#ifndef INCLUDED_OS_LIST_H
#define INCLUDED_OS_LIST_H

#ifndef INCLUDED_OS_TYPES_H
#include <os_types.h>
#endif /*INCLUDED_OS_TYPES_H*/

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

typedef struct os_list_node_t{
    struct os_list_node_t* prev;
    struct os_list_node_t* next;
}os_list_node_t;

typedef os_list_node_t os_list_t;

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

#define os_list_prev(L) (L)->prev
#define os_list_next(L) (L)->next
#define os_list_prev_next(L) os_list_next(os_list_prev(L))
#define os_list_next_prev(L) os_list_prev(os_list_next(L))
#define os_list_next_next(L) os_list_next(os_list_next(L))

#define os_list_init(L) (os_list_prev(L)=os_list_next(L)=(os_list_node_t*)(L))
#define os_list_is_empty(L) ((os_list_prev(L)==(L))?OS_TRUE:OS_FALSE)
#define os_list_is_one(L) (os_list_next_next(L)==(L))

// Lp -- N -- L
#define os_list_insert_before(L, N) \
do{                                 \
    os_list_prev_next(L) = (os_list_node_t*)(N);     \
    os_list_prev(N) = os_list_prev(L); \
    os_list_prev(L) = (os_list_node_t*)(N);          \
    os_list_next(N) = (os_list_node_t*)(L);          \
}while(0)

// L -- N -- Ln
#define os_list_insert_after(L, N)                  \
do{                                                 \
    os_list_next_prev(L) = (os_list_node_t*)(N);    \
    os_list_next(N) = os_list_next(L);              \
    os_list_next(L) = (os_list_node_t*)(N);         \
    os_list_prev(N) = (os_list_node_t*)(L);         \
}while(0)

#define os_list_remove(N) \
do{                       \
    os_list_prev_next(N) = os_list_next(N); \
    os_list_next_prev(N) = os_list_prev(N); \
    os_list_init(N);      \
}while(0)


// Lp -- L -- Ln -- Lp
// Np -- N -- Nn -- Np
// 1. Lp.next = Nn  :           L --> Ln --> Lp -next-> Nn -next-> Np --> N --> Nn
// 2. N.head.prev = L.tail:                  Lp <-prev- Nn
// 3. N.tail.next = L                        Np -next-> L
// 4. L.prev = N.prev                        Np <-prev- L
#define os_list_join(L, N) \
do{                        \
    if(os_list_is_empty(N)){ \
        break;             \
    }                      \
    os_list_prev_next(L) = os_list_next(N); \
    os_list_next_prev(N) = os_list_prev(L); \
    os_list_prev_next(N) = (L);             \
    os_list_prev(L) = os_list_prev(N);      \
    os_list_init(N);       \
}while(0)


#define os_list_member_of(ptr, type, member) \
    ((type *)( (char *)ptr - ((os_size_t)&((type *)0)->member) ))

#endif /*INCLUDED_OS_LIST_H*/