示例代码

定义

#define BUFFER_SIZE 0xF 
typedef struct {
    uint32_t wptr;   ///< buffer存储位置，索引范围：[0:2*BUFFER_SIZE+1]
    uint32_t rptr;   ///< buffer读取位置，索引范围：[0:2*BUFFER_SIZE+1]
    uint8_t buffer[BUFFER_SIZE+1];  ///< buffer大小为BUFFER_SIZE+1
}ring_buffer_t; 

使用

若BUFFER_SIZE=3，wptr和rptr的索引为[0:7]
1. wptr=rptr时buffer为空
2. wptr和rptr之间的差值为BUFFER_SIZE+1即4时buffer为满
3. wptr和rptr的范围通过pbuf->wptr &= (BUFFER_SIZE<<1)|0x1 确定，BUFFER_SIZE的取值应该是N个2进制1？？

__inline uint32_t ring_buffer_is_empty(ring_buffer_t *pbuf) {
    return (pbuf->wptr==pbuf->rptr);
}

__inline uint32_t ring_buffer_is_full(ring_buffer_t *pbuf) {
    return ((pbuf->wptr^pbuf->rptr)==(BUFFER_SIZE+1));
}

__inline void ring_buffer_flush(ring_buffer_t *pbuf) {
    pbuf->wptr = pbuf->rptr = 0;
}

void fill_ring_buffer(ring_buffer_t *pbuf, uint8_t data) {
    pbuf->buffer[pbuf->wptr&BUFFER_SIZE] = data;
    pbuf->wptr++;
    pbuf->wptr &= (BUFFER_SIZE<<1)|0x1;
}

uint8_t dump_ring_buffer(ring_buffer_t *pbuf) {
    uint8_t data;
    data = pbuf->buffer[pbuf->rptr&BUFFER_SIZE];
    pbuf->rptr++;
    pbuf->rptr &= (BUFFER_SIZE<<1)|0x1;

    return data;
}