#ifndef __LUNAIX_CAKE_H
#define __LUNAIX_CAKE_H

#include <lunaix/ds/llist.h>
#include <lunaix/spike.h>

#define PILE_NAME_MAXLEN 20

#define PILE_ALIGN_CACHE 0b0001
#define PILE_FL_EXTERN   0b0010

struct cake_pile;

typedef void (*pile_cb)(struct cake_pile*, void*);

struct cake_pile
{
    struct llist_header piles;
    struct llist_header full;
    struct llist_header partial;
    struct llist_header free;
    u32_t offset;
    u32_t piece_size;
    u32_t cakes_count;
    u32_t alloced_pieces;
    u32_t pieces_per_cake;
    u32_t pg_per_cake;
    u32_t options;
    char pile_name[PILE_NAME_MAXLEN+1];

    pile_cb ctor;
};

typedef unsigned short piece_t;

#define EO_FREE_PIECE ((piece_t)-1)

#define CAKE_FL_SIZE        128 
#define CAKE_FL_MAXLEN      \
    ((unsigned int)((CAKE_FL_SIZE - sizeof(ptr_t)) / sizeof(piece_t)))
struct cake_fl
{
    piece_t indices[CAKE_FL_MAXLEN];
    struct cake_fl* next;
} align(CAKE_FL_SIZE);

struct cake_s
{
    struct llist_header cakes;
    struct cake_pile* owner;
    void* first_piece;
    unsigned int used_pieces;
    unsigned int next_free;
    union {
        struct cake_fl* fl;
        struct {
            void* rsvd;
            piece_t free_list[0];
        };
    };
};

/**
 * @brief 创建一个蛋糕堆
 *
 * @param name 堆名称
 * @param piece_size 每个蛋糕切块儿的大小
 * @param pg_per_cake 每个蛋糕所占据的页数
 * @return struct cake_pile*
 */
struct cake_pile*
cake_new_pile(char* name,
              unsigned int piece_size,
              unsigned int pg_per_cake,
              int options);

void
cake_set_constructor(struct cake_pile* pile, pile_cb ctor);

/**
 * @brief 拿一块儿蛋糕
 *
 * @param pile
 * @return void*
 */
void*
cake_grab(struct cake_pile* pile);

/**
 * @brief 归还一块儿蛋糕
 *
 * @param pile
 * @param area
 */
int
cake_release(struct cake_pile* pile, void* area);

void
cake_init();

void
cake_export();

void
cake_reclaim_freed();

/********** some handy constructor ***********/

void
cake_ctor_zeroing(struct cake_pile* pile, void* piece);

#define DEADCAKE_MARK 0xdeadcafeUL

static inline void
cake_ensure_valid(void* area) {
    if (unlikely(*(unsigned int*)area == DEADCAKE_MARK)) {
        fail("access to freed cake piece");
    }
}

#endif /* __LUNAIX_VALLOC_H */