kopia lustrzana https://github.com/martin-ger/esp_mqtt
65 wiersze
1.6 KiB
C
65 wiersze
1.6 KiB
C
/**
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* \file
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* Ring Buffer library
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*/
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#include "ringbuf_mqtt.h"
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/**
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* \brief init a RINGBUF object
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* \param r pointer to a RINGBUF object
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* \param buf pointer to a byte array
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* \param size size of buf
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* \return 0 if successfull, otherwise failed
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*/
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I16 ICACHE_FLASH_ATTR RINGBUF_Init(RINGBUF * r, U8 * buf, I32 size) {
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if (r == NULL || buf == NULL || size < 2)
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return -1;
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r->p_o = r->p_r = r->p_w = buf;
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r->fill_cnt = 0;
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r->size = size;
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return 0;
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}
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/**
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* \brief put a character into ring buffer
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* \param r pointer to a ringbuf object
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* \param c character to be put
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* \return 0 if successfull, otherwise failed
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*/
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I16 ICACHE_FLASH_ATTR RINGBUF_Put(RINGBUF * r, U8 c) {
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if (r->fill_cnt >= r->size)
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return -1; // ring buffer is full, this should be atomic operation
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r->fill_cnt++; // increase filled slots count, this should be atomic operation
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*r->p_w++ = c; // put character into buffer
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if (r->p_w >= r->p_o + r->size) // rollback if write pointer go pass
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r->p_w = r->p_o; // the physical boundary
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return 0;
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}
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/**
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* \brief get a character from ring buffer
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* \param r pointer to a ringbuf object
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* \param c read character
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* \return 0 if successfull, otherwise failed
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*/
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I16 ICACHE_FLASH_ATTR RINGBUF_Get(RINGBUF * r, U8 * c) {
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if (r->fill_cnt <= 0)
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return -1; // ring buffer is empty, this should be atomic operation
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r->fill_cnt--; // decrease filled slots count
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*c = *r->p_r++; // get the character out
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if (r->p_r >= r->p_o + r->size) // rollback if write pointer go pass
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r->p_r = r->p_o; // the physical boundary
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return 0;
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}
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