112 lines
2.5 KiB
C
112 lines
2.5 KiB
C
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#include "ringbuffer.h"
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#define rt_ringbuffer_space_len(rb) ((rb)->buffer_size - rt_ringbuffer_data_len(rb))
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enum rt_ringbuffer_state
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{
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RT_RINGBUFFER_EMPTY,
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RT_RINGBUFFER_FULL,
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/* half full is neither full nor empty */
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RT_RINGBUFFER_HALFFULL,
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};
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rt_inline enum rt_ringbuffer_state rt_ringbuffer_status(struct rt_ringbuffer *rb)
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{
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if (rb->read_index == rb->write_index)
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{
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if (rb->read_mirror == rb->write_mirror)
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return RT_RINGBUFFER_EMPTY;
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else
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return RT_RINGBUFFER_FULL;
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}
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return RT_RINGBUFFER_HALFFULL;
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}
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/**
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* get the size of data in rb
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*/
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rt_size_t rt_ringbuffer_data_len(struct rt_ringbuffer *rb)
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{
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switch (rt_ringbuffer_status(rb))
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{
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case RT_RINGBUFFER_EMPTY:
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return 0;
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case RT_RINGBUFFER_FULL:
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return rb->buffer_size;
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case RT_RINGBUFFER_HALFFULL:
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default:
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if (rb->write_index > rb->read_index)
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return rb->write_index - rb->read_index;
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else
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return rb->buffer_size - (rb->read_index - rb->write_index);
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};
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}
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void rt_ringbuffer_init(struct rt_ringbuffer *rb,
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rt_uint8_t *pool,
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rt_int16_t size)
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{
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RT_ASSERT(rb != RT_NULL);
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RT_ASSERT(size > 0);
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/* initialize read and write index */
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rb->read_mirror = rb->read_index = 0;
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rb->write_mirror = rb->write_index = 0;
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/* set buffer pool and size */
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rb->buffer_ptr = pool;
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rb->buffer_size = RT_ALIGN_DOWN(size, RT_ALIGN_SIZE);
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}
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/**
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* put a character into ring buffer
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*/
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rt_size_t rt_ringbuffer_putchar(struct rt_ringbuffer *rb, const rt_uint8_t ch)
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{
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RT_ASSERT(rb != RT_NULL);
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/* whether has enough space */
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if (!rt_ringbuffer_space_len(rb))
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return 0;
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rb->buffer_ptr[rb->write_index] = ch;
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/* flip mirror */
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if (rb->write_index == rb->buffer_size-1)
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{
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rb->write_mirror = ~rb->write_mirror;
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rb->write_index = 0;
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}
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else
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{
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rb->write_index++;
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}
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return 1;
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}
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/**
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* get a character from a ringbuffer
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*/
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rt_size_t rt_ringbuffer_getchar(struct rt_ringbuffer *rb, rt_uint8_t *ch)
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{
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RT_ASSERT(rb != RT_NULL);
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/* ringbuffer is empty */
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if (!rt_ringbuffer_data_len(rb))
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return 0;
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/* put character */
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*ch = rb->buffer_ptr[rb->read_index];
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if (rb->read_index == rb->buffer_size-1)
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{
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rb->read_mirror = ~rb->read_mirror;
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rb->read_index = 0;
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}
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else
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{
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rb->read_index++;
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}
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return 1;
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}
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