#ifndef _LIBMAPLE_RING_BUFFER_H_
#define _LIBMAPLE_RING_BUFFER_H_

typedef unsigned char    u8;      // 无符号8位整型变量
typedef signed   char    int8;       // 有符号8位整型变量
typedef unsigned short   u16;     // 无符号16位整型变量
typedef signed   short   int16;      // 有符号16位整型变量
typedef unsigned int     u32;     // 无符号32位整型变量
typedef signed   int     int32;      // 有符号32位整型变量

#ifdef __cplusplus
extern "C" {
#endif
/**
 * Ring buffer type.
 *
 * The buffer is empty when head == tail.
 *
 * The buffer is full when the head is one byte in front of the tail,
 * modulo buffer length.
 *
 * One byte is left free to distinguish empty from full. */
typedef struct ring_buffer {
    volatile u8 *buf; /**< Buffer items are stored into */
    u16 head;         /**< Index of the next item to remove */
    u16 tail;         /**< Index where the next item will get inserted */
    u16 size;         /**< Buffer capacity minus one */
} ring_buffer;

typedef struct ring_buffer16 {
    volatile u16 *buf; /**< Buffer items are stored into */
    u16 head;         /**< Index of the next item to remove */
    u16 tail;         /**< Index where the next item will get inserted */
    u16 size;         /**< Buffer capacity minus one */
} ring_buffer16;
/**
 * Initialise a ring buffer.
 *
 *  @param rb   Instance to initialise
 *
 *  @param size Number of items in buf.  The ring buffer will always
 *              leave one element unoccupied, so the maximum number of
 *              elements it can store will be size - 1.  Thus, size
 *              must be at least 2.
 *
 *  @param buf  Buffer to store items into
 */
static inline void rb_init(ring_buffer *rb, u16 size, u8 *buf) {
    rb->head = 0;
    rb->tail = 0;
    rb->size = size - 1;
    rb->buf = buf;
}

static inline void rb_init16(ring_buffer16 *rb, u16 size, u16 *buf) {
    rb->head = 0;
    rb->tail = 0;
    rb->size = size - 1;
    rb->buf = buf;
}
/**
 * @brief Return the number of elements stored in the ring buffer.
 * @param rb Buffer whose elements to count.
 */
static inline u16 rb_full_count(ring_buffer *rb) {
    volatile ring_buffer *arb = rb;
    u32 size = arb->tail - arb->head;
    if (arb->tail < arb->head) {
        size += arb->size + 1;
    }
    return (u16)size;
}

static inline u16 rb_full_count16(ring_buffer16 *rb) {
    volatile ring_buffer16 *arb = rb;
    u32 size = arb->tail - arb->head;
    if (arb->tail < arb->head) {
        size += arb->size + 1;
    }
    return (u16)size;
}

/**
 * @brief Returns true if and only if the ring buffer is full.
 * @param rb Buffer to test.
 */
static inline int rb_is_full(ring_buffer *rb) {
    return (rb->tail + 1 == rb->head) ||
           (rb->tail == rb->size && rb->head == 0);
}

static inline int rb_is_full16(ring_buffer16 *rb) {
    return (rb->tail + 1 == rb->head) ||
           (rb->tail == rb->size && rb->head == 0);
}
/**
 * @brief Returns true if and only if the ring buffer is empty.
 * @param rb Buffer to test.
 */
static inline int rb_is_empty(ring_buffer *rb) {
    return rb->head == rb->tail;
}

static inline int rb_is_empty16(ring_buffer16 *rb) {
    return rb->head == rb->tail;
}
/**
 * Append element onto the end of a ring buffer.
 * @param rb Buffer to append onto.
 * @param element Value to append.
 */
static inline void rb_insert(ring_buffer *rb, u8 element) {
    rb->buf[rb->tail] = element;
    rb->tail = (rb->tail == rb->size) ? 0 : rb->tail + 1;
}

