kopia lustrzana https://github.com/OpenRTX/OpenRTX
100 wiersze
3.8 KiB
C
100 wiersze
3.8 KiB
C
/***************************************************************************
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* Copyright (C) 2025 by Federico Amedeo Izzo IU2NUO, *
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* Niccolò Izzo IU2KIN *
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* Frederik Saraci IU2NRO *
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* Silvano Seva IU2KWO *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 3 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, see <http://www.gnu.org/licenses/> *
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***************************************************************************/
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#ifndef NMEA_RBUF_H
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#define NMEA_RBUF_H
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#include <stdint.h>
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#include <stddef.h>
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* Ad-hoc ring buffer for storing NMEA sentences.
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*
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* The implementation of the ring buffer is lock-free, allowing to call the
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* put/get functions also from whithin an IRQ. This implementation limits the
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* buffer to have ONE producer and ONE consumer.
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* The sentences can be put into the buffer either one character at a time or
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* one sentence at a time; in either case the put functions ensure that only
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* valid sentences are inserted in the buffer. Extraction of sentences from the
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* buffer can be done only by a per-sentence basis.
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*/
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struct nmeaRbuf {
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size_t wrPos;
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size_t rdPos;
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size_t rdLimit;
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bool filling;
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char data[CONFIG_NMEA_RBUF_SIZE];
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};
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/**
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* Reset the internal state of a ring buffer.
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*
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* @param rbuf: pointer to ring buffer.
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*/
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void nmeaRbuf_reset(struct nmeaRbuf *rbuf);
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/**
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* Insert an NMEA sentence character.
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* This function implments a finite state machine guaranteeing that the stored
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* characters are always part of a valid NMEA sentence.
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*
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* @param rbuf: pointer to ring buffer.
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* @param c: incoming character.
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* @return zero on success, -1 if the ring buffer is full.
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*/
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int nmeaRbuf_putChar(struct nmeaRbuf *rbuf, const char c);
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/**
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* Insert a full NMEA sentence.
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* The sentence has to begin with an '$' character and terminate with a '\n'.
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*
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* @param rbuf: pointer to ring buffer.
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* @param sentence: NMEA sentence.
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* @return zero on success, -1 if the sentence is not valid and -2 if the ring
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* buffer is full
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*/
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int nmeaRbuf_putSentence(struct nmeaRbuf *rbuf, const char *sentence);
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/**
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* Extract a full NMEA sentence.
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* If the sentence is longer than the maximum size of the destination buffer,
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* the characters not written in the destination are removed from the ring
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* buffer anyways.
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*
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* @param rbuf: pointer to ring buffer.
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* @param buf: pointer to NMEA sentence destination buffer.
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* @param maxLen: maximum acceptable size for the destination buffer.
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* @return the length of the extracted sentence or -1 if the sentence is longer
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* than the maximum allowed size. If the ring buffer is empty, zero is returned.
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*/
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int nmeaRbuf_getSentence(struct nmeaRbuf *rbuf, char *buf, const size_t maxLen);
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#ifdef __cplusplus
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}
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#endif
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#endif // NMEA_RBUF_H
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