
    PR_BEGIN_MACRO(_e)->next = (_l); \
    (_e)->prev = (_l)->prev;         \
    (_l)->prev->next = (_e);         \
    (_l)->prev = (_e);               \
    PR_END_MACRO

/*
** Insert element "_e" into the list, after "_l".
*/
#define PR_INSERT_AFTER(_e, _l)            \
    PR_BEGIN_MACRO(_e)->next = (_l)->next; \
    (_e)->prev = (_l);                     \
    (_l)->next->prev = (_e);               \
    (_l)->next = (_e);                     \
    PR_END_MACRO

/*
** Return the element following element "_e"
*/
#define PR_NEXT_LINK(_e) ((_e)->next)
/*
** Return the element preceding element "_e"
*/
#define PR_PREV_LINK(_e) ((_e)->prev)

/*
** Append an element "_e" to the end of the list "_l"
*/
#define PR_APPEND_LINK(_e, _l) PR_INSERT_BEFORE(_e, _l)

/*
** Insert an element "_e" at the head of the list "_l"
*/
#define PR_INSERT_LINK(_e, _l) PR_INSERT_AFTER(_e, _l)

/* Return the head/tail of the list */
#define PR_LIST_HEAD(_l) (_l)->next
#define PR_LIST_TAIL(_l) (_l)->prev

/*
** Remove the element "_e" from it's circular list.
*/
#define PR_REMOVE_LINK(_e)                       \
    PR_BEGIN_MACRO(_e)->prev->next = (_e)->next; \
    (_e)->next->prev = (_e)->prev;               \
    PR_END_MACRO

/*
** Remove the element "_e" from it's circular list. Also initializes the
** linkage.
*/
#define PR_REMOVE_AND_INIT_LINK(_e)              \
    PR_BEGIN_MACRO(_e)->prev->next = (_e)->next; \
    (_e)->next->prev = (_e)->prev;               \
    (_e)->next = (_e);                           \
    (_e)->prev = (_e);                           \
    PR_END_MACRO

/*
** Return non-zero if the given circular list "_l" is empty, zero if the
** circular list is not empty
*/
#define PR_CLIST_IS_EMPTY(_l) ((_l)->next == (_l))

/*
** Initialize a circular list
*/
#define PR_INIT_CLIST(_l)            \
    PR_BEGIN_MACRO(_l)->next = (_l); \
    (_l)->prev = (_l);               \
    PR_END_MACRO

#define PR_INIT_STATIC_CLIST(_l) { (_l), (_l) }

#endif /* prclist_h___ */