static inline void rb_insert16(ring_buffer16 *rb, u16 element) {
    rb->buf[rb->tail] = element;
    rb->tail = (rb->tail == rb->size) ? 0 : rb->tail + 1;
}
/**
 * @brief Remove and return the first item from a ring buffer.
 * @param rb Buffer to remove from, must contain at least one element.
 */
static inline u8 rb_remove(ring_buffer *rb) {
    u8 ch = rb->buf[rb->head];
    rb->head = (rb->head == rb->size) ? 0 : rb->head + 1;
    return ch;
}
static inline u16 rb_remove16(ring_buffer16 *rb) {
    u8 ch = rb->buf[rb->head];
    rb->head = (rb->head == rb->size) ? 0 : rb->head + 1;
    return ch;
}

static inline u8 rb_peek(ring_buffer *rb) {
    u8 ch = rb->buf[rb->head];
    return ch;
}

static inline u8 rb_peek_byCount(ring_buffer *rb,u8 str[]) {
    u8 x;
    x=0;
    if (rb->buf[rb->head]==0x7E && rb_full_count(rb)>rb->buf[rb->head+1])
    {
        for(int i=0; i<rb->buf[rb->head+1]; i++)
        {
            str[i] = rb->buf[rb->head+i];
            x++;
        }
    }
    return x;
}

static inline u16 rb_peek16(ring_buffer16 *rb) {
    u8 ch = rb->buf[rb->head];
    return ch;
}
/**
 * @brief Attempt to remove the first item from a ring buffer.
 *
 * If the ring buffer is nonempty, removes and returns its first item.
 * If it is empty, does nothing and returns a negative value.
 *
 * @param rb Buffer to attempt to remove from.
 */
static inline int16 rb_safe_remove(ring_buffer *rb) {
    return rb_is_empty(rb) ? -1 : rb_remove(rb);
}
static inline int16 rb_safe_remove16(ring_buffer16 *rb) {
    return rb_is_empty16(rb) ? -1 : rb_remove16(rb);
}
/**
 * @brief Attempt to insert an element into a ring buffer.
 *
 * @param rb Buffer to insert into.
 * @param element Value to insert into rb.
 * @sideeffect If rb is not full, appends element onto buffer.
 * @return If element was appended, then true; otherwise, false. */
static inline int rb_safe_insert(ring_buffer *rb, u8 element) {
    if (rb_is_full(rb)) {
        return 0;
    }
    rb_insert(rb, element);
    return 1;
}
static inline int rb_safe_insert16(ring_buffer16 *rb, u16 element) {
    if (rb_is_full16(rb)) {
        return 0;
    }
    rb_insert16(rb, element);
    return 1;
}
/**
 * @brief Append an item onto the end of a non-full ring buffer.
 *
 * If the buffer is full, removes its first item, then inserts the new
 * element at the end.
 *
 * @param rb Ring buffer to insert into.
 * @param element Value to insert into ring buffer.
 * @return On success, returns -1.  If an element was popped, returns
 *         the popped value.
 */
static inline int rb_push_insert(ring_buffer *rb, u8 element) {
    int ret = -1;
    if (rb_is_full(rb)) {
        ret = rb_remove(rb);
    }
    rb_insert(rb, element);
    return ret;
}
static inline int rb_push_insert16(ring_buffer16 *rb, u16 element) {
    int ret = -1;
    if (rb_is_full16(rb)) {
        ret = rb_remove16(rb);
    }
    rb_insert16(rb, element);
    return ret;
}
/**
 * @brief Discard all items from a ring buffer.
 * @param rb Ring buffer to discard all items from.
 */
static inline void rb_reset(ring_buffer *rb) {
    rb->tail = rb->head;
}
static inline void rb_reset16(ring_buffer16 *rb) {
    rb->tail = rb->head;
}

#ifdef __cplusplus
} // extern "C"
#endif

#endif