/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 jsclist_h___
#define jsclist_h___

#include "jstypes.h"

/*
** Circular linked list
*/
typedef struct JSCListStr {
    struct JSCListStr *next;
    struct JSCListStr *prev;
} JSCList;

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

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

/*
** Return the element following element "_e"
*/
#define JS_NEXT_LINK(_e)         \
        ((_e)->next)
/*
** Return the element preceding element "_e"
*/
#define JS_PREV_LINK(_e)         \
        ((_e)->prev)

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

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

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

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

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

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

/*
** Initialize a circular list
*/
#define JS_INIT_CLIST(_l)  \
    JS_BEGIN_MACRO         \
        (_l)->next = (_l); \
        (_l)->prev = (_l); \
    JS_END_MACRO

#define JS_INIT_STATIC_CLIST(_l) \
    {(_l), (_l)}

#endif /* jsclist_h___ */
