#ifndef UC_MBUF_H_
#define UC_MBUF_H_
#include <stdint.h>
#include <stddef.h>

#ifdef __GNUC__
#   define UC_INLINE inline __attribute__((always_inline))
#else
#   define UC_INLINE inline
#endif

enum UC_MBUF_FLAGS {
    UC_MBUF_FL_MALLOC        = 0x0001, //MBuf and MBuf->bufstart are seperatly malloc'd
    UC_MBUF_FL_MALLOC_BUF    = 0x0001, //MBuf is not malloc'd. MBuf->bufstart is malloc'd
    UC_MBUF_FL_MALLOC_INLINE = 0x0002, //MBuf is one big malloc. Can't be resized
    UC_MBUF_FL_STATIC        = 0x0004, //MBuf and MBuf->bustart is user controlled. Can't be resized
};

struct MBuf {
    struct MBuf *next;
    uint8_t *p1;
    uint8_t *p2;
    uint8_t *p3;
    uint8_t *p4;
    void *cookie;
    uint32_t flags;
    uint32_t allocated;
    uint8_t *bufstart;
    uint8_t *head;
    uint8_t *tail;
    uint8_t inline_data[0];
};

/* Conventions:
 * push - prepend data to the buffer (in the head room part)
 * pull - remove data from the beginning of the message.
 * put  - Add data to the buffer.
 */
struct MBuf *uc_mbuf_new_hr(uint32_t len, uint32_t headroom);
#define uc_mbuf_new(len) uc_mbuf_new_hr((len), 0)

struct MBuf *uc_mbuf_new_inline_hr(uint32_t len, uint32_t headroom);
#define uc_mbuf_new_inline(len) uc_mbuf_new_inline_hr((len), 0)

void uc_mbuf_free(struct MBuf *mbuf);
struct MBuf *uc_mbuf_copy_data(struct MBuf *mbuf);

void uc_mbuf_init(struct MBuf *mbuf, uint8_t *buf, uint32_t len, uint32_t headroom, uint32_t flags);
void uc_mbuf_zero(struct MBuf *mbuf);
void uc_mbuf_reset(struct MBuf *mbuf);

static UC_INLINE uint32_t uc_mbuf_len(struct MBuf *mbuf)
{
    return (uint32_t)(mbuf->tail - mbuf->head);
}

static UC_INLINE uint32_t uc_mbuf_tailroom(struct MBuf *mbuf)
{
    return mbuf->allocated - (uint32_t)(mbuf->tail - mbuf->bufstart);
}

static inline uint32_t uc_mbuf_headroom(struct MBuf *mbuf)
{
    return (uint32_t)(mbuf->head - mbuf->bufstart);
}

uint8_t *uc_mbuf_put(struct MBuf *mbuf, uint32_t size);

uint8_t *uc_mbuf_push(struct MBuf *mbuf, uint32_t size);

uint8_t *uc_mbuf_pull(struct MBuf *mbuf, uint32_t size);

#undef UC_INLINE

#endif