[175] | 1 | /**
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| 2 | * \file
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| 3 | * Ring Buffer library
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| 4 | */
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| 5 |
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| 6 | #include "ringbuf.h"
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| 7 |
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| 8 |
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| 9 | /**
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| 10 | * \brief init a RINGBUF object
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| 11 | * \param r pointer to a RINGBUF object
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| 12 | * \param buf pointer to a byte array
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| 13 | * \param size size of buf
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| 14 | * \return 0 if successfull, otherwise failed
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| 15 | */
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| 16 | int16_t RINGBUF_Init(RINGBUF *r, uint8_t* buf, int32_t size)
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| 17 | {
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| 18 | if(r == NULL || buf == NULL || size < 2) return -1;
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| 19 |
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| 20 | r->p_o = r->p_r = r->p_w = buf;
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| 21 | r->fill_cnt = 0;
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| 22 | r->size = size;
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| 23 |
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| 24 | return 0;
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| 25 | }
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| 26 | /**
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| 27 | * \brief put a character into ring buffer
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| 28 | * \param r pointer to a ringbuf object
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| 29 | * \param c character to be put
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| 30 | * \return 0 if successfull, otherwise failed
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| 31 | */
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| 32 | int16_t RINGBUF_Put(RINGBUF *r, uint8_t c)
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| 33 | {
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| 34 | if(r->fill_cnt>=r->size)return -1; // ring buffer is full, this should be atomic operation
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| 35 |
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| 36 |
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| 37 | r->fill_cnt++; // increase filled slots count, this should be atomic operation
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| 38 |
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| 39 |
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| 40 | *r->p_w++ = c; // put character into buffer
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| 41 |
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| 42 | if(r->p_w >= r->p_o + r->size) // rollback if write pointer go pass
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| 43 | r->p_w = r->p_o; // the physical boundary
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| 44 |
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| 45 | return 0;
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| 46 | }
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| 47 | /**
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| 48 | * \brief get a character from ring buffer
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| 49 | * \param r pointer to a ringbuf object
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| 50 | * \param c read character
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| 51 | * \return 0 if successfull, otherwise failed
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| 52 | */
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| 53 | int16_t RINGBUF_Get(RINGBUF *r, uint8_t* c)
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| 54 | {
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| 55 | if(r->fill_cnt<=0)return -1; // ring buffer is empty, this should be atomic operation
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| 56 |
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| 57 |
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| 58 | r->fill_cnt--; // decrease filled slots count
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| 59 |
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| 60 |
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| 61 | *c = *r->p_r++; // get the character out
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| 62 |
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| 63 | if(r->p_r >= r->p_o + r->size) // rollback if write pointer go pass
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| 64 | r->p_r = r->p_o; // the physical boundary
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| 65 |
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| 66 | return 0;
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| 67 | }
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